Title

Laboratory Evaluation of Placement Behavior of Microgels for Conformance Control in Reservoirs Containing Superpermeable Channels

Abstract

Gel treatment has been proven an effective method to attack excessive water production in many mature oilfields. However, not all of the application projects have successful stories. The effectiveness of a gel treatment largely depends on the transport and placement behavior of gel materials in reservoirs to be treated. In this work, we carried out systematic studies to investigate the transport, placement, water-blocking ability, fluid diversion and sweep improvement, and matrix damage effect of micrometer-sized preformed particle gels (microgels) in reservoirs containing superpermeable (super-K) channels. The impact of the channel/matrix permeability contrast and the particle/pore size ratio in the channels and in the matrices was studied. The favorable conditions for gel treatments were identified. The results show that the microgel particles selectively penetrate, place in, and effectively shut off the super-K channels under proper conditions. The sweep improvement after gel treatments was evaluated through chemical tracer tests. The results clearly demonstrate delayed breakthrough, fluid diversion, and increased swept volume of the subsequent flooding fluid. In the experiments, the sweep improvement was in the range of 0.25-0.43 total pore volumes. A higher sweep improvement was achieved as the permeability contrast was higher (i.e., the reservoir was more heterogeneous). To achieve both good injectivity and water-blocking efficiency for the tested microgels, the particle/pore size ratio in the channel should be below 2. Meanwhile, the particle/pore ratio in the matrices should be kept above 5 to avoid significant damage to the matrices. The results of this study provide support for gel product selection and successful gel treatment designs and implementations.

Department(s)

Geosciences and Geological and Petroleum Engineering

Comments

The financial support from the Department of Energy of the United States and Hilcorp Alaska (Award Number DE-FE0031606) was appreciated. This material was based upon work supported by the Department of Energy under Award Number DE-FE0031606.

International Standard Serial Number (ISSN)

1520-5029; 0887-0624

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2022 American Chemical Society (ACS), All rights reserved.

Publication Date

03 Feb 2022

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