----

| Delaware                                  |   | 75-2310854          |
|-------------------------------------------|--------|---------------------|
| (State or other jurisdiction              |   | (I.R.S. Employer    |
| of incorporation or organization)         |   | Identification No.) |
|                                      |   |                |
| 6 Desta Drive, Suite 6500, Midland, Texas |   | 79705               |
| (Address of principal executive office)   |   | (Zip Code)          |

| Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.                                                                                                                                                                                                                                    |  ̈ Yes | x No      |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------|-----------|
|                                                                                                                                                                                                                                                                                                                                                       |       |      |
| Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.                                                                                                                                                                                                                               |  ̈ Yes | x No      |
|                                                                                                                                                                                                                                                                                                                                                       |       |      |
| Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.   | x Yes      |  ̈ No |
|                                                                                                                                                                                                                                                                                                                                                       |       |      |
| Indicate by check mark whether the registrant has submitted electronically and posted on its corporate website, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). |  ̈ Yes |  ̈ No |

| Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant's knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.x |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, or a non-accelerated filer.  See definition of “accelerated filer and large accelerated filer” in Rule 12b-2 of the Exchange Act. |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Large accelerated filer  ̈                                                                                                                                                                                                                            |   | Accelerated filer  ̈ |   | Non-accelerated filer  x |   | Smaller reporting company ̈ |   |

| Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). |  ̈ Yes | x No |
|---------------------------------------------------------------------------------------------------------|------------|------|

|   |
|--------|

----

|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | Page   |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|
| Part I                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 1.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | Business                                                                                                                                                    | 3      |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 1A.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | Risk Factors                                                                                                                                                | 7      |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 1B.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | Unresolved Staff Comments                                                                                                                                   | 10     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 2.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | Properties                                                                                                                                                  | 10     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 3.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | Legal Proceedings                                                                                                                                           | 11     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 4.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | (Removed and Reserved)                                                                                                                                      | 11     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Part II                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 5.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | Market for Registrant's Common Equity, Related                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |   |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | Stockholder Matters and Issuer Purchases of Equity Securities                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | 12     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 6.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | Selected Financial Data                                                                                                                                     | 13     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 7.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | Management's Discussion and Analysis of                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          |   |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | Financial Condition and Results of Operations                                                                                                                                   | 14     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 7A.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | Quantitative and Qualitative Disclosures About Market Risk                                                                                                  | 16     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 8.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | Financial Statements and Supplementary Data                                                                                                                 | 17     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 9.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | Changes in and Disagreements with Accountants                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |   |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | on Accounting and Financial Disclosure                                                                                                                                          | 30     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 9A.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | Controls and Procedures                                                                                                                                     | 30     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 9B.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | Other Information                                                                                                                                           | 31     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Part III                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 10.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | Directors, Executive Officers and Corporate Governance                                                                                                      | 32     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 11.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | Executive Compensation                                                                                                                                      | 32     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 12.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | Security Ownership of Certain Beneficial Owners and Management and                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |   |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | Related Stockholder Matters                                                                                                                                                     | 33     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 13.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | Certain Relationships and Related Transactions, and Director Independence                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | 33     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 14.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | Principal Accounting Fees and Services                                                                                                                      | 33     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Part IV                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Item 15.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | Exhibits and Financial Statement Schedules                                                                                                                  | 34     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Glossary of Oil and Gas Terms                                                                                                                   | 35                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |   |
| Signatures                                                                                                                                      | 37                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |

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| ·   | amends the definition of proved reserves to require the use of average commodity prices based upon the prior 12 month period rather than year-end prices; |
|--------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------|

| ·   | expands the type of technologies available to establish reserve estimates and categories; |
|--------------------|-------------------------------------------------------------------------------------------|

| ·   | modifies certain definitions used in estimating proved reserves; |
|--------------------|------------------------------------------------------------------|

| ·   | permits disclosure of probable and possible reserves; and |
|--------------------|-----------------------------------------------------------|

| ·   | permits disclosure of reserves based on different price and cost criteria, such as futures prices or management forecasts. |
|--------------------|----------------------------------------------------------------------------------------------------------------------------|

|                               |   | Proved Developed |   |   | Proved       |   |   | Total       |   |
|------------------------------------|--------|------------------|--------|--------|--------------|--------|--------|-------------|--------|
|                               |   | Producing        |   |   | Nonproducing |   |   | Undeveloped |   |   | Proved |   |
| Oil (Bbls)                         |   |             | 64,000 |   |         |   | -      |        |   |   | - |   |   |   | 64,000 |   |
| Gas (Mcf)                          |   |             | 22,000 |   |         |   | -      |        |   |   | - |   |   |   | 22,000 |   |
| Total (BOE)                        |   |             | 68,000 |   |         |   | -      |        |   |   | - |   |   |   | 68,000 |   |
|                               |   |             |   |   |         |   |   |        |   |   |   |   |   |   |   |   |
| Standardized measure of discounted |   |             |   |   |         |   |   |        |   |   |   |   |   |   |   |   |
| future net cash flows              |   |             |   |   |         |   |   |        |   |   |   |   |   | $ | 1,100,000 |   |

