【作者】 任岚； 黄静； 赵金洲； 贾久波； 谢斌； 黄波；

【机构】 "油气藏地质及开发工程"国家重点实验室·西南石油大学； 中国石油新疆油田分公司；

【摘要】 重复压裂是提高页岩储层单井产量和采收率的有效技术。初次压裂形成的复杂裂缝网络及随生产进行而被扰动的储层应力场和压力场为页岩气水平井重复压裂产能模拟带来挑战。本文基于页岩储层压后多重孔隙介质特征,考虑页岩气在开采过程中"有机质干酪根-无机质纳米孔隙-天然裂缝"的多尺度空间流动行为,以及储层参数和水力了裂缝导流能力随生产的动态变化,建立了页岩气水平井重复压裂产能预测的数学模型。基于矿场生产数据的历史拟合验证了该模型的可靠性。探讨了气井重复压裂后储层压力、吸附气含量、有效应力和水力裂缝渗透率变化规律。初次压裂后生产过程中的应力敏感效应使得水力裂缝导流能力随有效应力增加减小,对于目标区域,这种趋势在生产3年后变缓且趋于平稳。重复压裂恢复和增加了原有水力裂缝的导流能力,再次为页岩气的流动提供快速通道,提高页岩储层吸附气的采出程度。更多还原

【Abstract】 Refracturing is an encouraging way to uplift gas flow rate and ultimate gas recovery from shale gas wells.The existing fracture network,disturbed stress and pressure field make it a big challenge for production simulation of refractured shale horizontal wells.A numerical model is applied while considering the "kerogen system-inorganic matrix system-fracture system" flow behavior and dynamic variation of reservoirs parameters and hydraulic fracture conductivity.The model is verified against field data from the field.The change trend of reservoir pressure,adsorbed gas content,effective stress and hydraulic fracture permeability is explored.The stress sensitivity during the production process will reduce the flow capacity of hydraulic fracture with the increase of effective stress,and it presents a stable trend after 3 years production for the simulation field.Refracturing rebuilds a high flow channel for shale gas by restoring or increasing the conductivity of original hydraulic fractures.更多还原