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| Delaware(State or other jurisdiction ofincorporation or organization) |   | 76-0774429(I.R.S. EmployerIdentification No.) |   |
|-----------------------------------------------------------------------|--------|-----------------------------------------------|--------|

| Large accelerated filer                                            | o | Accelerated filer         | o |
|--------------------------------------------------------------------|---|---------------------------|---|
| Non-accelerated filer(Do not check if a smaller reporting company) | o | Smaller reporting company | x |

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| EXHIBIT |   |                                                                                                                                                                                                                                                                                                |   |                                                                     |
|---------|--------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------|--------------------------------------------------------------------------|
| NUMBER  |   | TITLE OF EXHIBIT                                                                                                                                                                                                                                                                                    |   | METHOD OF FILING                                                         |
|    |   |                                                                                                                                                                                                                                                                                                |   |                                                                     |
| 3.1     |   | Articles of Formation of Ridgewood Energy O Fund, LLC dated December 21, 2004.                                                                                                                                                                                                                      |   | Incorporated by reference to the Fund's Form 10 filed on April 21, 2006. |
|    |   |                                                                                                                                                                                                                                                                                                |   |                                                                     |
| 3.2     |   | Limited Liability Company Agreement between Ridgewood Energy Corporation and Investors of Ridgewood Energy O Fund, LLC dated February 16, 2005.                                                                                                                                                     |   | Incorporated by reference to the Fund's Form 10 filed on April 21, 2006. |
|    |   |                                                                                                                                                                                                                                                                                                |   |                                                                     |
| 31.1    |   | Certification of Robert E. Swanson, President and Chief Executive Officer, pursuant to Securities Exchange Act Rule 13a-14(a).                                                                                                                                                                      |   | Filed herewith.                                                          |
|    |   |                                                                                                                                                                                                                                                                                                |   |                                                                     |
| 31.2    |   | Certification of Kathleen P. McSherry, Executive Vice President and Chief Financial Officer, pursuant to Securities Exchange Act Rule 13a-14(a).                                                                                                                                                    |   | Filed herewith.                                                          |
|    |   |                                                                                                                                                                                                                                                                                                |   |                                                                     |
| 32      |   | Certifications pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of The Sarbanes-Oxley Act of 2002, signed by Robert E. Swanson, President and Chief Executive Officer of the Fund and Kathleen P. McSherry, Executive Vice President and Chief Financial Officer of the Fund. |   | Filed herewith.                                                          |
|    |   |                                                                                                                                                                                                                                                                                                |   |                                                                     |
| 99      |   | Report of Ryder Scott Company, L.P.                                                                                                                                                                                                                                                                 |   | Filed herewith                                                           |

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|                             | RIDGEWOOD ENERGY O FUND, LLC |                                                 |
|----------------------------------|------------------------------|------------------------------------------------------|
|                             |                         |                                                 |   |
|                             |                         |                                                 |   |
| Date:  August 23, 2010 | By:                          | /s/ ROBERT E. SWANSON       |   |
|                             |                         | Robert E. Swanson                                    |   |
|                             |                         | Chief Executive Officer(Principal Executive Officer) |   |
|                             |                         |                                                 |   |

| Signature                            | Capacity                                                                                  | Date                  |
|--------------------------------------|-------------------------------------------------------------------------------------------|-----------------------|
|                                 |                                                                                      |  August 23, 2010 |
| /s/ ROBERT E. SWANSON                | Chief Executive Officer  (Principal Executive Officer)                          |
| Robert E. Swanson                    |                                                                                      |
|                                 |                                                                                      |                  |
|                                 |                                                                                      |                  |
| /s/ KATHLEEN P. MCSHERRY             |  Executive Vice President and Chief Financial Officer (Principal Accounting Officer) | August 23, 2010       |
| Kathleen P. McSherry                 |                                                                                      |
|                                 |                                                                                      |                  |
| RIDGEWOOD ENERGY CORPORATION         |                                                                                      |                  |
|                                 |                                                                                      |                  |
| BY:  /s/ ROBERT E. SWANSON |   Chief Executive Officer of Manager                                            | August 23, 2010       |
| Robert E. Swanson                    |                                                                                      |                  |
|                                 |                                                                                      |                  |

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