**Exhibit23.6**

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February 8, 2010

 

Nexen Inc.

801-7th Avenue S.W.

Calgary, AB

T2P 3P7

 

**Attention: Reserves ReviewCommittee of the Board of Directors of Nexen Inc.**

 

**Re:****                            ****McDaniel & Associates -Report of Third Party for certain Canadian properties owned by Nexen Inc.,excluding Syncrude**

 

Ladiesand Gentlemen:

 

Pursuantto your request, McDaniel and Associates (“McDaniel”) has conducted anevaluation of Nexen Inc.’s (“Nexen”) proved and probable oil, condensate, natural gasliquids (NGL), natural gas, and synthetic crude oil reserves, as of December 31,2009, for certain fields owned by Nexen in Canada as shown in Table1A, which includes Nexen’s Canadian conventional, CBM, and Long Lake properties.  Nexen hasrepresented that these properties account for 39 percent of its total provedreserves (75 percent of its total probable reserves) and 98 percent of theproved reserves (99 percent of its probable reserves) in its Canadianproperties excluding Syncrude on an equivalent barrel basis as of December 31,2009, and that its reserve estimates have been prepared in accordance with theUnited States’ Securitiesand Exchange Commission (“SEC”) definitions. We havereviewed information provided to us by Nexen that they represent to be its estimate of the reserves, asof December 31, 2009, for the same properties as those which we evaluated.

 

Reservesincluded herein are expressed as reserves as represented by Nexen. Gross reserves are definedas the total estimated petroleum to be produced from these properties after December 31,2009. Working interest reserves are defined as that portion of the grossreserves attributable to the interests owned by Nexen after deducting all workinginterests owned by others. Net reserves are defined as working interestreserves after the deduction of royalties.

 

2200, Bow Valley Square 3,255 - 5 Avenue SW, Calgary AB  T2P3G6     Tel: (403) 262-5506     Fax: (403) 233-2744     www.mcdan.com

 

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| **Nexen Inc.**                                                         | **February 8, 2010** |
|------------------------------------------------------------------------|----------------------|
| **Report of Third Party for Canadian Properties,  excluding Syncrude** | **Page 2**           |

 

Estimatesof oil, condensate, NGL (collectively liquids), natural gas and synthetic crudeoil should be regarded only as estimates that may change as further productionhistory and additional information become available. Not only are such reservesestimates based on that information which is currently available, but suchestimates are also subject to the uncertainties inherent in the application ofjudgmental factors in interpreting such information.

 

Dataused in this evaluation were obtainedfrom reviews with Nexen personnel, Nexen files, from records on filewith the appropriate regulatory agencies, and from public sources. In thepreparation of this report we have relied, without independent verification,upon such information furnished by Nexen with respect to propertyinterests, production from such properties, current costs of operation anddevelopment, prices for production, agreements relating to current and futureoperations and sale of production, and various other information and data thatwere accepted as represented.  Furthermore, if in the courseof our examination something came to our attention which brought into questionthe validity or sufficiency of any of such information or data, we did not relyon such information or data until we had satisfactorily resolved our questionsrelating thereto or had independently verified such information or data. A fieldexamination of the properties was not considered necessary for the purposes ofthis report.

 

**Methodology and Procedures**

 

Theprocess of estimating reserves requires complex judgments and decision-makingbased on available geological, geophysical, engineering and economic data. Toestimate the economically recoverable oil, natural gas reserves and syntheticcrude oil and related future net cash flows, we consider many factors and makeassumptions including:

 

·                  expected reservoircharacteristics based on geological, geophysical and engineering assessments;

 

·                  futureproduction rates based on historical performance and expected future operatingand investment activities;

 

·                  future oil andgas prices and quality differentials;

 

·                  assumed effectsof regulation by governmental agencies; and

 

·                  futuredevelopment and operating costs.

 

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| **Nexen Inc.**                                                         | **February 8, 2010** |
|------------------------------------------------------------------------|----------------------|
| **Report of Third Party for Canadian Properties,  excluding Syncrude** | **Page 3**           |

 

Our estimates areprepared using standard geological and engineering methods generally acceptedby the petroleum industry, and the reserves definitions and standards requiredby the United States SEC.  Generallyaccepted methods for estimating reserves include volumetric calculations,material balance techniques, production and pressure decline curve analysis,analogy with similar reservoirs, and reservoir simulation.  The method or combination of methods used isbased on our professional judgment and experience.

