Saudi Arabian Oil Company

Kenneth Dejuan Johnson

Peter James Boul

Fluid loss control additives for a cement slurry are provided. An exemplary fluid loss control additive includes a copolymer containing 2-acrylamido-2-methylpropane sulfonic acid monomer units and acryloylmorpholine monomer units, and a graft copolymer. The graft copolymer contains a humate and, grafted onto the humate, a side-chain polymer containing at least one of acrylamide monomer units, acryloylmorpholine monomer units, acrylic acid monomer units, and 2-acrylamido-2-methylpropane sulfonic acid monomer units.

Fluid loss control additive

A method of setting a wellbore fluid includes injecting a drilling fluid including water, cementitious material, a phosphonic acid derivative, a sulfonate acrylic acid copolymer, and zinc oxide into a wellbore; introducing sodium hexametaphosphate to the drilling fluid to form the wellbore fluid; allowing the sodium hexametaphosphate to dissolve phosphonate-calcium complexes between the phosphonic acid derivative and the cementitious material, thereby reducing the hydration time; and allowing the water and cementitious material to react, thereby curing the wellbore fluid and forming a cement.

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Houston, TX, United States of America

Kenneth Dejuan Johnson