Evaluation of a Novel Recrosslinkable Hyperbranched Preformed Particle Gel for the Conformance Control of High-Temperature Reservoirs with Fractures

The existence of high conductivity features such as fractures, karst zones, and void space conduits can severely restrict the sweep efficien-cy of waterflooding or polymer flooding. Preformed particle gel (PPG), as a cost-effective technology, has been applied to control exces-sive water production. However, conventional PPG has limited plugging efficiency in high-temperature reservoirs with large fractures or void space conduits. After water breakthrough, gel particles can easily be washed out from the fractures because of the lack of particle -particle association and particle -rock adhesion. This paper presents a comprehensive laboratory evaluation of a novel water-swellable high-temperature resistant hyperbranched recrosslinkable PPG (HT-BRPPG) designed for North Sea high-temperature sandstone reser-voirs (130 & DEG;C), which can recrosslink to form a rubber -like bulk gel to plug such high conductivity features. This paper systematically evaluated the swelling kinetics, long -term thermal stability, and plugging performance of the HT-BRPPG. Bottle tests were used to test the swelling kinetic and recrosslinking behavior. High- pressure-resistant glass tubes were used to test the long -term thermal stability of the HT- BRPPG at different temperatures, and the testing lasted for more than 1 year. The plugging efficiency was evaluated by using a fractured model. Results showed that this novel HT- BRPPG could recrosslink and form a rubber -like bulky gel with temperature ranges from 80 to 130 & DEG;C. The elastic modulus of the recrosslinked gel can reach up to 830 Pa with a swelling ratio (SR) of 10. In addition, the HT- BRPPG with an SR of 10 has been stable for over 15 months at 130 & DEG;C. The core flooding test proved that the HT- BRPPG could efficiently plug the open fractures, and the breakthrough pressure is 388 psi/ft. Therefore, this novel HT- BRPPG could provide a solution to improve the conformance of high-temperature reservoirs with large fractures or void space conduits.

Automated summary

This paper presents a comprehensive laboratory evaluation of a novel water-swellable high-temperature resistant hyperbranched recrosslinkable preformed particle gel (HT-BRPPG), designed for North Sea high-temperature sandstone reservoirs. The results showed that the HT-BRPPG had good swelling kinetics, long-term thermal stability, and plugging performance, making it an effective solution for improving the conformance of high-temperature reservoirs with large fractures or void space conduits.