Asphaltene and Other Heavy-Organic Particle Deposition During Transfer and Production Operations

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 production wells and/or transfer pipelines. In many instances the amount of precipitation is rather large causing complete plugging of these conduits. Therefore, it is important to understand the behavior of suspended particles during flow conditions.In this paper we present an overview of the heavy organic deposition problem, its causes, effects and preventive techniques.. We~lso presen~. an analysis of the diffusional effects on the rate of solId partIcle depOSItIon during turbulent flow conditions (crude oil production generally falls within this regime). We utilize the turbulent boundary layer theory and the concepts of mass transfer to explain the particle deposition rates on the walls of the flowing conduits. The developed model accounts for the Brownian and eddy diffusivities as well as for inertial effects and other forces acting acting upon the particles.The analysis presented in this paper shows that rates of particle deposition (asphaltene, paraffin/wax, sand, and/or diamondoid) on the walls of the flowing channel, due solely to diffusional effects, are negligible. It is also shown that deposition rates decrease with with increasing particle size. However, when the deposition process is momentum controlled (large particles) higher deposition rates are predicted. It is shown a decrease in deposition~~tes with in~rea~ing c~de oil kinematic viscosity. An increase 10 depOSItIOn rates WIth IncreasIng production rates is also observed.

Modeling for batch phenol biodegradation with immobilized Alcaligenes faecalis

“…The liquid‐solid mass‐transfer coefficient of phenol from the main liquid phase to the surface of the cell‐immobilized polyurethane foams in stirred‐tank experiments is calculated using the following correlation, which is used for the calculation of mass‐transfer coefficient from liquid phase to low‐density solids in agitated dispersions25: where D S is the free diffusion coefficient of phenol in water, d P the equivalent diameter of the polyurethane foam, μ the viscosity of the solution containing phenol, ρ the density of the continuous phase, and Δρ the density difference between the liquid phase and the solid phase. Because the maximum phenol concentration in our experiments is 1600 mg/L, corresponding to a very small phenol holdup (V/V), the differences between the liquid density and viscosity of the solution containing phenol and those of the mineral salt medium are negligible according to the correlations proposed by Escobedo et al26 Thus, the density and viscosity of mineral salt medium, which can be measured experimentally, are used as those of the solution in the calculation of the liquid‐solid mass transfer coefficient.…”

Effect of Fluid Viscosity on Asphalthene Deposition Rate during Turbulent Flow in Oil Wells

“…3.The trend follows a linear relationship with the slope of viscosity variation of the crude oil to be so small compared to the unit pressure drop across the pipe. Considering the variation of the viscosity for the specified pressure range and using the experimental Data of Friedlander [2] and Beal [5], and assuming a typical value for the average radius of the particles, the rate of deposition of asphalting particles on oil well walls has been calculated. Expression used for deposition rate coefficient calculation is [1]:…”

“…Asphaltene is recognized as the heavy fraction of petroleum mixture, which is insoluble in some species such as paraffins but soluble in others such as aromatics (benzene, toluene, etc.) [2]. The liquid state of oil is the results of the equilibrium of these components in the liquid and vapor phases.…”

Numerical Modeling of Asphaltene Deposition

“…Modeling of asphaltene deposition requires two essential components. These are (1) thermodynamic model and (2) transport model. Thermodynamic model serves to provide information on precipitation of dissolved asphaltene.…”

“…Thermodynamic model serves to provide information on precipitation of dissolved asphaltene. This was pursued for example in [2]- [5]. The transport of precipitated asphaltene particles and their subsequent deposition on surfaces are described in the transport model.…”