鄂尔多斯盆地东部石盒子组盒8段储层特征及控制因素研究

THE RESERVOIR CHARACTERISTICS AND CONTROLLING FACTORS FOR THE 8TH LAYER OF SHIHEZI FORMATION IN EASTERN ORDOS BASIN

通过物性分析、铸体薄片、恒压压汞、恒速压汞等技术对鄂尔多斯盆地东部石盒子组盒8段储层样品经行分析,认为鄂尔多斯盆地东部石盒子组盒8段储层普遍为低渗透砂岩并具有孔喉较小、分选性较差和细歪度的特点,但同时恒速压汞实验表明大喉道对渗透率贡献大,是提高储层渗流能力的关键。另一方面通过对沉积微相、水动力条件、储层碎屑组分以及成岩溶蚀作用进行系统研究,认为强水动力砂体发育带的心滩微相是相对高渗储层发育的沉积微相,溶蚀作用是相对高渗储层形成的关键。在相对高渗储层形成过程中沉积作用和成岩作用是相辅相成的,强水动力粗粒心滩沉积有利于溶蚀作用的发生,溶蚀作用的发生又促进强水动力心滩沉积向相对高渗储层的转化。

By means of the physical property analysis,casting slice,constant-pressure mercury penetration,and constant-rate mercury penetration,the low permeability sandstone samples of the 8th Layer of Shihezi Formation in eastern Ordos Basin has been studied in this paper.Studies on them show the reservoris is the low permeability sandstone with low pore-minute-ness throat,bad sorting coefficient and slightly fine skewness,but studies based on constant-rate mercury penetration show the differences of pore throat characteristics of low permeability sandstone reservoir mainly lay in throats.so low permeability sandstone reservoir have high permeability sandstone.On the other hand,through systematic study of microfacies、hydrodynamic conditions,detrital composition,dissolution,that strong hydrodynamic conditions with channel bars relative permeability reservoirs development sedimentary microfacies,dissolution is the key to the formation of relatively high permeability reservoirs.At a relatively high permeability reservoirs during the formation of deposition and diagenesis are complementary,the strong hydrodynamic conditions with channel bars deposition is conducive to the occurrence of dissolution,dissolution occurred promote the strong hydrodynamic conditions with channel bars deposited to the relatively hypertonic storage conversion layer.