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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0001140361-10-024505.txt : 20100607
<SEC-HEADER>0001140361-10-024505.hdr.sgml : 20100607
<ACCEPTANCE-DATETIME>20100607172516
ACCESSION NUMBER:		0001140361-10-024505
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100603
FILED AS OF DATE:		20100607
DATE AS OF CHANGE:		20100607

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PRIMEENERGY CORP
		CENTRAL INDEX KEY:			0000056868
		STANDARD INDUSTRIAL CLASSIFICATION:	CRUDE PETROLEUM & NATURAL GAS [1311]
		IRS NUMBER:				840637348
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		ONE LANDMARK SQ
		CITY:			STAMFORD
		STATE:			CT
		ZIP:			06901
		BUSINESS PHONE:		2033585700

	MAIL ADDRESS:	
		STREET 1:		ONE LANDMARK SQ
		CITY:			STAMFORD
		STATE:			CT
		ZIP:			06901

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	KRM PETROLEUM CORP
		DATE OF NAME CHANGE:	19900614

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			McJunkin Red Man Corp
		CENTRAL INDEX KEY:			0001016497
		STATE OF INCORPORATION:			WV
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-07406
		FILM NUMBER:		10882116

	BUSINESS ADDRESS:	
		STREET 1:		2 HOUSTON CENTER
		STREET 2:		909 FANNIN, SUITE 3100
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77010
		BUSINESS PHONE:		(713) 655-1005

	MAIL ADDRESS:	
		STREET 1:		2 HOUSTON CENTER
		STREET 2:		909 FANNIN, SUITE 3100
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77010

	FORMER NAME:	
		FORMER CONFORMED NAME:	MCJUNKIN RED MAN Corp
		DATE OF NAME CHANGE:	20090522

	FORMER NAME:	
		FORMER CONFORMED NAME:	MCJUNKIN CORP
		DATE OF NAME CHANGE:	19960610
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-06-03</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000056868</issuerCik>
        <issuerName>PRIMEENERGY CORP</issuerName>
        <issuerTradingSymbol>PNRG</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001016497</rptOwnerCik>
            <rptOwnerName>McJunkin Red Man Corp</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2 HOUSTON CENTER</rptOwnerStreet1>
            <rptOwnerStreet2>909 FANNIN, SUITE 3100</rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77010</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>COMMON STOCK, $0.10 PAR VALUE</value>
            </securityTitle>
            <transactionDate>
                <value>2010-06-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>623521</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>12</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>OBLIGATIONS TO PAY SALE PROCEEDS</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-06-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>592345</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>COMMON STOCK, $0.10 PAR VALUE</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>592345</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The reporting person previously owned 623,521 shares of Common Stock, par value $0.10 per share of Prime Energy Corporation (the &quot;Shares&quot;). Pursuant to the Merger Agreement, dated as of December 4, 2006 among the reporting person, McJ Holding Corporation and Hg Acquisition Corp., as amended (the &quot;Merger Agreement&quot;), upon a sale of Shares by the reporting person from and after January 31, 2007, the reporting person has an obligation to remit to those persons who were the record holders of shares of the reporting person immediately prior to the effective time of the Merger (as defined in the Merger Agreement) an amount equal to 95% of the after tax proceeds from such sale. As disclosed above, the reporting person sold 623,521 shares of Common Stock and will distribute the proceeds in accordance with the Merger Agreement.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ McJunkin Red Man Corporation, Andrew Lane, Chairman, President and Chief Executive Officer</signatureName>
        <signatureDate>2010-06-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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