 

Discoveredoil and natural gas reserves are generally only produced when they areeconomically recoverable. As such, oil and gas prices, and capital andoperating costs have an impact on whether reserves will ultimately be produced.As required by SEC rules, reserves represent the quantities that we expect toeconomically recover using existing prices and costs. Estimates may changesubstantially as additional data from ongoing development activities andproduction performance becomes available and as economic conditions impactingoil and gas prices and costs change.

 

Generally, operations aresubject to various levels of government controls and regulations.  These laws and regulations may includematters relating to land tenure, drilling, production practices, environmentalprotection, marketing and pricing policies, royalties, various taxes and leviesincluding income tax, and foreign trade and investment, that are subject tochange from time to time.  Currentlegislation is generally a matter of public record, and additional legislationor amendments that will affect reserves or when any such proposals, if enacted,might become effective generally can not be predicted.  Changes in government regulations couldaffect reserves or related economics.  Inthe regions that are currently being evaluated we believe we have appliedexisting regulations appropriately.

 

**Nexen Estimates**

 

Nexen hasrepresented that estimated proved and probable reserves attributable to theevaluated properties arebased on SEC definitions. It represents that its estimates of the reservesattributable to these properties represent approximately 39 percent of its total company proved reserves before royalties andapproximately 75 percent of its total company probablereserves before royalties on a equivalent basis and are as follows,expressed in thousands of barrels (mbbl), millions of cubic feet (mmcf) and thousands of barrels of oilequivalent (mboe):

 

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| **Nexen Inc.**                                                         | **February 8, 2010** |
|------------------------------------------------------------------------|----------------------|
| **Report of Third Party for Canadian Properties,  excluding Syncrude** | **Page 4**           |

 

**Nexen’sestimate of****Reserves as of December 31,2009**

**Select Canadian Fields Evaluated by McDaniel and Associates**

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**Conventional, CBM, and Long Lake**

 
| **Nexen  Reserves**                               | ** ** | **Synthetic********Crude Oil********(mboe)** | ** ** | **Liquids********(mbbl)** | ** ** | **Natural********Gas********(mmcf** | ** ** | **Oil********Equivalent********(mboe)** | ** ** |
|---------------------------------------------------|------------|----------------------------------------------|------------|---------------------------|------------|-------------------------------------|------------|-----------------------------------------|------------|
| **Working  Interest Reserves (before royalties)** |       |                                         |       |                      |       |                                |       |                                    |       |
| Proved                                            |       | 318,248                                      |       | 32,036                    |       | 250,708                             |       | 392,069                                 |       |
| Probable                                          |       | 887,412                                      |       | 18,926                    |       | 73,718                              |       | 918,624                                 |       |
| **Working  Interest Reserves (after royalties)**  |       |                                         |       |                      |       |                                |       |                                    |       |
| Proved                                            |       | 290,761                                      |       | 26,517                    |       | 231,626                             |       | 355,882                                 |       |
| Probable                                          |       | 753,891                                      |       | 16,135                    |       | 68,170                              |       | 781,388                                 |       |

 

Note:Gas is converted to oil equivalent using a factor of 6,000 cubic feet of gasper 1 barrel of oil equivalent.

 

**Reserves Audit Opinion**

 

McDanielhas used all procedures and methods that it considers necessary to prepare thisreport.

 

Inour opinion, the information relating to estimated proved and probable reservesof oil, condensate, natural gas liquids, gas and synthetic crude oil containedin this report has been prepared according to the definitions and disclosureguidelines required by the United States SEC within Paragraphs 932-235-50-4,932-235-50-6, 932-235-50-7 and 932-235-50-9 of the Accounting Standards Update932-235-50, Extractive Industries — Oil and Gas (Topic 932): Oil and GasReserve Estimation and Disclosures (January 2010) of the FinancialAccounting Standards Board and Rules 4—10(a) (1)—(32) of Regulation S—Xand Rules 302(b) and 1201, 1202(a) (1), (2), (3), (4), (5), (8) ofRegulation S-K of the Securities and Exchange Commission.

