ASP Formulation Design for Heavy Oil

Abstract

The objective of the work detailed was to develop an alkaline-surfactant-polymer (ASP) and achieve good oil recovery at low surfactant concentrations. A combination of phase behavior tests, interfacial tension (IFT) measurements (by spinning drop tensiometer) and coreflood tests were used to develop a solution for an oil that had an API gravity of 15 and viscosity of 2,000 cP.The percentage of heavy oil in world oil production continues to rise as more light oil reservoirs have either depleted or reached their economic limit. However, the recovery factor from heavy oil reservoirs by both primary and secondary production is low, making these reservoirs candidates for chemical EOR technologies.Phase behavior tests were used as the primary screening method to identify surfactant formulations qualitatively and the promising candidates were validated by IFT measurements (between the surfactant solution and oil) at different salinities to identify the lowest IFT formulation. Static adsorption tests with reservoir core material were used as a further screening step to ensure formulation was a viable option. Finally, linear coreflood tests were performed at reservoir temperature to validate the formulation and optimize chemical concentration. In one coreflood, 80% of waterflood residual oil was recovered using only 0.15% total surfactants and 2,000 ppm polymer.The success of the ASP coreflood validates the ASP design for this heavy oil. Typically, heavy oil reservoirs may require lower surfactant concentrations due to higher permeability. As a result, such projects could potentially have a higher rewardrisk ratio than ASP projects in conventional oil reservoirs.

Experimentally investigation of the effects of nanoparticles‐enriched ASP formulations on the spontaneous imbibition in a fractured sandstone reservoir

“…Their results indicated that concentration of the surfactant has a significant influence on the optimum salinity of the ASP formulation; changing the surfactant concentration would alter the optimal salinity. The successful ASP core-flooding process achieved by Zhang et al (2012) validates the suitability of the ASP design for heavy oil reservoirs. Furthermore, because these reservoirs have a range of permeabilities in the higher end and lower surface area, they potentially demand a lower surfactant concentration, which makes them even a more appropriate target for ASP systems.…”

“…[12] Because recovery factor from heavy oil reservoirs by primary and secondary production mechanisms is low and because most of these reservoirs have high total acid number, they are a good target for ASP processes. Therefore, Zhang et al (2012) investigated the possibility of ASP-flooding process in these types of reservoirs. They conducted the corresponding experiments on unconsolidated surfactant plugs with high permeability (about 2 darcy), and porosity equals with 31%.…”

“…Furthermore, because these reservoirs have a range of permeabilities in the higher end and lower surface area, they potentially demand a lower surfactant concentration, which makes them even a more appropriate target for ASP systems. [2] Dang et al (2012) examined the performance of the ASP process in both conventional and unconventional reservoirs. They used both double-tailed anionic surfactants (such as docusate sodium) and non-ionic surfactants (such as Synperonic® PE/F68; Sigma-Aldrich, St. Louis, MO, USA) and three different alkali solutions including sodium carbonate, sodium metaborate tetrahydrate, and sodium metasilicate.…”

Application of Ultrashort Hydrophobe Surfactants with Cosolvent Characters for Heavy Oil Recovery

“…ASP flooding, however, has been also studied for more viscous oil. Laboratory experimental results show substantial incremental oil recovery by ASP flooding for oils with viscosities from 320 to 500 cp, − 2000 cp oil, and 16 000 cp oil . ASP floods for heavy oil in Canada include Taber South (Husky), Crowsnest (Husky), Suffield (Cenovus), and Mooney (BlackPearl).…”

New Insights on Chemical EOR Processes for Heavy Oil

“…They lie between 3 and 4 mg KOH per gram for the Venezuelan extra-heavy oil of the Orinoco Belt. Very promising results at the laboratory scale have been obtained with ASP slugs containing high concentrations of alkaline agents and limited, or even zero, concentrations of added surfactants (Liu et al, 2005;Bryan and Kantzas, 2007;Dong et al, 2009;Zhang et al, 2012). However, using in-situ generated surfactants implies that a significant amount the residual oil is mobilized by emulsification in water (Bryan and Kantzas, 2009;Ge et al, 2009;Wang and Dong, 2010;Pei et al, 2012a;Pei et al, 2012b;Kumar et al, 2012).…”