Evolution and Application of Sealing Ability of Gypsum Caprocks under Temperature-Pressure Coupling:An Example of the ZS5 Well in the Tazhong Area of the Tarim Basin  

作　　者：LIU Hua ZHAO Shan YANG Xianzhang ZHU Yongfeng WANG Shen ZHANG Ke 

机构地区：[1]National Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China),Qingdao,Shandong 266580,China [2]School of Geosciences,China University of Petroleum(East China),Qingdao,Shandong 266580,China [3]Laboratory for Marine Mineral Resources,National Laboratory for Marine Science and Technology,Qingdao,Shandong 266071,China [4]PetroChina Tarim Oil Field Company,Korla,Xinjiang 841001,China

出　　处：《Acta Geologica Sinica(English Edition)》2024年第1期168-184,共17页地质学报（英文版）

基　　金：funded by the National Natural Science Foundation of China(Grant No.42172147);PetroChina Major Science and Technology Project(Grant No.ZD2019-183-002).

摘　　要：Gypsum caprocks'sealing ability is affected by temperature-pressure coupling.Due to the limitations of experimental conditions,there is still a lack of triaxial stress-strain experiments that simultaneously consider changes in temperature and pressure conditions,which limits the accuracy of the comprehensive evaluation of the brittle plastic evolution and sealing ability of gypsum rocks using temperature pressure coupling.Triaxial stress-strain tests were utilized to investigate the differences in the evolution of the confinement capacity of gypsum rocks under coupled temperaturepressure action and isothermal-variable pressure action on the basis of sample feasibility analysis.According to research,the gypsum rock's peak and residual strengths decrease under simultaneous increases in temperature and pressure over isothermal pressurization experimental conditions,and it becomes more ductile.This reduces the amount of time it takes for the rock to transition from brittle to plastic.When temperature is taken into account,both the brittle–plastic transformation's depth limit and the lithological transformation of gypsum rocks become shallower,and the evolution of gypsum rocks under variable temperature and pressure conditions is more complicated than that under isothermal pressurization.The sealing ability under the temperature-pressure coupling is more in line with the actual geological context when the application results of the Well#ZS5 are compared.This provides a theoretical basis for precisely determining the process of hydrocarbon accumulation and explains why the early hydrocarbon were not well preserved.

关 键 词：temperature-pressure coupling gypsum caprocks brittle-plastic evolution sealing capacity Tarim Basin 

分 类 号：P618.13[天文地球—矿床学]