超高密度有机盐钻井液流变性和滤失量控制技术

Rheology and filtration control of ultra-high density organic salts drilling fluids

匡韶华 蒲晓林 罗兴树 廖天兵 陈光兵 徐博滔

KUANG Shaohua PU Xiaolin LUO Xingshu LIAO Tianbing CHEN Guangbing XU Botao

西南石油大学，四川成都　610500 中海油服油田化学事业部，河北三河　065201

Southwest Petroleum University, Chengdu 610500, China Oilfield Chemistry Department of China Oilfield Service Limited, Sanhe 065201, China

针对中海油缅甸区块存在异常高压的特点，开展了超高密度钻井液技术研究。分析了超高密度水基钻井液技术难点以及超高密度水基钻井液流变性和滤失量的影响机理，提出超高密度水基钻井液性能调控思路，研究了有机盐weight3对高密度钻井液性能的影响，进行了无黏土有机盐体系中的降滤失剂和封堵剂的优选实验，室内优选出密度为2.80 g/cm3的有机盐水基钻井液体系并对其进行室内评价。该体系的表观黏度小于100 mPa·s，高温高压滤失量小于15 mL，评价表明：体系的热稳定性好，可抗160 ℃高温；具有良好动力稳定性，室温下放置24 h后，上下钻井液的密度差为0.03 g/cm3；抗污染能力强，能抗5% NaCl、1%石膏和5%劣质土，体系的综合性能可满足现场需要。

Considering the abnormal high pressure of CNOOC Myanmar blocks, technical research of ultra-high density water-base drilling fluids is conducted. The technical difficulties and the influence mechanisms of rheological properties and filtration of ultra-high density water-base drilling fluids are analyzed. The regulation ideas of the properties are proposed. The effect of the organic salt weight3 for high-density drilling fluid properties is studied. The fluid loss agents and blocking agents in the system of organic salts and free-clay are optimized. A kind of water-base drilling fluids system is developed and evaluated, with the density being 2.80 g/cm3, apparent viscosity less than 100 mPa?s, and filter loss less than 15mL in HTHP. Evaluation shows that the system has good thermal stability and it can be resistant to 160 ℃. Besides it has good dynamic stability. The density difference of the system between the upper and lower drilling fluid is 0.03 g/cm3, when it is kept at room temperature for 24 hours. It also has strong anti-pollution capability and can be resistant to 5% NaCl, 1% gypsum and 5% poor-quality soil. So the system could meet the requirement of field application for its comprehensive performance.