Gel placement in heterogeneous systems with crossflow

K. S. Sorbie, R. S. Seright

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    Early water breakthrough can be a serious problem during waterflooding of heterogeneous reservoir formations. One possible remedy to this problem is to place a gel block in the high-permeability layer, thus diverting displacing brine into the less-permeable layers in order to sweep the remaining oil from these zones. In such a treatment, the gelant material must be placed in the correct location within the reservoir so that gel does not impair reservoir performance. In this paper, we study the dynamics of gel placement in heterogeneous (stratified) reservoir systems. The details of the gel placement are strongly affected by the level of communication between reservoir layers, which is characterized by the closeness of the system to vertical equilibrium (VE) conditions. We show that in viscous-stable injection of gelant in systems close to vertical equilibrium, considerable volumes of injected material can crossflow into the low-permeability layers, and subsequent gel formation can seriously reduce the performance of the continuing waterflood. Results from a range of experimental displacements in well characterized layered beadpacks are presented, along with supporting numerical simulations, which help to understand the mechanisms and benefits when performing gel treatments in reservoir systems with free crossflow. The central role of viscous crossflow in such systems is demonstrated. Since we consider only viscous forces in this work, the layered experimental packs are scaled only by the viscosity ratio (displacing to displaced), the geometry of the packs, the aspect ratio and the degree of vertical communication (closeness to VE). Thus the conclusions from the experimental and simulation results are directly applicable to similarly scaled viscous-dominated systems at the reservoir scale. Some analysis is also presented of the mechanism of disruption of slugs by viscous fingering in layered systems.

    Original languageEnglish
    Title of host publicationProceedings of the Eighth Symposium on Enhanced Oil Recovery Part 2 (of 2)
    Pages369-386
    Number of pages18
    Publication statusPublished - 1992
    EventEighth Symposium on Enhanced Oil Recovery - Tulsa, OK, USA
    Duration: 22 Apr 199224 Apr 1992

    Conference

    ConferenceEighth Symposium on Enhanced Oil Recovery
    CityTulsa, OK, USA
    Period22/04/9224/04/92

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  • Cite this

    Sorbie, K. S., & Seright, R. S. (1992). Gel placement in heterogeneous systems with crossflow. In Proceedings of the Eighth Symposium on Enhanced Oil Recovery Part 2 (of 2) (pp. 369-386)