Evolution features of in-situ permeability of low-maturity shale with the increasing temperature,Cretaceous Nenjiang Formation,northern Songliao Basin,NE China

作     者：HE Wenyuan MENG Qi'an LIN Tiefeng WANG Rui LIU Xin MA Shengming LI Xin YANG Fan SUN Guoxin HE Wenyuan;MENG Qi'an;LIN Tiefeng;WANG Rui;LIU Xin;MA Shengming;LI Xin;YANG Fan;SUN Guoxin

作者机构：Daqing Oilfield Co.Ltd.PetroChinaDaqing 163712China Exploration and Development Research Institute of Daqing Oilfield Co.Ltd.Daqing 163712China Heilongjiang Provincial Key Laboratory of Shale Oil&Tight Oil AccumulationDaqing 163712China 

出 版 物：《Petroleum Exploration and Development》 (石油勘探与开发（英文版）)

年 卷 期：2022年第49卷第3期

页      面：516-529页

核心收录：

学科分类：0820[工学-石油与天然气工程] 08[工学] 082002[工学-油气田开发工程] 

基　　金：Supported by the Special Major Scientific Research Project of PetroChina(2021ZZ10-01) 

主　　题：Songliao Basin Cretaceous Nenjiang Formation low-maturity shale in-situ conversion pore-fracture structure in-situ permeability shale oil 

摘      要：Temperature-triaxial pressure permeability testing at the axial pressure of 8 MPa and confining pressure of 10 MPa,closed shale system pyrolysis experiment by electrical heating and scanning electron microscopy analysis are used to study the evolution mechanism of in-situ permeability in the direction parallel to bedding of low-maturity shale from Member 2(K_(2)n_(2))of Cretaceous Nenjiang Formation in northern Songliao Basin with mainly Type I kerogen under the effect of *** the increasing temperature,the in-situ permeability presents a peak-valley-peak *** lowest value of in-situ permeability occurs at 375℃.Under the same temperature,the in-situ permeability decreases with the increase of pore *** in-situ permeability evolution of low-maturity shale can be divided into 5 stages:(1)From 25℃to 300℃,thermal cracking and dehydration of clay minerals improve the ***,the value of permeability is less than 0.01×10^(-3)μm^(2).(2)From 300℃to 350℃,organic matter pyrolysis and hydrocarbon expulsion result in mineral intergranular pores and micron pore-fractures,these pores and fractures form an interconnected pore network at limited scale,improving the *** the liquid hydrocarbon,with high content of viscous asphaltene,is more difficult to move under stress and more likely to retain in pores,causing slow rise of the permeability.(3)From 350℃to 375℃,pores are formed by organic matter pyrolysis,but the adsorption swelling of liquid hydrocarbon and additional expansion thermal stress constrained by surrounding stress compress the pore-fracture space,making liquid hydrocarbon difficult to expel and permeability reduce rapidly.(4)From 375℃to 450℃,the interconnected pore network between different mineral particles after organic matter conversion,enlarged pores and transformation of clay minerals promote the permeability to increase constantly even under stress constraints.(5)From 450℃to 500℃,the stable pore system and cro