Title

A Review of Responses of Bulk Gel Treatments in Injection Wells -- Part II: Water Responses and Economic Assessments

Abstract

Polymer bulk gels have been widely applied to mitigate excessive water production in mature oil fields by correcting reservoir permeability heterogeneity. This paper presents a comprehensive review of the water responses and the economic assessments of injection-well gel treatments. The survey includes 61 field projects implemented between 1985 and 2014 and compiled from SPE papers and U.S. DOE reports. Ten parameters were evaluated according to the reservoir lithology, formation type, and recovery process using the univariate analysis, stacked histograms, and scatterplots. Results indicated that gel treatments have very wide ranges of water injection/production responses and economic indicators. We identified that gel treatments do reduce the water production but not dramatically to really low levels. The water production continues to increase after the proactive treatments applied in undeveloped conformance problems at low water cuts ( < 50%). Contrarily, the water production decreases after the reactive treatments conducted in developed conformance issues at high water cuts ( > 50%). When successfully applied, gel treatments averagely reduce the water injection rate by 34% and the water cut by 10%; however, the water cut may also increase by 17%. For developed problems, the water cut may stabilize or increase after the remediation mainly in matrix-rock sandstone reservoirs, especially when small gel volumes are injected ( < 1000 barrels) into this formation type. Economically, gel treatments are appraised solely based on the oil production response and both water responses are not considered in the evaluation. Typically, gel treatments have cost of incremental oil barrel of 2$/barrel and payout time of 9.2 months and function for 1.9 years. They have better water responses and economics in carbonates than in sandstones and in unconsolidated and naturally-fractured than in matrix-rock formations; however, they have reverse tends with respect to the gel effective time. The gel effective time significantly decreases with the channeling strength, the aperture of flow channels, and the temperature of injected drive-fluids. Generally, the water production response and economic parameters improve as the injected gel volume increases and the treatment timing advances in the flooding life. For different application environments, the present review provides reservoir engineers with updated ideas about what are the low, typical, and high performances of gel treatments when applied successfully and how other treatment aspects affect the performances.

Meeting Name

SPE Western Regional Meeting 2018 (2018: Apr. 22-26, Garden Grove, CA)

Department(s)

Geosciences and Geological and Petroleum Engineering

International Standard Book Number (ISBN)

978-151086242-5

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2018 Society of Petroleum Engineers (SPE), All rights reserved.

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