|   |
|--------|

----

|            |   | Proved Reserves |   |   |   |   |
|-----------------|--------|-----------------|--------|--------|--------|--------|
|            |   |            |   |   |   |   |   | Total Oil |   |   | Percent of |   |
|            |   | Oil             |   |   | Gas    |   |   | Equivalent |   |   | Total Oil |   |
|            |   | (Bbls)          |   |   | (Mcf)  |   |   | (BOE) |   |   | Equivalent |   |
| Slaughter       |   |            | 42,000 |   |   |   | - |   |   |   | 42,000 |   |   |   | 61.8 | % |
| Hackberry Yates |   |            | 9,000  |   |   |   | - |   |   |   | 9,000 |   |   |   | 13.2 | % |
| Other           |   |            | 13,000 |   |   |   | 22,000 |   |   |   | 17,000 |   |   |   | 25.0 | % |
| Total           |   |            | 64,000 |   |   |   | 22,000 |   |   |   | 68,000 |   |   |   | 100.0 | % |

Item 

Item 

|   |
|--------|

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| Item 5. | Market for Registrant's Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities |
|---------|--------------------------------------------------------------------------------------------------------------|

|           |   | Total Number |   |   |          |   |
|----------------|--------|--------------|--------|--------|---------------|--------|
|           |   | of Units     |   |   | Average Price |   |
| Period         |   | Purchased    |   |   | Paid Per Unit |   |
| January 2010   |   |         | -      |   |          | $      | - |   |
| February 2010  |   |         | -      |   |          |   | - |   |
| March 2010     |   |         | 10.0   |   |          |   | 26.00 |   |
| April 2010     |   |         | -      |   |          |   | - |   |
| May 2010       |   |         | -      |   |          |   | - |   |
| June 2010      |   |         | 10.0   |   |          |   | 7.52 |   |
| July 2010      |   |         | -      |   |          |   | - |   |
| August 2010    |   |         | -      |   |          |   | - |   |
| September 2010 |   |         | 40.0   |   |          |   | 4.77 |   |
| October 2010   |   |         | -      |   |          |   | - |   |
| November 2010  |   |         | -      |   |          |   | - |   |
| December 2010  |   |         | -      |   |          |   | - |   |
| TOTALS         |   |         | 60.0   |   |          | $      | 8.76 |   |

|   |
|--------|

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|                                         |   | Years ended December 31, |     |
|----------------------------------------------|--------|--------------------------|----------|
|                                         |   | 2010                     |     |   | 2009 |   |   | 2008 |   |   | 2007 |   |   | 2006 |   |
| Revenues                                     |   | $                        | 604,228  |   |   | $ | 475,927 |   |   | $ | 916,979 |   |   | $ | 587,386 |   |   | $ | 570,591 |   |
|                                         |   |                     |     |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Net (loss) income                            |   |                     | (192,207 | ) |   |   | 7,367 |   |   |   | 388,384 |   |   |   | 119,649 |   |   |   | 157,428 |   |
|                                         |   |                     |     |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Partners' share of net (loss) income:        |   |                     |     |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|                                         |   |                     |     |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| General partners                             |   |                     | (17,089  | ) |   |   | 3,124 |   |   |   | 40,615 |   |   |   | 13,502 |   |   |   | 16,712 |   |
|                                         |   |                     |     |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Limited partners                             |   |                     | (175,118 | ) |   |   | 4,243 |   |   |   | 347,769 |   |   |   | 106,147 |   |   |   | 140,716 |   |
|                                         |   |                     |     |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Limited partners' net (loss) income per unit |   |                     | (16.70   | ) |   |   | .40 |   |   |   | 33.17 |   |   |   | 10.12 |   |   |   | 13.42 |   |
|                                         |   |                     |     |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Limited partners' cash                       |   |                     |     |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| distributions per unit                       |   |                     | .05      |   |   |   | .42 |   |   |   | 40.54 |   |   |   | 8.68 |   |   |   | 15.76 |   |
|                                         |   |                     |     |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Total assets                                 |   | $                        | 265,654  |   |   | $ | 311,934 |   |   | $ | 354,531 |   |   | $ | 364,162 |   |   | $ | 338,457 |   |

