Paleokarst Reservoir Characteristics And Controlling Factors Of Ordovician Majiagou 5 Formation In Daniudi Gas Field, Northern Shanxi

Daniudi gas field is located in the middle eastern Ordos Basin, an area of about 0.34 square kilometers. The ancient karst reservoir in member 51~55 of Ordovician Majiagou Formationof is the main focus of this paper. This paper is based on the geological background, core, slice, logging, capillary pressure curves and other data analysis. Combining with the results of previous studies on Ordovician Majiagou formation in Daniudi gas field, the karst reservoir characteristics and controlling factors are analysised.By analyzing the characteristics of the reservoir rocks, the pore structure characteristics, physical distribution and reservoir characteristics of the study area, it found that the main palaeokarst reservoir rocks are karst breccias, micro-dolomite, and limestone, the main pore structure in the study area is divided into four types, and though the comparative analysis of the results, the conclusion is that the porosity and permeability in Daniudi gas has poor correlation; impression method and residual thickness were applied to restore the ancient karst topography. By compare their advantages and disadvantages finally it uses a comprehensive analysis method to recover the ancient karst topography and carve out the ancient karst landform units. Daniudi diagenetic environment, the impact of diagenesis, tectonic and the influednce of sedimentary facies on ancient karst reservoir are analysised, finally it find the favorlable reservoir development area: Da48- Da38 wells area, Da88- Da29-Da 84 wells area, and Da 41- Da40- Da42 wells area.