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

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。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，随着海平面变化相互转化。马五10、马五8、马五72、马五61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，马五71、马五62亚段主要发育膏云坪、云坪及灰云坪微相，马五63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。

Study on high-frequency evolution of sedimentary facies of 6th-10th sub-members of the Ma 5 Member in the Daniudi Gas Field, Ordos Basin

High-frequency changes and unclear distribution of sedimentary microfacies of 6th-10th sub-members 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 6th-10th sub-members 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 6th-10th sub-members of the Ma 5 Member in this area were further analyzed. 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 transformed into each other with the change of sea level. 10th sub-member, 8th sub-member, 2nd layer of 7th sub-member and 1st layer of 6th sub-member of the Ma 5 Member mainly develop gypseous-dolomitic and dolomitic flat. 9th sub-member of the Ma 5 Member mainly develops dolomitic flat and limestone-dolomitic flat. 1st layer of 7th sub-member and 2nd layer of 6th sub-member of the Ma 5 Member mainly develop gypseous-dolomitic flat, dolomitic flat and limestone-dolomitic flat. 3rd layer of 6th 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 6th-10th sub-members 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.