Research On The Optimal Selection Of Schemes Of Polymer Flooding Conducted Upwards In The Second Array Of Southeast Block Of Bei-Three Area

The second array of Southeast Block of Bei-Three Area has entered into high water cut period now,the moisture content is 93.45% and the recovery degree is 46.82%;the moisture content of S?1-9 layers is 92.57% and the recovery degree is 36.67%;the moisture content of S?10-S?10 layers is 94.07% and the recovery degree is 53.5%.In order to ensure the reasonable use of the cost and the sustainable development of the block,it is important to confirm the reasonable time and pattern of upwards to the polymer flooding stage of S?1-9 layers.This paper formulate the suitable scheme for S?1-S?10 interval and design three schemes: using the original well pattern,exchange the original pattern and combining the new and old well.Using the numerical simulation analysis to evaluate the schemes.The best scheme for the whole interval is combining the new and old well,which the S?1-9 layers using the original oil wells and infilling wells to reduce the well spacing,the S?1-S?10 interval using the 250 m * 125 m pattern to develop the subsequent water flooding.Compared with the original well pattern and well-exchanged pattern,the recovery degree increased by 0.03% and 0.3%.In allusion to the S?1-9 layers,two kinds of single slug injection scheme are designed: injection of 5000mg/L polymer solution 0.18 PV,phased recovery degree is 8.37%;injection of 1500mg/L polymer solution 0.6PV,phased recovery degree is 12.96%.Three multi slug injection scheme are designed: injection of 0.06 PV,5000mg/L and 0.1PV,3000mg/L and 0.2PV,1500mg/L phase of polymer solution,the degree of recovery is 15.21%,the final recovery rate reached 51.88%.The degree of stage recovery is increased by 5.64% and 3.59% to the scheme which inject 0.1PV,3000mg/L and 0.06 PV,5000mg/L and 0.2PV,1500mg/L polymer solution and which inject 0.2PV,1500mg/L and 0.1PV,3000mg/L and 0.06 PV 5000mg/L polymer solution.