Organization
Qingdao Research Institute of Safety Engineering, SINOPEC, Qingdao 266000, China
摘要
当前，致密气藏产能预测方法多数只考虑单因素或双因素影响，且未考虑致密气藏双重渗流特征，存在产能评价结果不够准确等问题。文中以稳定渗流理论为基础，通过引入雷诺数判断高速非达西流动边界，同时考虑压裂措施区和非措施区存在不同的启动压力梯度、滑脱效应以及高速非达西流动效应等多因素影响，建立了致密气藏压裂井产能预测方法。研究结果表明：启动压力梯度和高速非达西流动均会造成附加压降，导致气井产能变小，若忽略其影响，将会对产能乐观评价；增产措施和滑脱效应会使气井的产能增大，若忽略其影响，将会对产能悲观评价；在采取增产激活措施时，渗透率达到一定值后，应主要增加缝长，而不是缝宽。文中模型通过简化就可得到一般的考虑单因素或双因素影响的产能预测方法，可对采取压裂酸化等措施的致密气田开发提供理论指导。
Abstract
Since the current tight gas reservoir productivity prediction methods only consider the influence of single factor or two factors, and do not consider the dual flow characteristics of tight gas reservoir, resulting in inaccurate productivity evaluation results. Based on the steady flow theory, the productivity prediction method of fractured wells in tight gas reservoir is established by introducing Reynolds number to judge the boundary of high-speed non-Darcy, and the influence of multiple factors, such as different starting pressure gradient, slippage effect and high-speed non-Darcy effect in the work area and the non-work area is considered. The results show that both start-up pressure gradient and high-speed non-Darcy will cause additional pressure drop, resulting in smaller gas well productivity, if the influence is ignored, the productivity will be evaluated optimistically; stimulation measures and slippage effect will increase the productivity of gas wells, if the influence is ignored, the productivity will be evaluated pessimistically; when stimulation measures are taken, when the permeability reaches a certain value, the fracture length will be increased rather than the fracture width. The model can provide theoretical guidance for the development of tight gas fields with fracturing and acidizing measures, and the general productivity prediction method considering the influence of single or double factors can be obtained by simplifying the model.
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