致密储层人工裂缝与天然裂缝夹角对水驱油效果的影响

Effect of the angle between hydraulic fracture and natural fracture on water flooding in tight reservoirs

王晓明 陈军斌 孙晨 柳文欣

WANG Xiaoming CHEN Junbin SUN Chen LIU Wenxin

西安科技大学地质与环境学院 西安石油大学陕西省油气井及储层渗流与岩石力学重点实验室

College of Geology and Environment, Xi’an University of Science and Technology, Xi’an 710054, Shaanxi, China Shaanxi Key Laboratory of Well Stability and Fluid & Rock Mechanics in Oil and Gas Reservoirs. Xi’an Shiyou University, Xi’an 710065, Shaanxi, China

为研究人工裂缝与天然裂缝夹角对水驱油效果的影响，考虑重力和裂缝对水驱油效果的影响，建立了非活塞式水驱油油水两相单向渗流模型，利用有限元分析方法，通过产量和含油率定量分析人工裂缝与天然裂缝夹角处于0°~90°时对水驱油效果的影响。研究表明：人工裂缝与天然裂缝夹角越大，油井产量越高，当人工裂缝与天然裂缝夹角为90°时，油井累积产量最高，且油井产量递减速度最小；人工裂缝与天然裂缝夹角增大，扩大了注入水波及基质系统的范围，驱油效果显著，当人工裂缝与天然裂缝夹角为90°时，裂缝系统和基质系统的驱油效果显著优于其他角度的裂缝分布，注入水波及范围最广，剩余油最少，但水驱油效率整体较低。该研究结果有助于认识裂缝分布对于水驱开发效果的影响，并预防水窜的发生。

In order to study the effect of the angle between hydraulic fracture and natural fracture on water displacement effect, a non-piston water flooding oil-water two-phase one-way seepage model was established considering the influence of both gravity and fracture on water displacement. And finite element method (FEM) was used to quantitatively analyze water displacement effect when the angle between hydraulic fracture and natural fracture was 0°~90° by production and the distribution of oil content. Results show that: the higher the angle between hydraulic fracture and natural fracture, the higher the oil well production. When the angle between hydraulic fracture and natural fracture was 90°, the cumulative production of oil well was the highest, and the production of oil well decline rate was the slowest; the greater the angle between hydraulic fracture and natural fracture was, the wider the spread range of injected water was in matrix system, and the effect of water flooding was remarkable. When the angle between hydraulic fracture and natural fracture is 90°, the water flooding effect in fracture and matrix systems was better than other fracture distributions, the spread range of injected water was the widest, and the remaining oil was the least, but the overall efficiency of water displacement was low. The research results are helpful to understand the effect of fracture distribution on water flooding development and prevent water breakthrough.

10.13639/j.odpt.2022.01.013