强抑制封堵钻井液体系研究及应用

Research and application of drilling fluid with strong inhibition and sealing capacity

张坤 刘南清 王强 王磊磊 龚纯武 郭剑梅

ZHANG Kun LIU Nanqing WANG Qiang WANG Leilei GONG Chunwu GUO Jianmei

中国石油集团渤海钻探工程有限公司泥浆技术服务分公司

Mud Service Company, CNPC Bohai Drilling Engineering Company Limited, Tianjin 300280, China

针对伊拉克米桑油田Fauqi区块钻井过程中易发生井壁坍塌、漏失难题，设计开发了新型强抑制封堵钻井液体系。该体系通过KCl、硅酸钠和聚胺抑制剂的多元复合作用，实现对页岩水化分散的有效抑制，页岩膨胀率较清水降低67.6%，毛细管吸入时间较清水降低64.4%。该体系在物理封堵基础上配合硅酸盐的化学固壁作用，低渗沙盘封堵试验滤失量仅为9.6 mL，能有效封堵地层孔隙、微裂缝，减少滤液对地层侵入，提高井壁稳定性，避免井下漏失发生。该体系在伊拉克米桑油田FQCS-41井的五开井段进行了现场应用，结果表明该体系在钻进过程中性能稳定，流变状态良好，井径规则，五开井段平均井径扩大率仅为1.2%。

Wellbore collapse and lost circulation tend to happen during the drilling in Fauqi Block of Missan Oil field, Iraq. To deal with these difficulties, a new type of drilling fluid system with strong inhibition and sealing capacity was designed and developed in this paper. Based on the multi-component combination of KCl, sodium silicate and polyamine inhibitor, this system could inhibit shale hydration and dispersion effectively, and its shale swelling rate and capillary suction time are 67.6% and 64.4% lower than those in fresh water. Based on the combination of the physical sealing with chemical wall stabilization effect of silicate, the filtration loss of this system in low-permeability sand plugging test is only 9.6 mL. It is demonstrated that this system can seal the formation fractures and micro fractures effectively, reduce the intrusion of fi ltrate into the formation, enhance wellbore stability and avoid downhole leakage.This system was applied on site in the fi fth section of Well FQCS-41 in Missan Oil field, Iraq. It is indicated that its performance is stable with good rheological property in the process of drilling, and the borehole diameter is regular with average diameter enlargement rate of 1.2% in the fi fth section.

10.13639/j.odpt.2017.05.009