蒙古塔木察格盆地塔南凹陷下白垩统南屯组三角洲沉积及储层特征  

Sedimentary and reservoir characteristics of delta in Early Cretaceous Nantun Formation in Ta'nan sag of Tamtsag Basin in Mongolia

作　　者：王建鹏[1] 刘招君[1,2] 苗长盛[3] 方石[1,2] 陈永成[1] 

机构地区：[1]吉林大学地球科学学院,长春130061 [2]油页岩实验中心,长春130061 [3]中国石化东北油气分公司勘探开发研究院,长春130062

出　　处：《世界地质》2011年第3期415-421,428,共8页World Geology

基　　金：吉林大学创新团队建设项目(201004001)及吉林大学研究生创新基金资助项目(20111043)联合资助

摘　　要：塔南凹陷为蒙古国塔木察格盆地的次级凹陷,盆地内发育三角洲沉积,且钻遇大规模油藏。综合利用地震、测井和岩心等资料,对塔南凹陷南屯组三角洲的沉积特征、展布、演化及储层物性进行研究。结果表明:本区三角洲可识别出三角洲平原、三角洲前缘和前三角洲3种亚相及6种微相,且集中发育于盆地的西北部;三角洲砂体的规模从南屯组初期到末期整体表现为逐渐扩张的趋势,加积和前积作用使得沉积范围迅速扩大。三角洲砂岩孔渗研究发现,塔南凹陷三角洲前缘砂体储层类型整体属于中孔超低渗型,水下分流河道砂体的孔隙度主要集中在17%～20%,渗透率主要集中在0.1×10^(-3)～10×10^(-3)μm^2,储集物性好;席状砂的孔隙度主要集中在15%～16%和19%～21%,渗透率主要集中在0.1×10^(-3)～5×10^(-3)μm^2,储集物性次之;河口坝砂体的储集物性最差,孔隙度主要集中在13%～17%,渗透率主要集中在0.1×10^(-3)～5×10^(-3)μm^2。Abstract： Ta＇nan sag was a sub-sag of Tamtsag Basin in Mongolia, in which developed delta facies and con- tained large-scale reservoirs. Through the comprehensive utilization of seismic, well logging and core data, the au- thors studied the sedimentary characteristics, distribution, evolution and reservoir property of delta in Nantun For- mation of Ta＇nan sag. The results showed that the delta in this area can be divided into three kinds of subfacies （delta plain, delta front, prodelta） and six kinds of microfacies, which are mostly located in the northwest of the basin. The scale of delta sand expanded gradually from the early stage to the last stage of Nantun Formation and the sedimentary range increased rapidly by sandstone showed that the sand reservoir aggradation and progradation. The porosity-permeability analysis of delta type of delta front in Ta＇nan sag belonged to medium porosity and superlow permeability type. The porosity and permeability of underwater distributary channel sand ranged from 17% to 20% and 0. 1×10-3 to 10 ×10-3 μm2 with the best reservoir property ; the porosity and permeability of sheet sand ranged from 15% to 16%, 19% to 21% and 0. 1 ×10-3 to 5 ×10-3μm2 with better reservoir property; the porosity and permeability of river mouth bar sand ranged from 13% to 17% and 0. 1 ×10-3 to 5 ×10-3μm2 with the worst reservoir property.

关 键 词：蒙古 塔木察格盆地 塔南凹陷 南屯组 三角洲 沉积特征 储层特征 

分 类 号：P618.130[天文地球—矿床学] P534.53[天文地球—地质学]