|   |
|--------|

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|                                      |   | Year Ended December 31, |   |
|-------------------------------------------|--------|-------------------------|--------|
|                                      |   | 2010                    |   |   | 2009 |   |   | 2008 |   |
| Oil production in barrels                 |   |                    | 7,815  |   |   |   | 8,104 |   |   |   | 8,456 |   |
| Gas production in mcf                     |   |                    | 4,620  |   |   |   | 6,888 |   |   |   | 9,727 |   |
| Total (BOE)                               |   |                    | 8,585  |   |   |   | 9,252 |   |   |   | 10,077 |   |
| Average price per barrel of oil           |   | $                       | 74.07  |   |   | $ | 55.00 |   |   | $ | 96.31 |   |
| Average price per mcf of gas              |   | $                       | 5.49   |   |   | $ | 4.39 |   |   | $ | 10.50 |   |
| Partnership distributions                 |   | $                       | 543    |   |   | $ | 4,875 |   |   | $ | 472,183 |   |
| Limited partner distributions             |   | $                       | 486    |   |   | $ | 4,413 |   |   | $ | 424,976 |   |
| Per unit distribution to limited partners |   | $                       | .05    |   |   | $ | .42 |   |   | $ | 40.54 |   |
| Number of limited partner units           |   |                    | 10,484 |   |   |   | 10,484 |   |   |   | 10,484 |   |

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|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |   | Page   |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|--------|
| Report of Independent Registered Public Accounting Firm                                                                                                    |   | 18     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |   |   |
| Balance Sheets                                                                                                                                             |   | 19     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |   |   |
| Statements of Operations                                                                                                                                   |   | 20     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |   |   |
| Statements of Changes in Partners' (Deficit) Equity                                                                                                        |   | 21     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |   |   |
| Statements of Cash Flows                                                                                                                                   |   | 22     |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |   |   |
| Notes to Financial Statements                                                                                                                              |   | 23     |

|   |
|--------|

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Report 

|   |
|--------|

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Southwest 

|                                       |   | December 31, |      |
|--------------------------------------------|--------|--------------|-----------|
|                                       |   | 2010         |      |   | 2009 |   |
|                                       |   |         |      |   |   |   |
| Assets                                     |   |         |      |   |   |   |
|                                       |   |         |      |   |   |   |
| Current assets:                            |   |         |      |   |   |   |
| Cash and cash equivalents                  |   | $            | 2,089     |   |   | $ | 11,723 |   |
| Receivable from Managing General Partner   |   |         | -         |   |   |   | 22,309 |   |
| New Mexico income tax deposits             |   |         | 9,896     |   |   |   | 7,378 |   |
| Total current assets                       |   |         | 11,985    |   |   |   | 41,410 |   |
|                                       |   |         |      |   |   |   |   |   |
| Oil and gas properties - using the full-   |   |         |      |   |   |   |   |   |
| cost method of accounting                  |   |         | 3,986,087 |   |   |   | 3,981,627 |   |
| Less accumulated depreciation,             |   |         |      |   |   |   |   |   |
| depletion and amortization                 |   |         | 3,732,418 |   |   |   | 3,711,103 |   |
|                                       |   |         |      |   |   |   |   |   |
| Net oil and gas properties                 |   |         | 253,669   |   |   |   | 270,524 |   |
|                                       |   |         |      |   |   |   |   |   |
|                                       |   | $            | 265,654   |   |   | $ | 311,934 |   |
|                                       |   |         |      |   |   |   |   |   |
| Liabilities and Partners' (Deficit) Equity |   |         |      |   |   |   |   |   |
|                                       |   |         |      |   |   |   |   |   |
| Current liability:                         |   |         |      |   |   |   |   |   |
| Payable to Managing General Partner        |   | $            | 185,687   |   |   | $ | - |   |
|                                       |   |         |      |   |   |   |   |   |
| Asset retirement obligation                |   |         | 222,830   |   |   |   | 262,047 |   |
|                                       |   |         |      |   |   |   |   |   |
| Partners' (deficit) equity:                |   |         |      |   |   |   |   |   |
| General partners                           |   |         | (33,125   | ) |   |   | (15,979 | ) |
| Limited partners                           |   |         | (109,738  | ) |   |   | 65,866 |   |
|                                       |   |         |      |   |   |   |   |   |
| Total partners' (deficit) equity           |   |         | (142,863  | ) |   |   | 49,887 |   |
|                                       |   |         |      |   |   |   |   |   |
|                                       |   | $            | 265,654   |   |   | $ | 311,934 |   |

