基于最优支撑剂指数法优化低渗气藏裂缝参数

现行裂缝参数设计方法没有考虑以压后有效渗透率为设计参数，也没有考虑经济允许的最佳压裂规模，因此不能确保压裂效果的长效性与经济性。基于支撑剂指数法，以经济最大化为目标，考虑非达西流动效应与压裂液伤害对裂缝渗透率的影响，结合经济因素、油藏规模、压裂规模间相互关系得到最优支撑剂指数函数，压裂已知规模气藏时，通过该关系函数可确定唯一的最优支撑剂指数及最优缝长，通过迭代求解可得到非达西流动条件下最优裂缝参数。计算结果表明，非达西流动效应越严重，最优支撑剂指数越小，最优缝长越小，最优缝宽越大，降低裂缝内非达西流动效应的影响需要设计低穿透比和高导流能力的裂缝。

Optimizing the Fracture Parameters of Low Permeability Gas Reservoirs

The effective fracture permeability and fracturing scale which are allowed by the economy is rarely considered in thepresent fracture design method，as a result，the long effectiveness and economics of the fracturing results can not be ensured.Based on the concept of Proppant Index，with maximization of economy profit as the objective，an optimal proppant indexfunction is established by considering the relationship between economic aspects，reservoir size and fracturing scale. For agiven reservoir size the only optimal proppant index and optimal fracture length can be determined by using this function，andwith the iteration method we can get the optimal fracture parameters under non-Darcy flow conditions. The results show that themore severe non-Darcy flow effect in the fracture，the smaller the optimal proppant index and fracture length is，and the largerthe optimal fracture width is，a fracture with lower penetration ration and higher fracture conductivity is needed to minimizethe non-Darcy flow effect.