定向井阶梯式钻井液密度调整法及其在井壁稳定中的应用  

Directional well stepped drilling fluid density adjustment method andits application in wellbore stability

作　　者：翟晓鹏 柯澳香[1,2] 许雪梅 马龙 郑强 楼一珊 ZHAI Xiaopeng;KE Aoxiang;XU Xuemei;MA Long;ZHANGH Qiang;LOU Yishan(Key Laboratory of Drilling and Production Engineering for Oil and Gas(Yangtze University),Wuhan 430100,Hubei;College of Petroleum Engineering,Yangtze University,Wuhan 430100,Hubei;Eastern Well Control Emergency Rescue Response Center,CNPC,Tianjin 300280)

机构地区：[1]油气钻采工程湖北省重点实验室(长江大学),湖北武汉430100 [2]长江大学石油工程学院,湖北武汉430100 [3]中国石油东部井控应急救援响应中心,天津300280

出　　处：《长江大学学报(自然科学版)》2025年第1期74-80,共7页Journal of Yangtze University(Natural Science Edition)

基　　金：中国石油科技创新基金项目“排量作用下裂缝转向扩展力学机理研究”(2019D-5007-0206);中国石油(中国)有限公司深圳分公司项目“水平段钻遇泥岩对完井及产能的影响规律研究”(CCL2020SZPS0421)。

摘　　要：目前临界坍塌压力确定的钻井液密度只能维持初始阶段井眼平衡,难以保持整个钻进阶段定向井井壁稳定,并且存在宽密度窗口时钻井液密度选取困难的问题。为了分析坍塌量与钻井液密度之间的动态关系,在线弹性岩石力学理论与Mogi-Coulomb破坏准则的基础上,引入蒙特卡洛统计模拟方法,建立了任意井筒的坍塌量计算模型,通过该模型分析不同井斜角以及不同钻井液密度条件下的井眼破坏情况,以此作为依据来实现对钻井液密度的阶梯式调整。结果表明:定向井井斜角在75°左右时坍塌风险最大,井壁坍塌量要高出直井段的50%,此时在密度窗口内阶梯式增大钻井液密度后,可使整体的坍塌量均控制在稳定井眼要求的范围内。南海某区块的实例表明,根据工程需求利用该模型的计算结果动态调整钻井液密度至1.46 g/cm^(3)时,能够使高风险井段的扩径率控制在10%以下,满足该地区钻井作业中对稳定井眼的要求。Currently,the drilling fluid density determined for the critical collapse pressure can only maintain the initial wellbore balance in the drilling process.It is challenging to sustain the stability of the wellbore throughout the entire drilling phase,especially when there is a wide density window,posing difficulties in selecting the drilling fluid density.In order to analyze the dynamic relationship between the amount of collapse and the density of drilling fluid,based on the linear elastic rock mechanics theory and the Mogi-Coulomb failure criterion,the Monte Carlo statistical simulation method is introduced to establish a calculation model for the amount of collapse of any wellbore.The model analyzes the wellbore damage under different inclination angles and different drilling fluid densities,and uses this as a basis to achieve a stepwise adjustment of drilling fluid density.The results show that the risk of collapse is the highest when the deviation angle of the directional well is about 75°,and the collapse amount of the wellbore is 50%higher than that of the vertical well section.At this time,the overall collapse amount can be controlled within the range of stable wellbore requirements after increasing the drilling fluid density step by step in the density window.An example of a block in the South China Sea shows that when the drilling fluid density is dynamically adjusted to 1.46 g/cm^(3)according to the calculation results of the model according to the engineering requirements,the expansion rate of high-risk well sections can be controlled below 10%,which meets the requirements of stable wellbore in drilling operations in this area.

关 键 词：井壁稳定 定向井筒 钻井液密度 坍塌体积 阶梯式 

分 类 号：TE254[石油与天然气工程—油气井工程]