Prevention and remediation of water and condensate blocks in wells

Abstract

The present invention relates to a method of removing and preventing water and condensate blocks in wells by contacting a subterranean formation with a composition comprising a low molecular weight fluorinated copolymer having perfluoro alkyl moieties which are no longer than C 6 . A fluorinated copolymer of low molecular weight of about 50,000 g/mol and a method of preparing the same are also disclosed.

What is claimed is: 
     
         1 . A fluorinated copolymer copolymerized from monomers comprising:
 (a) from about 30 wt % to about 90 wt % of at feast one monomer of formula I:
   R f -Q-A-C(O)—C(R)═CH 2   I
 
   wherein   R f  is a straight or branched-chain perfluoroalkyl group of from 2 to 6 carbon atoms,   R is H or CH 3 ,   A is O, S or N(R′), wherein R′ is H or an alkyl of from 1 to about 4 carbon atoms,   Q is alkylene of 1 to about 15 carbon atoms, hydroxyalkylene of 3 to about 15 carbon atoms, —(C n H 2n )(OC q H 2q ) m —, —SO 2 —NR′(C n H 2n )—, or —CONR′(C n H 2n )—, wherein R′ is H or an alkyl of from 1 to about 4 carbon atoms, n is 1 to about 15, q is 2 to about 4, and m is 1 to about 15;   (b) from about 10 wt % to about 70 wt % of at least one monomer or a mixture of monomers is selected from formula IIA, formula IIB, or formula IIC:
   (R 1 ) 2 N—(CH 2 ) r —Z—C(O)—C(R 2 )═CH 2   IIA
 
   (O)(R 3 )(R 4 )N—(CH 2 ) r —Z—C(O)—C(R 2 )═CH 2   IIB
 
   X − (R 5 )(R 4 )(R 3 )N + —(CH 2 ) r —Z—C(O)—C(R 2 )═CH 2   IIC
 
   
       wherein
 Z is —O— or —NR 5 —; R 1  is an alkyl group of from 1 to about 3 carbon atoms; R 2  is H or an alkyl radical of 1 to about 4 carbon atoms; R 3  and R 4  are each independently an alkyl of 1 to 4 carbon atoms, hydroxyethyl, benzyl, or R 3  and R 4  together with the nitrogen atom form a morpholine, pyrrolidine, or piperadine ring; R 5  is H or an alkyl of 1 to 4 carbon atoms, or R 3 , R 4  and R 5  together with the nitrogen atom form a pyridine ring; r is 2 to 4; provided that for formula IIA the nitrogen is from about 40% to 100% salinized; and 
 (c) from 0 wt % to about 7 wt % of a monomer of the formula III, IV, V or VI or a mixture thereof:
   CH 2 (O)CH 2 —CH 2 —O—C(O)—C(R 2 )═CH 2   III;
 
   Cl—CH 2 —CH(OH)CH 2 —O—C(O)—C(R 2 )═CH 2   IV;
 
   (R 6 )OC(O)C(R 6 )═CH 2   V;
 
   or 
   CH 2 ═CCl 2   VI
 
 
 
       wherein
 each R 2  is independently H or an alkyl radical of 1 to about 4 carbon atoms, and each R 6  is independently H or an alkyl of 1 to about 8 carbon atoms, wherein the fluorinated copolymer has an average molecular weight less than about 50,000 g/mol, 
 wherein any perfluoroalkyl moieties present in the fluorinated copolymer are no larger than 6 carbon atoms long. 
 
     
     
         2 . The fluorinated copolymer of  claim 1  having an average molecular weight less than about 20,000 g/mol. 
     
     
         3 . The fluorinated copolymer of  claim 1  having an average molecular weight less than about 10,000 g/mol. 
     
     
         4 . The fluorinated copolymer of  claim 1 , wherein the monomers of the fluorinated copolymer are copolymerized in the presence of dodecyl mercaptan. 
     
     
         5 . A method of preparing the fluorinated copolymer of  claim 1  comprising reacting 2-methyl-3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl ester, 2-methyl-,2-(diethylamino) ethyl ester, and dodecyl mercaptan under conditions suitable to make the fluorinated copolymer having an average molecular weight of about 20,000 g/mol.