| Based on the previous studies,the author collected a large amount of relevant data,conducted many works such as indoor core observation,identification of common rock flakes and casting sheets,X-ray diffraction experiments,scanning electron microscopy experiments,mercury injection,oil-water phase infiltration,nuclear magnetic resonance and other experiments made a comprehensive research on petrological characteristics,pore structure characteristics,seepage characteristics and oil content.According to its location and structural characteristics,Mahu depression is divided into Maxi slope area,Mabei slope area and Madong slope area.The strata in the study area are almost completely preserved.The main strata studied in this paper are the sandy conglomerate reservoirs of Triassic Baikouquan Formation in Maxi slope area and Mabei slope area,and the sandy conglomerate reservoirs of Permian Wuerhe Formation in Madong slope area,all of which are fan delta sedimentary facies.The lithology of the reservoir is mainly sand conglomerate,whose content is 60 ~ 70%,and the others are mudstone.There are many types of pore in gravel reservoir,including residual intergranular pore,intragranular dissolution pore,intergranular pore and micro-fracture;pore throat types are mainly flake and dot roar,and tubular roar,etc.The pore structure of gravel reservoir can be classified into I~IV types according to its physical properties and mercury injection experimental data,and its pore structure becomes worse in turn.The rock samples were selected for different types of pore structure for oil-water phase infiltration test and nuclear magnetic resonance experiment.The experiment found that the bound water saturation content of the glutenite reservoir in the Mahu sag is higher overall,and the wettability is mainly neutral to little Water wettability The pore structure plays an important role in the seepage characteristics of the reservoir. |
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