致密气和煤层气联合开发选区量化评价新方法

现有的致密气和煤层气联合开发选区评价方法存在着方法通用性不强、储量与储层物性等参数不能反映两气联采产量差异等问题。为此,以建立致密气和煤层气两气联采通用量化评价指标体系为目的,定义了两气联采有利区综合评价系数,以两气联采产量为评价目标,采用正交设计结合数值模拟手段,确定影响联采产量的关键参数及其对产量的影响程度,建立了两气联采开发选区量化评价新方法,并将新方法应用于鄂尔多斯盆地东缘KNW矿区的两气联采开发选区评价实践中。结果表明:(1)新方法建立和确定了两气地质赋存模式、关键评价参数及正交试验方案设计、评价参数对产量的影响程度、两气联采有利区综合评价系数等;(2)采用优选出的12个关键参数对KNW矿区两气联采开发选区的量化评价结果显示,该矿区南部、北部KNW-37井区为单采煤层气有利区,矿区内的KNW-10、KNW-33、KNW-9井区为单采致密气有利区,矿区中部和西南部为两气联采有利区。结论认为,所提出的致密气和煤层气联合开发选区量化评价新方法具有通用性,对两气联采开发选区具有参考意义。

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

Existing evaluation methods used for the development area selection of 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 effect 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 of 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 effect 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 of commingled production of tight gas and CBM.