Investigation On Flow Rule Of B-PPG Heterogeneous System In Porous Media

Most oil fields in China are found in continental sedimentary basins. They arecharacterized by complex geologic conditions and high permeability contrasts in sidereservoirs. In the absence of active aquifer，these oil fields were developed by water injectionat the early stage of their development. However, serious vertical and lateral heterogeneity informations resulted in a rapid increase in the water-cut of oil wells. A new kind of in-depthdiverting agent called B-PPG(Branched-Preformed Particle gel) has been developed to controlconformance of mature reservoirs.This paper mainly studies which factors influence B-PPG property, its flow rule in theporous media and why B-PPG can improve oil recovery.According to the research of the particles’ diameter and the viscosity of the system, theB-PPG system is stable and not sensitive to temperature and salinity.The sand-packed core experiments show that the pattern of the swelling particles passingthrough the pore throat is that while the particles were injected in the sand-packed core, firstlythe particles are blocked at the pore throat, then the particles deform and pass through whilethe pressure increasing. Its movement in the porous media can cause fluid diversion.Based on the study of the effective viscosity and the passing factor of B-PPG system,permeability, concentration and flow rate have a great impact on its effective viscosity, butthey have little effect on passing factor.The sand pack oil displacement experiments and visualization oil displacementexperiments also showed that B-PPG can improve the mobility ratio, and cause fluiddiversion. Therefore the B-PPG system can improve the heterogeneity and increase sweepefficiency, and improve the overall recovery.