有效改造体积压裂效果评价方法及应用

Evaluation Method and Application of ESRV Fracturing Effect

准确刻画压裂缝网改造体积以及厘清影响改造体积的主控因素,是非常规油气藏体积压裂有效实施的关键。然而,目前尚缺乏精确刻画缝网改造体积的方法,主控因素分析也过于简单,不能满足实际工程需求。针对该问题,提出了一种基于非结构化网格的复杂缝网有效改造体积刻画方法,该方法在精确刻画缝网系统的基础上,与实际生产动态紧密结合,采用随机森林算法分析影响改造体积的主控因素,评价方法更加客观,符合现场需求。现场应用结果表明:新方法所获得的改造体积与传统方式估计的改造体积相比更准确,平均相差16%;压裂缝网规模由多变量控制,影响改造体积的一级主控因素中,压裂施工参数影响占53.8%,地质及岩石力学参数影响占46.2%。该方法可为多段压裂水平井的优化设计及压裂后生产效果预测提供借鉴。

It is critical for effective implementation of stimulated reservoir volume fracturing in unconventional oil and gas reservoirs to accurately characterize the effective stimulated reservoir volume(ESRV)and clarify the main controlling factors affecting the stimulated volume.However,there is still no effective methods to accurately characterize the effective stimulated reservoir volume,and the analysis on main controlling factors is too simple to meet the demand of practical engineering.In response to this problem,an ESRV characterization method based on unstructured network was proposed to accurately characterize the fracture network system in combination with actual production,followed by the analysis of main controlling factors that affects the stimulated volume by random forests algorithm.The evaluation method is more objective,meeting the field demand.The results of the field application showed that the stimulated volume calculated by the new method was more accurate than that estimated by the traditional method,with an average difference of 16%;the fracturing fracture network was controlled by multiple variables;the influence of fracture construction parameter accounted for 53.8%and that of geological and rock mechanics parameters accounted for 46.2%among the primary main controlling factors affecting the stimulated volume.This method provides a reference for the optimal design of multi-stage fracturing of horizontal wells and the prediction of post-fracturing production.