WC Sea Side / Bottom Water Reservoir Waterflood Efficiency And Remaining Oil Distribution

With the sustainable development of Nanhai west offshore Wenchang natural water-drive oilfields, the main reservoirs have reached medium-high water cut stage, the impact on distribution of remaining oil by reservoir heterogeneity has increased. The research about remaining oil distribution becomes a top priority. The annual production of Wenchang oilfields accounted the annual output of Zhanjiang Branch for over65%during2009～2011. Thus, The stable production of Wenchang Oilfield Group is of great significance for Zhanjiang Branch to realize the production target. Therefore, carrying out remaining oil prediction technology and distribution research of the main reservoirs, clearing the potential tapping direction of remaining oil, formulating development and adjustment technical countermeasures, is of great important for further maintaining good development state of Wenchang Oilfields Group and achieving production mission goal of branch company.This research takes Wenchang19-1Oilfield as the object. By fitting the pressure value, we found that the pressure drop of every oil group is very small at the current reservoir pressure. It shows that the natural water energy of Wenchang19-1oilfield A, B platform is sufficient. The current recovery degree Ro are16.32%and25.22%, respectively, and the predicted ultimate recovery are36%and45%.The main factors of affecting remaining oil distribution can be attributed to geologic and development. We will find the main factors of affecting the distribution of remaining oil that well network of development, structural characteristics, aeolotropism, flowing units and water energy when uniting geology of target reservoir, logging interpretation of RPM saturation and results of numerical analogue. The residual oil distribution is matched with the sedimentary facies and the distribution of flow units.The adjustment strategy of development about the enhancing recovery degree of residual oil as follows:Wenchang19-1A has relatively greater potential to extract residual oil than Wen19-1-A7H, Wen19-1-A8Ha and Wen19-1-A9H. The north of Wen19-1-A1H, near the central Wen19-1-A31H、and the southern of Wen19-1-A9HB are the favorable area with remaining oil.Wenchang19-1B reservoir has great potential ability to extract in middle-late period, and the favorable area for producing the remaining oil is eastern region. We can consider the production on the back to Zhuhai when the production of Wen19-1-B1and Wen19-1-B3go into the late period. Numerical simulations predict that the amount of production increased with the amount of extract.