Low Permeability Oilfield Recoverable Reserves Calibration Method

This paper analyzes and summarizes in very great detail the development characteristics and law in low permeability oilfield,forecasting method of development indexes like watercut,oil production in low permeability oilfield by using the oilfield development dynamic data,scientifically predicts oilfield development indexes,forms the authentic calculation method,calibrates accurately the recoverable reserves and measures the recovery factor.Based on the introduction of calculation method of recoverable reserves in the early,middle and late development stage of oilfield,according to actual production data of the large amount of low permeability reservoirs,the type of Production decline law and the law of water-cut variation are obtained by calculation,they provide evidence for the prediction of development indexes and calculation method of the recoverable reserves. And we give the chart of watercut and recovery percent,which suitable for Low Permeability Oilfield on the basis of tong's chart.For the problem of how to choose the representative relative permeability curves in many samples,using the standardized improved method of the average relative permeability curve,we correct the calculation method of oil displacement efficiency and about the volume factor on this basis, and get satisfactory result. At the same time, by analyzing and comparing the recovery factor, effective thickness, reservoir permeability, well spacing density and numbers of oil and water well in 25 Low-permeability reservoirs,based on multiple regression principle,we produced three new formulas for calculating recovery factor of the low permeability oilfield.According to the developed characteristics of geological structure,well pattern,development stage and type of water drive in the oilfields,thinning geological unit,redefine geological reserves of every geological unit,calculate and demarcate its recoverable reserves,and analyze the results.By analyzing the method of improve the potential of recovery factor in water drive oilfields,evaluate the potential of geological unit,and also evaluate the potential of well pattern adjustment for every address unit and encryption for different oil price in detail,and show clearly direction of exploiting potentialities of developed fields.