【作者】 范勇刚；

【导师】 施泽进；

【作者基本信息】 成都理工大学 ， 矿产普查与勘探， 2010， 硕士

【摘要】 鄂尔多斯盆地姬塬地区位于盆地中西部天环凹陷与陕北斜坡交接部位。长8油层组是提交控制和预测储量的重要石油产层。随着石油产量和勘探规模的扩大,需要对储层的各项特征有更加深刻的认识。而区内成岩作用、储层特征等方面的研究缺乏。针对这一现状,本文以沉积学和石油地质理论为指导,利用钻井岩芯资料、薄片鉴定、扫描电镜、镜质体反射率等测试分析手段,对该区沉积微相、沉积作用及储层特征进行了深入地分析和探讨,取得了以下认识:对姬塬地区沉积相的分析研究表明长8油层组砂岩是河流背景下发育的河流三角洲沉积,其三角洲前缘的水下分流河道、河口坝以及三角洲平原的分流河道是砂体发育的有利相带。储层岩石学特征表明:研究区长8油层组岩石类型主要是岩屑长石砂岩和长石岩屑砂岩;石英含量主要在29.4%-71.4%之间,平均50.6%;长石含量主要在19%-58.8%之间,平均25.5%;岩屑含量在10.9%-49.4%之间,平均23.8%;砂岩粒度以细砂岩为主,分选较好为主,偏度为极正偏和正偏;胶结物类型主要为方解石胶结物和石英胶结物,方解石胶结物电子探针成分分析表明,方解石类型主要为铁方解石和不含铁方解石。孔隙类型以原生粒间孔为主,其次为长石溶孔。成岩作用分析研究表明:区内主要成岩作用类型为压实(压溶)作用、胶结作用、溶蚀作用和交代作用。对该区的孔隙演化进行了定量分析,认为压实作用和碳酸盐岩的胶结作用是工区内储层物性变差的主要原因。该区典型的成岩序列为:压实作用―早期粘土膜沉淀作用―长石溶蚀―石英次生加大―晚期铁方解石胶结―晚期局部溶蚀―烃类侵位,成岩阶段的划分表明研究区已达中成岩阶段A期,局部已经达到中成岩阶段B期。在成岩作用的分析基础之上将本区成岩相分为5类,其中Ⅰ类、Ⅱ类成岩相的砂岩可以成为好储层或较好储层,利用成岩相分类方案对长81成岩相的平面分布做了预测。在上述分析研究的基础上,结合收集整理的孔渗数据对姬塬地区储层特征开展研究,研究结果表明姬塬地区长8油层组为典型的低孔低渗储层,长81孔隙度介于3.62%-16.41%之间,平均10.9%,渗透率介于0.001×10-3μm2-13.69×10-3μm2,平均为1.1×10-3μm2;长82孔隙度介于3.06-13.61之间,平均9.44%,渗透率在0.001×10-3μm2-0.49×10-3μm2之间,平均0.75×10-3μm2;孔喉连通性差,孔隙组合类型为小孔隙-微喉/微细吼型与大孔隙-微喉/微细吼型;压汞曲线分析和孔隙结构参数计算表明储层孔隙结构复杂,变化性大。通过沉积、成岩作用的综合研究认为姬塬地区储层物性主要受原始沉积物质和后期成岩作用的影响。结合该区实际勘探情况,对姬塬地区长81油层组储层进行了储层分类和储层评价研究,指出该区长81储层类型以II类和III类为主,并指出长81段四个有利储层发育区,可作为该区下一步中生界石油勘探的有利目标。更多还原

【Abstract】 Jiyuan area is at the conjunction of Tianhuan sag on west and the slope on the northern Shanxi, in which the Chang-8 member of Yanchang Formation, as the reservoir, is of significance in controlling and predicting the reserve. While much research on this region is about the sedimentary, study in diagenesis and reservoir characteristics is scarce. Therefore, according to the theory of geology of petroleum, core data, thin section analysis, SEM and vitrinite reflectance, the author has deeply studied about the microfacies, the Sedimentation and the reservoir characteristics of the Chang-8 member of Yanchang Formation :Research on the sedimentary facies illustrates that the target sand reservoir developed on braided delta and is represented by the sand bodies of subaqueous distributary channels, mouth bar and distributary channels of delta plain.Research on rock characteristics indicates a prevail presence of lithic arkose and feldspathic litharenite that is homogeneous and is basically made up of packsand, calcite cement, and quartz cement. EMP shows calcite cement consists of ferrocalcite and nonferrous calcite. Quartz content ranges from 29.4% to 71.4% with an average of 50.6%; feldspar content ranges from 19% to 58.8% with an average of 25.5%; cuttings account for 10.9%-49.4% of total with average of 23.8%. Meanwhile, Ch8 is occupied by mainly primary intergranular pores and secondarily arkose dissolved pore.Research on diagenesis demonstrates over this area, compaction, cementation, denudation and metasomatism have had operated the geological development. Quantitative analysis on porosity evolution, moreover, illustrates that compaction and cementation should be substantially responsible for the deterioration of reservoir properties. Consequentially, the diagenetic process in the area can be described as seven steps: compaction→early disposition of clay film→feldspar dissolution→quartz secondary growth→late ferrocalcite cementation→late part corrosion→hydrocarbons emplacement. The area arrivaed in A period of the secondary diagenetic stage. Finally we classify the sandstone in the area into 5 categories, of which the ? and II categories represent qualified and less qualified reservoirs respectively.Combined with analyses above, research on reservoir characteristics summarise that the Chang-8 member of Yanchang Formation in Jiyuan area is a typical reservoir of poor poroperm characteristics. Specifically, the porosity of Ch81 fluctuates between 3.62% and 16.41% with an average of 10.9% and, its permeability ranges from 0.001×10-3μm2 to 13.69×10-3μm2 with an average of 1.1×10-3μm2; Ch82 has a porosity fluctuating between 3.06% and 13.61% with an average of 9.44% and a permeability that is from 0.001×10-3μm2 to 0.49×10-3μm2 with average of 0.75×10-3μm2.In general the pore configuration here is complex and unpredictable and, original disposition and late diagenesis affect the Chang8 fundamentally.Base on the area actual exploration situation,through reservior classification and the reservior appraisal research, reserviors of Chang81 principally belong to II and III categories of the sand body classification with four relatively advantaged regions that can be aimed to in the following exploration.更多还原