Study On Fluid Interface Migration Law Of CB Gas Cap Reservoir With Edge Water

CB reservoir is a typical offshore gas cap edge-water reservoir with small gas cap,wide oil band and strong edge-water.After reservoir development,the original equilibrium state of hydrodynamic system is broken,and the internal fluid interface becomes more and more complex,which makes it difficult to understand the residual oil.Therefore,it is of great significance to reveal the fluid migration law of gas cap edge water reservoir to determine the residual oil distribution pattern and later potentialtapping strategy of CB reservoir.Firstly,the performance of water and gas production of typical wells in the target reservoir is statistically analyzed,and the reservoir is divided into two displacement regions: edge-water area and gas-cap area.Secondly,according to the characteristics of reservoir edge water area,two-dimensional visualization experiment of strong edge water reservoir was carried out.Combined with reservoir numerical simulation,water cone morphology in different areas was accurately described.Thirdly,one-dimensional physical simulation experiments of gas-cap reservoir were carried out to study the migration and evolution law of oil-gas interface under the influence of many factors such as original gas-cap index,reservoir pressure,well distribution and edge water intensity.Finally,based on the experimental results and theoretical analysis,the residual oil distribution model of CB reservoir is put forward,and countermeasures are put forward for tapping the residual oil potential of CB reservoir from the perspectives of water injection to replenish energy and expanding sweep area.Through this study,it is helpful to improve the understanding of fluid migration mechanism in each region of CB small gas-cap and strong edge water reservoir,make the residual oil distribution pattern of such reservoir clearer,and provide theoretical basis for the exploitation of residual oil in the later stage of reservoir development.