Article pubs.acs.org/EF
Effect of Confinement on the Dynamic Contact Angle of Hydrocarbons Mehrdad Alfi,† Debjyoti Banerjee,‡ and Hadi Nasrabadi*,† †
Department of Petroleum Engineering, Texas A&M University, College Station, Texas 77840, United States Department of Mechanical Engineering, Department of Petroleum Engineering (Joint Courtesy Appointment), Faculty Fellow, Mary Kay O’Connor Process Safety Center, Texas A&M University, College Station, Texas 77840, United States
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ABSTRACT: Unconventional hydrocarbon reservoirs and their characteristics have promoted an area of research exploring the effect of small pore size on the reservoir fluid and its associated properties. There is a general agreement that (i) the confined fluid flow and associated properties in shale are substantially different from its corresponding bulk properties and (ii) these differences have a significant impact on the prediction of well performance and ultimate recovery in shale reservoirs. However, experimental measurements of fluid flow and properties in shale rocks are currently very limited, which has led to a significant amount of uncertainty in reservoir modeling. In this study, a nonfluidic device is designed, fabricated, packaged, and tested, and an experimental investigation of the gas−liquid contact angle of hydrocarbons confined in nanosized channels within a nanofluidic platform is conducted. Reservoirs in the nanofluidic chip are filled with a hydrocarbon liquid and epi-fluorescence imaging is simultaneously performed to investigate the contact angle. Pure hydrocarbon liquids, hexane, heptane, and octane are confined in nanosized channels, gas−liquid contact angle measurements are recorded, and images are captured by high-resolution confocal microscopy.
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INTRODUCTION The domestic unconventional reservoirs have been the focus of scientific interest over the past few years, because of the emergence of new technologies that enable the production of oil and gas from such resources, such as shale light oil and gas. However, there are complexities related to unconventional oil and gas reservoirs, one of which arises from the significant effect of small pore size on fluid flow and the properties of petroleum fluids in shale reservoirs. Shale matrix mainly consists of three categories of pores: micropores (diameters of 50 nm). Recent studies have shown that, on average, ∼20%−40% of pores are categorized as having diameters of
