Application of Polymeric microspheres in extra low permeability reservoir in Huabei Oilfield

Abstract

Aiming at the problems of low water displacement recovery effect in extra low permeability reservoir of Fault-block B10 in Huabei oilfield, the oil recovery technique of surfactant flooding under polymeric microspheres was proposed in this paper. According to the features of polymeric microspheres deep profile control technique, expansion, plugging capacity and migration ability of two samples were evaluated. On the basis of these, a polymeric microspheres matched with the B10 reservoir was selected and tested in the field. Field application indicated that average pressure elevation of each well was up to 4 MPa, corresponding wells efficiency were 88%, comprehensive water was decreased by 6.6% and cumulative incremental oil production was 3350t.Fault block B10 in Huabei Oilfield had an average porosity of 17.6% and an average permeability of 3.5×10−3μm2. It belonged to a low porosity ultra-low permeability reservoir. The surface crude oil viscosity was 90mPa.s, which belonged to ordinary heavy oil reservoir. Many years of water injection had formed a fixed water flow channel in the formation. The water injection wave and volume were not balanced, and the problem of inefficient or ineffective water injection circulation was becoming more and more prominent. At present, the comprehensive water cut had reached 90%. After surfactant flooding in some well groups, due to the serious heterogeneity of reservoir, displacement fingering was obvious and the implementation effect was poor. As a new type of deep profile control and flooding agent, polymer microspheres can form step-by-step plugging after entering the low-permeability reservoir, and greatly adjust the water flooding flow field and expand the sweep volume [1]. In order to explore the adaptability of polymer microsphere to B10 reservoir, a polymer microsphere suitable for B10 reservoir was selected by static expansion of microsphere and dynamic physical model plugging experiment of core. Field application showed that the polymer microsphere had good adaptability in B10 fault block.