Selection of the favorable coalbed methane(CBM) blocks in eastern Ordos basin

After 20 year exploration and development, the CBM industrialization hasn't been realized in eastern Ordos basin. With the enrichment of CBM exploration data, it is necessary to select favorable blocks. In this paper, firstly, in combination with previous research, the area shallower than 1500m in eastern Ordos basin may be divided into six blocks, and 9 parameters were chosen as selecting index, such as coal seam thickness, gas content, tectonic condition, hydrologic condition, coal structure, gas saturation, reservoir pressure gradient, permeability and the ratio of critical reservoir pressure to the reservoir pressure; secondly, the corresponding critical evaluation value was determined. The above 9 parameters are set as the evaluation index aggregate, evaluation unit as the object aggregate, favorable, sub-favorable and unfavorable as rating level aggregate. Then by using the fuzzy mathematics comprehensive evaluation method, the membership degree to the evaluation grades of the evaluation parameters for each evaluation unit was obtained, and by using hierarchy analytic process, the relative weight of every index was obtained. Finally, the membership degrees to the evaluation rating was obtained. According to the maximum membership degree principle, Wubao-Liulin was sorted as favorable area, Daning-Jixian and Hancheng as sub-favorable areas, and Zhungeer, Fugu, Hequ-LinXian as unfavorable areas, the CBM recovery in Wubao-Liulin is higher than that in Daning-Jixian and Hancheng, and Wubao-Liulin, Daning-Jixian and Hancheng were proposed as CBM priority development blocks in eastern Ordos basin.