柴达木盆地昆仑山前带下干柴沟组下段储层差异性  

Reservoir difference of the lower section of Lower Ganchaigou Formation in Kunlun piedmont zone,Qaidam Basin

作　　者：宫清顺 刘占国 龙国辉 朱军[2] 霍鹏 李朝琦 朱超 伍劲 宋光永 GONG Qingshun;LIU Zhanguo;LONG Guohui;ZHU Jun;HUO Peng;LI Zhaoqi;ZHU Chao;WU Jin;SONG Guangyong

机构地区：[1]中国石油杭州地质研究院 [2]中国石油青海油田公司勘探开发研究院 [3]中国石油青海油田公司采油一厂

出　　处：《海相油气地质》2023年第3期239-249,共11页Marine Origin Petroleum Geology

基　　金：中国石油集团基础性前瞻性重大科技专项“叠合盆地中下组合油气成藏与保持机制研究”(编号:2023ZZ02)资助。

摘　　要：昆仑山前带古近系下干柴沟组下段是柴达木盆地油气勘探的重点目的层。受砂岩储层发育程度差异所控制,昆仑山前带不同地区油气富集程度存在差异。为了明确储层的差异性及形成机制,利用岩心、测井及分析化验等资料,对昆仑山前带的切6区、乌南斜坡带、东柴山地区及弯西构造带的储层特征及控制因素进行了分析,认为下干柴沟组下段储层在时空上的差异性明显。昆仑山前带下干柴沟组下段发育以原生粒间孔为主的碎屑岩孔隙型储层,储层砂体成因类型为辫状河三角洲相的平原分流河道、前缘水下分流河道、河口坝、席状砂及滨浅湖相的滩坝。沉积相及成岩作用的双重叠加影响导致昆仑山前带储层发育程度存在明显差异。在同等埋深条件下,受沉积微相控制的储层沉积组构差异与砂体规模差异是储层物性差异的主因,辫状河三角洲前缘水下分流河道储层物性最好,其次为河口坝、平原分流河道,滩坝与席状砂的储层物性较差。在不同埋深条件下,受最大古埋深和古地温梯度等因素影响而形成的差异压实作用是不同区带储层物性差异的主因,切6区和弯西构造带的储层物性最好,乌南斜坡带的储层次之,东柴山地区的储层物性差。In Qaidam Basin,the Kunlun piedmont zone is an important area of oil and gas exploration,and the lower section of Paleogene Lower Ganchaigou Formation is its main oil-bearing layer.Controlled by the differences in the development of sandstone reservoir,the degrees of oil and gas enrichment showed differences in different belts of Kunlun piedmont zone.In order to clarify the difference and formation mechanism of reservoir of the lower section in Lower Ganchaigou Formation,by using core,wireline logging data and experiment data,this paper analyzed the reservoir characteristics and controlling factors in different belts of Kunlun piedmont zone,such as Qie6 block,Wunan slope belt,Dongchaishan area and Wanxi structural belt.It is believed that the reservoir characteristics in the lower section of Lower Ganchaigou Formation are significantly different in time and space.In Kunlun piedmont zone,the lower section of Lower Ganchaigou Formation develops clastic pore-type reservoirs,and the reservoir’s storage space is mainly the primary intergranular pore.There is five genetic types of sandbody in this study area,namely distributary channel,underwater distributary channel,estuarine bar,sheet sand in braided river delta facies,and beach bar in shore-shallow lake subfacies.The dual superposed effects of sedimentary facies and diagenesis result in significant differences in the development of reservoirs in Kunlun piedmont zone.There are average porosity and permeability values of 14.1%and 32.76×10-3μm^(2) in Qie6 block,13.4%and 36.48×10-3μm^(2) in Wanxi structural belt,6.7%and 2.38×10-3μm^(2) in Wunan slope belt,and 3.1%and 0.1×10-3μm^(2) in Dongchaishan belt.Under the same burial depth,the differences of sedimentary structure and sandbody scale,are the main reasons for reservoir physical properties’differences in different sedimentary microfacies,and underwater distributary channel had the best reservoir physical properties,followed by estuarine bar and distributary channel,and the physical properties of beach bar

关 键 词：储层差异性 碎屑岩 孔隙型储层 沉积相 差异压实作用 昆仑山前带 柴达木盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探]