A Single-Well Tracer Test To Estimate Wettability (1992)

A Single-Well Tracer Test To Estimate Wettability L.E.A. Ferreira; L.E.A. Ferreira U. of Texas Search for other works by this author on: This Site Google Scholar F.J. Descant; F.J. Descant U. of Texas Search for other works by this author on: This Site Google Scholar Mojdeh Delshad; Mojdeh Delshad U. of Texas Search for other works by this author on: This Site Google Scholar G.A. Pope; G.A. Pope U. of Texas Search for other works by this author on: This Site Google Scholar Kamy Sepehrnoori Kamy Sepehrnoori U. of Texas Search for other works by this author on: This Site Google Scholar Paper presented at the SPE/DOE Enhanced Oil Recovery Symposium, Tulsa, Oklahoma, April 1992. Paper Number: SPE-24136-MS https://doi.org/10.2118/24136-MS Published: April 22 1992 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Get Permissions Search Site Citation Ferreira, L.E.A., Descant, F.J., Delshad, Mojdeh, Pope, G.A., and Kamy Sepehrnoori. "A Single-Well Tracer Test To Estimate Wettability." Paper presented at the SPE/DOE Enhanced Oil Recovery Symposium, Tulsa, Oklahoma, April 1992. doi: https://doi.org/10.2118/24136-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Improved Oil Recovery Conference Search Advanced Search AbstractA single-well backflow tracer test to estimate reservoir wettability has been developed. This test consists of the injection of first brine containing tracers and then oil containing tracers. The tracers used are esters, similar to those used in the measurement of residual oil saturation, and nonreactive aqueous and oleic tracers for material balance control. The esters hydrolyze during a shut-in time and then the well is produced. The tracer production data, water cuts, and bottomhole pressures are all sensitive to wettability-dependent properties. The most important by far is relative permeability, but capillary pressure and mixing behavior (dispersion and capacitance) are also important. In the absence of fluid drift, reservoir properties such as permeability and porosity have little influence in the test results. From the results of the test, the preferential reservoir wettability may be directly inferred. By matching the test data using a compositional reservoir simulator, these properties can be estimated and used to infer wettability or simply used directly in subsequent simulations of the reservoir performance. We illustrate this process using a chemical flooding simulator. This is a reservoir simulator that includes the usual features of a finite-difference simulator in terms of reservoir description, plus compositional and chemical features needed for this application such as kinetics, partitioning, dispersion, and capacitance. Special care has been taken to ensure numerical accuracy. The CPU time on a CRAY Y-MP required for each simulation was: 10 seconds for a 1D-radial (31 blocks), 3 minutes for a 2D-areal (609 blocks), and 9 minutes for a 3D (1827 blocks) simulation, so many cases can be affordably studied.IntroductionWettability has been considered the most important factor that controls the location, distribution, and characteristics of the flow of fluids in a reservoir. Changes in the wetting conditions of the samples in core analysis have been shown to affect the transport properties of a reservoir such as relative permeability and capillary pressure, dispersion of tracers, waterflood behavior, tertiary recovery, irreducible water saturation, residual oil saturation, and electrical properties. Although wettability can be measured in the laboratory using cores, the wetting condition of the cores may be subject to error, mainly because of inadequate well coring fluid and handling techniques, problems with packing and preserving the cores, laboratory procedures for cleaning and preparing the samples, test temperature, and test fluid and test techniques. Thus, an in-situ method would obviously be of great advantage. The only in-situ method that we are aware of besides the one proposed here is that of Desbrandes and Bassiouni, who proposed using a wireline formation tester. Wettability impacts the economics of any recovery process because it affects the efficiency of the displacement of oil by water, alters the predicted breakthrough time and the required amounts of injected fluid to achieve a given reduction in oil saturation, is used to specify the kind of chemicals to be used in an enhanced recovery process, and affects the estimated reserves of the reservoir. Therefore, it is of great importance to know the reservoir wettability in order to predict the correct performance of the reservoir under study. An in-situ evaluation of reservoir wettability thus would be an attractive alternative not only because it is unaffected by extraneous fluids but it also would sample a much larger volume of the reservoir. The combined use of laboratory and well tests is the most likely to yield definitive results.P. 325^ Keywords: injection, reservoir, single-well tracer test, simulation, fluid dynamics, flow in porous media, radial simulation, tracer test analysis, pope, saturation Subjects: Reservoir Fluid Dynamics, Formation Evaluation & Management, Flow in porous media, Tracer test analysis This content is only available via PDF. 1992. Society of Petroleum Engineers You can access this article if you purchase or spend a download.