川西中坝致密砂岩气储层微观孔隙结构特征及分类评价  

Microscopic Pore Structure Characteristics and Classification Evaluation of Tight Sandstone Gas Reservoirs in the Zhongba Area of Western Sichuan

作　　者：刘林 刘向君[1,2] 桑琴[1,2] 熊健[1,2] 李玮[1,2] 梁利喜 Liu Lin;Liu Xiangjun;Sang Qin;Xiong Jian;Li Wei;Liang Lixi(Geosciences and Technology,Southwest Petroleum University,Chengdu,Sichuan 610500,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu,Sichuan 610500,China)

机构地区：[1]西南石油大学地球科学与技术学院,四川成都610500 [2]西南石油大学油气藏地质及开发工程全国重点实验室,四川成都610500

出　　处：《特种油气藏》2024年第5期31-40,共10页Special Oil & Gas Reservoirs

基　　金：国家科技重大专项“准噶尔盆地低渗透储层分类评价方法与关键工程地质参数研究”(2017ZX05001-004-005)。

摘　　要：川西中坝地区致密砂岩储层经历复杂的沉积作用和成岩演化,导致其储层物性差、孔隙结构复杂且非均质性强,给储层有效性评价和“甜点”预测带来困难。针对这一问题,以中坝地区须家河组致密砂岩储层为例,基于气测孔渗、铸体薄片、高压压汞及扫描电镜等岩石物理实验,系统评价了储层微观孔隙结构特征,并结合流动单元理论及BP神经网络技术进行储层分类测井评价,明确优质储层发育及分布特征。结果表明:研究区目的储层物性差,储集空间主要为次生粒间孔和溶蚀孔,喉道类型以点状和缩颈状为主,孔径主要为纳米—亚微米级;基于流动单元对储层进行分类,将储层分为4类(Ⅰ—Ⅳ)。流动单元指数(FZI)可有效表征储层孔隙结构及渗流特征,研究区须二段主要发育Ⅱ、Ⅲ类储层,气藏中部ZB9-65-46井区域Ⅰ类储层发育;中坝主体构造储层厚度大,以Ⅱ类储层为主,老坪坝和构造鞍部发育储层多为薄层,以Ⅲ类储层为主;有效储层纵向上主要发育在须二段上部,其厚度占储层总厚度的73.60%。研究结果可为同类型致密砂岩气藏的储层评价及高效开发提供科学依据。The tight sandstone reservoirs in Zhongba Area of western Sichuan have experienced complex sedimentation and diagenesis evolution,resulting in poor reservoir physical properties,complex pore structure and strong heterogeneity,which makes it difficult to effectively evaluate the reservoir and to predict the"sweet spots".To address this issue,this study focused on the tight sandstone reservoirs of the Xujiahe Formation in the Zhongba Area,and systematically evaluated the microscopic pore structure characteristics of the reservoirs based on rock physics experiments including porosity and permeability from gas logging,casting thin sections,high-pressure mercury intrusion,and scanning electron microscope.Additionally,reservoir classification and well logging evaluation are conducted to determine the development and distribution characteristics of high-quality reservoirs with flow unit theory and BP neural network technology.The results show that the physical properties of the target reservoirs in the study area are poor,the reservoir space is mainly secondary intergranular pores and dissolution pores,the throat types are mainly point-like and necked,and the pore size is mainly nano-submicron.Reservoirs are classified into four types(Ⅰ-Ⅳ)based on flow unit.The Flow Zone Index(FZI)can effectively characterize the pore structure and flow characteristics of the reservoirs.TypeⅡandⅢreservoirs are mainly developed in the second member of Xujiahe Formation in the study area,and type I reservoirs are developed in the ZB9-65-46 well field in the middle of the gas reservoir.The main structural reservoirs in the Zhongba Area are thick,predominantly typeⅡ,while the reservoirs in the Laopingba and structural saddles are mostly thin layers,mainly typeⅢ.Vertically,the effective reservoirs are primarily developed in the upper part of the second member of Xujiahe Formation,and its thickness accounts for 73.60%of the total reservoir thickness.The research results provide a scientific basis for reservoir evaluation and effic

关 键 词：致密砂岩 孔隙结构 流动单元 储层评价 须家河组 

分 类 号：TE122[石油与天然气工程—油气勘探]