_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 220801, “Rethinking Surfactant Huff ’n’ Puff for Enhanced Oil Recovery in the Bakken: Recent Pilot Field Study Using Multifunctional Biosurfactants,” by Megan R. Pearl, SPE, Locus Bio-Energy, and Eric Nelson and Josh Rothe, Creedence Energy Services, et al. The paper has not been peer reviewed. _ Since November 2019, the Bakken shale play has experienced a decline of 6% annually. In recent years, huff ’n’ puff enhanced-oil-recovery techniques typically were regarded as the most cost-effective methods for unconventional plays. However, novel biotechnology, proven in multiple US basins and expanded to Bakken for the first time in 2021, has shown very promising results. The complete paper provides details of a pilot study conducted on multiple wells showcasing the potential of this approach. Introduction Biosurfactants are a class of multifunctional surfactants that are proving effective in oil mobilization because of their complex and unique molecular structures, with multiple active sites and 3-nm micelles, allowing effortless penetration of many of the same pores as CO2. The successful application of biosurfactants has been reported with significant and sustained uplifts in production in the Appalachian, Permian, and Williston Basins. Well Selection Reservoir samples were analyzed from three 1-mile horizontal wells in the Middle Bakken: Frink, Woessner, and Neilsen. Produced-water characteristics are representative of standard Bakken brine; however, the lower surface tension of the Frink-produced water may indicate interference from a previous chemical treatment. Crude-oil characteristics also represent typical Bakken oil. The reduction in paraffin and solids content between the two Nielsen samples suggests potential paraffin deposition downhole. Mineralogical samples were unavailable for the selected wells, so cores from an analog well believed to be mineralogically representative of the trial wells were used. The cores were from the Parshall 2-36H well. Mineralogical characterization using X-ray diffraction showed the core to be primarily calcite and quartz. The carbon distribution of the crude oils was characterized by separating the fractions into normal alkane and isomer contents. The crudes have substantially similar composition and are characterized primarily by isomers. The total n-alkane content of less than 3% suggests that the oils have low paraffinic content. Surfactant Qualification Thirteen biosurfactant-based formulations were evaluated for the trial. Only the results of the best-performing formulation are discussed here. Fluid Compatibility. To determine brine stability and oil/water separation, emulsion break testing was conducted at 122°F. Samples were prepared by combining 50% (by volume) oil, 25% produced water, 22% fresh water, and a 3% biosurfactant-based surfactant blend. Results were consistent between Frink and Woessner samples. Neither crude was determined to be emulsifying. Liquid/Liquid Interactions. To characterize the ability of the biosurfactant-based surfactant blend to affect liquid/liquid interactions, surface-tension and interfacial-tension (IFT) measurements were conducted at various dilutions to recommend dosage and simulate dilution with flowback.
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Jun 1, 2025
Vanessa Ferreira Salvador + 12
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