Research On The System Efficiency Of The Oil Field Water Injection

The large system efficiency of the oil field water injection and optimization of theimprovement for the large system efficiency are researched in the thesis. Scope of theefficiency evaluation is extended from the surface part to wellbore and near borehole zones.The traditional surface part refers to the extent from input power of the engine to outputpower of the wellhead. The effect of surface efficiency, wellbore efficiency and near boreholezones pollution on the system efficiency is analyzed. Calculation model of the water injectionsurface efficiency and Optimization model based on minimization of injection distributionerror and energy consumption are built. The surface efficiency model includes pump stationmodel, injection pipeline network model and water distribution station model, etc. Solutionsto the calculation models are analytical method, numerical method, graphic method, andmodern optimization method. Calculation model of the wellbore efficiency is also built.Optimization design of proper injection distribution, technology of separate layer injectionand measures to fine separate layer injection for middle-low permeability reservoir are studied.For optimization design of proper injection distribution, well-to-well correlation is analyzedaccording to the reservoir geological data, and optimization method is built through thedividing coefficient and the direction proportion coefficient of fluid output. Sub-runnerinjection technology for highly deviated wells, distribution injection technology for deepwells, non-changeable-volume water mouth distribution technology and eccentric integrationfine-layer injection technology are studied in the thesis. For pollution assessment andimprovement measures of near zones, stimulation technologies of injection are studied,including separate-layer acidizing, nanometer depressing and organic polybasic aciddepressing, in order for the optimization of the injected water inflow performance.Relationship between injection water flooding efficiency and injection system efficiency, andthe theory of improvement of system efficiency by application of distribution optimization arestudied. The theory has great importance on the realization of optimal running of large system,improvement of system efficiency, decrease of injection energy consumption, realization ofhigh efficient, low loss of energy and scientific management for the oilfield.