| Reserves of heavy oil are extremely rich in the world.Nowadays,with the increasing depletion of the conventional oil and gas resources,heavy oil is undoubtedly an unconventional oil and gas resources demanding prompt exploration.The development methods of heavy oil reservoirs can be mainly divided into two kinds:thermal recovery and cold production.In china,the main development methods of heavy oil reservoirs are steam flooding,steam soak,conventional water flooding and so forth.The thermal recovery technologies are limited by the depth of the reservoir in deep-buried heavy oil reservoirs,and the economic benefits are difficult to be guaranteed at the same time.Acorrding to the classification standard of reservoirs,the heavy oil reservoir of WTG formation in J7 wellblock is a middle deep heavy oil reservoir.As the depth of production well is deeper and the thermal recovery technologies are limited,field test of water flooding is conducted in J008 area with the consideration of economic benefits at the same time.However,compared with most of heavy oil reservoirs which adopt water flooding method around the world,heavy oil reservoir of WTG formation in J7 wellblock is characterized by crude oil with high viscosity(the surface viscosity of crude oil is between 100.5mPa s and 10027mPa·s at 50℃)and low mobility.It is difficult to find the very similar heavy oil reservoir to compare and analyze.So it is necessary to study related aspects of water flooding to indicate whether water flooding is suitable for this heavy oil reservoir.In this paper,based on the actual production data of J008 area,the adaptability research of water flooding which includes laboratory experiment and field test in heavy oil reservoir of WTG formation in J7 wellblock was done by means of physical experiment,reservoir engineering method and reservoir numerical simulation method.In the part of laboratory experiment,several sets of foundation experiments of fluid and rock and water flooding experiments were completed.Futhermore,the change regularities of oil displacement efficiency,relative permeability curve,and water cut were analyzed.And the boundary of crude oil viscosity(1250mPa s)which is suitable for water flooding was confirmed at the same time.In the part of field test,the water flooding effects were analyzed by reservoir engineering method.And combined with the experimental results,the predictive study of development was done by 3D geological modeling method and reservoir numerical simulation method.The research results of this paper confirm that this reservoir can obtain the ideal development effects under the condition of water flooding.It means that water flooding is suitable for this heavy oil reservoir.And the possible reasons of water-cut remain stable in medium water-cut period were analyzed.Last but not least,some injection-production parameters were optimized,and follow-up development plans were designed.The results of this study can provide some references for the development of the same type heavy oil reservoirs. |
