Effect Of Remaining Oil In South Q-South W Block Of Sanan Development Zone

The object of this study is the South Q-South W block,south of South China Development Zone.After two times of encryption and adjustment,the area of the thin and surface layer is low,and the remaining oil is excavating.After the multi-disciplinary reservoir study,it is found that the block is not adapted to the thin oil layer due to the large well spacing and the complex underground structure.The thickness of the thin and surface layer after two encryption is low.At present,some thin oil layers and the outer surface layer are still used for poor or unmovable use,in order to improve the moving status of this part of the oil layer.We should tap the remaining oil potential and deploy the three infill well pattern.Using various dynamic and static data analysis of the block,the geological model is established and the distribution of residual oil is analyzed.The results show that the mining degree and the remaining reserves of different types of sand bodies are different;the remaining oil is scattered in the plane and in the longitudinal direction.The oil recovery is low and the remaining oil is relatively enriched.According to the current well network,the determination of the economic boundary principle and the reutilization of the well network,the block is adjusted by "uniform well distribution and selective drilling".Five different schemes of well distribution are proposed.Because the three encryption and adjustment objects in this block are mainly thin and poor oil layers in the sac,Portuguese and high oil layers,the injection production relationship of the two encrypt wells should be carefully considered in the well layout scheme,and the three encryption adjustment is mainly combined with the two encryption adjustment,and the injection production relation of the thin and poor oil layers is perfected together,and the injection production well spacing is reduced.Through the comparison of five different well layout schemes,plan two(in an encrypted well row,interwell interbed inter injection wells,three encryption to form a 250 x 250 m five point method area well network.There are 145 oil and water wells,including 79 wells and 66 wells.The comprehensive utilization rate of well pattern is high after the connection with original well pattern is returned.In the process of implementing the scheme,the reform of the supporting measures and the adjustment of the scheme are carried out in time.By optimizing the design of perforation scheme,optimizing the adjustment of water injection scheme,fracturing,acidification or chemical profile control and so on,the inter layer contradiction is relieved and the use degree of the thin oil layer is improved.Through the adjustment of three encryption schemes,the moving condition of the oil layer is improved,the control degree of water flooding is improved,the water injection structure of the block well network is adjusted,the oil recovery speed of the block is improved,the natural decline rate is slowed down,and the recovery rate is improved.After the implementation of a series of three encryption adjustment schemes and relevant supporting measures,the accuracy and speed of historical fitting can be improved,the potential size and distribution of residual oil can be studied,and the quantitative and detailed description of the distribution of residual oil can be realized.The results can effectively guide the compilation of the comprehensive oil field management scheme.It has important guiding significance for water flooding adjustment.