Numerical simulation of separate-layer injection-production effect and its influencing factors in offshore oilfield——by taking SZ36-1 oilfield in Bohai sea as an example

Based on the geological characteristics and fluid properties of SZ36-1 oilfield in Bohai sea, a theoretical model of row injection-production pattern is established by using CMG reservoir numerical simulation software, the effects of general injection and production, separate injection of water wells and "separate-layer injection-production", as well as its influencing factors are studied. The results show that the separate injection-production is beneficial to further expand the sweep volume of injected water in each layer and enhance water flooding recovery. However, the early or late separate production will weaken the oil increasing effect. The optimal time for the row injection-production pattern is that water cut reaches 90% water and the optimal injection rate is 33%. The recovery rate increases show a trend of "first up and then down" with the increase of well array distance ratio. The optimum well array distance ratio is 1.25. For the reservoir with strong plane heterogeneity, the separate injection-production can adjust the plane contradiction and improve the displacement front, advancing in "rectangular", so as to improve the oil production effect.