Research on Non-Newtonian flow seepage pattern of heavy oil and potential tapping strategy
Due to its high viscosity characteristics,the heavy flow exhibits non-Newtonian fluid flow behavior during water flooding in porous media,deviating from the Darcy seepage law.To elucidate the effects of the starting pressure gradient and viscosity variations of heavy oil on its seepage characteristics and water flooding patterns,rheological experimental data from the S Oilfield,where the crude oil has a formation viscosity ranging from 24 to 452 mPa·s,with an average of 150 mPa·s,were utilized.This analysis established the relationship between the starting pressure gradient and the mobility of the oil phase,as well as the relationship between the oil viscosity and the displacement pressure gradient.Based on the simulation results,a seepage mathematical model considering non-Newtonian seepage law is developed,and the numerical simulations are conducted for S oilfield.The results show,when considering the non-Newtonian seepage law of starting pressure gradient and variable viscosity,the water flooding swept area will be reduced and non-piston effect intensifies.The horizontal wells,with their larger displacement pressure gradient,effectively overcome the starting pressure,and reduce the viscosity,resulting in a significantly larger sweep area compared to directional well.Based on this,a chart was developed to quantitatively characterize the production range of directional and horizontal wells under different viscosities,providing guidance for the potential tapping strategy in heavy oil fields.Guided by this research,which integrated the study of non-Newtonian seepage characteristics and production range,the well location optimization for adjustment wells was carried out,leading to notable improvements:production increased from 25 m3/d to 70 m3/d,and the water cut decreased from 88%to 4%.The results provide valuable reference for the potential tapping in heavy oilfields.
Heavy oil reservoirNon-Newtonian fluidStarting pressureVariable viscosityProduction range
国家科技期刊平台
NSTL
万方数据
