-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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<SEC-DOCUMENT>0001140361-03-001875.txt : 20030604
<SEC-HEADER>0001140361-03-001875.hdr.sgml : 20030604
<ACCEPTANCE-DATETIME>20030604172200
ACCESSION NUMBER:		0001140361-03-001875
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030603
FILED AS OF DATE:		20030604

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			3TEC ENERGY CORP
		CENTRAL INDEX KEY:			0000903267
		STANDARD INDUSTRIAL CLASSIFICATION:	CRUDE PETROLEUM & NATURAL GAS [1311]
		IRS NUMBER:				631081013
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		700 MILAM STREET
		STREET 2:		SUITE 1100
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77002-2
		BUSINESS PHONE:		7138217100

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MIDDLE BAY OIL CO INC
		DATE OF NAME CHANGE:	19930504

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ENCAP ENERGY CAPITAL FUND III LP
		CENTRAL INDEX KEY:			0001086967

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-14745
		FILM NUMBER:		03733055

	BUSINESS ADDRESS:	
		STREET 1:		1100 LOUISIANA
		STREET 2:		SUITE 3150
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77002
		BUSINESS PHONE:		7136596100

	MAIL ADDRESS:	
		STREET 1:		1100 LOUISIANA
		STREET 2:		SUITE 3150
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77002
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0101</schemaVersion>

