Adsorption of organic acids in oil on crushed marble at varying temperatures and ambient pressure

Acknowledgments This work contains material supported by Premier COREX (UK) LTD through a Ph.D. studentship for MS. Any opinions, conclusions, or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of COREX (UK) LTD. Electron microscopy was performed in the Aberdeen Centre for Electron Microscopy, Analysis and Characterisation (ACEMAC) at University of Aberdeen (UoA); the authors thank John Still for the acquisition of the SEM images. XRD analysis was performed in the UoA X-ray Diffraction Laboratory by Professor Abbie McLaughlin. Sample preparation for adsorption and adsorption strength experiments and particle size analysis were performed in the School of Geosciences at UoA; the authors thank Colin Taylor for his help with the material preparation, acquisition and analysis of PSA. The authors thank Walter Ritchie for cutting and polishing of the marble blocks in the School of Geosciences at UoA. The authors thank Dr. Zeni Rahmawati her assistance in performing the GC-FID analysis and Emmanuel Chibuzor Osademe for his help in performing BET measurements. The authors gratefully acknowledge Dr. Morteza Aminnaji (Champion X), Dr. Stephen A. Bowden (University of Aberdeen), and Dr. Gregor Sneddon (Heriot-Watt University) for their insightful suggestions and comments during the planning and development of this work.Peer reviewe

A new practical method to evaluate the Joule-Thomson coefficient for natural gases

© 2017, The Author(s). The Joule–Thomson (JT) phenomenon, the study of fluid temperature changes for a given pressure change at constant enthalpy, has great technological and scientific importance for designing, maintenance and prediction of hydrocarbon production. The phenomenon serves vital role in many facets of hydrocarbon production, especially associated with reservoir management such as interpretation of temperature logs of production and injection well, identification of water and gas entry locations in multilayer production scenarios, modelling of thermal response of hydrocarbon reservoirs and prediction of wellbore flowing temperature profile. The purpose of this study is to develop a new method for the evaluation of JT coefficient, as an essential parameter required to account the Joule–Thomson effects while predicting the flowing temperature profile for gas production wells. To do this, a new correction factor, CNM, has been developed through numerical analysis and proposed a practical method to predict CNM which can simplify the prediction of flowing temperature for gas production wells while accounting the Joule–Thomson effect. The developed correlation and methodology were validated through an exhaustive survey which has been conducted with 20 different gas mixture samples. For each sample, the model has been run for a wide range of temperature and pressure conditions, and the model was rigorously verified by comparison of the results estimated throughout the study with the results obtained from HYSYS and Peng–Robinson equation of state. It is observed that model is very simple and robust yet can accurately predict the Joule–Thomson effect

Natural gas hydrate promotion capabilities of toluene sulfonic acid isomers

The purpose of this study was to investigate the natural gas hydrate promotion capabilities of the hydrotrope Toluene Sulfonic Acid (TSA) isomers as an additive. The capabilities of TSA isomers were measured with different concentrations. The optimum additive concentration for hydrate formation was determined for the given pressure, temperature, mixing condition, and cooling time. The natural gas hydrate promotability of para-TSA was found to be 20% and 35% more than meta-TSA and ortho-TSA respectively at the optimum concentration. Beyond the optimum TSA concentration, the hydrate formation declined as the ice formation reduced the overall gas-to-water volume ratio in the hydrates

Natural gas hydrate promotion capabilities of toluene sulfonic acid isomers

The purpose of this study was to investigate the natural gas hydrate promotion capabilities of the hydrotrope Toluene Sulfonic Acid (TSA) isomers as an additive. The capabilities of TSA isomers were measured with different concentrations. The optimum additive concentration for hydrate formation was determined for the given pressure, temperature, mixing condition, and cooling time. The natural gas hydrate promotability of para-TSA was found to be 20% and 35% more than meta-TSA and ortho-TSA respectively at the optimum concentration. Beyond the optimum TSA concentration, the hydrate formation declined as the ice formation reduced the overall gas-to-water volume ratio in the hydrates

The Effect of pH and Mineralogy on the Retention of Polymeric Scale Inhibitors on Carbonate Rocks for Precipitation Squeeze Treatments

Abstract The bulk "apparent adsorption" behavior (Γapp, vs. Cf) of 2 polymeric scale inhibitors (SI), PPCA and PFC, onto carbonate mineral substrates has been studied for initial solution pH values of pH 2, 4 and 6. The 2 carbonate minerals used, calcite and dolomite, are much more chemically reactive than sandstone minerals (e.g. quartz, feldspars, clays etc.) which have already been studied extensively. In nearly all cases, precipitates formed at higher SI concentrations were due to the formation of sparingly soluble SI/Ca complexes. A systematic study has been carried out on the SI/Ca precipitates formed, by applying both ESEM/EDX and particle size analysis (PSA), and this identifies the morphology and the approximate composition of the precipitates. For PPCA, at all initial solution pH values, regions of pure adsorption (Γ) ([PPCA] &amp;lt;100ppm) and coupled adsorption/ precipitation (Γ/Π) are clearly observed for both calcite and dolomite. PFC at pH = 4 and 6 also showed very similar behavior with a region of pure adsorption (Γ) for [PFC] &amp;lt; 500ppm and a region of coupled adsorption/precipitation (Γ/Π) above this level. However, the PFC/calcite case at pH 2 showed only pure adsorption, while the PFC/dolomite case at pH 2 again showed coupled adsorption/ precipitation at higher PFC concentrations. For both SIs on both carbonate substrates, precipitation is the more dominant mechanism for SI retention than adsorption above a minimum concentration of ~100 – 500 ppm SI. The actual amount of precipitate formed varies from case to case, depending on the specific SI, substrate (calcite/dolomite) and initial pH (pH 2, 4 and 6). Although the qualitative behavior of both PPCA and PFC was similar on both carbonate substrates, the apparent adsorption of PPCA was higher on calcite than on dolomite; PFC apparent adsorption was higher on dolomite than on calcite. It is discussed in the paper how these observations are related to the reactivity of the different carbonate minerals, the resulting final pH (which affects the dissociation of the SI), Ca-SI binding and the solubility of the resulting complex.</jats:p

Adsorption of organic acids in oil on crushed marble at varying temperatures and ambient pressure

Adsorption of organic constituents of reservoir fluids onto the surface of grains constituting carbonate reservoirs is believed to determine reservoir wettability and, at the pore scale, the flow of fluids in them. In this study, the effect of grain surface modification, duration of exposure, and temperature on stearic acid and cyclohexanepentanoic acid adsorption and their adsorption strengths on crushed marble, our model for carbonate reservoir rock, is investigated. The amount of stearic acid or cyclohexanepentanoic acid adsorbed onto the marble grains was determined using Gas Chromatography-Flame Ionization Detector (GC-FID). To characterise marble grains, Particle Size Analysis (PSA), Nitrogen Adsorption–desorption analysis (NAD), Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) were performed. Adsorption of stearic acid and cyclohexanepentanoic acid reached equilibrium after 336 h and altered the contact angle of the marble from water-wet to oil-wet. The amount of adsorption for both acids on marble increased with temperature. Adsorption results indicated that adsorption mechanisms are a combination of physical and chemical adsorption for both acids on marble grains. The adsorption strength experiments also showed that stearic acid adsorption on the marble is stronger than cyclohexanepentanoic acid adsorption. The results suggest that understanding the impact of temperature on adsorption and adsorption strength of polar components in the oil phase on rock surface is essential in carbonate reservoirs to reduce remaining oil saturation