鄂尔多斯盆地大牛地气田马五_(6~10)亚段沉积相高频演化特征

High-frequency Evolution of Sedimentary Facies of Sub-members from 6^(th)to 10^(th)of the Ma 5 Member in the Daniudi Gas Field,Ordos Basin

鄂尔多斯盆地大牛地气田马五_(6~10)亚段沉积微相高频变化,分布特征尚不明确,严重制约了天然气勘探与开发。综合利用岩心、薄片、测井及野外露头等资料,详细分析了该地区马五_(6~10)亚段碳酸盐岩岩石类型及测井响应特征,划分了4种沉积微相,进一步分析了该地区马五_(6~10)亚段高频沉积相演化特征。研究表明,马五期海平面整体呈下降趋势,发育局限台地亚相,云坪、膏云坪、灰云坪微相在空间上彼此相邻,纵向上相互叠置,随海平面的涨落沉积微相在膏云坪、云坪和云坪、灰云坪、云灰坪之间频繁转化。马五_(10)、马五_(8)、马五_(7)^(2)、马五_(6)^(1)亚段主要发育膏云坪和云坪微相,马五_(9)亚段主要发育云坪和灰云坪微相,马五_(7)^(1)、马五_(6)^(2)亚段主要发育膏云坪、云坪及灰云坪微相,马五_(6)^(3)亚段则由西向东依次发育膏云坪、云坪、灰云坪、云灰坪微相。研究区海平面升降控制了沉积亚相的演化,更为高频的次级海平面变化控制着沉积微相快速变化。鄂尔多斯盆地大牛地气田马五_(6~10)亚段沉积相高频演化特征研究,将有力支撑大牛地气田马家沟组深部天然气资源的开发动用,同时为大牛地气田马家沟组沉积模式研究提供依据。

High-frequency changes and unclear distribution of sedimentary microfacies of sub-members from 6^(th)to 10^(th)of the Ma 5 Member in the Daniudi gas field,Ordos Basin seriously restrict the exploration and development of natural gas.Comprehensive use of cores,thin sections,logging and field outcrops and other data,the rock types and logging response characteristics of sub-members from 6^(th)to 10^(th)of the Ma 5 Member in this area were analyzed in detail,divided into 4 sedimentary microfacies,the high-frequency evolution of sedimentary facies in sub-members from 6^(th)to 10^(th)of the Ma 5 Member in this area were further analyzed.The results show that the sea level of the Ma 5 Member shows a downward trend and then restricted platform develops.The microfacies of dolomitic flat,gypseous-dolomitic flat and limestone-dolomitic flat are adjacent to each other and superimposed on each other,and with the fluctuation of sea level,the sedimentary microfacies are frequently transformed between the gypseous-dolomitic flat,the dolomitic flat and the dolomitic flat,the dolomitic-limestone flat,and the limestone-dolomitic flat.10^(th)sub-member,8^(th)sub-member,2 nd layer of 7^(th)sub-member and 1^(st)layer of 6^(th)sub-member of the Ma 5 Member mainly develop gypseous-dolomitic and dolomitic flat.9^(th)sub-member of the Ma 5 Member mainly develops dolomitic flat and limestone-dolomitic flat.1^(st)layer of 7^(th)sub-member and 2^(nd)layer of 6^(th)sub-member of the Ma 5 Member mainly develop gypseous-dolomitic flat,dolomitic flat and limestone-dolomitic flat.3 rd layer of 6^(th)sub-member of the Ma 5 Member develops gypseous-dolomitic flat,dolomitic flat,limestone-dolomitic flat and dolomitic-limestone flat from west to east.The fluctuation of sea level in the study area controls the change of sedimentary sub-facies,and changes of high-frequency sea level control changes of high-frequency evolution of microfacies.Study on the high-frequency evolution of sedimentary facies of sub-members from 6^(th)to 10^(th)of the Ma 5 Member in the Daniudi gas field,Ordos Basin will strongly support the development and utilization of natural gas resources in the deeper Majiagou Formation of the Daniudi gas field,and provide a basis for sedimentary model of the Majiagou Formation of the Daniudi gas field.