川西坳陷致密砂岩储层敏感性评价及主控因素研究——以中坝气田为例  

Sensitivity evaluation and main controlling factor investigation of tight sandstone reservoir in western Sichuan depression:a case study of Zhongba gas field

作　　者：张楚越 曹建[1] 桑琴[2] 刘林 邓茜雯 ZHANG Chuyue;CAO Jian;SANG Qin;LIU Lin;DENG Qianwen(Northwest Sichuan Gas Division,PetroChina Southwest Oil and Gas Field Company,Jiangyou,Sichuan 621709,China;School of Geoscience and Technology,Southwest Petroleum University,Chengdu 610500,China)

机构地区：[1]中国石油西南油气田公司川西北气矿,四川江油621709 [2]西南石油大学地球科学与技术学院,成都610500

出　　处：《中国科技论文》2023年第9期1041-1048,共8页China Sciencepaper

摘　　要：致密气砂岩储层在注水开发过程中受矿物组成、孔喉特征及非均质性等因素的影响,易造成储层损害,制约致密气高效开发。基于岩心孔渗、铸体薄片、扫描电子显微镜及流体驱替等岩石物理实验,获取储层物性、孔隙结构、黏土矿物及储层敏感性等特征,系统评价川西中坝气田上三叠统须家河组二段(T_(3)x^(2))致密砂岩储层伤害类型及其主要控制因素。结果表明:须二段致密砂岩储层表现为弱速敏、中等偏弱-中等偏强水敏、中等偏弱盐敏、无-弱酸敏、弱-中等偏强碱敏和中等偏强应力敏。丝缕状伊利石和半蜂窝状伊/蒙混层的相对含量较高,导致储层水敏感特征显著;铁绿泥石、钾长石及斜长石等碱敏矿物发育,决定了碱敏损害程度;岩石颗粒分选差,喉道细小,微裂缝发育,使储层应力敏感性明显。在开发过程中应控制合理的生产压差及工作液pH值,且可加入防膨剂或微粒稳定剂,减少储层损害程度。研究结果对同类型气藏改善开发效果具有借鉴意义。In the process of waterflood development,the tight gas sandstone reservoir is affected by mineral composition,pore throat characteristics and heterogeneity,which is easy to cause reservoir damage and restrict the efficient development of tight gas.Based on the petrophysical experiments such as core porosity and permeability,cast thin sections,scanning electron microscopy and fluid displacement,the reservoir physical properties,pore structure,clay minerals and reservoir sensitivity are obtained,and the damage types and main controlling factors of tight sandstone reservoirs in member 2 of Upper Triassic Xujiahe formation(T_(3)x^(2))in Zhongba gas field in western Sichuan basin are systematically evaluated.The results show that the tight sandstone of the Xu2 formation is characterized by weak velocity sensitivity,moderately weak-moderately strong water sensitivity,moderately weak salt sensitivity,no-weak acid sensitivity,weak-moderately strong alkali sensitivity and moderately strong stress sensitivity.The relative high content of filamentous illite and semi-combinde illite/montmorillonite blends leads to the significant water-sensitive characteristics of the reservoir.The development of alkali-sensitive minerals such as iron-bearing chlorite,potassium feldspar and plagioclase determines the degree of alkali-sensitive damage.The rock particles are poorly sorted,the throat is small and the micro-fractures are developed,resulting in sensitive reservoir stress.The findings in the present work demonstrate that reasonable production pressure difference and pH value of working fluid should be controlled in the process of development,and anti-swelling agent or particlate stabilizer can be added to reduce the damage degree of reservoir,which may also shed some light on improving the development effect of the same type of gas reservoir.

关 键 词：致密砂岩储层 敏感性 须家河组 孔隙结构 黏土矿物 

分 类 号：P631.8[天文地球—地质矿产勘探]