Evaluating The Gas Filling Capability Of Shanxi Formation In Sulige Area Of Ordos Basin

Based on the principle and method of Reservoir Geochemistry and petroleum Geology, by taking core, logging and testing gas date as research object, using various research methods, the hydrocarbon source rock of Shanxi Formation in Sulige Area were studied in particular. Analysis of the distribution and controlled factors of gas and water, this studies quantitatively the filling capacity of Shanxi Formation'gas.The formation water of Upper Paleozoic stores inⅡandⅢreservoir of the wing of main channel in Sulige Area. Because of the flat ground and the different size sand bodies that are the heterogeneity reservoir for the migration of the river channel, the gas-water transition zone in gas reservoir is disparity. The relations of gas and water distribution becomes further complicated for combining with the intensity difference of the buoyancy and gas expansion of filling.The characteristic of the coal gas source rocks of Shanxi Formation is wide range and large thickness in Sulige Area. And its contribution of the gas generating is the highest. The gas generating amount of the mudstone and coal seams is respectively 499218×108m3 and 295114×108m3. Its amount is 46.84% of the gas generating amount of the hydrocarbon source rocks of the Upper Paleozoic.By the measure and analysis of the homogenization temperatures in the fluid inclusions, in the base of the restoration the burial and ancient temperature history of single well, the author concludes that oil-gas injection occurs two times in Shanxi Formation. The early filling time is about 210~160Ma ago. The late filling occurs in the late Jurassic-Early Cretaceous period and the geological time is about 140 ~ 100Ma ago. The late filling of natural gas is the main accumulation period.In the Shanxi Formation the main grows the compact reservoir, and the high porosity and permeability reservoir range is small. The gas only fills a part of pores by continuous buoyancy-driven in the traps. The most of the small pore storage space is completely filled on the role of gas expansion like piston. So the distribution of gas and water was reversed. However, when the relative strength of natural gas filling becomes large, sand traps may be completely filled, and gas-water interface disappears. The gas buoyancy-driven role is large in the area where the high quality reservoir develops.