郝丽华, 甘仁忠, 潘丽燕, 阮东, 刘成刚. 玛湖凹陷风城组页岩油巨厚储层直井体积压裂关键技术[J]. 石油钻探技术, 2021, 49(4): 99-105. DOI: 10.11911/syztjs.2021092
引用本文: 郝丽华, 甘仁忠, 潘丽燕, 阮东, 刘成刚. 玛湖凹陷风城组页岩油巨厚储层直井体积压裂关键技术[J]. 石油钻探技术, 2021, 49(4): 99-105. DOI: 10.11911/syztjs.2021092
HAO Lihua, GAN Renzhong, PAN Liyan, RUAN Dong, LIU Chenggang. Key Technology of Volumetric Fracturing in Vertical Wells of Hugely Thick Shale Oil Reservoirs in the Fengcheng Formation of the Mahu Sag[J]. Petroleum Drilling Techniques, 2021, 49(4): 99-105. DOI: 10.11911/syztjs.2021092
Citation: HAO Lihua, GAN Renzhong, PAN Liyan, RUAN Dong, LIU Chenggang. Key Technology of Volumetric Fracturing in Vertical Wells of Hugely Thick Shale Oil Reservoirs in the Fengcheng Formation of the Mahu Sag[J]. Petroleum Drilling Techniques, 2021, 49(4): 99-105. DOI: 10.11911/syztjs.2021092

玛湖凹陷风城组页岩油巨厚储层直井体积压裂关键技术

Key Technology of Volumetric Fracturing in Vertical Wells of Hugely Thick Shale Oil Reservoirs in the Fengcheng Formation of the Mahu Sag

  • 摘要: 玛湖凹陷风城组页岩油储层砂体埋藏深、厚度大、整体含油、基质致密、富含金属离子,压裂面临着纵向动用程度不足、裂缝复杂程度低、加砂风险高、常规胍胶压裂液不配伍等改造难点。为充分释放其页岩油勘探潜力,通过精细描述储层力学性质,评价缝网形成的主控因素,建立可压性指数计算模型,结合人工裂缝纵向扩展能力优选射孔簇及层间距,形成了纵向精细分层方法。基于天然裂缝发育程度,通过优选体积压裂工艺,采用大排量施工提高缝内净压力、不同粒径支撑剂组合多尺度充填、缓增幅泵注安全加砂,优化大规模组合改造工艺,配套研发低伤害耐温聚合物压裂液,最终形成了玛湖凹陷风城组页岩油巨厚储层直井体积压裂关键技术。该技术在MY1井风城组页岩油储层施工成功率100%,压裂后获日产50 m3高产油流,开创了玛湖凹陷非常规油藏勘探新局面,对指导该储层后续页岩油效益开发意义重大。

     

    Abstract: Shale oil reservoirs in the Fengcheng Formation of the Mahu Sag are characterized by a large buried depth of sandbodies, huge thickness, overall oil-bearing properties, dense matrix, and enrichment in metal ions. As a result, fracturing is prone to be insufficient in vertical extension and unable to cover the reservoir, with low fracture complexity, high sanding risks, and an incompatibility of conventional guar gum fracturing fluid. Based on a detailed description of reservoir mechanical properties and an evaluation of the main controlling factors of fracture networks, a calculation model of fracability index was built to fully exploit the exploration potential of the shale oil in this area. In light of the vertical fracture propagation, the perforation clusters and cluster spacing were determined to develop a fine vertical layered approach. In accordance with the development of natural fractures, the optimized volumetric fracturing technology was upgraded, and the net pressure in fracture was increased by construction with high pumping rate. Multi-scale filling was realized with the combination of proppants of different sizes, and a gradual pumping rate increase was employed to ensure safe sand adding. Further, a series of temperature-resistant and salt-resistant polymer fracturing fluids were developed. As a result, the key technology was developed for volumetric fracturing in vertical wells of hugely thick shale oil reservoirs in the Fengcheng Formation of the Mahu Sag. This technology has been successfully applied in Well MY1 in the shale oil reservoirs of the Fengcheng Formation, with a high-yield oil flow of 50 m3 per day after stimulation treatment. This started a new and promising prospect of unconventional reservoir exploration in the Mahu Sag, which is of great significance in guiding the subsequent shale oil development in this area.

     

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