Logging Evaluation Research Of Water-flooded Zone In Tuha Yanmuxi Oilfield

After more than 10 years of water injection development,Yanmuxi oilfield has entered the high water-cut period in large areas,and the comprehensive water-cut rate has reached over 78%.It is quite common that the main producing layer of tertiary reservoir is flooded.At present,the water content of most production Wells increases rapidly and the production decreases seriously,which poses great challenges to the production and increase of oil fields.In the process of secondary development of Yanmuxi oilfield,the logging interpretation of water-flooded strata is becoming more and more complex and the difficulty of evaluation is increasing.The formation is affected by long-term water injection and the reservoir parameters of physical properties all undergo relatively large changes.Especially in heterogeneous reservoirs,long-term water drive development leads to changes in the movement of underground oil and water and the distribution of oil and gas,which is difficult to accurately grasp.In such a complex and changeable situation,it is more difficult to find the remaining oil accumulation area by logging interpretation of the water-flooded layer,and the requirements for oil and water subdivision and water-flooded level in the layer are higher and higher.In this paper,the flooding mechanism of oil field is studied through simulated water flooding experiment of rock samples in the study area.Based on logging data and core analysis data in the study area,the data of oil and water testing,logging interpretation conclusion and dynamic monitoring data are compared and analyzed.The logging response characteristics and parameter sensitivity characteristics of water flooded layers under different water flooding degrees are summarized.Based on the combination of core analysis data and logging data,a quantitative interpretation model for logging in flooded strata is established.Finally,the grey theory evaluation model is used to evaluate the watered-out layer of the study area.Through the above research work,the fine identification of water-out degree of water-out layer in the study area was realized.Through comparison of production test results,the interpretation coincidence rate was increased from the original 68.6% to 88.6%,and the accuracy of interpretation and evaluation was significantly improved.The adaptability of this method to the interpretation and evaluation of water-out layer in the study area was verified.