基于压裂停泵曲线的压裂裂缝形态分析方法:以玛湖致密砾岩储层M井区为例

Fracture Geometry Analysis Method Based on Pumping Curves:A Case Study of M Well Block in Mahu Tight Conglomerate Reservoir

水平井分段压裂技术可显著提升单井产能,但井间或段间增产效果差异较大,明确压裂效果差异原因的一大关键是明确人工裂缝形态。现有压裂裂缝形态监测手段成本高昂,难以实现所有井的动态监测。压裂施工曲线数据量较大且容易获得,但目前对其利用十分有限,如何充分利用大量的压裂施工曲线,获取地层关键参数及认识人工裂缝形态,是急需解决的问题。对玛湖砾岩油藏压裂泵注曲线的特征进行研究,基于压裂施工曲线停泵阶段的水锤特征判断裂缝复杂程度,明确压裂段的裂缝发育情况;利用分形理论结合不稳定渗流理论形成砾岩油藏压裂停泵曲线分析方法,该方法可结合微地震监测结果,根据泵注曲线压降特征反演得到人工裂缝总缝长等信息。研究方法得到的裂缝总缝长与一体化压裂模拟结果具有一致性,能够高效、有效地评价压裂效果。

The productivity of wells can be significantly enhanced through multi-stage hydraulic fracturing of horizontal wells,though there is notable variability in the production uplift across different wells or stages.Understanding the geometries of hydraulic fractures is pivotal to discerning the cause of this variation.Currently available methods for monitoring fracture geometry are expensive and do not support dynamic,well-specific monitoring.Conversely,the data volume from fracturing pumping curves is extensive and easily obtainable.Yet,the current use of this data is rather limited.A pressing challenge lies in effectively harnessing this copious fracturing curve data to deduce vital reservoir parameters and to gain a deeper comprehension of hydraulic fracture geometries.The characteristics of fracture pumping curves within the Mahu conglomerate reservoir were studied.The complexity of fractures and the occurrence of sand plugging at the fractured stage were identified by analyzing the water hammer effects evident in shut-in curves.A shut-in curve analysis method for conglomerate reservoirs in the Mahu region was proposed,grounded in fractal theory and transient seepage theory.This approach amalgamates micro-seismic monitoring outcomes to ascertain the total length of hydraulic fractures and other pertinent details via shut-in curve inversion.The total fracture lengths deduced through the proposed method aligns with the results of integrated fracturing simulations and can serve as an efficient metric for evaluating fracturing efficacy.