|   |
|--------|

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Southwest 

|                                     |   | Years ended December 31, |     |
|------------------------------------------|--------|--------------------------|----------|
|                                     |   | 2010                     |     |   | 2009 |   |   | 2008 |   |
| Revenues                                 |   |                     |     |   |   |   |   |   |   |
|                                     |   |                     |     |   |   |   |   |   |   |
| Oil and gas income                       |   | $                        | 604,201  |   |   | $ | 475,906 |   |   | $ | 916,527 |   |
| Interest income                          |   |                     | 27       |   |   |   | 21 |   |   |   | 452 |   |
|                                     |   |                     | 604,228  |   |   |   | 475,927 |   |   |   | 916,979 |   |
| Expenses                                 |   |                     |     |   |   |   |   |   |   |   |   |   |
|                                     |   |                     |     |   |   |   |   |   |   |   |   |   |
| Production                               |   |                     | 653,352  |   |   |   | 320,014 |   |   |   | 390,171 |   |
| Depreciation, depletion and amortization |   |                     | 21,315   |   |   |   | 23,872 |   |   |   | 17,769 |   |
| Accretion expense                        |   |                     | 17,982   |   |   |   | 22,081 |   |   |   | 17,778 |   |
| General and administrative               |   |                     | 103,786  |   |   |   | 102,593 |   |   |   | 102,877 |   |
|                                     |   |                     | 796,435  |   |   |   | 468,560 |   |   |   | 528,595 |   |
|                                     |   |                     |     |   |   |   |   |   |   |   |   |   |
| Net (loss) income                        |   | $                        | (192,207 | ) |   | $ | 7,367 |   |   | $ | 388,384 |   |
|                                     |   |                     |     |   |   |   |   |   |   |   |   |   |
| Net (loss) income allocated to:          |   |                     |     |   |   |   |   |   |   |   |   |   |
|                                     |   |                     |     |   |   |   |   |   |   |   |   |   |
| Managing General Partner                 |   | $                        | (15,380  | ) |   | $ | 2,812 |   |   | $ | 36,554 |   |
|                                     |   |                     |     |   |   |   |   |   |   |   |   |   |
| General Partner                          |   | $                        | (1,709   | ) |   | $ | 312 |   |   | $ | 4,061 |   |
|                                     |   |                     |     |   |   |   |   |   |   |   |   |   |
| Limited partners                         |   | $                        | (175,118 | ) |   | $ | 4,243 |   |   | $ | 347,769 |   |
|                                     |   |                     |     |   |   |   |   |   |   |   |   |   |
| Per limited partner unit                 |   | $                        | (16.70   | ) |   | $ | .40 |   |   | $ | 33.17 |   |

|   |
|--------|

----

Southwest 

|                         |   | General  |    |   | Limited  |   |     |   |   |
|------------------------------|--------|----------|---------|--------|----------|--------|----------|--------|--------|
|                         |   | Partners |    |   | Partners |   |     | Total  |   |
| Balance at December 31, 2007 |   | $        | (12,049 | )      |     | $      | 143,243  |   |   | $ | 131,194 |   |
|                         |   |     |    |   |     |   |     |   |   |   |   |   |
| Net income                   |   |     | 40,615  |   |     |   | 347,769  |   |   |   | 388,384 |   |
|                         |   |     |    |   |     |   |     |   |   |   |   |   |
| Distributions                |   |     | (47,207 | )      |     |   | (424,976 | )      |   |   | (472,183 | ) |
|                         |   |     |    |   |     |   |     |   |   |   |   |   |
| Balance at December 31, 2008 |   |     | (18,641 | )      |     |   | 66,036   |   |   |   | 47,395 |   |
|                         |   |     |    |   |     |   |     |   |   |   |   |   |
| Net income                   |   |     | 3,124   |   |     |   | 4,243    |   |   |   | 7,367 |   |
|                         |   |     |    |   |     |   |     |   |   |   |   |   |
| Distributions                |   |     | (462    | )      |     |   | (4,413   | )      |   |   | (4,875 | ) |
|                         |   |     |    |   |     |   |     |   |   |   |   |   |
| Balance at December 31, 2009 |   |     | (15,979 | )      |     |   | 65,866   |   |   |   | 49,887 |   |
|                         |   |     |    |   |     |   |     |   |   |   |   |   |
| Net loss                     |   |     | (17,089 | )      |     |   | (175,118 | )      |   |   | (192,207 | ) |
|                         |   |     |    |   |     |   |     |   |   |   |   |   |
| Distributions                |   |     | (57     | )      |     |   | (486     | )      |   |   | (543 | ) |
|                         |   |     |    |   |     |   |     |   |   |   |   |   |
| Balance at December 31, 2010 |   | $        | (33,125 | )      |     | $      | (109,738 | )      |   | $ | (142,863 | ) |

