北极永久冻土层固井水泥浆

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。 

A Well Cementing Slurry Used in Arctic Permafrost

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.