Gel plugs and pigs for pipeline use
AssigneeClearwater International, LLC
InventorsKevin W. Smith, Kevin M. Schwartz
Life of this patent
Estimating the term…
Abstract
Coacervate gels having excellent shear viscosities and other properties are made with anionic or cationic polymers, a smaller amount of a surfactant having a charge opposite that of the polymer, and a hydrophobic alcohol. The Zeta Potential of the gel is maintained at an absolute value of at least 20. Optional gel promoting additives include betaines and amine oxides. A preferred gel comprises poly diallyl dimethyl ammonium chloride, a lesser amount of sodium lauryl sulfonate, and lauryl alcohol. The gels are particularly useful forming plugs and pigs for separating fluids in pipes.
Claims40
An aqueous gel comprising water and, by weight based on the water, (a) 0.1% to 5% of an anionic or cationic polymer, (b) a lesser amount but at least 0.01% of a surfactant having from 8 to 22 carbon atoms and a charge opposite that of said polymer, (c) from 0.001 to 5% of a hydrophobic alcohol, (d) up to 5% of an amphoteric surfactant, and (e) up to 5% of an amine oxide, said gel having a Zeta Potential of an absolute value of at least 20 millivolts.
Method of making an aqueous gel comprising adding to water 0.1% to 5%, by weight based on the water, cationic polymer and a lesser amount but at least 0.01% by weight of an anionic surfactant having from 8 to 22 carbon atoms, in the presence of 0.001% to 5% linear or branched alkyl alcohol of the general formula CMH2M+2−N(OH)N, where M is a number from 6-23, and N is 1 when M is 6-12, but where M is 13-23, N may be a number from 1 to 3, and optionally in the presence of at least one of (a) up to 5% by weight amphoteric surfactant and (b) up to 5% by weight amine oxide, the ratio of said cationic polymer to said anionic surfactant being effective to provide a Zeta Potential having an absolute value of at least 20 millivolts.
17 An aqueous gel comprising a water-soluble polymer in an amount no greater than 1% by weight, having at least one of (a) a zero shear viscosity of at least 45,000 following the zero shear viscosity extrapolation procedure of Asadi, Conway and Barree in SPE 73755 or (b) a “{fraction (10/100)} {fraction (20/40)}” settling rate result at 60 minutes of no more than 8 millimeters.
18 An aqueous gel of claim 17 wherein said water-soluble polymer is cationic and is present in said gel in an amount no greater than 0.7%.
19 A well treatment fluid comprising a proppant and a gel of claim 18.
20 An aqueous gel of claim 18 including an anionic surfactant in an amount less than that of said polymer, and a small amount of a hydrophobic alcohol.
21 Method of separating two portions of fluid for movement in a pipe comprising placing between said portions of fluid in said pipe an aqueous gel separating pig comprising a water-soluble polymer in an amount no greater than 1% by weight, having at least one of (a) a zero shear viscosity of at least 45,000 following the zero shear viscosity extrapolation procedure of Asadi, Conway and Barree in SPE 73755 or (b) a “{fraction (10/100)} {fraction (20/40)}” settling rate result at 60 minutes of no more than 8 millimeters.
22 Method of claim 21 including forming an isolated segment of at least one of said portions of fluid by placing an additional aqueous gel pig in said pipe a desired distance from said separating pig, said additional aqueous gel pig comprising a water-soluble polymer in an amount no greater than 1% by weight, having at least one of (a) a zero shear viscosity of at least 45,000 following the zero shear viscosity extrapolation procedure of Asadi, Conway and Barree in SPE 73755 or (b) a “{fraction (10/100)} {fraction (20/40)}” settling rate result at 60 minutes of no more than 8 millimeters.
23 Method of claim 21 wherein at least one of said portions of fluid is a cleaning fluid.
24 Method of claim 21 wherein at least one of said portions of fluid is a drying fluid.
25 Method of claim 21 wherein at least one of said portions of fluid is a well cementing fluid.
26 Method of claim 21 wherein at least one of said portions of fluid is a hydrocarbon fluid.
27 Method of claim 21 wherein one of said portions of fluid is a gas and the other of said portions of fluid is a liquid.
28 Method of claim 21 further including moving said portions of fluid through said pipe.
29 Method of claim 22 further including moving said isolated segment of fluid through said pipe.
30 Method of separating two portions of fluid for movement in a pipe comprising placing between said portions of fluid in said pipe an aqueous gel separating pig comprising water and, by weight based on the water, (a) 0.1% to 5% of an anionic or cationic polymer, (b) a lesser amount but at least 0.01% of a surfactant having from 8 to 22 carbon atoms and a charge opposite that of said polymer, (c) from 0.001 to 5% of a hydrophobic alcohol, (d) up to 5% of an amphoteric surfactant, and (e) up to 5% of an amine oxide, said gel having a Zeta Potential of an absolute value of at least 20 millivolts.
31 Method of claim 30 including forming an isolated segment of at least one of said portions of fluid by placing an additional aqueous gel pig in said pipe a desired distance from said separating pig, said additional aqueous gel pig comprising water and, by weight based on the water, (a) 0.1% to 5% of an anionic or cationic polymer, (b) a lesser amount but at least 0.01% of a surfactant having from 8 to 22 carbon atoms and a charge opposite that of said polymer, (c) from 0.001 to 5% of a hydrophobic alcohol, (d) up to 5% of an amphoteric surfactant, and (e) up to 5% of an amine oxide, said gel having a Zeta Potential of an absolute value of at least 20 millivolts.
32 Method of claim 30 wherein at least one of said portions of fluid is a cleaning fluid.
33 Method of claim 30 wherein at least one of said portions of fluid is a drying fluid.
34 Method of claim 30 wherein at least one of said portions of fluid is a well cementing fluid.
35 Method of claim 30 wherein at least one of said portions of fluid is a hydrocarbon fluid.
36 Method of claim 30 wherein one of said portions of fluid is a gas and the other of said portions of fluid is a liquid.
37 Method of claim 30 further including moving said portions of fluid through said pipe.
38 Method of claim 30 wherein said polymer is a cationic polymer and said hydrophobic alcohol is a linear or branched alkyl alcohol of the general formula CMH2M+2−N(OH)N, where M is a number from 6-23, and N is 1 when M is 6-12, but where M is 13-23, N may be a number from 1 to 3, said gel including at least one of (a) 0.001% to 5% amine oxide and (b) 0.001% amphoteric surfactant.
39 Method of claim 30 wherein said amine oxide comprises lauryl amine oxide and is present in an amount from 0.001% to 2%.
40 Method of claim 31 further including moving said isolated segment of fluid through said pipe.
Dependencies are inferred from the claim text.