鄂尔多斯盆地中东部奥陶系储层控制因素分析

鄂尔多斯盆地中东部奥陶系呈现出宽缓的盆缘含硬石膏白云岩坪与盆缘硬石膏白云岩坪相带，为孔洞型储层的成层发育、大面积展布创造了良好的条件。中部地区储层物性明显好于东部地区。本文从古岩溶地貌、古沟槽展布、压释水分布以及孔洞充填物类型的差异，系统分析了储层分布的控制因素。进而利用电子探针分析、同位素分析及包裹体测温，探讨了孔隙充填物的类型及形成环境。充填物中的白云石主要包括微成水微晶白云石、淡水白云石及马鞍状白云石三种类型，方解石主要包括微咸水粉细晶方解石、淡水方解石及铁方解石三种类型。微咸水微晶白云石和微成水粉细晶方解石主要形成于同生期层间岩溶发育期，淡水白云石及淡水方解石主要形成于裸露期风化壳岩溶发育期，马鞍状白云石及铁方解石主要形成于中深埋藏环境。

The Controlled Factors of Reservoir in the Ordovician of Middle-Eastern Ordos Basin

The square-built dolomite flat containing karstenite and karstenite-dolomite flat in the Ordovician of middle-eastern Ordos Basin provide the favorable condition for the stratify development of pores and holes and the large acreage distributing. The reservoir capability on the middle excel to the eastern. In this paper, according to the ancient karst landform, the distribution of the ancient groove, the distribution of the compacted released water and the difference of filling matter in the pores and the holes, analysis the controlling factors of reservoir. Using the electron probe microanalyzer, the isotope and fluid inclusion, are discussed the types and forming surrounding of filling matter. The dolomites contain mainly the brackish water fine crystalline dolomites, the fresh water dolomites and the saddle dolomites. The calcites contains the brackish water fine crystalline calcites, the fresh water calcites and Fe-calcites. The brackish water fine crystalline dolomites and the brackish water fine crystalline calcites is formed in the course of the interval karst in the course of sedimentary, the fresh water dolomites and the fresh water calcites is formed in the course of the weathering crust karst in the course of denudation, the saddle dolomites and Fe-calcites is formed in the course of middle-deep bury.