Polymer Flooding In Heavy Oil Reservoirs Research Articles

Status of Polymer-Flooding Technology

Polymer flooding is the most commonly applied chemical enhanced-oil-recovery technique. This paper provides an update on the status of polymer-flooding technology, focusing more on field applications than on theoretical and laboratory research. It covers the following topics: • Mechanisms of polymer flooding • Polymers used • Polymer-solution stability • Technical screening criteria • Laboratory and simulation work • Performance-monitoring technique • Summary of pilots and large-scale applications • Experience and learning from field projects • Polymer flooding in heavy-oil reservoirs • Polymer viscoelastic properties • Problems associated with polymer flooding and their solutions • Future developments The data and analysis presented in this paper will give readers updated information describing polymer flooding, as well as a guide to the relevant research. Survey data will also provide operators with reference data for project design and optimization.

A mechanistic analysis of viscous fingering in low-tension polymer flooding in heavy-oil reservoirs

Modeling of the low tension polymer flooding (LTPF) in heavy oil reservoirs suffers from the paucity of detailed knowledge of viscous instability or fingering effects. Major limitations of previous approaches for studying viscous fingering in immiscible displacements are that the reported experiments have been conducted utilizing the linear displacements schemes in the media with high, single-phase permeabilities. Consequently, viscous instability has not been studied in low-permeability media and using the displacement schemes similar to the oil-field patterns (e.g., five-spot). To help understand viscous fingering in LTPF in heavy oil reservoirs and to overcome the limitations of previous studies, we conducted experiments in the low-permeability, one-quarter, five-spot patterns. New insights into the main driving mechanisms for viscous fingering are proposed. In summary, the mechanisms of spreading, splitting, coalescence, and microscopic crossflow drive the finger growth. In addition, the viscous fingers are readily initiated in the porous medium, but they can be damped out before traveling very far. This damping of the viscous fingers is due to the flow of the two phases in a direction transverse to the direction of bulk fluid movement as a result of dispersive processes such as stream splitting. Also, the initially-developed fingers may deteriorate over the time of displacement. This depends on the distance between the injector and producer and width of the porous medium. The presence of instabilities that look like fingers and stable displacements behind the unstable front were discovered. The results also indicate that a stable zone exists and progresses at varying velocities. Finally, we reveal three different types of displacements that occur in LTPF: stable displacements, displacement with macroscopic viscous fingering, and displacements with both macroscopic and microscopic viscous fingering.