|   |
|--------|

----

Southwest 

|                                                   |   | Years ended December 31, |     |
|--------------------------------------------------------|--------|--------------------------|----------|
|                                                   |   | 2010                     |     |   | 2009 |   |   | 2008 |   |
| Cash flows from operating activities:                  |   |                     |     |   |   |   |   |   |   |
|                                                   |   |                     |     |   |   |   |   |   |   |
| Cash received from oil and gas sales                   |   | $                        | 623,992  |   |   | $ | 460,939 |   |   | $ | 965,498 |   |
| Cash paid to suppliers                                 |   |                     | (628,650 | ) |   |   | (494,685 | ) |   |   | (444,251 | ) |
| Interest received                                      |   |                     | 27       |   |   |   | 21 |   |   |   | 452 |   |
| Net cash (used in) provided by operating activities    |   |                     | (4,631   | ) |   |   | (33,725 | ) |   |   | 521,699 |   |
|                                                   |   |                     |     |   |   |   |   |   |   |   |   |   |
| Cash flows used in investing activities:               |   |                     |     |   |   |   |   |   |   |   |   |   |
|                                                   |   |                     |     |   |   |   |   |   |   |   |   |   |
| Addition of oil and gas properties                     |   |                     | (4,460   | ) |   |   | (1,216 | ) |   |   | (34,159 | ) |
|                                                   |   |                     |     |   |   |   |   |   |   |   |   |   |
| Cash flows used in financing activities:               |   |                     |     |   |   |   |   |   |   |   |   |   |
|                                                   |   |                     |     |   |   |   |   |   |   |   |   |   |
| Distributions to partners                              |   |                     | (543     | ) |   |   | (4,875 | ) |   |   | (472,183 | ) |
|                                                   |   |                     |     |   |   |   |   |   |   |   |   |   |
| Net (decrease) increase in cash and cash equivalents   |   |                     | (9,634   | ) |   |   | (39,816 | ) |   |   | 15,357 |   |
|                                                   |   |                     |     |   |   |   |   |   |   |   |   |   |
| Beginning of year                                      |   |                     | 11,723   |   |   |   | 51,539 |   |   |   | 36,182 |   |
|                                                   |   |                     |     |   |   |   |   |   |   |   |   |   |
| End of year                                            |   | $                        | 2,089    |   |   | $ | 11,723 |   |   | $ | 51,539 |   |
|                                                   |   |                     |     |   |   |   |   |   |   |   |   |   |
| Reconciliation of net (loss) income to net cash        |   |                     |     |   |   |   |   |   |   |   |   |   |
| provided by operating activities:                      |   |                     |     |   |   |   |   |   |   |   |   |   |
|                                                   |   |                     |     |   |   |   |   |   |   |   |   |   |
| Net (loss) income                                      |   | $                        | (192,207 | ) |   | $ | 7,367 |   |   | $ | 388,384 |   |
|                                                   |   |                     |     |   |   |   |   |   |   |   |   |   |
| Adjustments to reconcile net (loss) income to net cash |   |                     |     |   |   |   |   |   |   |   |   |   |
| provided by operating activities:                      |   |                     |     |   |   |   |   |   |   |   |   |   |
|                                                   |   |                     |     |   |   |   |   |   |   |   |   |   |
| Depreciation, depletion and amortization               |   |                     | 21,315   |   |   |   | 23,872 |   |   |   | 17,769 |   |
| Accretion expense                                      |   |                     | 17,982   |   |   |   | 22,081 |   |   |   | 17,778 |   |
| Settlement of asset retirement obligations             |   |                     |     |   |   |   |   |   |   |   |   |   |
| for plugged and abandoned wells                        |   |                     | (57,199  | ) |   |   | (5,203 | ) |   |   | (18,078 | ) |
| Decrease (increase) in receivables and deposits        |   |                     | 19,791   |   |   |   | (14,967 | ) |   |   | 48,971 |   |
| Increase (decrease) in payables                        |   |                     | 185,687  |   |   |   | (66,875 | ) |   |   | 66,875 |   |
|                                                   |   |                     |     |   |   |   |   |   |   |   |   |   |
| Net cash (used in) provided by operating activities    |   | $                        | (4,631   | ) |   | $ | (33,725 | ) |   | $ | 521,699 |   |
|                                                   |   |                     |     |   |   |   |   |   |   |   |   |   |
| Noncash investing and financing activities:            |   |                     |     |   |   |   |   |   |   |   |   |   |
| Increase in oil and gas properties –             |   |                     |     |   |   |   |   |   |   |   |   |   |
| Asset retirement obligations                           |   | $                        | -        |   |   | $ | 4,908 |   |   | $ | 7,593 |   |

|   |
|--------|

----

Southwest 

| 1. | Organization |
|----|--------------|

|                                                              | Limited  |   | General  |
|-------------------------------------------------------------------|----------|--------|----------|
|                                                              | Partners |   | Partners |
| Interest income on capital contributions                          | 100%     |   | -        |
| Oil and gas sales                                                 | 90%      |   | 10%      |
| All other revenues                                                | 90%      |   | 10%      |
| Organization and offering costs (1)                               | 100%     |   | -        |
| Syndication costs                                                 | 100%     |   | -        |
| Amortization of organization costs                                | 100%     |   | -        |
| Property acquisition costs                                        | 100%     |   | -        |
| Gain/loss on property disposition                                 | 90%      |   | 10%      |
| Operating and administrative costs (2)                            | 90%      |   | 10%      |
| Depreciation, depletion and amortization of oil and as properties | 100%     |   | -        |
| All other costs                                                   | 90%      |   | 10%      |

