库车坳陷下白垩统巴什基奇克组碎屑岩储集层的岩石磁学特征  

Rock magnetic properties of Lower Cretaceous clastic reservoir rocks in Bashijiqike Formation,Kuqa Depression(Xinjiang)

作　　者：高云路 潘永信[1,2] GAO Yun-lu;PAN Yong-xin(CAS Key Laboratory of Earth and Planetary Physics,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院地质与地球物理研究所地球与行星物理重点实验室,北京100029 [2]中国科学院大学地球与行星科学学院,北京100049

出　　处：《地球物理学进展》2020年第5期1665-1674,共10页Progress in Geophysics

基　　金：国家自然科学基金创新群体项目(41621004)资助.

摘　　要：识别含油气层是油气勘探开发的重要环节,因此准确判断储层中含油气层的特征尤为重要.油气进入储集层之后会导致储集层发生一系列成岩作用,形成流体包裹体或自生矿物等,对含油气层的物性产生重要影响.为确定含气层与背景地层岩石磁学性质的差异,本文针对库车坳陷克深地区下白垩统巴什基奇克组碎屑岩储集层样品,进行了系统的岩石磁学研究,包括磁化率、天然剩磁强度、磁滞回线、等温剩磁获得曲线和反向场退磁曲线、κ-T曲线、低温有场及零场冷却曲线等.研究结果发现,巴什基奇克组碎屑岩储集层中磁性矿物主要为赤铁矿和磁铁矿,与背景地层样品的磁学性质(磁化率、天然剩磁强度、非磁滞剩磁强度等)相比,含气层样品磁性略微增强,指示细颗粒磁铁矿含量相对升高,这与成藏过程中还原性碳氢化合物对储集层改造作用结果密切相关.Identifying and characterizing oil/gas reservoirs is important in petroleum exploration.With the filling of oil/gas into rocks,a series of diageneses,such as the formation of fluid inclusions or authigenic minerals,happened over the processes,producing an important influence on properties of oil/gas reservoirs.In this paper,the rock magnetic properties of clastic reservoirs rocks in Lower Cretaceous Bashijiqike Formation at Kuqa Depression,Xinjiang,are analyzed to investigate whether there are differences in rock magnetic properties between the gas-bearing strata and the background strata.Magnetic susceptibility,natural remanent magnetization,hysteresis loops,acquisition of saturation isothermal remanent magnetization and back-field demagnetization curves,κ-T curves and low-temperature zero-field cooling/field cooling curves were measured.Results show that magnetic minerals in clastic reservoirs rocks of Bashijiqike Formation are mainly hematite and magnetite.Compared to the rock magnetic properties of background samples(magnetic susceptibility,natural remanence,anhysteretic remanence,etc),the magnetic properties of gas-bearing samples are slightly enhanced,indicating fine-grained magnetite is relatively enriched,and it is closely related to modification of reservoirs by reducing hydrocarbon during reservoir processes.

关 键 词：碎屑岩储集层 岩石磁学 含气层 磁铁矿 赤铁矿 

分 类 号：P318[天文地球—固体地球物理学]