华北平原蓟县系雾迷山组碳酸盐岩热储岩体原位环境下力学特性研究  

Carbonates of the Wumishan Formation,Jixian System in the North China Plain:Mechanical properties under in-situ geothermal conditions

作　　者：周伟 马啸[3,4] 陈文毅 高锐 王雁 胡大伟 ZHOU Wei;MA Xiao;CHEN Wenyi;GAO Rui;WANG Yan;HU Dawei(School of Mechatronic Engineering,Southwest Petroleum University,Chengdu 610500,China;Geothermal Energy Research Center,Southwest Petroleum University,Chengdu 610500,China;State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;ENN Science and Technology Development Co.,Ltd.,Langfang 065001,China)

机构地区：[1]西南石油大学机电工程学院,四川成都610500 [2]西南石油大学地热能研究中心,四川成都610500 [3]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [4]中国科学院大学,北京100049 [5]新奥科技发展有限公司,河北廊坊065001

出　　处：《地学前缘》2024年第6期95-103,共9页Earth Science Frontiers

基　　金：国家自然科学基金项目(52179114);国家重点研发计划政府间国际科技创新合作项目(2023YFE0112900)。

摘　　要：碳酸盐岩在热储层高温高压原位环境下的物理力学特性不清楚,导致井壁稳定性评估缺乏准确数据与机理支撑。以蓟县系雾迷山组碳酸盐岩热储层岩石为研究对象,沿地层延展方向寻找合适的露头进行取样。在确保岩性、成分和地质年代与现场钻井岩心一致的基础上,研究了高温高压下碳酸盐岩力学特性演化规律与温度作用机理。得到以下结论:温度的升高使碳酸盐岩的强度阈值随围压的增长速度变缓。当围压由40 MPa增加至60 MPa时,在室温下峰值强度增加了15.9%,而在150℃下峰值强度仅增加了7.9%。在110℃后,摩擦角随温度的增加而减小,黏聚力随温度的增加而增加。碳酸盐岩力学特性随温度变化的机制是温度诱导的增强效应和损伤效应共同作用的结果。在本文研究的温度范围内,温度不会导致碳酸盐岩矿物成分发生化学变化,但会引起不同矿物颗粒间的不均匀热膨胀,导致晶间热应力增加,温度对碳酸盐岩力学特性的作用机理主要以热膨胀导致矿物颗粒间微裂缝压密为主。成果将为华北平原碳酸盐岩热储层的井壁稳定性分析提供准确数据与研究基础。The uncertainties in the mechanical properties of carbonate rocks under high-temperature,high-pressure in-situ geothermal conditions lead to a lack of accurate data and mechanistic understanding for assessing wellbore stability.In this study,carbonates of the Wumishan Formation of the Jixian System are investigated,and suitable outcrops are identified along the stratum extension direction for sampling purposes.The mechanical properties of the reservoir rocks under the combined effect of high temperature and high pressure are studied,and the mechanism of the effect of temperature on the rock’s mechanical properties is analyzed.The increase in temperature led to a slower growth rate of the strength threshold of carbonate rocks with increasing confining pressure.When the confining pressure increased from 40 to 60 MPa,the peak strength increased by 15.9%at room temperature and only by 7.9%at 150℃.Above 110℃,the friction angle decreased while cohesiveness increased with increasing temperature.Within the temperature and confining pressure ranges in this study,the observed temperature effect was the result of the temperature-induced enhancement and weakening of rock mechanical properties.Within the studied temperature range,temperature had no effect on the chemical composition of minerals in carbonate rocks,but temperature variation could lead to uneven thermal expansion among different mineral particles,resulting in increased intercrystalline thermal stress and causing micro-fracture compaction between mineral particles.Results from this study provide accurate data and a research basis for wellbore stability analysis in the carbonate thermal reservoirs of the North China Plain.

关 键 词：华北平原 碳酸盐岩 蓟县系雾迷山组 岩石力学 高温 

分 类 号：P642[天文地球—工程地质学] P314[天文地球—地质矿产勘探]