|   | (1) | All organization costs in excess of 3% of initial capital contributions will be paid by the Managing General Partner and will be treated as a capital contribution.  The Partnership paid the Managing General Partner an amount equal to 3% of initial capital contributions for such organization costs. |
|--------|-----|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | (2) | Administrative costs in any year, which exceed 2% of capital contributions shall be paid by the Managing General Partner and will be treated as a capital contribution. |
|--------|-----|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| 2. | Summary of Significant Accounting Policies |
|----|--------------------------------------------|

|   |
|--------|

----

| 2. | Summary of Significant Accounting Policies - continued |
|----|--------------------------------------------------------|

|   |
|--------|

----

|                                                        |   | 2010   |    |   | 2009   |   |
|-------------------------------------------------------------|--------|--------|---------|--------|--------|--------|
| Beginning of year                                           |   | $      | 262,047 |   |   | $      | 240,261 |   |
| Reduction of obligations due to wells plugged and abandoned |   |   | (57,199 | )      |   |   | (5,203 | ) |
| Accretion expense                                           |   |   | 17,982  |   |   |   | 22,081 |   |
| Revisions of previous estimates                             |   |   | -       |   |   |   | 4,908 |   |
| End of year                                                 |   | $      | 222,830 |   |   | $      | 262,047 |   |

| 4. | Commitments and Contingent Liabilities |
|----|----------------------------------------|

|   |
|--------|

----

| 5. | Related Party Transactions |
|----|----------------------------|

| 6. | Oil and Gas Reserves Information (unaudited) |
|----|----------------------------------------------|

| ·   | amends the definition of proved reserves to require the use of average commodity prices based upon the prior 12-month period rather than year-end prices; |
|--------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------|

| ·   | expands the type of technologies available to establish reserve estimates and categories; |
|--------------------|-------------------------------------------------------------------------------------------|

| ·   | modifies certain definitions used in estimating proved reserves; |
|--------------------|------------------------------------------------------------------|

| ·   | permits disclosure of probable and possible reserves; and |
|--------------------|-----------------------------------------------------------|

| ·   | permits disclosure of reserves based on different price and cost criteria, such as futures prices or management forecasts. |
|--------------------|----------------------------------------------------------------------------------------------------------------------------|

|   |
|--------|

----

| 6. | Oil and Gas Reserves Information (unaudited) - continued |
|----|----------------------------------------------------------|

|                            |   | Oil (bbls) |    |   | Gas (mcf) |   |
|---------------------------------|--------|------------|---------|--------|-----------|--------|
| Total Proved -                  |   |       |    |   |      |   |
| January 1, 2008                 |   |       | 90,000  |   |      |   | 104,000 |   |
|                            |   |       |    |   |      |   |   |   |
| Revisions of previous estimates |   |       | (22,000 | )      |      |   | (20,000 | ) |
| Production                      |   |       | (8,000  | )      |      |   | (10,000 | ) |
| December 31, 2008               |   |       | 60,000  |   |      |   | 74,000 |   |
|                            |   |       |    |   |      |   |   |   |
| Revisions of previous estimates |   |       | 14,000  |   |      |   | (31,000 | ) |
| Production                      |   |       | (8,000  | )      |      |   | (7,000 | ) |
| December 31, 2009               |   |       | 66,000  |   |      |   | 36,000 |   |
|                            |   |       |    |   |      |   |   |   |
| Revisions of previous estimates |   |       | 6,000   |   |      |   | (9,000 | ) |
| Production                      |   |       | (8,000  | )      |      |   | (5,000 | ) |
| December 31, 2010               |   |       | 64,000  |   |      |   | 22,000 |   |
|                            |   |       |    |   |      |   |   |   |
| Proved developed reserves -     |   |       |    |   |      |   |   |   |
| December 31, 2008               |   |       | 60,000  |   |      |   | 74,000 |   |
| December 31, 2009               |   |       | 66,000  |   |      |   | 36,000 |   |
| December 31, 2010               |   |       | 64,000  |   |      |   | 22,000 |   |

|   |
|--------|

----

| 6. | Oil and Gas Reserves Information (unaudited) - continued |
|----|----------------------------------------------------------|

|                                          |   | 2010   |      |   | 2009   |   |      | 2008   |   |
|-----------------------------------------------|--------|--------|-----------|--------|--------|--------|-----------|--------|--------|
| Future cash inflows                           |   | $      | 4,849,000 |   |   | $      | 3,744,000 |   |   | $ | 3,072,000 |   |
| Production, development and abandonment costs |   |   | 2,968,000 |   |   |   | 2,245,000 |   |   |   | 1,705,000 |   |
| Future net cash flows                         |   |   | 1,881,000 |   |   |   | 1,499,000 |   |   |   | 1,367,000 |   |
| 10% annual discount for estimated             |   |   |      |   |   |   |      |   |   |   |   |   |
| timing of cash flows                          |   |   | 781,000   |   |   |   | 687,000   |   |   |   | 593,000 |   |
| Standardized measure of discounted            |   |   |      |   |   |   |      |   |   |   |   |   |
| future net cash flows                         |   | $      | 1,100,000 |   |   | $      | 812,000   |   |   | $ | 774,000 |   |

