A new quantitative evaluation method for development area selection of tight gas and CBM commingled production

Abstract

Existing evaluation methods used for the development area selection for commingled production of tight gas and coalbed methane (CBM) are poorly universal and their parameters (e.g. reserves and reservoir physical properties) cannot reflect the production rate difference during commingled production of tight gas and CBM. In this paper, an integrated evaluation coefficient used for evaluating favorable commingled production areas of tight gas and CBM was defined so as to establish a universal quantitative evaluation index system. Then, by means of orthogonal design together with numerical simulation, the key parameters influencing the commingled production rate and their influence degree on the production rate were determined by taking the commingled production rate as the evaluation target. Finally, a new quantitative evaluation method for the development area selection for commingled production of tight gas and CBM was established. And the following research results were obtained. First, by virtue of the new quantitative evaluation method, the geological occurrence model of tight gas and CBM, the key evaluation parameter and the orthogonal experiment design are established, and the influence degree of evaluation parameters on production rate and the integrated evaluation coefficient of favorable commingled production area of tight gas and CBM are determined. Second, the quantitative evaluation results on the development areas of commingled production of tight gas and CBM in KNW Block based on 12 selected key parameters show that the southern KNW Block and the Well block KNW-37 in the north of KNW Block are the favorable areas for single production of tight gas, Well blocks KNW-10, KNW-33 and KNW-9 are the favorable areas for single production of CBM, and the central and southwestern areas are the favorable areas for the commingled production of tight gas and CBM. In conclusion, this new quantitative evaluation method is universal and can be used as reference for the development area selection for commingled production of tight gas and CBM.