Toe-To-Heel Waterflooding: Field Scale Numerical Simulation Study

Toe-To-Heel Waterflooding: Field Scale Numerical Simulation Study Litong Zhao; Litong Zhao Alberta Research Council Search for other works by this author on: This Site Google Scholar Alex Turta Alex Turta Alberta Research Council Search for other works by this author on: This Site Google Scholar Paper presented at the SPE/DOE Symposium on Improved Oil Recovery, Tulsa, Oklahoma, April 2004. Paper Number: SPE-89380-MS https://doi.org/10.2118/89380-MS Published: April 17 2004 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Zhao, Litong, and Alex Turta. "Toe-To-Heel Waterflooding: Field Scale Numerical Simulation Study." Paper presented at the SPE/DOE Symposium on Improved Oil Recovery, Tulsa, Oklahoma, April 2004. doi: https://doi.org/10.2118/89380-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 Improved Oil Recovery Conference Search Advanced Search AbstractApplication of conventional waterflooding to heavy oil reservoirs is plagued with problems. The unfavorable water/oil mobility ratio often aggravates the negative effects of water channeling and gravity segregation. In order to overcome these difficulties, a novel process, Toe-To-Heel Waterflooding (TTHW) has been developed. The TTHW process utilizes a horizontal producer (HP) and a vertical injector (VI). The horizontal leg of the HP is located at the top of the formation and the VI is placed near the toe of the horizontal producer, in a staggered line drive configuration. The basic idea is to take advantage of the gravity segregation. When water is injected, an early water break-through from VI to the toe of the HP significantly reduces the pressure drop between VI and HP, making gravity an important factor. By gravity segregation, injected water goes to the bottom of the formation, and gradually pushes the oil upward toward the HP at the top of the formation.The current paper is the third in a series of technical articles presenting laboratory and simulation work on TTHW in view of field applications. Results from laboratory tests demonstrated that the TTHW process was a more effective displacement process, compared to the conventional waterflooding with vertical producers and injectors. A 3-D numerical simulation study of the TTHW process at field scale using Computer Modeling Group's (CMG) STARS reservoir simulator was conducted. Based on an inverted nine-spot pattern, the performance of the TTHW process is compared to that of conventional waterflooding under various reservoir and operational conditions.The simulation results suggest that the best conditions for TTHW to give better performance over conventional vertical-to-vertical waterflooding are large pay thickness and high permeability. In this type of reservoirs, the water segregation due to gravity is significant, making TTHW more effective. In addition, for lower permeability (< 500 md) and higher oil viscosity (> 500 mPa·s) reservoirs, conventional water flooding is almost not applicable due to very low water injectivity. Using TTHW, the injectivity can be significantly improved, resulting in a significant increment on oil recovery. TTHW process extends waterflooding technique to reservoirs that cannot be water flooded by conventional method.IntroductionWaterflooding is the oldest method for improved oil recovery following primary production. Conventional water flooding involves injecting water from a vertical well and producing fluid from another vertical well at a distance. The effectiveness of the process depends on the sweep efficiency, which is determined by a number of reservoir parameters. Two leading phenomena affecting sweep efficiency are water channeling due to reservoir heterogeneity, and water/oil segregation due to gravity (if oil/water density contrast exists). For thick pay zone, or under the condition of unfavorable water/oil mobility ratio, such as heavy oil, the negative effect of the above two factors are aggravated 1,2. To overcome those difficulties, traditional ways are to use chemicals such as polymer, surfactant, micro-foams, etc. Keywords: liquid production, horizontal producer, modeling & simulation, tthw process, upstream oil & gas, liquid injection, oil viscosity, injector, producer, enhanced recovery Subjects: Improved and Enhanced Recovery, Waterflooding This content is only available via PDF. 2004. Society of Petroleum Engineers You can access this article if you purchase or spend a download.

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