Solubility Of Methane Research Articles

An experimental study of gas solubility in glycerin based drilling fluid applied to well control

The drilling fluid is the primary barrier element against a kick. In the path of drilling fluids evolution, synthetic-based drilling fluid (SBDF) is commonly used on offshore rigs due to its benefits to the high level of drilling complexity, especially at deep and ultra-deep-water scenarios. However, when formation gas dissolves in the mud due to high pressure and high temperature, the complexity of kick detection increases significantly. Furthermore, environmental concerns raised a red flag on SBDF usage due to potential impacts on the marine environment, with most governmental agencies around the world passing very strict regulations. Considering both aspects - safety, and environmental concerns - glycerin emerges as a potential candidate to perform a key role as a base drilling fluid (GBDF). At first, a GBDF has the potential to behave as an SBDF due to its benefits, such as lubricity and shale stabilization, and, at the same time, it has the same characteristics of water-based drilling fluid (WBDF) with very low methane solubility, the major component of natural gas. Additionally, GBDF is considered to be more environmentally friendly than SBDF. In this work, we first analyzed the PVT properties and rheology of three different molar composition glycerin-based drilling fluids: 100% glycerin, 50-50% glycerin/brine, and 40–60% glycerin/brine. Then, we performed the PVT properties analysis of methane (10–50% molar mass) mixed with each of these GBDF mentioned. In a systematic constant composition expansion through a visual high-resolution PVT cell under temperature and pressure range conditions of 20–80 °C and 0–55 MPa, respectively, and rheology characterization. The GBDF exhibited interesting results for density and rheology parameters similar to an SDBF and no methane solubility. Finally, mathematical correlations are proposed and applied to illustrate a pit-gain calculation comparing to an n-paraffin-based drilling fluid. • No solubilization can be considered between methane and glycerin drilling fluid under HPHT conditions studied. • Glycerin drilling fluid potential to behave as a synthetic drilling fluid and as water drilling fluid at the same time. • Crude glycerin drilling fluid showed a stable rheological trend regardless of the increase in temperature and shear rate. • The desire fluid density can be achieved by adding water in glycerin solution reducing the need for fluid thickening.

Gas-hydrogeochemical conditions of the Bilche-Volytsia oil-gas-bearing area (Carpathian foredeep, Ukraine)

Introduction. Water-dissolved gases in exploratory oil and gas hydrogeology are the fundamental criteria of oil and gas potential. Their quantitative and qualitative characteristics allow to study the conditions of formation and preservation of the hydrocarbon deposits and to identify the perspective searching areas. The purpose of article was to determine the vertical and lateral gas-hydrogeochemical zonation of the Bilche-Volytsia oil and gas zone, to assess the role of water-dissolved gases in the formation of gas fields with the prospect of predicting new hydrocarbon deposits. The research methods base on the calculation and interpretation of the following parameters: gas saturation of water, saturation pressure, gas saturation coefficient. Graphs of dependences based on experimental studies from published scientific publications were used to determine the solubility of methane. The results of research. Nitrogen-methane composition of water-dissolved gases of the Upper Jurassic and Upper Cretaceous aquifers in combination with specific geochemical characteristics of groundwater of the north-western and central parts of the Bilche-Volytsia OGBA indicate the open hydrodynamic conditions, which, in general, are unfavourable for the formation and preservation of hydrocarbon deposits. In deep-submerged reservoirs of the south-eastern part of this area, water-dissolved gases of the Upper Jurassic and Upper Cretaceous aquifers are characterized by high contents of methane homologues. In the Upper Badenian aquifer the lateral distribution of water-dissolved methane is presented in the growth of its portions from the West and East European platforms in the direction of the sub-submerge of the Carpathians, which is due to an increase in the degree of hydrogeological closure of structures. Increased methane contents also spatially tend to transverse tectonic faults, which determines their role in the vertical migration of water-hydrocarbon mixtures. Water-dissolved gases of the highly productive Lower Sarmatian aquifer are mainly methane, occasionally nitrogen-methane. The gas saturation of the waters directly correlates with the proximity to gas deposits. Laterally, the portion of water-dissolved methane is directly correlated with TDS of water, the high values of which accordingly reflect the structures of a high degree of hydrogeological stagnation. Conclusions. The portions of water-dissolved methane increase from the West and East European platforms in the direction of the sub-submerge of the Carpathians, which is effect of higher degree of hydrogeological closure of structures. It has been established that water-dissolved methane, nitrogen and carbon dioxide have different sources of origin and different spatiotemporal mechanisms of water saturation. The hydrodynamically closed structures (favourable for the formation and preservation of hydrocarbon deposits) characterized by high relative and absolute contents of dissolved methane. Increased methane contents also spatially tend to transverse tectonic faults, which determines their role in the vertical transportation of water-hydrocarbon mixtures. Deep hydrodynamically closed aquifers of the Bilche-Volytsia OGBA often are marked by high nitrogen contents of non-air origin. Its source can be rock organic matter, bound rock nitrogen released during metamorphism, nitrogen of deep genesis.

