Study On Remaining Oil Distribution And Well Pattern Reconstruction In X Oilfield

In order to solve the problems of low development potential of well pattern and serious heterogeneity of reservoir development in X oilfield in high water cut period,this paper takes the experimental area of X oilfield as the research object,studies the distribution characteristics and causes of remaining oil through numerical simulation technology on the basis of historical fitting,and provides the corresponding adjustment ideas of well pattern measures.In order to alleviate the contradiction between layers caused by long-term "combined injection and production" development,on the premise of comprehensive consideration of nine kinds of reservoir attribute characteristics such as geological reserves and oil-bearing area of each small layer in the target block,the development layer system is re divided by fuzzy cluster analysis method,the SII-PI2 small layer in the target block is divided into the first set of development layer system,and PI3-PI4 is divided into the second set of development layer system,and mining is carried out In order to work out the adjustment scheme of layered water injection well network,this paper introduces the economic indexes such as loan interest rate and tax rate to deduce the improved Yu Qitai formula and the improved decline method formula on the basis of shelkachov formula,and calculates the two formulas respectively through shelkachov formula,the improved Yu Qitai formula and the improved decline method formula.According to the calculation results,the well spacing of the first development layer system should be 100-200 m,and that of the second development layer system should be 200-400 m,On the basis of the above research,through the way of polymer flooding production well and injection well substitution,five well pattern reconstruction schemes with different well spacing are put forward,and the five schemes are simulated respectively by numerical simulation technology,and their development achievements such as recovery degree,water cut,water cut rise rate and oil production speed are statistically analyzed.Based on the comprehensive study and comparison of five schemes,including recovery factor,water cut rise factor,oil recovery rate,development period and economic index,it is determined that the fifth scheme of well pattern reconstruction with the first set of well pattern spacing of 150 m and the second set of well pattern spacing of 300 m is the best scheme,with recovery factor of 45.14%,recovery factor of 2.12% higher than the original scheme,and economic benefit expected to be higher than other schemes,both the development effect and the economic index reach the best effect.