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US 9,175,207 B2Granted
Surfactant-less alkaline-polymer formulations for recovering reactive crude oil
AssigneeBoard of Regents, The University of Texas System
InventorsUpali P. Weerasooriya, Gary A. Pope
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Abstract
Compositions and methods for oil recovery using a surfactant-less alkaline-polymer system in hard water or hard brine is described in the instant invention. The formulation further includes a chelating agent, an alkaline agent (which can be the same as the chelating agent), and a co-solvent. The formulations as disclosed herein are capable of forming a surfactant in-situ resulting in Winsor Type III micro-emulsions of low interfacial tension.
Claims50
A surfactant-less alkaline-polymer composition for treating a hydrocarbon-bearing formation, said composition comprising:
- (a) water selected from the group consisting of hard water and hard brine, wherein the water comprises divalent cations selected from the group consisting of Ca+2, Ba+2, Mg+2, Sr+2, and combinations thereof;
- (b) a chelating agent, wherein the agent is operable for forming a soluble salt with the divalent cations when subjected to reservoir conditions of the hydrocarbon-bearing formation, and wherein the chelating agent is selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), ethylenediamine tetracetic acid tetra sodium salt (EDTA Na4), EDTA salts, acrylic polymers, ascorbic acid, tetrasodium iminodisuccinate, citric acid, dicarboxymethylglutamic acid, ethylenediaminedisuccinic acid (EDDS), maleic acid, nitrilotriacetic acid (NTA), nonpolar amino acids, methionine, oxalic acid, phosphoric acid, polar amino acids, arginine, asparagine, aspartic acid, glutamic acid, glutamine, lysine, ornithine, siderophores, desferrioxamine B, hydrolysed wool, succinic acid, sodium silicate, sodium orthosilicate, other polycarboxylates, and combinations thereof;
- (c) an alkaline agent, wherein
- (i) the alkaline agent comprises the chelating agent, a different alkaline agent, or a combination thereof, and
- (ii) the alkaline agent is operable for interacting with carboxylic acid in the hydrocarbon-bearing formation at reservoir conditions of the hydrocarbon-bearing formation to generate an in-situ soap;
- (d) a non-ionic co-solvent, wherein
- (i) the co-solvent is hydrophilic,
- (ii) the co-solvent is operable for interacting with the in-situ generated soap at the reservoir conditions of the hydrocarbon-bearing formation to produce an optimum surfactant, and
- (e) a polymer, wherein the water, the chelating agent, the alkaline agent, the co-solvent, and the polymer are mixed together in the composition, and
- wherein the surfactant-less alkaline-polymer composition does not include a surfactant other than the non-ionic co-solvent.
7 more elements
A method of treating a hydrocarbon-bearing formation to recover oil comprising:
- (a) injecting a surfactant-less alkaline-polymer composition into the hydrocarbon bearing formation, wherein the surfactant-less alkaline-polymer composition comprises
- (i) water, wherein
- (A) the water is selected from the group consisting of hard water and hard brine, and
- (B) the water comprises divalent cations selected from the group consisting of Ca+2, Ba+2, Mg+2, Sr+2, and combinations thereof,
- (ii) a chelating agent, wherein the chelating agent is selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), ethylenediamine tetracetic acid tetra sodium salt (EDTA Na4), EDTA salts, acrylic polymers, ascorbic acid, tetrasodium iminodisuccinate, citric acid, dicarboxymethylglutamic acid, ethylenediaminedisuccinic acid (EDDS), maleic acid, nitrilotriacetic acid (NTA), nonpolar amino acids, methionine, oxalic acid, phosphoric acid, polar amino acids, arginine, asparagine, aspartic acid, glutamic acid, glutamine, lysine, ornithine, siderophores, desferrioxamine B, hydrolysed wool, succinic acid, sodium silicate, sodium orthosilicate, other polycarboxylates, and combinations thereof.
- (iii) an alkaline agent, wherein the alkaline agent comprises the chelating agent, a different alkaline agent, or a combination thereof,
- (iv) a non-ionic co-solvent, wherein the co-solvent is hydrophilic, and
- (v) a polymer, wherein the water, the agent, the co-solvent, the alkaline agent, and the polymer are mixed together in the surfactant-less alkaline-polymer composition;
- and
- wherein the surfactant-less alkaline-polymer composition does not include a surfactant other than the non-ionic co-solvent.
- (b) generating a surfactant in-situ in the hydrocarbon bearing formation, wherein
- (i) the alkaline agent forms a soap after injecting the surfactant-less alkaline-polymer composition into the hydrocarbon formation, and
- (ii) the co-solvent interacts with the in-situ generated soap and makes an optimum surfactant;
- and
- (c) recovering the oil from the hydrocarbon-bearing formation.
12 more elements
Dependencies are inferred from the claim text.