A Novel High-temperature Gel to Control the Steam Channeling in Heavy Oil Reservoir

Abstract

Controlling the steam channeling is a major challenge for increasing production in heavy oil reservoirs developed by steam injection. The conventional gel used in water flooding reservoirs always has poor heat resistance, so this paper proposed a novel high-temperature gel (HTG) blocking agent on the basis of a laboratory experimental study. The HTG consists of nonionic filler and unsaturated amide monomer with graft polymerization and crosslinking. The optimal gel system has a high gelling strength and controllable gelation time, which is achieved through incomplete orthogonal design method. Then the stability and plugging performance are studied through singular and parallel sand-pack experiments.The results indicate that the HTG has strong salt resistance and dilution resistance. In addition, the HTG can still maintain high strength at 200°C for 72hr. The singular sand-pack experiments suggest that the HTG has good injectability that ensures the on-site construction safety. Moreover, the HTG has a high breakthrough pressure gradient after gelling and could keep the plugging ratio above 99.8% after gel breakthrough when the subsequent injected volume reaches 10PV. The results obtained in parallel sand-pack experiments show that the HTG can effectively plugging the steam channeling after injecting into the high permeability sand-pack from the production end, and force the subsequent steam to enter the low permeability sand-pack. That raises the producing degree of the low permeability sand-pack. Finally, the difference between high and low permeability sand-pack liquid production is reduced by 99.098%, indicating that the producing profile is tremendously improved, and the oil recovery is enhanced by 41.34%. As a result, the novel HTG blocking agent can be used to control the steam channeling in heavy oil reservoir.

Terpolymer Gel System Formed by Resorcinol–Hexamethylenetetramine for Water Management in Extremely High-Temperature Reservoirs

“…Moreover, lean zones (or thief zones) with high water saturation will cause great heat loss, etc. 13,14 Therefore, it is of major importance to develop a gel system for extremely high-temperature reservoirs (above 150 °C) and steam-flooded reservoirs.…”

“…However, viscous fingering and steam gravity override caused by formation heterogeneity and mobility differences between formation fluids and steam can lead to early steam channeling. Moreover, lean zones (or thief zones) with high water saturation will cause great heat loss, etc. , Therefore, it is of major importance to develop a gel system for extremely high-temperature reservoirs (above 150 °C) and steam-flooded reservoirs.…”

In situ organically cross‐linked polymer gel for high‐temperature reservoir conformance control: A review

“…Besides, thermally oil recovery has been extensively deployed for the development of heavy oil and oil sand reservoirs. It consequently increased reservoir temperature and produced steam channeling . An understanding has been founded based on the operational works in dealing with high‐temperature reservoirs.…”

“…It consequently increased reservoir temperature and produced steam channeling. 2,3 An understanding has been founded based on the operational works in dealing with hightemperature reservoirs. Petroleum reservoirs can be categorized as high-temperature reservoirs if the temperature is more than 80°C.…”

Effect of Different Phenolic Compounds on Performance of Organically Cross-Linked Terpolymer Gel Systems at Extremely High Temperatures

“…Polymer gel systems that involve the use of acrylamide polymers and cross-linker systems have become the most widely applied method to improve oil recovery (IOR) that addresses the excessive water production problems in oil and gas reservoirs. − They are fluid-based systems that can form a continuous, three-dimensional (3D), solidlike network structure in the reservoir. Polymer gels operate, for the most part, either by diverting fluid flow from high-permeability, low-oil saturation flow paths to low-permeability, high-oil saturation flow paths, thus promoting improved sweep efficiency and incremental oil production, or by reducing oil-production operating costs by controlling excessive production of water or gas. − However, as the resources and recoverable reserves of conventional reservoirs decrease, more and more hydrocarbon resources are gradually produced from high-temperature and high-salinity reservoirs. − Moreover, most heavy oil reservoirs worldwide use thermal methods to improve oil recovery; however, viscous fingering and steam gravity override caused by permeability anisotropy and mobility differences between displaced and displacing fluids can lead to early steam channeling and decreased oil production. , Therefore, it is of great importance to investigate the performance and mechanisms of polymer gel systems for extremely high temperature reservoirs and steam-flooded reservoirs.…”