Oil well spacer fluids
AssigneeHalliburton Company
InventorJimmie L. Watson
Life of this patent
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Abstract
A high stability, nondamaging spacer fluid is provided containing readily available weighting agents such as calcium carbonate and iron carbonate dispersed in water using a polymer viscosifier, a salt inhibitor, a primary sulfonated dispersant and a secondary fatty acid amide dispersion. Conventional high density weighting agents can also be used. The spacer fluid is stable over a temperature range of about 32.degree.-300.degree. F for extended periods with densities ranging from 11 to 17.6 pounds per gallon.
Claims11
A high stability nondamaging fluid for maintaining a hydrostatic pressure on a subterranean formation intersected by a well comprising water, a viscosifier which is present in an effective concentration to suspend weighting agent, said viscosifier being selected from a hydratable hydroxy alkyl substituted cellulose polymer wherein the hydroxy alkyl substituents have 2-3 carbon atoms;
- an inhibitor which is present in an effective concentration to inhibit clay swelling comprising at least one water soluble halide salt of alkali metal, alkaline earth metal or ammonium;
- a water insoluble, relatively inert finely divided particulate solid weighting agent having a mean particle size in the range of about 2-20 microns, said weighting agent being present in a concentration to give the desired fluid density;
- and a dispersant having a concentration of less than about 1.5% by weight of said fluid, said dispersant comprising at least one or a combination of a condensation product of naphthalene sulfonate and formaldehyde or a fatty acid amide-lignin liquor mixture, wherein the fatty acid precursor contains about 14-18 carbon atoms, the amine precursor is a low molecular weight amino sulfonic acid having 1-6 carbon atoms and the lignin is sulfonated.
A high stability nondamaging fluid for maintaining a hydrostatic pressure on a subterranean formation intersected by a well comprising water;
- a viscosifier which is present in an effective concentration to suspend weighting agent up to about 0.1% by weight of said fluid, said viscosifier being selected from a hydratable hydroxy alkyl cellulose polymer wherein the the hydroxy alkyl group has 2-3 carbon atoms;
- an inhibitor which is present in an effective concentration to inhibit clay swelling up to about 15% by weight of said fluid comprising at least one water soluble halide salt of alkali metal, alkaline earth metal or ammonium in which the halide is bromide or chloride;
- a water insoluble, acid soluble finely divided particulate solid weighting agent having a specific gravity of at least 2.0 and a mean particle size in the range of about 2-20 microns, said weighting agent comprising at least one or a combination of calcium carbonate or iron carbonate and being present in a concentration to give the desired fluid density;
- and a dispersant having a concentration of less than about 1.5% by weight of said fluid, said dispersant comprising at least one or a combination of condensation product of naphthalene sulfonate and formaldehyde or a fatty acid amide-lignin liquor mixture, wherein the fatty acid precursor contains about 14-18 carbon atoms, the amine precursor is a low molecular weight amino sulfonic acid having 1-6 carbon atoms and the lignin is sulfonated.
A method of controlling the hydrostatic pressure in a well adjacent a subterranean formation without damaging said formation comprising placing in said well a fluid having a density sufficient to maintain a hydrostatic pressure on said formation which is higher than the pressure exerted by the fluid in said formation, said fluid comprising water;
- a viscosifier which is present in an effective concentration to suspend weighting agent, said viscosifier being selected from a hydratable hydroxy alkyl cellulose polymer wherein the hydroxy alkyl substituents have 2-3 carbon atoms;
- an inhibitor which is present in an effective concentration to inhibit clay swelling comprising at least one water soluble halide salt of alkali metal, alkaline earth metal or ammonium;
- a relatively inert water insoluble finely divided particulate weighting agent having a mean particle size in the range of about 2-20 microns, said weighting agent being present in a concentration to give the desired fluid density;
- and a dispersant comprising at least one or a combination of a condensation product of naphthalene sulfonate and formaldehyde or a fatty acid amide-lignin liquor mixture, wherein the fatty acid precursor contains about 14-18 carbon atoms, the amine precursor is a low molecular weight amino sulfonic acid having 1-6 carbon atoms and the lignin is sulfonated.
Dependencies are inferred from the claim text.