Abstract:The Shaan X block on the east side of Jingbian Oilfield is a new development zone. The Lower Paleokarst and Paleotopography is more complicated, and the gas and water distribution law is unclear. In this study, based on drilling and logging data, cores, thin slices and other analysis tests in the area, the reservoir characteristics, paleo-geomorphic characteristics and gas-water distribution laws were studied in the area. Through observation of cores and thin slices, it can be seen that typical karst breccias are developed in the lower paleokarst reservoirs in this area. The reservoir lithology is mainly fine powder crystal dolomite, and the reservoir space is mainly composed of dissolved pores, intercrystalline micropores and crack. Compared with the Jingbian area, this area has an overall deviation of porosity and permeability, weak dissolution, and tighter reservoirs. The study of paleogeomorphology is mainly studied through the combination of impression method and residual thickness method for qualitative and quantitative paleomorphology restoration. The results show that the study area is in the transition zone between karst slopes and karst depressions as a whole, and grooves are only developed in the northern part of the study area. From the high part to the low part of the paleogeomorphology, the reservoir gradually becomes dense and the physical properties gradually deteriorate. Based on the distribution characteristics of gas and water on the plane, combined with the characteristics of reservoirs and paleogeomorphology, it can be seen that the gas and water of Shaan X block is controlled by paleogeomorphology as a whole, and partially controlled by current structures. Among them, there is basically no water in the relatively high part of the paleogeomorphology in the west. The gas and water in the area near the groove in the northeast area are complex, and the water outlet wells are mainly located in the low-lying parts of the present structure. The paleogeomorphology in the southeast area is a karst depression, the reservoir is basically tight, and the gas wells generally produce water.