Acetate and electricity generation from methane in conductive fiber membrane- microbial fuel cells

Microbial conversion of methane to electricity, fuels, and liquid chemicals has attracted much attention. However, due to the low solubility of methane, it is not considered a suitable substrate for microbial fuel cells (MFCs). In this study, a conductive fiber membrane (CFM) module was constructed as the bioanode of methane-driven MFCs, directly delivering methane. After biofilm formation on the CFM surface, a steady voltage output of 0.6 to 0.7 V was recorded, and the CFM-MFCs obtained a maximum power density of 64 ± 2 mW/m2. Moreover, methane oxidation produced a high concentration of intermediate acetate (up to 7.1 mM). High-throughput 16S rRNA gene sequencing suggests that the microbial community was significantly changed after electricity generation. Methane-related archaea formed a symbiotic consortium with characterized electroactive bacteria and fermentative bacteria, suggesting a combination of three types of microorganisms for methane conversion into acetate and electricity.

Predicting methane solubility in water and seawater by machine learning algorithms: Application to methane transport modeling

The upward migration of methane from natural gas wells associated with fracking operations may lead to contamination of groundwater resources and surface leakage. Numerical simulations of methane transport in the subsurface environment require knowledge of methane solubility in the aqueous phase. This study employs machine learning (ML) algorithms to predict methane solubility in aquatic systems for temperatures ranging from 273.15 to 518.3 K and pressures ranging from 1 to 1570 bar. Four regression algorithms including regression tree (RT), boosted regression tree (BRT), least square support vector machine (LSSVM) and Gaussian process regression (GPR) were utilized for predicting methane solubility in pure water and mixed aquatic systems containing Na+, K+, Ca2+, Mg2+, Cl− and SO4-2. The experimental data collected from the literature were used to implement the models. We used Grid search (GS), Random search (RS) and Bayesian optimization (BO) for tuning hyper-parameters of the ML models. Moreover, the predicted values of methane solubility were compared against Spivey et al. (2004) and Duan and Mao (2006) equations of state. The results show that the BRT-BO model is the most rigorous model for the prediction task. The coefficient of determination (R2) between experimental and predicted values is 0.99 and the mean squared error (MSE) is 1.19 × 10−7. The performance of the BRT-BO model is satisfactory, showing an acceptable agreement with experimental data. The comparison results demonstrated the superior performance of the BRT-BO model for predicting methane solubility in aquatic systems over a span of temperature, pressure and ionic strength that occurs in deep marine environments.

