Conditions Of Analysis Of The Coalbed Methane Upper Palaeozoic In Southeast Ordos Basin

By using drilling, logging and laboratory analysis data and predecessors’studying results in this paper, integrated use of petroleum geology, sedimentary petrology, natural gas geology, coal petrology, multidisciplinary knowledge such as well logging geology, on this basis that, we research detailedly the southeastern ordos basin coalbed methane reservoiring condition supper palaeozoic, specialy we study that on the three aspects with the coal and rock characteristics, coal reservoir conditions and CBM later preservation conditions. We get the result:the basic structure on the southeastern ordos basin tend to be west shelving monoclinic, on the boundary exists reverse thrust nappe structure zone. Mining area is located in the area of Seoul development more sets of strata (taiyuan and shanxi group), and the larger thickness of coal seam, wider distribution range, higher coal and rock thermal evolution degree, at the stage of high maturity thermal evolution, hydrocarbon generation potential, higher hydrocarbon generation intensity, for hydrocarbon of the main gas phase, all that provide sufficient gas source conditions For coalbed methane rich integration. The porosity of coal reservoirs in the study area is an average of about5%; the coal reservoir permeability is differences, and to a certain extent, affected by coal body structure. The content of coal seam gas is mainly distributed in8and12m3/t; Coal adsorption saturation is mainly between in46%8and46%; reservoir temperature is higher than others, the original ground stress is lower than others, all that provides favorable reservoir environment occurrence for coalbed methane reservoir. The whole structure is relatively stable, Buried depth of coal seam and the overpressure zone, the coal seam buried depth shallow And in the overpressure zone. The roof and floor lithology Coal seam mainly mudstone and sandy mudstone, fan belt surrounded wide, good continuity, and distribution, all that provides favorable conditions for late save.Hancheng district water type is given priority to with CaCl2and NaHC03, the type of NaHCo3water is easily to produce local layer flow, overpressureformed by the formation water flow not free, forming a block type of CBM reservoir. To sum up, Ordos basin in Seoul area coal measures strata upper palaeozoic, With its sufficient gas source, good reservoir and powerful later preservation conditions determines CBM rich integration in the area.