Characterization Of Fluid Leakage Channels In Hong004 Area Hongshanzui Oilfield,Junggar Basin

The northwestern margin of the Junggar basin is an important oil and gas production area in China,and is rich in heavy oil resources.Hong004 Area is located in the east of Hongshanzui oilfield.After nearly 10 years of heavy oil steam mining.The appearance of oil and water seeps out of the surface in the meantime.There are two main leakage points,which are located in the north（Hongqian 2 station）and west（Hongqian 3 station）of the study area.This surface leakage has not only led to a sharp reduction in production,but also a problem of life safety and environmental pollution.In this paper,the sedimentology,petroleum geology,tectonic geology,logging geology and geophysics are used to analyze the characteristics of the deposit and structure of the Hong004 Area,and combined with the interpretation results of potential method,the distribution characteristics of seepage channels in oil and water are studied,and the leakage pattern is summarized.Based on 3D seismic data,we use Discovery and other software to complete the structural interpretation of the study area.Two sets of fault systems are stored in the study area.The deep reverse fault is mainly concentrated in the southern part of the study area,and the correlation with the leakage point is poor.The shallow reverse fault is closely related to the leakage point in the West.The study area is mainly braided river sedimentary facies,which can be divided into3 microfacies:river channel,channel bar and floodplain.The river channel sedimentary microfacies,whether physical or lithologic,are more advantageous to migration of oil and water than other sedimentary microfacies.Channel Sandbodies can provide a channel for lateral migration of oil and water.The distribution characteristics of sand bodies in the two oil layer of Hong004 Area are analyzed.The sand body of the two oil layer is mainly channel sand body.Among them,the J₁b₂ sand body is related to the northern ground leakage point,and the J₁b₄ sand body is related to the two leakage points in the western and northern parts.The unconformable surface of the Jurassic and overlying strata in the study area is inclined to the southeast and through the whole area,which is directly related to the ground leaking point in the north,and has an indirect correlation with the ground leakage point in the West.According to the results of inversion interpretation of potential method,the vertical distribution of resistivity is an objective response to fracture,unconformity and seepage channel.Through the analysis of the characteristics of the resistivity indicated by oil and water,combine with the drilling data near the ground leakage point and the geological characteristics of the sand body distribution and fracture in the study area,the direction of oil and water migration is directly indicated and the distribution characteristics of the leakage channel are studied and analyzed.There are different leakage modes in the tow leakage points.The leakage point of the Hongqian 3 station is far away from the production well,and the leakage of oil and water is transported to the Cretaceous thick sand layer along the unconformable surface of the production layer,and the longitudinal channel provided by the shallow fault is channeling to the surface.There is no fracture near the leaking point in the Hongqian 2 station and it is located on the unconformable surface,and the oil and water which have leaked through the production layer are moved to the Cretaceous thick sand layer along the unconformity surface of the production layer,and the surface is fleeing from the weak area of the quaternary system.