Technology Research On Waterflood Adjustment For M Block Of YS Oilfield

Most oil layers of YS oilfield belongs to low permeability and extremely lowpermeability reservoirs. The development effect is the same as other low permeability andextremely low permeability reservoirs. The oil well production is low. After fracturingoperation, decline fast and stable production status is poor; after breakthrough, the water cutrises rapidly, and fluid productivity index and oil producing index fall fast; oil production rateis slow, and recovery ratio is low. The overall oilfield development effect is poor. So for lowpermeability water drive reservoir, how to adjust water flood to realize the reasonable waterinjection and promote the balanced use of two types of oil reservoirs is significant toimproving the development effect and controlling the oil field production decline.First, geology static data and production performance data of M block of YS oilfield areanalyzed, and the comprehensive development curve of production status are mapped. Gain awhole understanding about general geological situation and development process of researchblock. From this, the present problems existing in the development process are realized.Secondly, considering bottom-hole flowing pressures of production wells and injectionwells, water oil ratio, oil production rate and well pattern form, establish the forecastinginjection-production ratio formula of the research block. The injection-production ratio andannual contribution are determined. Influencing factors of dividing coefficient aredetermineded, including permeability, effective thickness, injection/production well number,injector producer, measures transforming coefficient, and position coefficient. With the greycorrelation analysis method, the main influence factors weight are determined; planar andvertical dividing coefficient are created; water injection amount formulas of single well andlayer are established to calculate the injection rate of wells and layers. With oil wells andwater wells production dynamic data, and the grey correlation analysis method, interwellconnectivity and flowing direction of injected water are studied, to provide the basis forinjection rate scheme adjustment.In the end, according to the static data, the3D geological model of M block isestablished with Petrel software; combining with dynamic development data, establish thenumerical simulation model with Eclipse software, and conduct develop dynamic matching.The matching result is within precision allowed. According to the matching results, the rulesof planar residual oil and longitudinal residual oil are analyzed; the adjustment principles ofinjection rate are made. The injection rate schemes are forecast and evaluated. Cyclicwaterflooding is studied for the research block, and comprehensive adjustment scheme is determined, combined with the oil well production system adjustment.