Method for inhibiting the deposition of wax from a wax-containing oil

Claim 2

The method in accordance with claim 1 wherein said inhibitor is copolymer ethylene/vinyl acetate, copolymer ethylene/ethyl acrylate or copolymer ethylene/methyl methacrylate.

Claim 3

The method in accordance with claim 1 wherein said inhibitor is incorporated into said wax-containing oil as a solution of the copolymer dissolved in an organic solvent.

Claim 4

The method defined in claim 1 wherein the inhibitor is incorporated into said wax-containing oil at an oil temperature sufficiently high to maintain the wax dissolved in the oil, and wherein said oil is thereafter cooled to a temperature below the solidification temperature of the wax.

Claim 5

The method defined in claim 1 wherein said inhibitor is incorporated into said wax-containing oil in an amount to provide therein an effective concentration of said inhibitor between about 5 and 2,000 ppm.

Claim 7

The method defined in claim 7 wherein said inhibitor is added to said oil as a solution containing about 10 to 50 weight percent of said copolymer dissolved in an organic solvent.

Claim 8

The method defined in claim 7 wherein said inhibitor is a copolymer of ethylene and vinyl acetate containing from about 10 to 70 weight percent vinyl acetate and exhibiting a melt index between about 1 and 600 grams per 10 minutes.

Claim 9

The method defined in claim 7 wherein the inhibitor is incorporated into said wax-containing oil at an oil temperature sufficiently high to maintain the wax dissolved in the oil, and wherein said oil is thereafter cooled to a temperature below the solidification temperature of the wax.

Claim 11

The method defined in claim 11 wherein said wax deposition inhibitor is a copolymer of ethylene and vinyl acetate containing about 39 to 42 weight percent vinyl acetate and exhibiting a melt index between about 1 and 600 grams per 10 minutes.

Claim 12

In a method for operating a well for the produc-tion of wax-containing petroleum from a subterranean formation wherein the petroleum flows from the formation into the well and is accumulated therein at a temperature sufficiently high to maintain the wax dissolved in the petroleum and wherein said petroleum is transported to the surface through a production tubing, said petroleum being cooled to a temperature below the solidification temperature of the wax whereupon wax participates from the petroleum and tends to deposit on the interior surface of the production tubing and on the interior surfaces of surface equipment causing them to become plugged with wax, the imProvement which comprises adding to the wax-containing petroleum in the well a wax deposition inhibitor comprising a copolymer of ethylene and a monoethylenically unsaturated ester characterized by the following formula: wherein (1) R is hydrogen or an alkyl group containing from about one to 25 carbon atoms and R is a vinyl or allyl group, or (2) R is an Alpha , Beta -unsaturated alkylene and R1 is an alkyl group containing from about one to 25 carbon atoms.

Claim 13

The method defined in claim 13 wherein said inhibitor is incorporated into said petroleum in an amount to provide therein an effective concentration between about 5 and 2,000 ppm.

Claim 14

The method defined in claim 14 wherein said wax deposition inhibitor is added to said petroleum as a solution of the copolymer dissolved in an organic solvent.

Claim 15

The method defined in claim 15 wherein said monoethylenically unsaturated ester is vinyl acetate.

Claim 16

The method defined in claim 16 wherein said copolymer contains from about 10 to 70 weight percent vinyl acetate.