钻井液用耐低温乳化剂的研制与性能评价

Preparation and performance evaluation of low temperature emulsifier for oil-based drilling fluid

油基钻井液性能稳定,常应用于复杂地层开发,但在零下低温环境中存在黏度、切力上涨过快的问题。为解决这一问题,制备了一种耐低温高性能乳化剂ZF-SB,该乳化剂具有超低凝点(-33℃),解决了传统液体乳化剂零下低温无法流动的问题,可显著降低油水界面张力,由其配制的乳状液粒径在0.6~4.2μm之间,粒径分布窄,其破乳电压为1397V,有利于油基钻井液在低温条件下的稳定状态。另外,由耐低温乳化剂ZF-SB配制的油基钻井液在0℃以下仍具有良好的流变性,避免了油基钻井液由于低温增稠效应而造成井底当量循环密度(ECD值)高、井漏和压力控制难等问题。

Oil-based drilling fluid has stable properties,which is often used in complex formation development.However,the viscosity and shear force rise too fast in sub-zero low temperature environment.In order to solve this problem,a low-temperature and high-performance emulsifier ZF-SB was prepared.The emulsifier had an ultra-low freezing point(-33℃),which can solve the problem that traditional liquid emulsifiers cannot flow at zero temperature,and significantly reduce the interfacial tension of oil and water.The emulsion prepared by this emulsifier had a particle size of 0.6~4.2μm with narrow particle size distribution and a demulsification voltage of 1397V.It was conducive to the stable state of oil-based drilling fluid at low temperature.In addition,the oil-base drilling fluid prepared by low-temperature emulsifier ZF-SB had good fluidity at sub-zero temperature,which can avoid the problems of high ECD value,loss and pressure control caused by the thickening effect of low temperature.