Solubility Calculations of Methane and Ethane in Aqueous Electrolyte Solutions

Accurate calculation of light hydrocarbon solubilities in aqueous electrolyte solutions is critical for petroleum and geochemical applications. However, very few electrolyte Equations of State (e-EoS) have been used for calculation of light hydrocarbon solubilities. Thermodynamic calculation of gas (methane and ethane) solubilities in aqueous solutions of chloride salts are presented. This work introduces a new parameter estimation approach (which can predict well the liquid densities of aqueous solutions) for the electrolyte Cubic Plus Association EoS (e-CPA). The cation/anion–water interaction parameters are obtained from the regression of experimental mean ionic activity coefficients and liquid densities. The results show that the e-CPA with the new parameter estimation approach gives good agreements with the corresponding experimental data. The cation/anion–gas interaction parameters are obtained from the regression of experimental gas solubilities. The results show that the e-CPA with the new parameter estimation approach correlates the gas solubilities reasonably well. The gas dissolution mechanisms and salting effects are extensively analyzed and discussed for a deeper understanding of gas dissolution in aqueous electrolyte solutions.

A Monte Carlo Model of Gas-Liquid-Hydrate Three-phase Coexistence Constrained by Pore Geometry in Marine Sediments

Gas hydrates form at relatively high pressures in near-surface, organic-rich marine sediments, with the base of the hydrate stability field and the onset of partial gas saturation determined by temperature increases with depth. Because of pore-scale curvature and wetting effects, the transition between gas hydrate and free gas occurrence need not take place at a distinct depth or temperature boundary, but instead can be characterized by a zone of finite thickness in which methane gas bubbles and hydrate crystals coexist with the same aqueous solution. Previous treatments have idealized pores as spheres or cylinders, but real pores between sediment grains have irregular, largely convex walls that enable the highly curved surfaces of gas bubbles and/or hydrate crystals within a given pore to change with varying conditions. In partially hydrate-saturated sediments, for example, the gas–liquid surface energy perturbs the onset of gas–liquid equilibrium by an amount proportional to bubble-surface curvature, causing a commensurate change to the equilibrium methane solubility in the liquid phase. This solubility is also constrained by the curvature of coexisting hydrate crystals and hence the volume occupied by the hydrate phase. As a result, the thickness of the three-phase zone depends not only on the pore space geometry, but also on the saturation levels of the hydrate and gaseous phases. We evaluate local geometrical constraints in a synthetic 3D packing of spherical particles resembling real granular sediments, relate the changes in the relative proportions of the phases to the three-phase equilibrium conditions, and demonstrate how the boundaries of the three-phase zone at the base of the hydrate stability field are displaced as a function of pore size, while varying with saturation level. The predicted thickness of the three-phase zone varies from tens to hundreds of meters, is inversely dependent on host sediment grain size, and increases dramatically when pores near complete saturation with hydrate and gas, requiring that interfacial curvatures become large.

Atmosphere-Pressure Methane Oxidation to Methyl Trifluoroacetate Enabled by a Porous Organic Polymer-Supported Single-Site Palladium Catalyst

The efficient conversion of methane into methanol at low temperature under low pressure remains a great challenge largely because of the inertness and poor solubility of methane. Herein, we report ...

Solubility of Carbon Dioxide, Hydrogen Sulfide, Methane, and Nitrogen in Monoethylene Glycol; Experiments and Molecular Simulation.

Knowledge on the solubility of gases, especially carbon dioxide (CO2), in monoethylene glycol (MEG) is relevant for a number of industrial applications such as separation processes and gas hydrate prevention. In this study, the solubility of CO2 in MEG was measured experimentally at temperatures of 333.15, 353.15, and 373.15 K. Experimental data were used to validate Monte Carlo (MC) simulations. Continuous fractional component MC simulations in the osmotic ensemble were performed to compute the solubility of CO2 in MEG at the same temperatures and at pressures up to 10 bar. MC simulations were also used to study the solubility of methane (CH4), hydrogen sulfide (H2S), and nitrogen (N2) in MEG at 373.15 K. Solubilities from experiments and simulations are in good agreement at low pressures, but deviations were observed at high pressures. Henry coefficients were also computed using MC simulations and compared to experimental values. The order of solubilities of the gases in MEG at 373.15 K was computed as H2S > CO2 > CH4 > N2. Force field modifications may be required to improve the prediction of solubilities of gases in MEG at high pressures and low temperatures.

Bulk and Interfacial Properties of the Decane + Water System in the Presence of Methane, Carbon Dioxide, and Their Mixture.

