Effect of Asphaltene Deposition on Dynamic Displacements of Oil by Water

Abstract

Effect of Asphaltene Deposition on Dynamic Displacements of Oil by Water V.A. Kamath; V.A. Kamath U. of Alaska Fairbanks Search for other works by this author on: This Site Google Scholar Jiede Yang; Jiede Yang U. of Alaska Fairbanks Search for other works by this author on: This Site Google Scholar G.D. Sharma G.D. Sharma U. of Alaska Fairbanks Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Western Regional Meeting, Anchorage, Alaska, May 1993. Paper Number: SPE-26046-MS https://doi.org/10.2118/26046-MS Published: May 26 1993 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Kamath, V.A., Yang, Jiede, and G.D. Sharma. "Effect of Asphaltene Deposition on Dynamic Displacements of Oil by Water." Paper presented at the SPE Western Regional Meeting, Anchorage, Alaska, May 1993. doi: https://doi.org/10.2118/26046-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search nav search search input Search input auto suggest search filter All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Western Regional Meeting Search Advanced Search AbstractThe flocculation and deposition of asphaltenes in porous media and their interactions with rock and fluids represent complex phenomena which need to be investigated under dynamic flowing conditions. In this paper, experimental results are provided to determine the effect of asphaltene deposition on the dynamic displacements of heavy oil by water in consolidated as well as unconsolidated porous media. Dynamic method was used for in-situ asphaltene precipitation in the porous media. Several dynamic displacement experiments were conducted to understand the displacement of heavy oil by water at various degrees of asphaltene deposition.The results show that, while the increase in asphaltene deposition increased pore plugging and reduced the absolute permeability of the porous media, it also improved the displacement performance and oil recovery by water flooding. It is believed that the improvement in displacement performance may be partly due to improvement in the relative oil permeability caused by end point saturation and wettability changes and partly also due to the flow diversion effect of asphaltene deposition.IntroductionMany field cases and laboratory studies have reported precipitation and deposition of asphaltenes in porous media during recovery of asphaltic crudes by immiscible or miscible gas flooding operations. In some field cases, the reported asphaltene deposition in reservoirs has been so severe that reduced well injectivities and productivities have been experienced. Other field conditions conducive to asphaltene flocculation include: natural depletion, gas-lift operations, caustic flooding and well treatments by acidization.Asphaltenes represent polar, polyaromatic and high molecular weight hydrocarbon fractions of crude oil which are partly dissolved and partly kept in finely dispersed colloidal suspension stabilized by non-polar resin fractions of the crude. The ratio of polar to nonpolar components and the ratio of high to low molecular weight components control the solubility of asphaltenes and resins within the crude. Any action of chemical, mechanical or electrical nature which result in alteration these ratios depeptize the asphaltene micelle and cause their flocculation. For example, in miscible flooding, the injection of miscible gases (solvents) can result in asphaltene precipitation due to alteration of resin to asphaltene ratio of the crude. The amount of asphaltene precipitation depends upon the reservoir oil composition (the original asphaltene and resin content of the crude), the solvent composition, the pressure and temperature conditions and the phase behavior of solvent-oil mixtures. The onset and amount of asphaltene deposition can be predicted using either thermodynamic molecular solubility models, or thermodynamic colloidal models.The dynamics of oil displacement in porous media by injection fluid becomes complex as in-situ asphaltene flocculation takes place. Such asphaltene flocculation can lead to several simultaneous interactions with rock and fluids and can alter rock and fluid properties. Some of these interactions are described here.The first type of interaction that can result from asphaltene precipitation is their aggregate formation and adsorption on the rock surfaces. Many investigators have measured the extent and nature of the adsorption of a well characterized asphaltene fraction on various rock and mineral surfaces. Several factors which control the adsorption of asphaltene on rock surfaces include:the presence, thickness and stability of water films on the rock surfaces;the chemical and structural nature of the rock mineral substrate;P. 179^ Keywords: reduction, asphaltene deposition, oilfield chemistry, wax inhibition, asphaltene precipitation, relative permeability, adsorption, asphaltene remediation, absolute permeability, interaction Subjects: Production Chemistry, Metallurgy and Biology, Flow Assurance, Reservoir Fluid Dynamics, Improved and Enhanced Recovery, Inhibition and remediation of hydrates, scale, paraffin / wax and asphaltene, Precipitates (paraffin, asphaltenes, etc.), Flow in porous media This content is only available via PDF. 1993. Society of Petroleum Engineers You can access this article if you purchase or spend a download.