长岭凹陷乾北地区青三段低渗透储集层特征与主控因素  

Characteristics and Main Controlling Factors of Low Permeability Sandstone Reservoir of the 3rd Member of the Qingshankou Formation in the Qianbei Aera,Changling Sag

作　　者：胡鹏[1] 鲍志东[2] 于兴河[1] 刘学超 华正秋[4] 刘俊玲 黄玉欣[4] 

机构地区：[1]中国地质大学(北京)能源学院,北京100083 [2]中国石油大学(北京)地球科学学院,油气资源与探测国家重点实验室,北京102249 [3]盎亿泰地质微生物技术(北京)有限公司,北京102249 [4]中国石油吉林油田分公司勘探开发研究院,吉林松原138001 [5]中石化西北局塔河采油一厂,新疆轮台841600

出　　处：《矿物岩石地球化学通报》2017年第2期308-318,共11页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：国家油气重大专项(2011ZX05028);中石油天然气股份有限公司重大科技专项(2013E-0501)

摘　　要：松辽盆地长岭凹陷上白垩统青山口组三段低渗透储集砂体发育,是其区内油气勘探的重点目标。基于岩石薄片、扫描电镜、X射线衍射、物性及压汞测试等资料,对长岭凹陷乾北地区青三段低渗透储集层特征与控制因素进行详细研究。结果表明:青三段储集层岩性以岩屑长石砂岩、长石砂岩为主,杂基含量较高,成分与结构成熟度均较低;储集层平均孔隙度为11.9%,平均渗透率为2.8×10^(-3)μm^2,为典型低孔-低渗储集层;储集空间类型多样,以粒间孔、粒内孔为主,孔隙结构具有4种典型类型。青三段低渗透储集层的形成是沉积作用、成岩作用等多种因素综合作用的结果。湖泛期三角洲前缘末端沉积背景下储集砂岩粒度较细,杂基含量较高,原生孔隙相对较少且连通性较差,奠定了低渗透储集层形成的物质基础;埋藏阶段压实作用和胶结作用的成岩改造,使得原生孔隙大量减少、孔隙结构趋于复杂化,储集层物性整体变差,是形成低渗储集层的关键因素;低渗透背景下,构造成因裂缝局部发育,可有效提高储集层的渗流能力,是相对优质储集层形成的有利条件。The 3rd Member of upper Cretaceous Qingshankou Formation（K2qn3） , rich in low-permeability sandstones is the key target strata for petroleum exploration in the Changling Sag of the Songliao Basin. With an integrated approach of thin- section petrography, constant velocity mercury injection test, scanning electron microscopy and X-ray diffractometry, charac- teristics and main controlling factors of the low-permeability of K2qn3 sandstones in the Qianbei Area of the Changling Sag are analyzed. The main lithology of the reservoir is dominated by arkose and lithoclastic arkose. As the average porosity is 11.9% and the average permeability is 2.8×10^-3μm^2, the reservoir is classified as typical low-porosity and low-permeability reser-voir. It has a variety of reservoir space types, mainly intergranular pores and intragranular pores. The reservoir pore structure can be subdivided into 4 types. The formation of low-permeability sandstones results from the combining influence of sedi- mentary environment and diagenesis. Sandstones deposited at the end of deltaic front during flooding period is characterizedby fine grains of high matrix content, building up the material for the development of low permeability reservoir. During the burial stage, primary porosity was sharply reduced and pore structure tended to be complicated. The quality of reservoir became poorer and poorer as the result of compaction and cementation, which was the key point for the formation of low perme- ability reservoir. Under the background of low permeability, locally-developed tectonic fractures might improve percolation capacity effectively, which would benefit the development of relatively high-quality reservoirs.

关 键 词：低孔-低渗透 储集层特征 主控因素 青三段 乾北地区 长岭凹陷 

分 类 号：P618.13[天文地球—矿床学]