Study On The Well Pattern Adjustment Method In Different Partitions For The Complicated Fault-block Reservoirs

Compared with conventional reservoirs,complicated fault-block reservoirs have unique geologic and development properties,such as,small oil-bearing areas,irregular shapes,complicated oil-water relationship,abundant faults,uneasy to develop.With most of the oilfield have entered high water-cut stage in our country,the difficulty in development of complicated fault-block reservoirs increases.Consequently,based on the characteristics of the oilfield structure and concentrating rules of remaining oil,the study on well pattern adjustment method in different partitions for the complicated fault-block reservoirs is meaningful to the EOR.Based on documents study and statistical analysis,the typical classification of different types of complicated fault-block reservoirs is summed up.Method of first level reservoir partition is determined on the basis of the characteristics of oilfield structure,faults distribution and seepage characteristics of different types of complicated fault-block reservoirs.Combined with the concentrating rules of remaining oil of reservoirs at high water-cut stage,the characteristic index and policy limits for method of second level reservoir partition are determined.According to different types of fault-block reservoir,the study about the encrypted oil well position and the relative position of oil and water wells in different partitions is carried out.Based on the study about the optimization of zonal well pattern,the study about comprehensive well pattern adjustment methods for different fault-block reservoirs is conducted.By means of reservoir numerical simulation technology,the concentrating rules and causes of remaining oil of different reservoir partitions are analyzed by water flooding flow and pressure gradient distribution.Reservoir engineering method is also applied to establish the economic policy limits of the single-well encryption,the single-well encryption chart of fan-shaped opening fault-block reservoir is established.The optimal arrangement of oil and water wells to the potential tapping of remaining oil is summed up.The optimal scheme of well pattern deployment at early development stage and the comprehensive well pattern adjustment methods at the high water-cut stage is formed considering the number of injection-production wells,the shape of well pattern,the position of wells.Taking equilibrium displacement as the target of optimization,a optimization program about injection-production well group with one water well and two oil wells spacing at the high water-cut stage is compiled using reservoir engineering method,and the effects of main factors on the reasonable injection-production well spacing are analyzed,such as formation dip angle,the average reservoir permeability and water saturation of oil wells.