**EXHIBIT 31.2**

 

**Certifications**

 

I,Marvin F. Romanow, certify that:

 

1.               I have reviewed this annual report on Form 10-Kof Nexen Inc.

 

2.               Based on my knowledge, this report does notcontain any untrue statement of a material fact or omit to state a material factnecessary to make the statements made, in light of the circumstances underwhich such statements were made, not misleading with respect to the periodcovered by this report;

 

3                  Based on my knowledge, the financialstatements, and other financial information included in this report, fairlypresent in all material respects the financial condition, results of operationsand cash flows of the registrant as of, and for, the periods presented in thisreport;

 

4.               The registrant’s other certifying officer(s) andI are responsible for establishing and maintaining disclosure controls and procedures(as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) andinternal control over financial reporting (as defined in Exchange Act Rule 13a-15(f) and15d-15(f)) for the registrant and we have:

 

(a)   designed such disclosure controls andprocedures, or caused such disclosure controls and procedures to be designed underour supervision, to ensure that material information relating to theregistrant, including its consolidated subsidiaries, is made known to us byothers within those entities, particularly during the period in which thisreport is being prepared;

 

(b)   designed such internal control over financialreporting, or caused such internal control over financial reporting to be designedunder our supervision, to provide reasonable assurance regarding thereliability of financial reporting and the preparation of financial statementsfor external purposes in accordance with generally accepted accounting principles;

 

(c)   evaluated the effectiveness of the registrant’sdisclosure controls and procedures and presented in this report our conclusionsabout the effectiveness of the disclosure controls and procedures, as of theend of the period covered by this report based on such evaluation; and

 

(d)   disclosed in this report any change in theregistrant’s internal control over financial reporting that occurred during theregistrant’s most recent fiscal quarter (the registrant’s fourth fiscal quarterin the case of an annual report) that has materially affected, or is reasonablylikely to materially affect, the registrant’s internal control over financialreporting; and;

 

5                The registrant’s other certifying officer(s) andI have disclosed, based on our most recent evaluation of internal control overfinancial reporting, to the registrant’s auditors and the audit committee ofregistrant’s board of directors (or persons performing the equivalentfunction):

 

(a)              all significant deficiencies and materialweaknesses in the design or operation of internal control over financial reportingwhich are reasonably likely to adversely affect the registrant’s ability torecord, process, summarize and report financial information; and

 

(b)              any fraud, whether or not material, thatinvolves management or other employees who have a significant role in the registrant’sinternal control over financial reporting.

 
| Date:  | February 21, 2008 | /s/ Marvin F. Romanow       |
|--------|------------------------|-----------------------------|
|   |                   | Marvin F. Romanow           |
|   |                   | Executive Vice President    |
|   |                   | and Chief Financial Officer |

 

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