致密气藏水平井分段压裂缝参数优化

摘要

At present, multiple-fractured horizontal well is a hot spot for the development of tight gas reservoir and unconventional gas reservoir. Its stimulation greatly depends on the fracture parameters. Many scholars at home and abroad have done optimization on single factor for fracture parameters, but the combined influence of each parameter are less considered, so that fracture parame⁃ters combination optimization is desiderated. This article explores the influence law of different fracture parameters on the develop⁃ment of tight gas reservoir by numerical simulation in X tight gas reservoir. Then comprehensive influence of different fracture pa⁃rameters on well productivity is studied by orthogonal test. And the best fracture parameter combination for X tight gas reservoir is 6 fractures, fracture length of 140 m and fracture conductivity of 30 μm2·cm, fracture with staggered distribution, and fracture spac⁃ing in central is greater than that of the root and toe. The order of fracture parameters effect on X tight gas reservoir is the fracture distribution>fracture conductivity>fracture spacing>the number of fracture>fracture length. And it is further proposed that optimiz⁃ing fracture distribution and improving fracture conductivity are the primary way to achieve stimulation for X tight gas reservoir, not simply by increasing the length and the number of fractures.%目前水平井分段压裂技术是致密气藏和非常规气藏开发的热点增产手段，而该技术的增产效果很大程度上取决于压裂缝参数。国内外很多学者对裂缝参数单因素进行了优化研究，很少考虑各参数对产能的综合影响作用，亟需裂缝参数组合优选研究。通过对X致密气藏进行数值模拟研究，探究了不同裂缝参数对致密气藏开采的影响规律，利用正交试验方法研究了不同裂缝参数对产能的综合影响作用。结果表明，X致密气藏的最佳裂缝参数组合是：压裂缝6条、裂缝长度140 m、裂缝导流能力30μm2·cm、裂缝错开分布、水平井中部裂缝间距大于根部和趾部裂缝间距。裂缝参数对X致密气藏开采效果的影响顺序是：裂缝分布>裂缝导流能力>裂缝间距>裂缝数>裂缝长度，并进一步提出X致密气藏为实现压裂增产，应主要通过优化裂缝分布方式，提高裂缝的导流能力，而不是单纯的增加裂缝的条数和长度。