Study On Induction Period Of Particle Fouling In Gathering Pipeline Of Ultra-high Water Content

Some of China's earlier developed oil fields have entered the development period of ultra-high water content,with the comprehensive value being more than 90%.A large number of problems emerge along with the ultra-high water content period,such as high liquid production and high water cut of single well,high salinity and water incompatibility in different blocks,which contribute to an increasing trend of particle fouling in gathering pipelines with ultra-high water content.For this issue,systematic theoretical analysis and numerical simulation investigations were conducted in this paper.Also,a theoretical model of induction period for particle fouling was deduced,which provides guidance for oilfield fouling control measures.Based on parameters calculation and model optimization for the transport,adhesion and removal stages of particle fouling in gathering pipelines,the initial deposition model for particle fouling was established.Moreover,numerical simulations of particle fouling were performed with the Fluent software,in which Reynolds stress model and enhanced wall function were adopted to solve the flow field,while discrete phase model was utilized to solve the particle movement.The inlet velocity boundary function was supplied in the numerical model to provide fully developed inlet turbulent velocity.By utilizing preferred formula of adhesion efficiency,the wall boundary function was loaded to determine the adhesion or removal state of particles.As a result,the deposition velocity and removal efficiency of the initial deposition under different influence factors were obtained.Furthermore,the rationality of the numerical model was validated by sensitivity analysis of model mesh,comparison of wall shear stress between simulated results and empirical formula results,comparison of particle transport velocity between simulated results and empirical formula results and comparison of initial net deposition velocity between simulated results and experimental data.Subsequently,influence factors on the initial deposition of particle fouling in gathering pipelines with ultra-high water contents were analyzed based on the numerical model,and the effect rules of particle concentration,particle diameter,mainstream velocity and wall roughness on the deposition velocity and removal efficiency were determined.Finally,based on the effect of particle fouling on the pressure drop variation of pipe flow,the formula of the measurable induction period of particle fouling was proposed,and the applicable formula for equivalent particle size of deposited particle fouling was determined.Then a case study was further performed,which clarifies the effect of pipe diameter and pressure gauge accuracy on the induction period of particle fouling.