 

Incomparing the detailed proved and proved plus probable reserves estimatesprepared by us to those prepared by Nexen, we have found differences, bothpositive and negative. In our opinion, the proved and proved plus probablereserves for the reviewed properties as estimated by Nexen are, in aggregatewhen compared to our estimates on the basis of equivalent barrels, reasonablewithin the established audit tolerance guidelines as set forth in the StandardsPertaining to the Estimating and Auditing of Oil and Gas Reserves Informationpromulgated by the Society of Petroleum Engineers.

 

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| **Nexen Inc.**                                                         | **February 8, 2010** |
|------------------------------------------------------------------------|----------------------|
| **Report of Third Party for Canadian Properties,  excluding Syncrude** | **Page 5**           |

 

The analyses of theseproperties, as reported herein, were conducted within the context of an auditof a distinct group of properties in aggregate as part of the total corporatelevel reserves.  Extraction and use ofthese analyses outside of this context may not be appropriate withoutsupplementary due diligence.

 

McDanielis an independent petroleum engineering consulting firm that has been providingpetroleum consulting services throughout the world for over 50 years. McDanieldoes not have any financial interest, including stock ownership, in Nexen. Ourfees were not contingent on the results of our evaluation. This letter reporthas been prepared at the request of Nexen and should not be used for purposesother than those for which it is intended.

 

Thisreport was prepared by McDaniel & Associates Consultants Ltd. for theexclusive use of Nexen Inc.  It is not tobe reproduced, distributed, or made available, in whole or in part to anyperson, company, or organization other than Nexen Inc. without the knowledgeand consent of McDaniel & Associates Consultants Ltd.  We reserve the right to revise any of theestimates provided herein if any relevant data existing prior to preparation ofthis report was not made available or if any data provided was found to beerroneous.

 

If there are anyquestions, please contact the writer directly at (403) 218-1379.

 

Sincerely,

 
| **McDaniel & Associates  Consultants Ltd.** |                                |
|------------------------------------------------------|-------------------------------------|
|                                                 |                                |
|                                                 |                                |
| “signed by P. A. Welch”                    |                                |
|                                                 |                                |
| P. A. Welch, P. Eng.                                 |                                |
|                                                 |                                |
|                                                 |                                |
| CC:                                                  | Mr. David  Richardson, P. Eng. |   |
|                                                 | Canadian Oil and Gas,               |   |
|                                                 | Division Reserves  Manager          |   |
|                                                 |                                |   |
|                                                 | Mr. Brad Kopas                 |   |
|                                                 | Deloitte &  Touche LLP     |   |

 

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| **Nexen Inc.**                                                         | **February 8, 2010** |
|------------------------------------------------------------------------|----------------------|
| **Report of Third Party for Canadian Properties,  excluding Syncrude** | **Page 6**           |

 

**Table 1A**

**NexenFields Evaluated by McDaniel**

**CanadianOil and Gas properties, excluding Syncrude**

**As of December 31, 2009**

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| ** ** | ** ** | **BUSINESS UNIT** | ** ** | **PROPERTY NAME**       |
|------------|------------|-------------------|------------|-------------------------|
| 1          |       | CBM               |       | CBM - CORBETT           |
| 2          |       | CBM               |       | CBM - DORIS             |
| 3          |       | CBM               |       | CBM - THUNDER           |
| 4          |       | CDN GAS           |       | BALZAC                  |
| 5          |       | CDN GAS           |       | HATTON                  |
| 6          |       | CDN GAS           |       | HATTON EAST             |
| 7          |       | CDN GAS           |       | MEDICINE HAT            |
| 8          |       | HEAVY OIL         |       | CACTUS LAKE             |
| 9          |       | HEAVY OIL         |       | COURT                   |
| 10         |       | HEAVY OIL         |       | MARSDEN                 |
| 11         |       | HEAVY OIL         |       | SENLAC                  |
| 12         |       | HEAVY OIL         |       | WINTER                  |
| 13         |       | LONG LAKE         |       | LONG LAKE Phase 1       |
| 14         |       | LONG LAKE         |       | LONG LAKE SOUTH Phase 1 |

 

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