鄂尔多斯盆地北部马家沟组中组合储层形成机理  

Formation mechanism of the mid-assemblage of Majiagou Formation in the northern Ordos Basin

作　　者：雷涛 丁晓琪[3] 田胤瑜[3] 唐明远 杨帅杰 崔梦迪 LEI Tao;DING Xiaoqi;TIAN Yinyu;TANG Mingyuan;YANG Shuaijie;CUI Mengdi(Institute of Advanced Studies,China University of Geosciences,Wuhan 430074,China;North China Company,SINOPEC,Zhengzhou 450006,China;Energy College,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]中国地质大学(武汉)高等研究院,湖北武汉430074 [2]中国石化华北油气分公司,河南郑州450006 [3]成都理工大学能源学院,四川成都610059

出　　处：《天然气地球科学》2024年第10期1750-1763,共14页Natural Gas Geoscience

基　　金：中国石化科技攻关项目“鄂尔多斯盆地元古—下古生界成藏条件与目标评价”(编号:P20043-2)资助。

摘　　要：鄂尔多斯盆地奥陶系马家沟组中组合(马五5⁃10亚段)的天然气勘探已实现局部突破,但因为储层形成机理尚存争议,制约了天然气的下一步勘探。充分利用盆地东北部府谷天生桥马家沟组野外地质剖面和盆内大牛地气田石103井的全取心资料,划分中组合的储层类型,分析不同类型储层的形成机理。结果表明:①马家沟组中组合发育3种类型的储层:相控孔隙型储层、溶控孔洞型储层和断控缝洞型储层,相控和溶控型储层受岩相控制明显,而断控型储层受岩相控制弱;②相控孔隙型储层受云岩相控制,与灰岩伴生的粉晶白云岩物性最好;③溶控孔洞型储层受加里东期承压水溶蚀作用控制,表生期破裂作用、去白云石化、灰质组分溶蚀,三位一体构成溶控孔洞型储层;④断控缝洞型储层受加里东—海西期、印支期和燕山期断裂控制,沿断裂分布。The natural gas exploration of the mid-assemblage of Ordovician Majiagou Formation in the Ordos Basin has got local breakthroughs,but the formation mechanism of reservoirs is still controversial,which re⁃stricts the next step of natural gas exploration.This article fully utilizes the field geological outcrop of the Majia⁃gou Formation in the Fugu Tianshengqiao in the northeast of the basin and the whole coring Well Shi 103 of the Daniudi Gas Field in the basin,dividing the reservoir types of the Mid-assemblage,and analyzing the formation mechanisms of different types of reservoirs.The following results have been achieved:(1)Three types of reser⁃voirs developed in the Mid-assemblage of Majiagou Formation:Lithofacies-controlled porous reservoir,karstcontrolled vuggy reservoir and fault-controlled fracture-cavern reservoir.The first and second types of reservoir are controlled by lithofacies significantly,but the last type of reservoir is weakly not controlled by lithofacies nearly.(2)Facies-controlled porous reservoir is controlled by dolomite lithofacies,and the physical properties of the very fine-crystal size dolomite associated with limestone are the best.(3)Karst-controlled vuggy reser⁃voir is controlled by the confined-water dissolution.Epigenetic fracturing,dedolomitization and calcite dissolu⁃tion,integrated to form a karst-controlled vuggy reservoir.(4)Fault-controlled fracture-cavern reservoir is con⁃trolled by faults developed in Caledonian-hercynian,Indosinian and Yanshan Period.These reservoirs are dis⁃tributed along the faults.The above understanding provides a basis for the next exploration of the Mid-assem⁃blage of Majiagou Formation in terms of reservoir formation mechanism.

关 键 词：岩溶 白云岩 断控储层 马家沟组 天生桥 鄂尔多斯盆地 

分 类 号：TE122.1[石油与天然气工程—油气勘探]