Method of using phthalic and terephthalic acids and derivatives thereof in well treatment operations
The flow of a fluid may be diverted from a high permeability zone to a low permeability portion of a subterranean formation by use of a diverter having the structural formula (I): wherein: R 1 is —COO—(R 5 O) y —R 4 ; R 2 and R 3 are selected from the group consisting of —H and —COO—(R 5 O) y —R 4 ; provided that at least one of R 2 or R 3 is —COO—(R 5 O) y —R 4 and further provided that both R 2 and R 3 are not —COO—(R 5 O) y —R 4 ; R 4 is —H or a C 1 -C 6 alkyl group; R 5 is a C 1 -C 6 alkylene group; and each y is 0 to 5. Anhydrides of formula (I) are also acceptable as the diverter.
1. A method of stimulating a subterranean formation penetrated by a well with a diverting agent, the method comprising:
(A) introducing into the well a fluid comprising particulates of a compound of formula (I):
or an anhydride thereof
wherein:
R 1 is —COO—(R 5 O) y —R 4 ;
R 2 and R 3 are selected from the group consisting of —H and —COO—(R 5 O) y —R 4 ;
provided that at least one of R 2 or R 3 is —COO—(R 5 O) y —R 4 and further provided that both R 2 and R 3 are not —COO—(R 5 O) y —R 4 ;
R 4 is —H or a C 1 -C 6 alkyl group;
R 5 is a C 1 -C 6 alkylene group; and
each y is 0 to 5
the particulates having a sized distribution to form bridging solids on the face of a high permeability zone of the formation and block the penetration of the fluid into the high permeability zone of the formation;
(B) forming a filter cake of the particulates on the face of the high permeability zone and increasing resistance to flow of the well treatment fluid through the high permeability zone by a pressure drop through the filter cake; and
(C) diverting the flow of the fluid to a low permeability portion of the formation.
2. The method of claim 1 , wherein R 2 is —H and R 3 is —COO—(R 5 O) y -R 4 .
3. The method of claim 2 , wherein y is 0 and R 4 is —H.
4. The method of claim 2 , wherein R 2 is —COO—(R 5 O) y -R 4 and R 3 is —H.
5. The method of claim 4 , wherein y is 0 and R 4 is —H.
6. The method of claim 1 , wherein the compound is phthalic anhydride.
7. The method of claim 1 , wherein the compound is terephthalic anhydride.
8. The method of claim 1 , wherein the compound is phthalic acid.
9. The method of claim 1 , wherein the compound is terephthalic acid.
10. The method of claim 1 , wherein the fluid is an acidizing fluid having from about 70 to about 99 volume percent of aqueous acid and further wherein the strength of the acid is greater than or equal to 10%.
11. The method of claim 1 , wherein the fluid is a wellbore completion fluid or a fluid loss pill.
12. The method of claim 1 , wherein the high permeability zone has natural fractures.
13. The method of claim 1 , wherein the subterranean formation is sandstone or carbonate.
14. The method of claim 1 , wherein the amount of compound of formula (I) in the fluid is from about 0.01 to about 30 volume percent.
15. The method of claim 1 , wherein the compound of formula (I) is fully dissolvable at in-situ downhole conditions.
16. The method of claim 1 , wherein at least 60% of the particulates of formula (I) in the fluid have a particle size between from about 150 μm to about 2000 μm.