|                                                   |   | 2010   |      |   | 2009   |   |     | 2008   |   |
|--------------------------------------------------------|--------|--------|-----------|--------|--------|--------|----------|--------|--------|
| Sales of oil and gas produced, net of production costs |   | $      | 49,000    |   |   | $      | (156,000 | )      |   | $ | (526,000 | ) |
| Changes in prices and production costs                 |   |   | 132,000   |   |   |   | 58,000   |   |   |   | (1,481,000 | ) |
| Changes of production rates (timing) and others        |   |   | (47,000   | )      |   |   | (41,000  | )      |   |   | 239,000 |   |
| Revisions of previous quantities estimates             |   |   | 73,000    |   |   |   | 100,000  |   |   |   | (271,000 | ) |
| Accretion of discount                                  |   |   | 81,000    |   |   |   | 77,000   |   |   |   | 255,000 |   |
| Discounted future net cash flows -                     |   |   |      |   |   |   |     |   |   |   |   |   |
| Beginning of year                                      |   |   | 812,000   |   |   |   | 774,000  |   |   |   | 2,558,000 |   |
| End of year                                            |   | $      | 1,100,000 |   |   | $      | 812,000  |   |   | $ | 774,000 |   |

|   |
|--------|

----

| 7. | Selected Quarterly Financial Results – (unaudited) |
|----|----------------------------------------------------------|

|                  |   | Quarter |    |
|-----------------------|--------|---------|---------|
|                  |   | First   |    |   | Second |   |   | Third |   |   | Fourth |   |
| 2010:                 |   |    |    |   |   |   |   |   |   |   |   |   |
| Total revenues        |   | $       | 158,154 |   |   | $ | 161,319 |   |   | $ | 146,361 |   |   | $ | 138,394 |   |
| Total expenses        |   |    | 142,434 |   |   |   | 456,549 |   |   |   | 157,925 |   |   |   | 39,527 |   |
| Net (loss) income     |   | $       | 15,720  |   |   | $ | (295,230 | ) |   | $ | (11,564 | ) |   | $ | 98,867 |   |
|                  |   |    |    |   |   |   |   |   |   |   |   |   |   |   |   |   |
| Net (loss) income per |   |    |    |   |   |   |   |   |   |   |   |   |   |   |   |   |
| limited partners unit |   | $       | 1.30    |   |   | $ | (25.40 | ) |   | $ | (1.04 | ) |   | $ | 8.44 |   |

|                                    |   | Quarter |    |
|-----------------------------------------|--------|---------|---------|
|                                    |   | First   |    |   | Second |   |   | Third |   |   | Fourth |   |
| 2009:                                   |   |    |    |   |   |   |   |   |   |   |   |   |
| Total revenues                          |   | $       | 80,390  |   |   | $ | 120,848 |   |   | $ | 142,560 |   |   | $ | 132,129 |   |
| Total expenses                          |   |    | 116,025 |   |   |   | 132,360 |   |   |   | 135,820 |   |   |   | 84,355 |   |
| Net (loss) income                       |   | $       | (35,635 | ) |   | $ | (11,512 | ) |   | $ | 6,740 |   |   | $ | 47,774 |   |
|                                    |   |    |    |   |   |   |   |   |   |   |   |   |   |   |   |   |
|    Net (loss) income per |   |    |    |   |   |   |   |   |   |   |   |   |   |   |   |   |
|    limited partners unit |   | $       | (3.13   | ) |   | $ | (1.05 | ) |   | $ | .53 |   |   | $ | 4.05 |   |

|   |
|--------|

----

Item 

Item 

| ·   | management of the Managing General Partner has evaluated the effectiveness of the disclosure controls and procedures as of the end of the period covered by this report; |
|--------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| ·   | this evaluation was conducted under the supervision and with the participation of management of the Managing General Partner, including the chief executive and chief financial officers of the Managing General Partner; and |
|--------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| ·   | it is the conclusion of chief executive and chief financial officers of the Managing General Partner that these disclosure controls and procedures are effective in ensuring that information that is required to be disclosed by the Partnership in reports filed or submitted with the SEC is recorded, processed, summarized and reported within the time periods specified in the rules and forms established by the SEC. |
|--------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| ·   | pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of our assets; |
|--------------------|--------------------------------------------------------------------------------------------------------------------------------------------------|

| ·   | provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that our receipts and expenditures are being made only in accordance with authorizations of management and our Board of Directors; and |
|--------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| ·   | provide reasonable assurance regarding prevention or timely detection of any unauthorized acquisition, use or disposition of our assets that could have a material effect on the financial statements. |
|--------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   |
|--------|

