HEAT-RESISTANT, WATER-REDUCING ADDITIVE COMPONENT FOR CEMENT GROUTING IN OIL AND GAS WELLS

Abstract

The invention relates to a technical solution for reducing water discharge by simultaneously combining two heat-resistant materials with two different mechanisms of action on cement mortar water discharge (a mechanism of pore filling on the mud film and a mechanism of increasing the viscosity of the liquid phase of the mortar); and utilizing the synergistic effect between these materials.Specifically, the invention proposes a thermally stable water loss reduction additive for oil and gas well cement grout with the following composition and requirements: (a) ultrafine silica material for water loss reduction by filling the pores on the mud film, where the ultrafine silica material has d50 ≤0.04μm and d95 ≤ 3µm and is present in a quantity of 10 to 12% by weight of the additive; (b) liquid glass for water loss reduction by increasing the viscosity of the grout liquid phase with a density in the range of 1.14 to 1.16 g / cm³ and is present in a quantity of 85 to 87% by weight of the additive; and (c) lignosulfonate present in a quantity of 3 to 5% by weight of the additive.