用于油基钻井液堵漏的氯氧镁水泥浆体系

氯氧镁水泥具有优良的机械和热性能，常作为工业地板、防火、砂轮和墙体保温材料。针对常规水泥浆存在的抗侵污能力和酸溶性差，无法处理油基钻井液恶性漏失问题。利用氯氧镁水泥硬化体系的多元结晶相，采用DISP-S作为分散剂，DOT和Atmp复配作为缓凝剂，对氯氧镁水泥体系进行了优化，设计了一种可应用于油基钻井液大型漏失的堵漏水泥浆体系。实验结果表明，该堵漏水泥浆的密度为1.76 g/cm3，沉降稳定性良好，自由水含量几乎为0，失水量小于40 mL，在60℃下的稠化时间可达230 min，在中低温范围内水泥石的抗压强度均在30 MPa以上，侵入油基钻井液的水泥石仍然具备一定的力学性能，并且能在浓盐酸中完全溶解。 

A Magnesium Oxychloride Cement Slurry for Controlling Loss of Oil Base Drilling Fluids

Magnesium oxychloride cement has excellent mechanical and thermal performance and is widely used in industrial flooring, fire control, grind wheel making and wall insulation. Conventional cement has some disadvantages as well cementing material such as poor contamination resistance, poor acid solubility and inability to deal with severe mud losses. To resolve these problems, a magnesium oxychloride cement slurry was developed using DISP-S as dispersant, and DOT and Atmp compound as retarder. The set magnesium oxychloride cement has polycrystalline phase in it and the slurry is able to deal with severe loss of oil base mud. Laboratory experimental results showed that a magnesium oxychloride cement slurry of 1.76 g/cm3 has very good settling stability, zero free water, filtration rate of less than 40 mL, thickening time of 230 min at 60℃, and set cement with compressive strength of greater than 30 MPa in intermediate and low temperatures. The set cement, even mixed with some invading oil base mud, still maintains certain level of mechanical properties, and is able to dissolve completely in concentrated hydrochloric acid.