Molecular dynamics simulations are carried out to study the two-phase behavior of the n-decane + water system in the presence of methane, carbon dioxide, and their mixture under reservoir conditions. The simulation studies were complemented by theoretical modeling using the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (EoS) and density gradient theory. Our results show that the presence of methane and carbon dioxide decreases the interfacial tension (IFT) of the decane + water system. In general, the IFT increases with increasing pressure and decreasing temperature for the methane + decane + water and carbon dioxide + decane + water systems, similar to what has been found for the corresponding decane + water system. The most important finding of this study is that the presence of carbon dioxide decreases the IFT of the methane + decane + water system. The atomic density profiles provide evidence of the local accumulation of methane and carbon dioxide at the interface, in most of the studied systems. The results of this study show the preferential dissolution in the water-rich phase and enrichment at the interface for carbon dioxide in the methane + carbon dioxide + decane + water system. This indicates the preferential interaction of water with carbon dioxide relative to methane and decane. Notably, there is an enrichment of the interface by decane at high mole fractions of methane in the methane/decane-rich or methane/carbon dioxide/decane-rich phase. Overall, the solubility of methane and carbon dioxide in the water-rich phase increases with increasing pressure and temperature. Additionally, we find that the overall performance of the PC-SAFT EoS and the cubic-plus-association EoS is similar with respect to the calculation of bulk and interfacial properties of these systems.

Experimental study on methane dissolved in surfactant-alkane system

A surfactant-polyalkane system is investigated using chemical reagents to dissolve methane and control coal seam gas from low-energy, high-efficiency, safety, and environmental protection perspectives. At different temperatures and pressures, a high-temperature and high-pressure reactor, gas chromatograph, and other related experimental equipment were used to perform methane dissolution experiments, and a single surfactant sodium oleate (NaOA) and n-hexane demonstrated superior results. The single-factor experiments of temperature, pressure, and NaOA addition were performed and fitted via a response surface analysis. The optimal conditions for methane solubility were as follows: temperature of 34 °C, pressure of 4.5 MPa, NaOA addition of 85 g/L, and time of 1 h. The optimal effect of the surfactant-polyalkane system in dissolving methane was achieved with 32.31 mL/100 mL. Meanwhile, the change in the surface structure of coal before and after washing with the system was compared using scanning electron microscopy. The results indicated that the gas after washing with the surfactant-polyalkane system dissolved, and the surface pore structure of the coal changed. Moreover, the specific surface area and pore size of the coal surface increased after washing. Hence, the desorption of gas from the coal surface into the system becomes easy, thereby reducing the gas content in the coal sample.

Morphology and dynamics of self-assembled structures in mixed surfactant systems (SDS + CAPB) in the context of methane hydrate growth

Presence of small dosages of surfactants in the aqueous phase has been reported to enhance the rate of gas hydrate (clathrate) formation. In this work, using extensive atomistic molecular dynamics (MD) simulations, we have investigated how SDS (surfactant) aggregates in the presence/absence of CAPB (co-surfactant) at ambient conditions (temperature 298 K and pressure 1 bar) and at hydrate forming conditions (temperature 275 K and pressure 50 bar) resulting in altered growth kinetics of methane hydrate. We observe that SDS forms aggregates of different sizes and shapes depending on the thermodynamic condition starting from random distributions of the surfactants. In the presence of the CAPB co-surfactant, tightly packed mixed aggregates are formed. Using various structural order parameters, we demonstrate that shape of the aggregates deviates from spherical as well as cylindrical symmetry. During the aggregation process in presence of methane, the methane molecules get absorbed into the aggregates, enhance the aggregation kinetics and provide structural flexibility to the aggregates. This result is partly in agreement with previous experimental observations that SDS (with or without a co-surfactant) may form micelle-like structures under hydrate forming conditions and that methane gets absorbed by these aggregates leading to enhanced solubility of methane in the aqueous phase. Further, we have investigated the dynamics of shape fluctuations of the aggregates and observed that several distinct relaxation timescales exist in these heterogenous systems.

