含碳酸钙的海泡石钻井液的封堵性能

摘要

通过室内实验和理论分析,研究了不同温度、压力条件下添加碳酸钙前后海泡石水基钻井液对不同渗透性地层的封堵性能,论证将碳酸钙作为堵漏剂添加到海泡石钻井液中的可行性.在实验温度为27～204℃、实验压力为2 070 kPa和6 895 kPa条件下进行流变性和滤失性测试,结果表明,除了在149℃时,其他各温度下海泡石钻井液流变性质较好、悬固能力较强,高温高压滤失量较低.孔隙堵塞器(PPA)实验中用孔径10～90 μm的渗透性陶瓷盘模拟地层,实验结果表明,不含碳酸钙的海泡石钻井液不能封堵孔隙,而含碳酸钙的海泡石钻井液可在较短时间内封堵孔隙,且在高温下也能保持碳酸钙颗粒悬浮,使用温度可高达193℃.扫描电镜分析及理想充填理论分析结果验证了PPA实验结果.%The aim is to investigate the plugging ability of sepiolite clay water base drilling fluids before and after CaCO3 added over a wide range of high permeable zones at high temperature and high pressure conditions,to verify the feasibility of CaCO3 as loss preventer material (LPM) into the sepiolite drilling mud.The rheology and loss tests at 27-204 ℃ and 2 070 or 6 895 kPa reveal that the sepiolite drilling mud shows good rheology and high solid suspension capability at all temperatures except 149 ℃,and low loss circulation at high temperature and high pressure.The Permeability Plugging Apparatus (PPA) experiment,in which the 10-90 μm permeable ceramic plate was simulated as formation,shows that the sepiolite drilling mud without CaCO3 can not plug the pores,while the sepiolite drilling mud with CaCO3 can plug the pores quickly and keep the CaCO3 particles suspended even at high temperature (up to 193 ℃).The PPA experiment results were proved by the analysis using SEM and ideal packing theory.