Abstract: A cement system for use in treating lost circulation includes a slurry of cement, water and a super-absorbent polymer which absorbs free water in the slurry to form a gel—ore preferably a solid-like structure—when placed in the well, and which releases the absorbed water to the cement hydration reaction as the cement sets. The absorption of water causes the slurry to develop a solid-like structure. In one embodiment, the superabsorbent is polyacrylamide or modified crosslinked poly(meth)acrylate. Also presented is a method of treating lost circulation by pumping the above-mentioned cement system.

Abstract: A cement system for use in treating lost circulation includes a slurry of cement, water and a super-absorbent polymer which absorbs free water in the slurry to form a gel—ore preferably a solid-like structure—when placed in the well, and which releases the absorbed water to the cement hydration reaction as the cement sets. The absorption of water causes the slurry to develop a solid-like structure. In one embodiment, the superabsorbent is polyacrylamide or modified crosslinked poly(meth)acrylate. Also presented is a method of treating lost circulation by pumping the above-mentioned cement system.

Abstract: A surfactant composition for use in well treatment, particularly for removing oil-based mud deposits from a well prior to cementing, comprises an alkylpolyglucoside in a solution of a mutual solvent for water and hydrocarbon. The composition can be used to formulate a chemical wash by dissolving the composition at a concentration of about 1%-10% (e.g. 5%) by weight in water or brine.

Abstract: Systems for retarding setting in an oilfield well cement slurry comprise a solution of a phosphonate selected from methylene phosphonic acid derivatives and a phosphate, in particular selected from the following salts or the corresponding acids: mono-phosphates (ortho-phosphates PO42; meta-phosphates PO3), acyclic poly-phosphates (pyrophosphates P2O74, tripolyphosphates P3O105) or cyclic poly-phosphates. The system preferably may also comprise a retarder booster and is more particularly applicable to cementing at low or medium temperatures.

Abstract: A surfactant composition for use in well treatment, particularly for removing oil-based mud deposits from a well prior to cementing, comprises an alkylpolyglucoside in a solution of a mutual solvent for water and hydrocarbon. The composition can be used to formulate a chemical wash by dissolving the composition at a concentration of about 1%-10% (e.g. 5%) by weight in water or brine.