Oil and water distribution during advanced water injection process in low permeability reservoir

By using advanced water injection technique,low pressure and low permeability reservoir in Niujuanhu block of Santanghu Basin was effectively exploited,whereas the oil production fell and water content increased rapidly,the study was aimed at characterizing oil and water distribution during advanced water injection process.The micro-pore structure of reservoir was analyzed through mercury curve and CT scanning,oil and water distribution was studied by core experiment and micro-model experiment.Results show that there’s a severe micro-heterogeneity in Santanghu reservoir,and the distribution of oil and water changed during water injection process.With injection pressure and advanced injection time increased,the heterogeneity of reservoir became stronger,and injection water penetrated into high permeability zone which led to a micro-fingering,consequently water content of production well during advanced water injection increased rapidly.Therefore,the injection pressure and advanced injection time should be optimized in low pressure and low permeability reservoir with strong heterogeneity.