Cement compositions and methods
AssigneeSchlumberger Technology Corporation
InventorsAnatoly Vladimirovich Medvedev, Dominic Vincent Perroni, Laure Martin-Al-Khatib, Adam Ethan Keilers, Petr Kolchanov
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Abstract
Cement slurries are prepared that comprise water, a hydraulic cement and particles of an oil-absorbent material. The particles are present in an amount sufficient to alter a property of a non-aqueous drilling fluid. The cement slurry is placed in a subterranean well, whereupon the slurry contacts residual drilling fluid on casing and formation surfaces. The oil-absorbent material in the cement slurry may reduce the mobility of the drilling fluid, thereby improving zonal isolation.
Claims16
A method for cementing a subterranean well, comprising:
- preparing a cement slurry comprising water, a hydraulic cement and particles of an oil-absorbent material, wherein the particles absorb a non-aqueous component of a drilling fluid and alter rheological properties of the drilling fluid within the subterranean well, and wherein an amount of the oil-absorbent material particles varies, in portions of the cement slurry, between 0% by weight of the cement (BWOC) and 40% BWOC;
- placing the cement slurry in the subterranean well and thereby creating a cement sheath in the subterranean well with a variable oil-absorbent material amount;
- allowing the oil-absorbent material particles to contact the non-aqueous drilling fluid component, thereby altering the rheological properties of the drilling fluid and swelling the oil-absorbent material particles;
- wherein the oil-absorbent material particles are elongated, having an aspect ratio between 1.1 and 2000 before the swelling and between 2.2 and 3500 after the swelling.
A method for establishing zonal isolation in a subterranean well, comprising:
- preparing a cement slurry comprising water, a hydraulic cement, and particles of an oil-absorbent material, wherein the particles absorb a non-aqueous component of a residual drilling fluid present in the subterranean well along casing and formation surfaces thereof and alter rheological properties of the residual drilling fluid within the subterranean well, and wherein an amount of the oil-absorbent material particles varies, in portions of the cement slurry, between 0% by weight of the cement (BWOC) and 40% BWOC;
- placing the cement slurry in the subterranean well and thereby creating a cement sheath in the subterranean well with a variable oil-absorbent material amount;
- allowing the oil-absorbent material particles to contact the residual drilling fluid, thereby altering the rheological properties of the drilling fluid and swelling the oil-absorbent material particles, wherein the oil-absorbent material particles are elongated, having an aspect ratio between 1.1 and 2000 before the swelling and between 2.2 and 3500 after the swelling.
Dependencies are inferred from the claim text.