基于微地震监测的深层页岩储层压裂效果评价

Evaluation of Fracturing Effectiveness in Deep Shale Reservoirs Based on Micro-Seismic Monitoring

摘要: 威荣气田五峰–龙马溪组优质页岩储层埋深普遍超过3500米，属于深层页岩气范畴，威荣深层页岩具有“一深、两低、三高”的特点，一深：储层埋藏深；两低：低脆性、低裂缝发育程度；三高：高温、高应力、高应力差，导致压裂难以形成复杂裂缝、难以形成裂缝有效支撑。模拟表明，压裂裂缝有效率为28.7%~44.5%，平均42.8%实践表明开发效果并不理想，为准确评价储层压裂效果，评估现有压裂工艺的适用性，气田开发过程中开展了井中微地震监测，利用监测数据开展缝网展布特征分析、压裂体积计算、暂堵效果评价及天然裂缝发育情况分析等研究，成果为威荣气田压裂效果综合评价、压裂设计调整、开发方案优化等工作提供了技术参考。

Abstract: The buried depth of the high-quality shale reservoirs in the Weirong Gas Field’s Wufeng-Longmaxi Formation generally exceeds 3500 meters, belonging to the category of deep shale gas. The deep shale of Weirong Gas Field has the characteristics of “one deep, two lows, and three highs”. One deep refers to the deep burial of the reservoir; two lows refer to low brittleness and low fracture development; three highs refer to high temperature, high stress, and high stress difference, which makes it difficult to form complex fractures and difficult to effectively support the fractures. Simulation shows that the effective rate of fracturing fractures is 28.7%~44.5%, with an average of 42.8%. Practice shows that the development effect is not ideal. To accurately evaluate the fracturing effect of the reservoir and assess the applicability of the existing fracturing technology, micro-seismic monitoring in the well was carried out during the development of the gas field. The monitoring data was used to analyze the characteristics of fracture network distribution, calculate the fracturing volume, evaluate the temporary plugging effect, and analyze the development of natural fractures. The results provide technical references for the comprehensive evaluation of fracturing effects, adjustment of fracturing designs, and optimization of development plans in the Weirong Gas Field.