考虑基质收缩效应的矩形煤层气藏有限导流裂缝井产能评价

Production Evaluation of Well in Rectangular Coalbed Methane Reservoirs with Finite Conductivity Fracture and Matrix Shrinkage Effect

为了弥补煤层气藏产能评价模型的不足,提出针对基质收缩特性的产能评价模型。阐述了基质收缩效应在煤层气藏产能评价中的影响,通过结合稳态扩散定律、达西渗流定律、Duhamel褶积以及裂缝导流能力转换因子,引入新的拟时间函数,实现了在煤层气藏产能评价中考虑基质收缩效应、有限导流裂缝以及矩形边界,研究了准确高效计算产能评价模型的方法,通过对算法的优化和验证,表明评价方法达到了商业软件化的强度。拟合结果表明,新的评价模型能够较好的拟合现场生产数据,评价结果符合储层及气藏基本认识,误差较小。

To make up the inadequacy of CBM reservoir productivity evaluation model, capacity evaluation model is proposed for matrix shrinkage properties. The paper expounds the influence of matrix shrinkage effect on the evaluation of CBM reservoir capacity. Combine with the steady state diffusion law, Darcy seepage law, Duhamel convolution and fracture diverting capacity conversion factor, introducing the new time function, it is realized that matrix shrinkage effect, finite conductivity crack and rectangular boundary are considered in CBM reservoir productivity evaluation. This paper studies the method to calculate the productivity evaluation model accurately and efficiently. Through the optimization and verification of the algorithm, it shows that the evaluation method has reached the strength of commercial software. The fitting results show that the new evaluation model can better fit the field production data, and the evaluation results are in line with the basic understanding of reservoir and gas reservoir, with small error.