泥质粉砂储层欠平衡水平井井壁稳定性演化规律  

Wellbore stability evolution law of underbalanced horizontal well in argillaceous siltstone reservoirs

作　　者：邱艺 马天寿[1] 陈颖杰 杨赟 邓昌松[4] QIU Yi;MA Tianshou;CHEN Yingjie;YANG Yun;DENG Changsong(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu 610500,China;Tight Oil and Gas Project Division,PetroChina Southwest Oil&Gas Field Company,Chengdu 610056,China;Drilling and Production Engineering Technology Research Institute,Chuanqing Drilling Engineering Co.Ltd.,CNPC,Xi'an 710021,China;PetroChina Tarim Oilfield Company,Korla 841000,China)

机构地区：[1]西南石油大学油气藏地质及开发工程国家重点实验室,四川成都610500 [2]中国石油西南油气田分公司致密油气勘探开发项目部,四川成都610056 [3]中国石油川庆钻探工程有限公司钻采工程技术研究院,陕西西安710021 [4]中国石油塔里木油田分公司,新疆库尔勒841000

出　　处：《中南大学学报（自然科学版）》2023年第3期967-983,共17页Journal of Central South University:Science and Technology

基　　金：四川省杰出青年科技人才项目(2020JDJQ0055),国家自然科学基金资助项目(41874216)。

摘　　要：以苏里格气田长7组泥质粉砂储层为对象,研究泥质粉砂储层欠平衡水平井井壁稳定演化规律。首先,开展泥质粉砂岩矿物组成、微观结构和力学性能实验,分析井壁失稳微观机理;其次,基于流固化多场耦合理论,考虑岩石吸水扩散引起的强度劣化特征,建立欠平衡水平井井壁稳定多场耦合有限元模型,并验证模型的正确性;最后,对比有限元模拟和电测井径,分析泥质粉砂储层欠平衡水平井井壁稳定演化规律。研究结果表明:考虑泥质水化模拟的井径与完井电测实际井径吻合程度高,证实了有限元模型的准确性;考虑泥质水化作用情况下,钻开地层50 h内,归一化屈服面积(AN)迅速增大,随后增速逐渐变缓,钻开地层240 h后归一化屈服面积增幅达98.72%,主要是泥质水化后岩石强度劣化所致,但AN<0.20能够满足欠平衡钻井井壁稳定的要求;随着时间推移,欠平衡与过平衡工况下的AN之比由2.73降至2.20,近平衡与过平衡工况下的AN之比由1.90降至1.50,说明井筒压力是影响井壁失稳的主导因素,但泥质水化作用的影响随着时间增加而增强;当钻井液溶质质量分数高于地层流体时,反射系数、化学膨胀系数、溶质传递系数和溶质质量分数越大,则AN越低、井壁越稳定;而岩石吸水扩散系数和渗透率越大,则AN越大、井壁越不稳定。Taking the argillaceous siltstone reservoir of Chang 7 group in Sulige gas field as the object,the wellbore stability evolution law of underbalanced horizontal well in argillaceous siltstone reservoirs was investigated.Firstly,the mineral composition,microstructure and mechanical property tests of argillaceous siltstone rocks were conducted to analyze the microscopic mechanisms of wellbore instability.Secondly,based on the multi-field coupling theory,the rock strength weaking characteristics caused by water absorption and diffusion was considered,the multi-field coupled finite element model(FEM)of wellbore stability was established for the underbalanced horizontal well,and the correctness of the model was verified.Finally,the hole diameter obtained by FEM simulation and wireline logging was compared,and the wellbore stability evolution law of underbalanced horizontal well in argillaceous siltstone reservoirs was analyzed.The results show that the simulated hole diameter with considering argillaceous hydration is in good agreement with the actual hole diameter measured by wireline logging,which confirms the accuracy of the FEM.When the effect of argillaceous hydration is considered,the normalized yield zone area(AN)increases rapidly within 50 h after drilling into the formation,the increasing rate then gradually decreases,and the increasing amplitude reaches 98.72%after 240 h.It is mainly caused by rock strength weaking after argillaceous hydration,but AN<0.20 can meet the requirements of wellbore stability of underbalanced drilling.As time goes on,the AN ratio of underbalanced to overbalanced conditions decreases from 2.73 to 2.20,and the AN ratio of near-balanced to overbalanced conditions decreases from 1.90 to 1.50.It indicates that the wellbore pressure is the dominant factor affecting wellbore instability,but the influence of argillaceous hydration increases with time.When the solute concentration of drilling fluid is higher than that of formation fluid,the larger the reflection coefficient,chemical expansio

关 键 词：致密气 泥质粉砂岩 水平井 欠平衡钻井 井壁稳定 演化规律 

分 类 号：TE21[石油与天然气工程—油气井工程]