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US 12,571,110 B2Granted
Metal sulfide scale dissolver for oilfield application
AssigneeHalliburton Energy Services, Inc.
InventorsAlex Yi-Tsung Lu, Zhiwei Yue
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Abstract
A method may include providing a treatment fluid comprising a metal sulfide dissolver and a base fluid. The metal sulfide dissolver includes a chelating agent, a boosting agent, and a dispersing agent. The treatment fluid is then injected to contact a metal sulfide scale, which dissolves at least partially. The treatment fluid may be injected into a wellbore as a standalone treatment or as an additive.
Claims20
A method comprising:
- providing a treatment fluid comprising:
- a metal sulfide dissolver comprising a chelating agent, a boosting agent, and a dispersing agent,
- wherein the chelating agent comprises tetrakis (hydroxymethyl) phosphonium sulfate (THPS), salts thereof, or combinations thereof in an amount of about 0.025 wt % to about 0.1 wt % by weight of the treatment fluid,
- wherein the boosting agent comprises citric acid in an amount of about 0.02 wt % to about 0.07 wt % by weight of the treatment fluid,
- wherein the dispersing agent comprises polydiallyldimethylammonium chloride (polyDADMAC) in an amount of about 20 ppm to about 200 ppm by weight of the treatment fluid;
- and
- a base fluid;
- contacting a metal sulfide scale with the treatment fluid;
- and
- dissolving from 55% to 95% of the metal sulfide scale with the treatment fluid.
7 more elements
A method comprising:
- preparing a treatment fluid comprising:
- a metal sulfide dissolver comprising a chelating agent, a boosting agent, and polydiallyldimethylammonium chloride (polyDADMAC),
- wherein the chelating agent comprises tetrakis (hydroxymethyl) phosphonium sulfate (THPS), salts thereof, or combinations thereof in an amount of about 0.025 wt % to about 0.1 wt % by weight of the treatment fluid,
- wherein the boosting agent comprises citric acid in an amount of about 0.02 wt % to about 0.07 wt % by weight of the treatment fluid,
- wherein the polydiallyldimethylammonium chloride (polyDADMAC) is present in an amount of about 20 ppm to about 200 ppm by weight of the treatment fluid;
- and
- a base fluid;
- introducing the treatment fluid into a wellbore;
- and
- contacting scale with the treatment fluid to dissolve from 55% to 95% of the scale.
7 more elements
A treatment fluid comprising:
- an iron sulfide dissolver comprising from about 0.025 wt % to about 0.1 wt % tetrakis (hydroxymethyl) phosphonium sulfate (THPS), from about 0.02 wt % to about 0.07 wt % by weight of citric acid, and from about 20 ppm to about 200 ppm by weight of polydiallyldimethylammonium chloride (polyDADMAC);
- and
- a base fluid comprising an aqueous fluid with a pH of about 6 to about 7, wherein the treatment fluid dissolves from 55% to 95% of a scale in a subterranean operation.
Dependencies are inferred from the claim text.