SPE Paper # 29488 Solid Particle Deposition During Turbulent Flow Production Operations Joel Escobedo and G.Ali Mansoori*, U. of Illinois at Chicago SPE Members ABSTRACT The production and transportation of petroleum fluids could be severely affected by deposition of suspended particles (i.e. asphaltene, paraffin/wax, sand, and/or diamondoid) in the prouction wells and/or transfer piplines. In many instancesthe amount ofprecipiaion is rather largecausing complete plugging of these conduits. Therefre, it is important to understand the bhaviorofsuspndedpaticlesduringfow conditions. In this paper we present an analysis ofthe diffusional effects on the rate of solid particle deposition during turbulent flow conditions (crude oil prodction generally falls within this regime). Theturbulent bundarylayertheorand the concepts of massansferhavebenutilizedto calculate theparticledepsition rates on the walls of the fowing conduit. The developd model accounts for the eddy and Brownian diffusivities as well as for inertial effects. The analysis presented in this paper shows that rates of solid particledeposition(duringcrudeoilproducion)onthewallsofthe fowingchannelduesolely todiffusionalefectsaesmall. It is also shown thatdepsition rates decrease with increasing particle sie. However, hen the processis momentum conolled (lagepaticlesies)higher depsitionratesare epcted. (*) Corresponding author, emails: mansoori@uic.edu; gali.mansoori@gmail.com 439 INTRODUCTION Numerouseprimentalworkshave revealedthecolloidalnatureof the heavy asphaltene fraction of a crude oil. We consider the asphaltenes to eis in crude oil as bth dissoled and suspended particles (1, 2, 3). Disprsed asphaltenes are sterically stabilized by neual resins, they are electrically charged (4), and have a diameter of 30-0 A (5). The stability of these particles canb disruptedbyaddition of solvents (i.e. n-heptane), i t could also b disrupted during fow conditions due to shear stresses, or by counterbalancing theweak asphaltene paticle charge. The laeris an important phenomenon since during crude oil prouction a streaming ptential is generated which is blieved to cause asphaltene aggregation (6). When solvents are used to preipitate asphaltenes,theresulting aggregatesmayhave a diameter as large as30(/). In aditionto asphaltenesthere mayb othertypsof particles suspended in the crude oil as well. For instance, sand particles sept from the reseroir matri. paraffin crystals if the tempraure falls below he cloud pint of he crude. and/or diamondoids. Production and transprtation of petroleum fluids could b seerely affected by depsitionofasphaltene (and other sspnded paticles). In many instances the amount of precipitation is rather large causing complete plgging of the flowing channel. Therefore, it is imprtant to understand the behaior of the suspnded particles (asphaltenes, sand, paraffin/wax. diamondoid etc.)during fow conditions. This papr presents a theoretical analysis of the diffusional DOI: 10.2118/29488-MS Preprint This paper was presented and appeared in Pages 439-446 of Proceedings of the 1995 SPE Production Operation Symposium held in Oklahoma City, OK, USA, 2-4 April, 1995