北极永久冻土层固井水泥浆

A Well Cementing Slurry Used in Arctic Permafrost

近年来,北极地区石油勘探开发进度明显加快,市场前景良好。针对北极永久冻土层最低温度达-9℃的超低温以及该地区作业时间宝贵的问题,要求水泥浆体系在负温环境下候凝时间短且24 h有强度发展。通过研发低温胶凝材料C-SE8和缓凝剂H10S,并复配G级油井水泥和其他添加剂,分别用淡水、海水和14%NaCl溶液配制超低温水泥浆体系。评价结果表明,密度为1.50 g/cm3的水泥浆在-10℃下的24 h抗压强度可达3.6 MPa以上,密度为1.90 g/cm3的水泥浆在-10℃下的24 h抗压强度可达6.8 MPa以上;该体系适用温度为-10℃~30℃,浆体具有良好的流变性能,且稠化时间易调整,满足北极永久冻土层固井施工要求。

Petroleum exploration and development in the Arctic area in recent years has been accelerating.Well cementing operation in this area has long been facing with ultra-low temperature(-9℃)and the precious time available for operation;the cement slurry is required to have strength development in 24 hours at temperatures below zero.Using a self-developed low temperature gelling agent C-SE8 and a self-developed retarder H10S,several ultra-low temperature cement slurries were formulated with class G cement and other additives in fresh water,sea water and 14%NaCl solution.Evaluation of the cement slurries showed that a cement slurry of 1.50 g/cm3 had 24 h compressive strength of at least 3.6 MPa at-10℃;another cement slurry of 1.90 g/cm3 had 24 h compressive strength of at least 6.8 MPa at-10℃.The working temperatures of the cement slurries were between-10℃and 30℃.The cement slurries had good rheology,and the thickening time can be easily adjusted,making them suitable for well cementing in arctic permafrost.