A Laboratory Experimental Study on Enhancing the Oil Recovery Mechanisms of Polymeric Surfactants

Abstract

In order to evaluate the physical and chemical properties of polymer surfactants and analyze their oil displacement mechanisms, three types of poly-surfactant used in the Daqing oil field were chosen to be researched, and the oil displacement effects were studied using poly-surfactants of different viscosity, dehydrating rate, and core permeability. The main purpose is to determine the reasonable range of different characteristic indexes of polymeric surfactant flooding. The oil displacement effect of 15 cores was analyzed, and the effects of viscosity, the dehydrating rate of emulsion, and permeability on EOR (Enhanced Oil Recovery) were analyzed. The oil displacement mechanisms of polymeric surfactants were researched using a photolithographic glass core. This paper explores the mechanism underlying production enhancement as an EOR target, while simultaneously conducting laboratory tests to assess the physical and chemical properties of polymeric surfactants. The poly-surfactant agents exhibit a notable increase in viscosity, with the optimal displacement effect observed at a core effective permeability exceeding 400 mD, resulting in a potential EOR of 15% or higher. Moreover, at a viscosity ranging between 40 and 70 mPa·s, the total EOR can reach 73%, with the peak efficiency occurring at a viscosity of 60 mPa·s. The water loss rate of the emulsion, ranging between 30% and 70%, achieves optimal performance at 50%. The poly-surfactants’ higher viscosity extends the oil sweep area, enhancing recovery efficiency, and noticeably reducing residual oil compared to water flooding. During poly-surfactant flooding, a substantial amount of residual oil is extracted and transformed into droplets. The rapid emulsification of the polymeric surfactant solution with crude oil forms a stable emulsion, contributing to its significant oil recovery effect. This research provides valuable technical support for EOR in thin and low-quality reservoirs of onshore multi-layered sandstone reservoirs.

Experimental Investigation of the Effect of Surfactant–Polymer Flooding on Enhanced Oil Recovery for Medium Crude Oil

“…An increase in the concentration of these mixtures will increase the ultimate oil recovery and as recorded from polymeric surfactant concentrations of (1.5 wt% and 10 wt%) and (2.0 wt% and 10 wt%), oil recoveries of 57.6% and 63.5% were recorded, respectively, resulting in an incremental recovery of 32.9% and 38.8% compared to water flooding. Despite the different experimentations offered by [ 36 , 39 , 40 , 41 , 42 , 43 ] to obtain oil recoveries from different PS concentrations, the results obtained in this article uniquely follow the similar trends of substantial incremental oil recoveries during PS injection compared to water and polymer injections. The in situ interfacial tension should be investigated to confirm the optimum surfactant concentration, and since a highly soapy effect was noticed with increased surfactant concentration, a flooding scenario adopting water alternating with a surfactant is recommended to reduce the soapy effects of the surfactants.…”

“…Using a polymer (partially hydrolyzed polyacrylamide) and surfactant (sodium dodecyl sulfate) [ 38 ] recorded an incremental oil recovery of 23% and 20% during surfactant flooding as opposed to water flooding. From the PS experimental flooding carried out by [ 39 ], the rapid emulsification of oil led to a substantial increase in the oil recovered compared to water and polymer flooding. A synthesis of Fatty Acid Methyl Ester and Ethyl Acrylate by [ 40 ] to produce a PS resulted in a 0.5% increase in oil recovery compared to water flooding.…”