Comprehensive Evaluation of a High-Temperature Resistant Re-Crosslinkable Preformed Particle Gel for Water Management
Gel treatment has been widely applied to control conformance for improving oil recovery and control water production in mature oil fields. However, most of the hydrogel systems are limited when being applied in the harsh environments of high temperatures. A systematic evaluation was conducted in this study to evaluate a modified PPG product, the high temperature resistant re-crosslinkable preformed particle gel (HT-RPPG) which can re-crosslink to form a bulky material and keep thermostable in the large-opening features after placement. This material was developed to overcome the limitations of conventional PPGs in the reservoirs with large- opening features such as open fractures, void conduits, wormholes, and so on. The HT-RPPG can swell up to 18 times of its original size at room temperature (23˚C), and the swelling ratio is independent of brine concentration and types. We conducted a series of experiments to evaluate the effect of particle size, temperatures, swelling ratios, brine types on re-crosslinking time, as well as the gel strength, blocking performance and thermostability after re-crosslinking. Smaller particle sizes result in the HT-RPPGs swell and re-crosslink much faster. Higher temperatures increase the swelling and re-crosslinking rate, while the larger swelling ratios (more feeding brine) can slow down the re-crosslinking time. HT-RPPG re-crosslinking process can be delayed when the particles contact with Ca2+. Additionally, the re-crosslinking of HT-RPPG is a temperature-responsive reaction which can only start after reaching the target temperature of 100 °C or above. The HT-RPPG has kept its volume and strength stable at 100 to 130 °C for over 10 months so far. A blocking performance test was conducted by using the tubing model to simulate void-space conduit (VSC), and breakthrough pressure reached to 427 psi/ft.
B. Yu et al., "Comprehensive Evaluation of a High-Temperature Resistant Re-Crosslinkable Preformed Particle Gel for Water Management," Fuel, vol. 309, article no. 122086, Elsevier, Feb 2022.
The definitive version is available at https://doi.org/10.1016/j.fuel.2021.122086
Geosciences and Geological and Petroleum Engineering
Keywords and Phrases
Conformance improvement; High-temperature reservoir; Re-crosslinkable preformed particle gel; Thermostable; Void-space conduit; Water management
International Standard Serial Number (ISSN)
Article - Journal
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01 Feb 2022