致密油藏直井体积压裂非稳态产能评价模型

Logging Company, Huabei Petroleum Engineering Company Ltd., SINOPEC, Xinxiang 453000, China Research Institute of Exploration and Development, Huabei Company, SINOPEC, Zhengzhou 450006, China Research Institute of Exploration and Development, Liaohe Oilfield Company, PetroChina, Panjin 124010, China No.1 Oil Production Plant, Huabei Company, SINOPEC, Qingyang 745000，China)

基于渗透率区域分形和动边界法，文中建立了一种可用于致密油藏直井体积压裂改造非稳态产能评价的解析模型。模型考虑了人工裂缝网络展布及启动压力梯度的影响，并应用已建立的模型对分形系数、启动压力梯度、改造半径（等效于改造体积SRV）等影响产能的参数进行了分析。结果表明：分形系数只对初期产能有影响且影响很大，分形系数负值越大，体积压裂改造越彻底，初期产能越高；启动压力梯度对整个生产期都有影响，对后期产能影响尤为突出，启动压力梯度值越大，产能越低，双对数曲线越晚趋于平缓；改造半径也对整个生产期都有影响，对前期产能影响要远大于后期，改造半径越大，产能增加越显著。这为合理开发致密储层及体积压裂改造优化设计提供了一定的参考。

Based on fractal permeability area and moving boundary method, a non-steady state productivity evaluation analytical model being available for the volume fracturing for vertical well in tight oil reservoir is established. The model takes the effect of artificial fracture network distribution and threshold pressure gradient into consideration. Some parameters, such as fractal coefficient, threshold pressure gradient and reconstruction radius (equivalent to SRV), are analyzed by using the established model. The results show that fractal coefficient only has obvious influence on initial productivity. The greater fractal coefficient negative value is, the more thoroughly reconstruction of volume fracturing is and the higher initial productivity is. Threshold pressure gradient has effect on whole production period, especially on later productivity. The greater threshold pressure gradient value is, the lower productivity is and the later log-log type curve turns to smooth-out. Reconstruction radius also has effect on whole production period, but especially on initial productivity. The larger reconstruction radius is, the higher productivity is, which has a certain reference value for reasonable development and volume fracturing of tight reservoir.

10.6056/dkyqt201501018