    <documentType>4</documentType>
<periodOfReport>2003-06-03</periodOfReport>
<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000903267</issuerCik>
        <issuerName>3TEC ENERGY CORP</issuerName>
        <issuerTradingSymbol>TTEN</issuerTradingSymbol>
</issuer>
<reportingOwner>
<reportingOwnerId>
            <rptOwnerCik>0001086967</rptOwnerCik>
            <rptOwnerName>ENCAP ENERGY CAPITAL FUND III LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector>
<isOfficer>0</isOfficer>
<isTenPercentOwner>1</isTenPercentOwner>
<isOther>0</isOther>
<officerTitle></officerTitle>
<otherText></otherText>
</reportingOwnerRelationship>
</reportingOwner>
<nonDerivativeSecurity>
<securityTitle>
<value>Common Stock</value>
</securityTitle>
<transactionDate>
<value>2003-06-03</value>
</transactionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>X</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>70000</value>
</transactionShares>
<transactionValue>
<value>14.01</value>
<footnoteId id="F1"/>
</transactionValue>
<transactionAcquiredDisposedCode>
<value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>1590992</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeSecurity>
<nonDerivativeSecurity>
<securityTitle>
<value>Common Stock</value>
</securityTitle>
<transactionDate>
<value>2003-06-03</value>
</transactionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>X</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>20000</value>
</transactionShares>
<transactionValue>
<value>13.89</value>
<footnoteId id="F2"/>
</transactionValue>
<transactionAcquiredDisposedCode>
<value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>1590992</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeSecurity>
<nonDerivativeSecurity>
<securityTitle>
<value>Common Stock</value>
</securityTitle>
<transactionDate>
<value>2003-06-03</value>
</transactionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>X</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>20000</value>
</transactionShares>
<transactionValue>
<value>15.13</value>
<footnoteId id="F3"/>
</transactionValue>
<transactionAcquiredDisposedCode>
<value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>1590992</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeSecurity>
<nonDerivativeSecurity>
<securityTitle>
<value>Common Stock</value>
</securityTitle>
<transactionDate>
<value>2003-06-03</value>
</transactionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>X</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>372393</value>
</transactionShares>
<transactionValue>
<value>3.00</value>
<footnoteId id="F4"/>
</transactionValue>
<transactionAcquiredDisposedCode>
<value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>1590992</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeSecurity>
<nonDerivativeSecurity>
<securityTitle>
<value>Common Stock</value>
</securityTitle>
<transactionDate>
<value>2003-06-03</value>
</transactionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>X</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>57688</value>
</transactionShares>
<transactionValue>
<value>14.01</value>
<footnoteId id="F1"/>
</transactionValue>
<transactionAcquiredDisposedCode>
<value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>1590992</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeSecurity>
<nonDerivativeSecurity>
<securityTitle>
<value>Common Stock</value>
</securityTitle>
<transactionDate>
<value>2003-06-03</value>
</transactionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>X</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>16341</value>
</transactionShares>
<transactionValue>
<value>13.89</value>
<footnoteId id="F2"/>
</transactionValue>
<transactionAcquiredDisposedCode>
<value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>1590992</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeSecurity>
<nonDerivativeSecurity>
<securityTitle>
<value>Common Stock</value>
</securityTitle>
<transactionDate>
<value>2003-06-03</value>
</transactionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>X</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>17800</value>
</transactionShares>
<transactionValue>
<value>15.13</value>
<footnoteId id="F3"/>
</transactionValue>
<transactionAcquiredDisposedCode>
<value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>1590992</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeSecurity>
<nonDerivativeSecurity>
<securityTitle>
<value>Common Stock</value>
</securityTitle>
<transactionDate>
<value>2003-06-03</value>
</transactionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>X</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>65716</value>
</transactionShares>
<transactionValue>
<value>3.00</value>
<footnoteId id="F4"/>
</transactionValue>
<transactionAcquiredDisposedCode>
<value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>1590992</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeSecurity>
<derivativeSecurity>
<securityTitle>
<value>Series D Preferrred Stock</value>
</securityTitle>
<conversionOrExercisePrice>
<value>24.00</value>
</conversionOrExercisePrice>
<transactionDate>
<value>2003-06-03</value>
</transactionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>J</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
<footnoteId id="F5"/>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>192846</value>
</transactionShares>
<transactionValue>
<value>0</value>
<footnoteId id="F5"/>
</transactionValue>
<transactionAcquiredDisposedCode>
<value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<exerciseDate>
<value>2000-02-03</value>
</exerciseDate>
<expirationDate>
<value>2003-06-03</value>
<footnoteId id="F5"/>
</expirationDate>
<underlyingSecurity>
<underlyingSecurityTitle>
<value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares>
<value>192846</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>0</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</derivativeSecurity>
<derivativeSecurity>
<securityTitle>
<value>Stock Option (right to buy)</value>
</securityTitle>
<conversionOrExercisePrice>
<value>14.01</value>
</conversionOrExercisePrice>
<transactionDate>
<value>2003-06-03</value>
</transactionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>X</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>70000</value>
</transactionShares>
<transactionValue>
<value>0</value>
</transactionValue>
<transactionAcquiredDisposedCode>
<value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<exerciseDate>
<value>2001-12-19</value>
</exerciseDate>
<expirationDate>
<value>2011-12-18</value>
</expirationDate>
<underlyingSecurity>
<underlyingSecurityTitle>
<value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares>
<value>70000</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>0</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</derivativeSecurity>
<derivativeSecurity>
<securityTitle>
<value>Stock Option (right to buy</value>
</securityTitle>
<conversionOrExercisePrice>
<value>13.89</value>
</conversionOrExercisePrice>
<transactionDate>
<value>2003-06-03</value>
</transactionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>X</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>20000</value>
</transactionShares>
<transactionValue>
<value>0</value>
</transactionValue>
<transactionAcquiredDisposedCode>
<value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<exerciseDate>
<value>2002-01-02</value>
</exerciseDate>
<expirationDate>
<value>2012-01-01</value>
</expirationDate>
<underlyingSecurity>
<underlyingSecurityTitle>
<value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares>
<value>20000</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>0</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</derivativeSecurity>
<derivativeSecurity>
<securityTitle>
<value>Stock Option (right to buy)</value>
</securityTitle>
<conversionOrExercisePrice>
<value>15.13</value>
</conversionOrExercisePrice>
<transactionDate>
<value>2003-06-03</value>
</transactionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>X</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>20000</value>
</transactionShares>
<transactionValue>
<value>0</value>
</transactionValue>
<transactionAcquiredDisposedCode>
<value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<exerciseDate>
<value>2003-01-02</value>
</exerciseDate>
<expirationDate>
<value>2013-01-01</value>
</expirationDate>
<underlyingSecurity>
<underlyingSecurityTitle>
<value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares>
<value>20000</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>0</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</derivativeSecurity>
<derivativeSecurity>
<securityTitle>
<value>Warrant</value>
</securityTitle>
<conversionOrExercisePrice>
<value>3.00</value>
</conversionOrExercisePrice>
<transactionDate>
<value>2003-06-03</value>
</transactionDate>
<transactionCoding>
<transactionFormType>4</transactionFormType>
<transactionCode>X</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionTimeliness>
<value></value>
</transactionTimeliness>
<transactionAmounts>
<transactionShares>
<value>372393</value>
</transactionShares>
<transactionValue>
<value>0</value>
</transactionValue>
<transactionAcquiredDisposedCode>
<value>D</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<exerciseDate>
<value>1999-08-27</value>
<footnoteId id="F6"/>
</exerciseDate>
<expirationDate>
<value>2004-08-27</value>
</expirationDate>
<underlyingSecurity>
<underlyingSecurityTitle>
<value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares>
<value>372393</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts>
<sharesOwnedFollowingTransaction>
<value>0</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature>
<directOrIndirectOwnership>
<value>D</value>
</directOrIndirectOwnership>
<natureOfOwnership>
<value></value>
</natureOfOwnership>
</ownershipNature>
</derivativeSecurity>
<footnotes>
<footnote id="F1">The reporting person obtained and sold the common stock as a result of the cashless exercise of stock options the exercise price of which was $14.01 per share.</footnote>
<footnote id="F2">The reporting person obtained and sold the common stock as a result of the cashless exercise of stock options the exercise price of which was $13.89 per share.</footnote>
<footnote id="F3">The reporting person obtained and sold the common stock as a result of the cashless exercise of stock options the exercise price of which was $15.13 per share.</footnote>
<footnote id="F4">The reporting person obtained and sold the common stock as a result of the cashless exchange of warrants, the price of which was $3.00 per share.</footnote>
<footnote id="F5">The shares of Series D Preferred Stock were called for redemption on June 3, 2003, by the issuer at a price equal to $24.00 plus declared and unpaid dividends of $0.21 per share.</footnote>
<footnote id="F6">Sixty percent of the Warrants were exercisable beginning August 27, 1999. The remaining 40% became exercisable over time.</footnote>
</footnotes>
<ownerSignature>
<signatureName>By: EnCap Investments L.L.C., its general partner</signatureName>
<signatureDate>2003-06-04</signatureDate>
</ownerSignature>
<ownerSignature>
<signatureName>By: David B. Miller, Managing Director</signatureName>
<signatureDate>2003-06-04</signatureDate>
</ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----