钻井液用纳米复合封堵剂的研制

Development of nano-composite plugging agent for drilling fluid

中国石油海洋工程公司承钻的深井逐年增多,面临超长作业段封堵、高井下温度等复杂工况,对钻井液封堵技术提出了更高要求。为有效提升渤海等区块现用钻井液体系的封堵防塌性能,通过聚合物分子结构设计、构效关系研究、聚合工艺优化,成功研制了聚合物纳米封堵剂,有效加强微孔隙、微裂缝的封堵,同时提高内部抑制性,减少钻井液滤液由于压差作用侵入地层引起微裂缝、微裂隙的延伸,减少井壁失稳、起下钻遇阻等复杂事故发生率。室内评价结果表明,该产品是一种性能优良的抗高温封堵材料,单剂抗温能力达到200℃,抗盐能力达到20%质量浓度的NaCl,性能优于现有产品LPF,并且与有机盐钻井液配伍性良好,具有很好的应用前景。

The number of deep wells drilled by PetroChina Offshore Engineering Company is increasing year by year.Faced with complex drilling conditions such as ultra-long drilling section plugging and high downhole temperature,higher requirements are put forward for drilling fluid technology.To effectively improve the plugging and anti-sloughing characteristics of the drilling fluid system currently used in Bohai and other blocks,a polymer nano plugging agent is developed through polymer molecule structure design,structural-activity relationship study,and polymerization process optimization.The plugging agent developed can effectively strengthen the plugging of micro-pores and micro-fractures,improve internal inhibition,and reduce the extension of micro-fractures and micro-fissures caused by the formation intrusion of drilling fluid due to pressure difference to reduce the incidence of complex accidents such as wellbore instability and tripping resistance.The indoor evaluation results of this plugging agent show that it is a kind of high-temperature resistant plugging material with a single dose temperature resistance of 200℃and salt resistance at the density of 20%NaCl.The agent′s performance is better than the existing product LPF.Besides,the agent is compatible with organic salt drilling fluid and its application potential is ideal.