考虑非达西流效应的致密气藏压裂优化设计方法研究

摘要

A methodology based on Proppant Number approach for optimal fracture treatment design of tight natural gas wells considering non-Darcy flow effects in the design process is presented, which can also take into account the gel damage. Simulation shows that the optimized fracture dimension should have shorter length and wider width when taking into account the on-Darcy flow and gel damage. In the condition of fixed fracturing scale, in order to obtain the maximum productivity index , the longer the fracture , the higher conductivity the fracture need. Study hold that no matter from the aspect of fracture conductivity or effective fracture length , during the process of optimizing design of low permeability or tight reservoir, should give more attention to the fracture conductivity when pursuing long fracture, for the purpose of diminishing the on-Darcy flow influence the productivity of gas well.%基于无因次支撑剂系数的方法,探讨了如何在考虑非达西效应的情况下,优化致密气藏气井压裂设计的方法.同时该方法可以考虑聚合物残渣的伤害.模拟发现,考虑非达西流效应以及残渣伤害设计的最优裂缝尺寸所需裂缝长度较短,缝宽较宽.在压裂规模确定的情况下为了获得最大的采油指数,造缝越长,需要的裂缝导流能力也越高.研究认为,不论从裂缝导流能力方面,还是从有效裂缝长度方面,在低渗或致密气藏压裂优化设计过程中,在追求缝长的同时应当更多的关注裂缝导流能力,以减小非达西流效应对气井产能的影响.