苏里格桃2井区马家沟组古岩溶储层特征研究

发布时间：2018-02-16 04:20

本文关键词： 古岩溶地貌储层特征马家沟组桃2井区　出处：《西安石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：桃2井区位于鄂尔多斯盆地苏里格气田东南部,区域构造上属于陕北斜坡西北部,工区面积约700km~2，，近年来,该区下古生界有了一定的突破,但对马家沟组岩溶储层的认识还远不能满足目前勘探开发的实际需要。论文综合分析录井、测井、岩心、岩屑、薄片、试气以及部分生产资料,结合前人研宄成果,对研宄区奥陶系马家沟组马五r马五4亚段古岩溶储层的沉积微相、成岩作用类型、储集空间、物性特征及孔隙结构等做了较为系统的研究,主要根据“桃2井区石炭系地层厚度图”、“桃2井区马五/底至奥陶系顶厚度图”以及“桃2井E前石炭系古地质图”,利用定性判识与定量指标相结合的方法恢复了研宄区奥陶系古岩溶地貌,并以此为基础进行岩溶储层的综合评价。研究结果表明:研究区奥陶系马家沟组马五「马五4亚段储层为典型的碳酸盐岩夹薄层膏岩岩溶储层,岩石类型以泥-微晶白云岩、微粉晶白云岩及粉晶云岩分布较为广泛,局部可见较厚层泥晶灰岩;岩溶储层经历了白云石化作用、压实、压溶作用、岩溶作用、胶结作用等成岩作用,其中以毛细管浓缩白云石化和回流渗透白云石化为主的白云石化作用以及同生期、表生期和埋藏期三期岩溶作用的叠加作用是优质储层形成的关键;储层物性以特低孔、低渗为特征,储集空间中以晶间溶孔、膏模孔、溶洞或溶孔充填残余孔、非选择性溶孔、构造缝和溶缝为有效的储渗空间类型;储层溶洞主要以半充填-全充填型为主,充填物主要为方解石,大量充填孔洞的方解石是导致储层物性变差的重要原因;储层裂缝以水平缝为主,垂直缝次之,斜交缝较为少见,裂缝在粉晶云岩和含泥云岩中相对较发育,多为半充填-全充填缝,充填物以方解石和石英为主,这是影响裂缝改善储层物性和促进天然气运移的重要因素;根据孔隙结构参数和毛管压力曲线特征,将孔隙结构划分为四类;储层类型主要为裂缝一孔洞型、裂缝一孔隙型;综合孔隙度、渗透率、测井含气饱和度、压汞曲线类型和无阻流量等指标,将研究区奥陶系马家沟组马五i-马五4亚段储层划分为4类,发现研究区主要分布III+IV类储层,II类储层呈孤岛状分布在研究区的部分地区,而I类储层零星分布于研究区中;同时结合白云石化分布趋势区平面图及奥陶系岩溶古地貌图,认为II类储层主要分布于白云石化作用较强烈的地E 且二者与中级规模的残丘具有良好的对应关系。
[Abstract]:The Tao-2 well area is located in the southeast of Sulige gas field in Ordos Basin. The regional structure belongs to the northwestern part of northern Shaanxi slope, and the area of the area is about 700km2. In recent years, there has been a certain breakthrough in the Lower Paleozoic in this area. However, the understanding of the karst reservoir in Majiagou formation is far from satisfying the actual needs of exploration and development at present. This paper synthetically analyzes mud logging, logging, core, cuttings, thin slices, gas test and some production materials, and combines the results of previous studies. The sedimentary microfacies, diagenesis type, reservoir space, physical properties and pore structure of paleokarst reservoir of Mawulma No. 4 member of Majiagou formation of Ordovician in the study area are systematically studied. Based on "Carboniferous formation thickness map", "Mawu / Dei-Ordovician top thickness map" and "Preco Carboniferous paleogeology map" in Tao-2 well area, the method of combining qualitative identification with quantitative index is used to recover. The paleokarst geomorphology of Ordovician in the study area, On the basis of this, the comprehensive evaluation of karst reservoir is carried out. The results show that the reservoir of Mawu "Mawu 4 member of Majiagou formation of Ordovician system in the study area is typical carbonate rock thin layer gypsum rock karst reservoir, and the rock type is mud-microcrystalline dolomite." Microcrystalline dolomite and powdery dolomite are widely distributed, and thicker mudstone limestone can be seen locally. The karst reservoir has undergone diagenesis, such as dolomitization, compaction, pressure-dissolution, karstification, cementation and other diagenetic processes, such as dolomitization, compaction, pressure dissolution, karstification, cementation, etc. Among them, the dolomitization with capillary concentration and reflux permeating dolomitization as well as the superposition of karst in syngenic, epigenetic and burial stages are the key to the formation of high quality reservoirs, and the physical properties of reservoirs are very low porosity. The reservoir space is characterized by intergranular dissolving pore, gypsum mold pore, cavern or dissolving hole filling residual pore, non-selective dissolved pore, structural fracture and dissolved fracture as effective type of storage and permeability space, while the reservoir caverns are mainly semi-filled and fully filled. The filling material is mainly calcite, and a large number of calcite filled with holes is the important reason for the poor physical properties of reservoir, the fracture of reservoir is mainly horizontal fracture, the vertical fracture is the second, and the oblique fracture is rare. The fractures are relatively developed in powdery dolomite and mud-bearing dolomite, most of them are half-filled and fully filled fractures, and the main filling materials are calcite and quartz, which are the important factors that affect the improvement of reservoir physical properties and promote the migration of natural gas. According to the parameters of pore structure and the characteristics of capillary pressure curve, the pore structure is divided into four categories: the reservoir type is mainly fracture-hole type, fracture-pore type, comprehensive porosity, permeability, logging gas saturation, The reservoir of Mawui-Mawu 4 submember of Majiagou formation of Ordovician in the study area is divided into 4 types, such as mercury injection curve type and unobstructed flow rate. It is found that the III IV type reservoir and type II reservoir are mainly distributed in the study area as isolated islands in some areas of the study area. The type I reservoir distributes sporadically in the study area, at the same time, combined with the dolomitization distribution trend area plane map and the Ordovician karst paleogeomorphology map, It is considered that the type II reservoir is mainly distributed in the area where dolomitization is relatively strong and that the two reservoirs have a good correspondence with the middle scale residual hills.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

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