庆城页岩油藏结构化驱油压裂技术研究与应用

Research and Application of Structured Flooding Fracturing Technology in the Qingcheng Shale Oil Reservoir

  • 摘要: 庆城页岩油储层纵横向非均质性强,脆性指数和储层压力系数小,需进行大规模体积压裂,但黄土高原地貌复杂,干旱缺水,大规模体积压裂存在供水不足的问题。针对以上问题,采用数值模拟方法优选了压裂增能模式,将内部井分为增能井与非增能井,以提高液体利用率,实现了兼顾增能与减水的目标;采用增能井与非增能井差异化压裂工艺参数,采取优化调整压裂顺序等措施,创新形成了结构化驱油压裂技术,不仅提高了井组内部地层能量、实现了缝控程度最大化,还改善了压裂用水供应不足的问题。该技术在庆城页岩油藏应用效果良好,与常规体积压裂相比平均单井节省压裂液5 000 m3,支撑剂1 200 m3,初期产油量提高1.1 t/d。研究表明,结构化驱油压裂技术能够实现降本增效,具有较好的现场推广应用价值。

     

    Abstract: Qingcheng shale oil reservoirs have strong lateral and vertical heterogeneity, a low brittleness index, and a small reservoir pressure coefficient, necessitating large-scale volume fracturing. However, the complex topography of the Loess Plateau, characterized by arid conditions and water scarcity, poses the challenge of insufficient water supply for large-scale volume fracturing. In response to these issues, a numerical simulation method was used to optimize the fracturing energy enhancement mode. The internal wells were divided into energy enhancement wells and non-energy enhancement wells to improve the liquid utilization rate and achieve the goals of both energy enhancement and water usage reduction. Through differentiated fracturing process parameters for energy enhancement and non-energy enhancement wells and the optimization of fracturing sequences, a structured flooding fracturing technology was innovatively developed. This structured flooding fracturing technology not only increased the formation energy within the well group and maximized the degree of fracture control but also ameliorated the issue of insufficient water supply for fracturing. The technology showed good application results in Qingcheng shale oil. Compared with conventional volume fracturing, the new technology saved an average of 5 000 m3 of fracturing fluid and 1 200 m3 of proppant per well, with an initial oil production increase of 1.1 t/d. The results show that structured flooding fracturing technology can reduce costs and increase efficiency, and it has good value for field promotion and application.

     

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