Study on Pore Structure and Seepage Characteristics in Huhenuoren Oilfield

Abstract

Pore structure and seepage characteristics have been studied in view of the problem of watercut rose rapidly in Nantun formation of huhenuoren oilfield of Hailar basin. Fan delta deposition with characteristics of close resource, rapidly accumulation results in pore distribution does not uniform, communication are weak. Throat distribution takes on dual peak. Left peak corresponds to smaller throat, which is invalid throat; Right peak corresponds to bigger throat, which is valid throat and seepage channel. There exists big difference in pore structure. Microanisotropy is very strong. Movable oil saturation is relatively low. Water relative permeability takes on convex shape. Strong water sensitivity and big Jamin effect brought about that injection water hard to displace oil below 1μm throat radius. The oil production above 1μm throat radius is about 77% of total oil production by NMR test. Throats above 1μm radius are preferred path of injection water, are the main reason for watercut rising rapidly.