| The geological development conditions of polymer flooding in offshore oil fields are complex with high investment and high technical risk.It is particularly important to grasp and highlight the characteristics of polymer flooding potential evaluation in offshore oil fields to improve the accuracy and reliability of the evaluation results of polymer flooding potential.Through collecting and sorting static and dynamic data of tertiary oil recovery blocks at home and abroad,the research status and influencing factors of polymer flooding technology are summarized.Compared with the reservoir type,reservoir permeability and heterogeneity,viscosity of crude oil,oil layer temperature,formation water salinity,13 blocks in Bohai oilfield are not suitable for polymer flooding technology,and the other 21 blocks can be used to evaluate the potential of polymer flooding.According to the characteristics and development status of Bohai heavy oil reservoir,combined with polymer flooding technology,the reservoir in Bohai oil field are divided into four types,and the difference of polymer injection conditions among the four types of reservoirs are compared.Through the analysis of the polymer flooding conditions and the dynamic and static conditions of the reservoir,the technical characteristics of the potential evaluation of polymer flooding in offshore oil fields are expounded,and the accuracy and reliability of the evaluation results of the potential of polymer flooding in offshore oil fields are improved.Based on the evaluation method of reservoir numerical simulation technology and combined with the Monte Carlo principle,a set of potential evaluation method of polymer flooding is proposed,which can take into consideration both the technology and the risk.According to the geological characteristics of Bohai heavy oil reservoir,a numerical model is established based on X reservoir and its history is fitted.On this basis,the influencing factors of the development efficiency of polymer flooding enhanced oil recovery technology in Bohai heavy oil reservoir are studied.As a result of potential evaluation,polymer flooding in each block of X reservoir has good development results,and the expected recovery range is 4.28% to 6.30%.The enhanced oil recovery is 5.05% to 6.02% and the expected value is 5.58%.The risk of polymer flooding in most blocks is less and the risk resistance is stronger.The potential of polymer flooding in A area,E area,F area and H area is larger,the recovery is not less than 5.6%,the risk is relatively small and the risk index is not more than 16.04%.Therefore,it is suggested that the polymer flooding can be taken the lead in the implementation of the polymer flooding in these blocks.The field test of recovery rate provides guidance for enhanced injection recovery technology of polymer flooding in Bohai oilfield. |
