Effect of Heterogeneity on Propagation, Placement, and Conformance Control of Preformed Particle Gel Treatment in Fractures

Abstract

Preformed particle gels (PPG) have been successfully applied as a plugging agent to solve the conformance problem in fractured reservoirs. They are injected to plug fractures and then divert displacing fluid into poorly swept zones and areas. However, PPG propagation and plugging mechanisms through open fractures have not been studied thoroughly. This paper investigated the influence of some factors (particle size, brine concentration, heterogeneity, injection flow rate, and brine salinity) on gel injectivity and plugging performance for water flow through opening fractures. Five-foot tubes were used to mimic opening fractures. Three models were designed to gain understanding on how fracture geometry and PPG properties affect gel injection and plugging efficiency, including (1) single fracture with uniform fracture width, (2) single fracture with different widths, and (3) two parallel fractures with different width ratios between each other. Results from single uniform fracture experiments showed that PPG injection pressure was more sensitive to gel strength than gel particle size. When large PPG size and high gel strength were used, high injection pressure and large injection pore volume were required for PPG and brine to reach fracture outlets. Results from single heterogeneous fracture model experiments showed PPG injection pressure increased as the fracture heterogeneity in sections increased. Particle gel accumulated at the choke point within each fracture and caused injection pressure to increase accordingly. Furthermore, results showed that having a lower salinity within a fracture, which was less than the brine salinity that was used to prepare PPG, would improve the PPG plugging efficiency for water flow. Parallel fracture models results showed that when weak PPG was used, a large volume of PPG flowed into a large fracture width and a small portion of the gel particle volume flowed into small fracture width. However, with increased gel strength and fracture width ratio, PPG only flowed through larger fracture widths. This paper demonstrates important impact elements of gel propagation and water flow for different opening fracture situations.

Meeting Name

SPE Improved Oil Recovery Conference (2016: Apr. 11-13, Tulsa, OK)

Department(s)

Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Efficiency; Flow Of Water; Hydraulics; Oil Well Flooding; Parallel Flow; Particle Size; Petroleum Engineering; Petroleum Industry; Petroleum Reservoir Evaluation; Petroleum Reservoirs; Water Injection; Conformance Control; Fracture Experiments; Fracture Geometries; Fracture Heterogeneities; Fractured Reservoir; High Injection Pressures; Injection Flow Rate; Injection Pressures

International Standard Book Number (ISBN)

978-1613994399

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2016 Society of Petroleum Engineers (SPE), All rights reserved.

Publication Date

01 Apr 2016

Link to Full Text

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