庆城夹层型页岩油地质工程一体化压裂技术

Geological Engineering Integrated Fracturing Technology for Qingcheng Interlayer Shale Oil

针对庆城夹层型页岩油储层物性致密、原始油藏压力系数低和湖相沉积非均质性强的特点,采用大型物理模拟试验、水平检查井取心观察和微地震频度与震级分析等方法,明确了裂缝系统以人工主裂缝为主、支/微裂缝为辅;根据细分切割裂缝思路,采用桥塞/球座分段多簇射孔联作工艺为主体技术;从地质工程甜点综合特征出发,优化布缝策略、段簇组合和簇间距;基于限流压裂原理,采用暂堵控制多簇裂缝扩展,以大量现场压裂资料为样本集,优化压裂关键参数;根据压裂对缝网导流能力的需求,优化压裂液和支撑剂的粒径组合。通过上述研究,形成了庆城夹层型页岩油地质工程一体化压裂技术。庆城页岩油区块的180口水平井应用页岩油地质工程一体化压裂技术完成4590段压裂,压裂后单井初期产量达到了14.5 t/d,第1年产量递减率降低10百分点以上。研究和现场应用表明,页岩油地质工程一体化压裂技术可以实现油藏与裂缝的匹配,有效支撑了庆城页岩油百万吨级产能建设,为陆相页岩油资源高效动用和效益开发提供了技术支持。

Qingcheng interlayer shale oil possesses the characteristics of tight reservoirs,a low pressure coefficient in the original reservoirs,and significant heterogeneity in lacustrine sediment.According to the methods of large-scale physical model experiment,coring observation of horizontal inspection wells,and microseismic frequency and magnitude analysis,the fracture morphology of the fracture system was mainly artificial main fracture,followed by branch/microfractures.The idea of subdividing and cutting fractures was applied,and the segmented multi-cluster perforation joint cropping process using bridge plug/ball block was taken as the main technology.Starting from the comprehensive sweet spot characteristics of geological engineering,the fracture layout strategy,segment and cluster combinations,and cluster spacing were optimized.Based on the principle of limited entry fracturing,the multi-cluster fracture propagation was controlled by temporary plugging,and the key parameters of fracturing were optimized with a large number of on-site fracturing data as the sample set.According to the demands for fracture network flow conductivity,the particle size combination of fracturing fluid and proppant was optimized,and the development of a geological engineering integrated fracturing technology specific to Qingcheng interlayer shale oil was formed.The 180 horizontal wells in Qingcheng shale oil block were fractured in 4590 stages using the geological engineering integrated fracturing technology.After fracturing,the initial production of a single well reached 14.5 t/d,and the production decline rate in the first year was reduced by more than 10 percentage points.The research and field applications have demonstrated that the the geological engineering integrated fracturing technology for shale oil can effectively match oil reservoirs and fractures,thereby providing vital support for achieving a million-ton production capacity in Qingcheng shale oil.This technology also contributes to the efficient utilization and beneficial development of continental shale oil resources.