The Research Of Coal Reservoir’s Geological Modeling In Hancheng Mining Area

Coalbed methane(CBM) as an unconventional gas, its exploitation value become more and more attracte to the countries increasingly.At present, the geological modeling theories and methods for CBM reservoir characteristics premature are not maturity. Conventional experimental methods and log interpretation methods can not accurately represent the permeability properties numerical size of coal rock, because the coal rocks are easily broke and its dual porosity and low permeability characteristics, so the geologic modeling methods cannot employ the ordinary methods used in sandstone reservoirs. This paper summarized a set of comprehensive coal reservoir modeling ideas and methods applied in the coal reservoir geological characteristics, which can provide strong support to the numerical simulation of coalbed methane wells and scientific guidance for the accurate prediction of favorable reservoir area of the coal, as well as the well network deployment, it has important practical significance for the development of coalbed methane production.Taking the Han Cheng area as the study object. Based on the analysis of the data of logging data and core sample research, established the stratigraphic depositional model of the study area, and completed the fine description of the three sets of the coal reservoirs including 3 #, 5 #, 11 #. Different parts of the coal samples were collected, the paper analyzed the cleat and micro crack control factors including coal rock types, stress, tectonic location, etc. Found the relationship between the coal rock type and cleat development. Through optimized well logging curve type, set up many types of coal and rock parameter logging identification chart, and completed the study of coal and rock type logging identification method. Concluded the spatial distribution law of different kinds of coal and rock mining area. According to the data of hydraulic fracturing, calculated the geostress values of different well-blocks. Based on the well test data and the seepage theory, through analysis of a large number data, concluded the relationship between the permeability properties and coal rock types, the distribution of stress field, etc, and established their corresponding mathematical relationship.Coal reservoir permeability is mainly affected by coal rock micro-fracture and cleat, and the both are controlled by ground stress field and coal rock types.Therefore, first of all, used the deterministic modeling methods to establish the coal reservoir rock types and ground stress field model. Based on the relationship between permeability and in-situ stress, used the stochastic modeling methods to establish Hancheng mining area coal reservoir physical model under the double constraints of the coal rock types and ground stress field, and formed a set of suitable modeling method for coal reservoir. The method improved the geological modeling accuracy of the Coalbed methane reservoir greatly, and provided guidance to the deployment and programming of the mining area.