----

Item 

|   |
|--------|

----

Item 10.                   Directors, Executive Officers and Corporate Governance

Item 

|   |
|--------|

----

Item 

Item 

Item 

| For the Year Ended December 31, |   | 2010   |   |   | 2009   |   |
|---------------------------------|--------|--------|--------|--------|--------|--------|
| Audit Fees                      |   | $      | 19,034 |   |   | $      | 17,163 |   |
| Audit Related Fees              |   |   | -      |   |   |   | - |   |
| Tax Fees                        |   |   | -      |   |   |   | - |   |
| All Other Fees                  |   |   | -      |   |   |   | - |   |
|                            |   |   |   |   |   |   |   |   |
| TOTAL                           |   | $      | 19,034 |   |   | $      | 17,163 |   |

|   |
|--------|

----

Item 

| (a)    | (1)    | Financial Statements:                                                                                                                                                                                |
|--------|--------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|   |   |                                                                                                                                                                                                 |
|   |   | Included in Part II of this report                                                                                                                                                                   |
|   |   |                                                                                                                                                                                                 |
|   |   | Report of Independent Registered Public Accounting Firm                                                                                                                                              |
|   |   | Balance Sheets                                                                                                                                                                                       |
|   |   | Statements of Operations                                                                                                                                                                             |
|   |   | Statements of Changes in Partners' (Deficit) Equity                                                                                                                                                  |
|   |   | Statements of Cash Flows                                                                                                                                                                             |
|   |   | Notes to Financial Statements                                                                                                                                                                        |
|   |   |                                                                                                                                                                                                 |
|   | (2)    | Schedules required by Article 12 of Regulation S-X are either omitted because they are not applicable or because the required information is shown in the financial statements or the notes thereto. |
|   |   |                                                                                                                                                                                                 |
|   | (3)    | Exhibits:                                                                                                                                                                                            |

| 4      | (a)    | Certificate of Limited Partnership of Southwest Oil & Gas Income Fund X-A, L.P., dated January 29, 1990.  (Incorporated by reference from Partnership's Form 10-K for the fiscal year ended December 31, 1990.) |
|--------|--------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|   |   |                                                                                                                                                                                                                          |
|   | (b)    | Agreement of Limited Partnership of Southwest Oil & Gas Income Fund X-A, L.P. dated January 29, 1990.  (Incorporated by reference from Partnership's Form 10-K for the fiscal year ended December 31, 1990.)    |
|   |   |                                                                                                                                                                                                                          |
|   | 31.1   | Rule 13a-14(a)/15d-14(a) Certification                                                                                                                                                                                        |
|   | 31.2   | Rule 13a-14(a)/15d-14(a) Certification                                                                                                                                                                                        |
|   | 32.1   | Certification of Chief Executive Officer and Chief Financial Officer Pursuant to 18 U.S.C. Section 1350, as adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002                                                 |

|   |
|--------|

----

Glossary 

|   |
|--------|

----

|   |
|--------|

----

Signatures

|   | Southwest Oil & Gas Income Fund X-A, L.P., |
|--------|------------------------------------------------|
|   | a Delaware limited partnership            |
|   |                                           |
| By:    | Southwest Royalties, Inc., Managing            |
|   | General Partner                                |
|   |                                           |
|   |                                           |
| By:    | /s/ Mel G. Riggs                               |
|   | Mel G. Riggs                                   |
|   | President and Chief Executive Officer          |
|   |                                           |
| Date:  | March 29, 2011                                 |

|                                                                                  |   |                                                                                  |
|---------------------------------------------------------------------------------------|--------|---------------------------------------------------------------------------------------|
| /s/ Clayton W Williams                                                                |   | /s/ Mel G. Riggs                                                                      |
| Clayton W. Williams, Chairman of the Board                                            |   | Mel G. Riggs, President, Chief Executive                                              |
| and a Director                                                                        |   | Officer and a Director                                                                |
|                                                                                  |   |                                                                                  |
| Date:           March 29, 2011 |   | Date:           March 29, 2011 |
|                                                                                  |   |                                                                                  |
|                                                                                  |   |                                                                                  |
|                                                                                  |   |                                                                                  |
|                                                                                  |   |                                                                                  |
| /s/ Michael L. Pollard                                                                |   |                                                                                  |
| Michael L. Pollard, Senior Vice President                                             |   |                                                                                  |
| and Chief Financial Officer                                                           |   |                                                                                  |
|                                                                                  |   |                                                                                  |
| Date:           March 29, 2011 |   |                                                                                  |
|                                                                                  |   |                                                                                  |
|                                                                                  |   |                                                                                  |