Research On Identification Of Gas Reservoir And Distribution Of Gas-Water In The Xujiahe Member, GuangAn Oil Field

GuangAn Xujiahe gas reservoir is a lithologic gas reservoir in the low amplitude structure .Its reservoir with the characteristic of complicated reservoir spreading, strong heterogeneity in both vertical and horizontal, it also has a feature of poor reservoir physical property which represents in low porosity and permeability, high water cut and high water-gas ratio and small pore throats. All these result in the hard development. So we need to discuss the identification methods of the gas reservoir and research its gas-water distribution laws, which are significant to enhance the benefit of gas field development.Based on the comprehensive analysis of regional geological data, logging data, test data and its analysis, this paper researches the logging interpretation model and its parameters, gas reservoir identification methods and gas-water distribution laws in the compact sandstone gas reservoir of the GuangAn Xujiahe gas reservoir systematically.First, we do the comprehensive analysis about each logging interpretation models and their parameters using the core analysis data, logging data and test data. Then we do the research on the quantitative evaluation of reservoir model and method based on the"core calibrating log". We set up the shale content model, porosity calculation model, permeability calculation model, the water saturation model and the irreducible water saturation modle, and determine the parameters in the shale and the parameter of the formation water resistivity. Using the test data and electrical property data of the individual layer, we know the sorts and name standard of the Xujiahe producing pay and determine the recognition models and identification standards of each producing pay.Then through the study about the identification methods of the compact sand reservoirs in GuangAn Xujiahe gas reservoir, we got the methods of qualitative identification to reservoirs, identification of natural gas reservoirs in a direct way by the difference in three-porosity, identification of dense gas reservoir with sonic traveltime difference way and quantitative identification of natural gas reservoirs with the movable water analysis method, and all of them are applied well.Finally, using the well logging interpretation data, test data,production data and analysis assay data, we build the vertical distribution patterns and the characteristic of gas-water distribution in profiles in different pore structure types, different structural positions and depositional positions. Based on the well logging interpretation data, the isopach maps of the available reservoirs and the sedimentary microfacies maps, we study the gas saturation distribution and the characteristics of gas-water plane distribution of each stratum,and summarize the gas-water distribution model. Then we can analyse the characteristics of gas-water distribution and controlling factors in Xujiahe formation and pointed out the available development area.