超深低孔特低渗砂岩储层的孔隙成因及控制因素——以库车坳陷克深地区巴什基奇克组为例  

Porosity Origin and Controlling Factors of Ultra-Deep,Low Porosity and Ultra-Low Permeability Sandstone Reservoirs:A Case Study of Bashijiqike Formation in Keshen Area of Kuqa Depression,Tarim Basin

作　　者：孙海涛[1] 钟大康[1] 李勇[2] 毛亚昆[1] 杨宪彰[1,2] Sun Haitao;Zhong Dakang;Li Yong;Mao Yakun;Yang Xianzhang(College of Geosciences, China University of Petroleum, Beijing 102249, China;PetroChina Tarim Oilfield Company, Korla 841000, Xinjiang, China)

机构地区：[1]中国石油大学(北京)地球科学学院,北京102249 [2]中国石油塔里木油田分公司,新疆库尔勒841000

出　　处：《吉林大学学报（地球科学版）》2018年第3期693-704,共12页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(41302108);国家重大科技专项项目(2016ZX05002-004-011)~~

摘　　要：库车坳陷克深地区白垩系巴什基奇克组砂岩经过了漫长的埋藏过程和复杂的成岩演化,形成了一套超深低孔特低渗储层。本文详细描述了该储层的孔隙成因类型,并分析了其控制因素。通过鉴定大量铸体薄片和荧光薄片,并利用场发射扫描电镜与激光共聚焦显微镜等手段进行分析,综合考虑形态、规模和成因3个依据识别出8类孔隙和2类裂缝,认为该低孔特低渗储层为孔隙型储层,次生成因控制的孔隙占主导地位;并提出早期长时间浅埋藏及所处的碱性环境导致了弱压实及强胶结,后期的构造挤压进一步减孔,而晚期溶蚀虽是次生孔隙形成的主要原因,但其并未大规模有效改善储层的低孔现状。As a result of a complex diagenetic evolution,a reservoir with low porosity and ultra-low permeability exists in the ultra-deep sandstones of Bashijiqike Formation of Cretaceous in the Keshen area of Kuqa depression,Tarim basin.This paper presents an overview of the types and origin of the sandstone porosity and the controlling factors.Based on the identification of many cast and fluorometricslices by using the field emission scanning electron microscope and confocal microscope,eight types of pores and two kinds of fissures in this sandstone reservoir are recognized according to their shape,scale and origin.The pores are dominated by the secondary pores,which is the result of the following complex geological process：1）The sandstone was buried shallow for a long time in the early stage,so no porosity-decreasing effect occurred during the weak compaction;2）The Early Cementation saved some primary intergranular pores;3）The porosity was further decreased by the effect of the tectonic compression in the late burial process;4）The secondary pores were mainly formed by the later dissolution,but which didn’t evidently change the porosity of the sandstone reservoir.

关 键 词：库车坳陷 白垩系 砂岩储层 成岩作用 控制因素 

分 类 号：P618.13[天文地球—矿床学]