Determination of Front Locations in a Multilayer Composite Reservoir (1989)

Determination of Front Locations in a Multilayer Composite Reservoir K. Anbarci; K. Anbarci Pennsylvania State U. Search for other works by this author on: This Site Google Scholar A.S. Grader; A.S. Grader Pennsylvania State U. Search for other works by this author on: This Site Google Scholar T. Ertekin T. Ertekin Pennsylvania State U. Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, October 1989. Paper Number: SPE-19799-MS https://doi.org/10.2118/19799-MS Published: October 08 1989 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Anbarci, K., Grader, A.S., and T. Ertekin. "Determination of Front Locations in a Multilayer Composite Reservoir." Paper presented at the SPE Annual Technical Conference and Exhibition, San Antonio, Texas, October 1989. doi: https://doi.org/10.2118/19799-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Annual Technical Conference and Exhibition Search Advanced Search AbstractA pressure transient interpretation method for multi-layer composite reservoirs with or without crossflow is presented. The proposed solution includes wellbore skins and storage effects and it is applicable to radial systems with either an infinite outer boundary, a constant pressure outer boundary or a closed outer boundary. Flood fronts in the layers may be located at different positions away from the well.The detection of reservoir properties and the location of the fronts in the different layers plays an important role in the design and operation of secondary and tertiary recovery processes. The proposed new model addresses the need for an interpretation technique that provides the ability to monitor the location of flood fronts via pressure transient analysis.The mathematical model is posed with the diffusivity equations for each layer and each fluid zone behind and ahead of the fronts. The boundary conditions at the interfaces can be with or without crossflow. The analytical solution is obtained using Laplace transformation. The new model is successfully tested with respect to four special cases presented in the literature. The sensitivity of the model to reservoir properties is also discussed.IntroductionMost oil reservoirs are stratified and originally each permeable layer may have homogeneous physical properties. Yet, some discontinuities in rock and fluid properties may be created by secondary or tertiary oil recovery processes. The discontinuities are caused by moving fronts, and the detection of the locations of the fronts in the different layers plays an important role in the design and operation of these enhanced oil recovery processes. While there have been studies published on the determination of front location by pressure transient analysis in petroleum reservoirs of a single homogeneous permeable layer, the very same problem remained unsolved for multilayer reservoirs with formation crossflow.One of the earliest works in the area of composite systems is presented by Kazemi, who introduced the use of conventional presented by Kazemi, who introduced the use of conventional pressure fall-off testing to approximate the location of a fire front in an pressure fall-off testing to approximate the location of a fire front in an in-situ combustion process. In his model, Kazemi considered the effect of temperature on the termodynamic properties of reservoir fluids. Eggenschwiler et al. modeled the burned volume as a radial region adjacent to an injection well in an in-situ combustion project, creating a new pressure transient model for a composite reservoir. Obut and Ertekin pressure transient model for a composite reservoir. Obut and Ertekin presented a solution for pressure transient behavior of composite systems presented a solution for pressure transient behavior of composite systems in the presence of an infinite conductivity fracture. Streltsova and McKinley obtained the expression for pressure drawdown at a well when t > 1 in a reservoir with radial discontinuity by using an approximate Laplace inversion technique.Lefkovits et al. used the early time straight line to estimate (kh) for layered reservoirs without cross flow and no skin or uniform skin damage in each layer. Cobb et al. indicated the approximate time when pseudosteady state flow begins for a single well in a two layered reservoir pseudosteady state flow begins for a single well in a two layered reservoir without cross flow and no flow outer boundary, with other properties being the same for both layers. Compared to the approximate value of (tDA)pss = 0.1 for a single layer system, Earlougher et al. state that the time which pseudosteady state flow begins depends also on the relationship between porosity, thickness and compressibility in the various layers. Raghavan et al. proposed a technique for estimating the kh ratio between layers for a single well in the center of a circular two-layer system. Tariq and Ramey introduced the wellbore storage in their solution to the commingled system and used Stehfest algorithm for the numerical inversion of Laplace transforms. For a layered reservoir with crossflow two formulations were first presented by Jacquard. Later, Jacquard's. solution was computed for two layers by Pottier.Representation of interlayer flow by a pseudosteady state approximation formed the basis of a study by Polubarinova-Kocina. This approximation reduces the partial differential equations to a system of one dimensional equations. The recent works published by Gao and Bourdet also employ similar assumptions. Kucuk et al. offered an analysis technique which made the observation that the wellbore pressure is sensitive only to the total system behavior and the flow rates are sensitive to the layer properties. properties. P. 285 Keywords: upper layer, reservoir, wellbore storage, society of petroleum engineers, crossflow, determination, outer boundary condition, boundary condition, wellbore pressure, dimensionless wellbore pressure Subjects: Formation Evaluation & Management, Drillstem/well testing This content is only available via PDF. 1989. Society of Petroleum Engineers You can access this article if you purchase or spend a download.