摘要
川渝地区龙马溪组页岩微裂缝、层理发育,致使钻井过程中极易发生坍塌失稳,造成阻卡等复杂情况的频繁发生。通过多种方法评价了龙马溪组页岩在4种不同流体中的井壁稳定性能。膨胀分散试验表明龙马溪组页岩水化膨胀性能较弱,在不同流体介质中的分散性能均较弱;CT层析成像技术和压力穿透试验发现,在与流体接触的极短时间内,页岩内裂缝便可萌生并扩展;随着流体抑制和封堵能力的增强,龙马溪组页岩裂缝的形成可得到明显的推迟或阻止,并显著地降低压力在页岩中的传递效应,起到稳定井壁的作用;不同流体浸泡后页岩抗压强度和内聚力具有明显的差异,其中蒸馏水浸泡后降低程度最大,油基钻井液中降低最小。该研究可为井壁失稳机理分析提供理论参考。
The micro-crack and stratification of the Longmaxi formation shale in Sichuan and Chongqing area makes it easy for the shale to collapse in the drilling process,resulting in frequent occurrence of complicated situations such as struck pipe.The wellbore stability of Longmaxi shale in four different fluids was evaluated by various methods.The expansion and dispersion experiments show that the hydration swelling property of Longmaxi shale is weak and its dispersibility in different fluid media is also relatively weak.The CT tomography and pressure penetration experiments show that the cracks in the shale can form and expand within a very short time after contact with the fluid.With the enhancement of the ability of fluid inhibition and plugging,the formation of cracks in Longmaxi shale can be obviously delayed or prevented,and the transmission effect of pressure in shale can be significantly reduced,which thus play a role of wellbore stability.The compressive strength and cohesion of shale are significantly different after soaking in different fluids,among which the decrease is the greatest after soaking in distilled water and the reduction is the smallest after soaking in oil-based drilling fluid.This study can provide theoretical reference for the mechanism analysis of borehole instability.
作者
王显光
高书阳
褚奇
张亚云
王松
甄剑武
Wang Xianguang;Gao Shuyang;Chu Qi;Zhang Yayun;Wang Song;Zhen Jianwu(The State Key Laboratory of Shale Hydrocarbon Enrichment Mechanism and Effective Development,Beijing 100101;Sinopec Research Institute of Petroleum Engineering,Beijing,100101;College of Chemistry&Environmental Engineering,Yangtze University,Jingzhou,434023,Hubei)
出处
《长江大学学报（自然科学版）》
CAS
2020年第2期45-52,I0004,I0005,共10页
Journal of Yangtze University(Natural Science Edition)
基金
国家自然科学基金项目“页岩油气高效开发基础理论研究”(51490650)
国家科技重大专项“彭水地区常压页岩气勘探开发示范工程”(2016ZX05061)。
关键词
龙马溪组
页岩
井壁稳定性能
膨胀分散性能
微观结构
微裂缝封堵
抗压强度
Longmaxi formation
shale
borehole stability
expansion dispersion property
microstructure
micro-crack plugging
compressive strength
作者简介
第一作者:王显光(1979-),男,博士,高级工程师,现主要从事非常规资源开发用钻井液技术方面的研究工作,Email:wangxg.sripe@sinopec.com。
