Research On X Oil Field In Y Area Permeability Reservoir With High Water Content

The reserves of low permeability reservoirs are abundant,which are of great potential for exploitation.However,the strong vertical heterogeneity can lead to serious interlayer interference that is further aggravated in high water cut stage.Therefore,the optimization research,based on its reservoir characteristics,about water displacement technique in the longitudinal in low permeability reservoir at the high water cut stage is of great significance to achieve the inter-layer and inner layer of balanced recovery and EOR.Based on the pseudo threshold pressure gradient model,a numeral simulation program,modified the well production calculation methods,is made for multilayer low permeability reservoirs.An interference coefficient is defined to quantify the extent of interlayer interference.Using this parameter,interlayer interference factors,characteristic and mechanism of interlayer interference were studied.According to thorough analyses of the influence factors of layer series subdivision and recombination,a definition of synthetic effective mobility is proposed.It,consisting of static indexes(permeability,viscosity)and dynamic indicators(oil saturation,injection pressure,threshold pressure gradient),can fully reflect the impact of either single-factor or multi-factors.Besides,in terms of the average change in the effective permeability of the hydraulic fracturing reservoir,a data chart is established to calculate the average effective permeability under different scales of fracturing of low permeability reservoir.Then,depending on the study of the policy limit for low permeability layer series subdivision and recombination in high water cut stage,a multi-factor optimization technique is finally proposed.Furthermore,two techniques,separate-layer water allocation technology and variable density perforation technology,are brought forward to realize the equilibrium development effect among layers after conducting subdivision and recombination.The optimization method about water displacement technique in the longitudinal in low permeability reservoir at the high water cut stage is applied in block 5 of Bonan oilfield,which provides certain guiding significance to effectively reduce the impact of vertical heterogeneity and improve development result.