Study On Sand Production Regularity In Foamy Oil Reservoir

A serious of sand production often occurs in unconsolidated sandstone.It will bring a lot of troubles,such as the erosion or damage of pipeline and equipment,even leading casing failure and production reduction.Sand production,especially for heavy oil reservoir in unconsolidated sandstone,is often accompanied with foamy oil flow,in which a higher change of pressure and viscosity promotes sanding and deformation of rock skeleton.So the study of sanding mechanism and foamy oil flow in unconsolidated sandstone will have more significance in petroleum production.From the understanding of the typical characteristics of unconsolidated heavy oil reservoir,the sanding mechanism,influence factors and foamy oil flow in unconsolidated sandstone have been studied in this paper.On this basis,the theoretical coupled model of fluid seepage considering the dynamic characteristics of foamy oil and solid deformation is established,and the quantitative prediction model of the production is also given.Numerical solution is carried on the application software Comsol,so the influence of in-situ stress,the strength of reservoir,production pressure drawdown and foamy oil flow on loose sandstone has carried on,and research and analysis the big wormhole area of space-time change law in the process of development.The research results show that the strength of the rock,production pressure drawdown,insitu stress,the angle of the perforation length,perforation length and heterogeneity are the important factors affecting sanding.If reservoir rock strength is smaller,the production pressure drawdown is larger,in-situ stress heterogeneity is stronger,perforating angle and the perforation length is smaller and porosity heterogeneity is the stronger,sand production ability of loose sand reservoir will be stronger;Considering foamy oil flow,establishment speed of the production pressure drawdown and porosity heterogeneity is the important factors affecting the sand production ability.If establishment speed of the production pressure drawdown is faster,the dispersed bubbles will precipitate faster,so the drag force on rock grains is stronger;If the heterogeneity of porosity is stronger,the partial pressure gradient will be bigger,and this will produce the greater drag force when the the dispersed bubbles blocked pore,in turn,rock particles are more likely to fall off from the skeleton and sand production will become easy.