摘要
针对川西中江区块沙溪庙组井壁失稳技术难题,分析了沙溪庙组泥岩的矿物组成、微观结构及理化性能,揭示了沙溪庙组井壁失稳机理。沙溪庙组属于典型的硬脆性泥岩,黏土矿物含量高,水化作用强,其中伊利石含量最高,微纳米尺度裂隙发育,钻井液滤液侵入后,伊利石、伊蒙混层等分布不均匀,比亲水量大,水化膜斥力大,裂缝不断扩展,易发生井壁坍塌。结合“多元协同”井壁稳定理论,优选了烷基糖苷类抑制剂、微纳米封堵剂等,构建了适用于沙溪庙组的烷基糖苷高性能防塌钻井液体系。通过室内实验可知,该体系流变性良好,API滤失量小于3 mL,高温高压滤失量不大于8 mL,岩样滚动回收率为98.87%,膨胀率小于3%,抑制性优良,对微裂缝和孔隙封堵能力强。现场应用表明,烷基糖苷高性能防塌钻井液能有效抑制沙溪庙组地层坍塌,机械钻速高,无井下复杂事故发生,为保证中江区块沙溪庙组“安全、高效、经济”钻井施工提供了技术支撑。
Borehole wall instability has long been a problem encountered in drilling the Shaximiao formation in the block Zhongjiang,western Sichuan.To solve this problem,the claystones from the Shaximiao formation was studied for their mineral composition,microstructure and physical-chemical properties.The study results have revealed the mechanisms of borehole wall instability of the Shaximiao formation.The Shaximiao formation is a typical hard and brittle rock with high content of clay minerals(mostly illite)which are strongly hydratable.The formation is developed with plenty of micrometer-and nanometer-sized fractures,which will expand continually when mud filtrate invasion take place and finally,collapse.The inhomogeneous distribution of illite and illite/montmorillonite mixed layer in the rocks,high specific water absorptivity and high repulsive force of the hydration films have made the expansion of the microfractures even worse.An alkyl glycoside inhibitive agent and a nanometer plugging agent were selected to formulate a high-performance anti-collapse drilling fluid based on the“Multivariate collaboration”borehole stabilization theory.Laboratory experiment on the performance of this drilling fluid has shown that this drilling fluid has good rheology,API filter loss of less than 3 mL,HTHP filter loss of 8 mL or less,percent cuttings recovery of 98.87%,swelling rate of less than 3%.These data indicate that the drilling fluid has good inhibitive capacity and good capacity of plugging the microfractures and micropores.Field application has shown that the alkyl glycoside drilling fluid can effectively inhibit the collapse of the Shaximiao formation.High ROP was obtained with this drilling fluid,and no downhole troubles have been encountered.The use of the alkyl glycoside drilling fluid has provided a technical support to safely,efficiently and economically drill the Shaximiao formation.
作者
陈文可
郑和
龚厚平
许春田
蔡巍
石水健
周成裕
暴丹
CHEN Wenke;ZHENG He;GONG Houping;XU Chuntian;CAI Wei;SHI Shuijian;ZHOU Chengyu;BAO Dan(Jiangsu Drilling Company of Huadong Petroleum Engineering Co.,Ltd.,Sinopec,Yangzhou,Jiangsu 225261;Chongqing University of Science and Technology,School of Chemistry and Chemical Engineering,Chongqing 401331;Chongqing Oil and Gas Field Chemical Engineering Technology Research Center,Chongqing 401331)
出处
《钻井液与完井液》
CAS
北大核心
2023年第4期438-445,共8页
Drilling Fluid & Completion Fluid
基金
重庆市自然科学基金面上项目“页岩地层基于热致液-固相变原理的堵漏颗粒原位自生成型及其自适应封堵调控机制”(CSTB2022NSCQ-MSX1554)
重庆市教委科学技术研究项目“页岩地层致密承压封堵机理与温敏智能型堵漏剂研发”(KJQN202101548)
重庆科技学院科研资助项目“热致形状记忆智能型堵漏剂的研制及自适应封堵作用机理”(ckrc2021030)资助。
关键词
防塌钻井液
井壁失稳
沙溪庙组
地层坍塌
微观结构
Anti-collapsing drilling fluid
Borehole instability
Shaximiao Formation
Formation collapse
Microstructure