压裂裂缝地面微地震监测技术

Surface micro-seismic monitoring technology for fractured fractures

为明确薄差油层压裂裂缝形态、走向,验证砂体发育特征,建立了注采井驱动关系,开展压裂裂缝地面微地震监测。按要求埋置三分量检波器,在仪器放置点各连接一套监测仪器系统检测储层压裂过程中地层发生破裂形成的声波,以此确定裂缝方位、形态,判断平面及纵向油层发育存在的差异。5口井压裂监测结果表明,砂体发育与裂缝波及体积呈正相关性,表外差层裂缝延伸能力差,波及孔隙体积与压裂液规模相当;表内薄差层裂缝延伸能力强,波及孔隙体积大于压裂液体积。多层合段压裂时缝间干扰界限在1.5m,隔层厚度小于界限时,裂缝延伸相互抑制,形态无法区分。裂缝形体及走向与砂体非均质性关系明显,纵向上发育越好的层裂缝能量剖面越大,平面上发育越好的方向裂缝能量剖面延伸越明显。应用压裂裂缝地面微地震监测技术,有助于分析裂缝形态、走向及砂体发育特征,有效指导压裂方案设计。

In order to clarify the shape and trend of fractured fractures in thin and bad reservoirs and verify the development characteristics of sand bodies,the driving relationship of injection-production wells was established,and surface micro-seismic monitoring of fractured fractures was carried out in this paper.In order to determine the orientation and shape of fractures,and to judge the reservoir development difference between horizontal direction and vertical direction,the three-component geophone was buried according to the requirementsand a set of monitoring instrument system was connected at each point of the instrument placement to detect the acoustic wave caused by breakdown of formation during fracturing.The fracturing monitoring results of five wells show that the sand body development was positively correlated with the volume affected by the fracture.The fracture extension ability of the outer bad layer was poor,and the sweep pore volume was equal to the scale of fracturing fluid.However,the fracture extension ability of the inner thin and poor layer was strong,and the sweep pore volume was larger than the fracturing fluid volume.When multiple layers were fractured together,the interval interference limit was 1.5m,and when the thickness of the barrier was less than the limit,the fracture extension was mutually restrained,and the shape cannot be distinguished.When the relationship between fracture shape,strike and heterogeneity of sand body was obvious,the fracture energy profile of the layer with better vertical development was larger,and the fracture energy profile extended more obviously in the direction with better horizontal development.The application of surface micro-seismic monitoring technology for fractured fracture is helpful to analyze fracture morphology,strike and sand body development characteristics,thus effectively guiding the design of fracturing scheme.