Petrophysical properties of the Green Canyon Block 955 hydrate reservoir inferred from reconstituted sediments: Implications for hydrate formation and production

We explore the petrophysical behavior of the two interbedded lithofacies (sandy silt and clayey silt) that constitute the Green Canyon Block 955 hydrate reservoir in the deep-water Gulf of Mexico by performing experiments on reconstituted samples of the reservoir material. Sandy silts reconstituted to the in situ porosity have a permeability of 11.8 md (1.18 × 10−14 m2), which is similar to the intrinsic permeabilities measured in intact cores from hydrate reservoirs of similar grain size offshore Japan (Nankai Trough) and offshore India. Reconstituted clayey silts have a much lower intrinsic permeability of 3.84 × 10−4 md (3.84 × 10−19 m2) at the in situ stress. The reconstituted sandy silt is less compressible than the clayey silt. Mercury injection capillary pressure measurements demonstrate that the largest pores with the clayey silt are still smaller than the pores remaining after 90% hydrate saturation in sandy silt. We interpret that the methane solubility in pores of clayey silt is always less than that necessary to form hydrate, which explains why no hydrate is present in the clayey silt. We upscale the reservoir properties to estimate the behavior of interbedded sandy silt and clayey silt. We find the upscaled intrinsic horizontal and vertical permeabilities for the entire reservoir interval are 8.6 md (8.6 × 10−15 m2) and 1.4 × 10−3 md (1.4 × 10−18 m2). We estimate that during reservoir production, a maximum vertical strain of approximately 12% will result. Ultimately, this study will inform reservoir simulation models with petrophysical properties at scales of both individual lithofacies and reservoir formation.

Modeling of methane migration from gas wellbores into shallow groundwater at basin scale

Methane contamination of drinking water resources is one of the major concerns associated with unconventional gas development. This study assesses the potential contamination of shallow groundwater via methane migration from a leaky natural gas well through overburden rocks, following hydraulic fracturing. A two-dimensional, two-phase, two-component numerical model is employed to simulate methane and brine upward migration toward shallow groundwater in a generic sedimentary basin. A sensitivity analysis is conducted to examine the influence of methane solubility, capillary pressure–saturation relationship parameters and residual water saturation of overburden rocks, gas leakage rate from the well, tilted formations, and low-permeability sediments (i.e., claystones) on the transport of fluids. Results show that the presence of lithological barriers is the most important factor controlling the temporal–spatial distribution of methane in the subsurface and the arrival time to shallow groundwater. A pulse of high leakage rate is required for early manifestation of methane in groundwater wells. Simulations reveal that the presence of tilted features could further explain fast-growing methane contamination and extensive lateral spreading reported in field studies.

Solubility of Methane in Alkylpyridinium-Based Ionic Liquids at Temperatures between 298.15 and 343.15 K and Pressures up to 4 MPa

Ionic liquids (ILs) are promising solvents for gas absorption and separation processes. In this work, the solubility of methane in four alkylpyridinium-based ILs, namely, 1-butylpyridinium bis(trif...

Effect of silver nanoparticles on the solubility of methane and ethane in water

In this work, the solubility of methane and ethane were studied in aqueous dispersion of silver nanoparticles (1, 5, and 10 ppm) at temperatures of 1, 2.5, 10, and 11.5 °C for methane and 2.5, 5, 10, 15.5 °C for ethane and at initial pressures 1 to 5.5 and 0.35–2.15 MPa for methane and ethane, respectively. The nanoparticles were synthesized and characterized through UV–vis spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM) image. The results demonstrated that silver nanoparticles increased the solubility of methane and ethane up to 13 and 16% compared with pure water, respectively. The solubility of methane and ethane were enhanced by increasing the nanoparticles mass loading. The effect of nanoparticles on ethane solubility was more significant than methane solubility.

Solubility of methane in octamethylcyclotetrasiloxane: Experimental measurement and thermodynamic modeling

Liquid storage is a potential method for low-pressure storage of natural gas. In this work, octamethylcyclotetrasiloxane (OMCTS) was selected as a solvent for methane storage. Experimental measurements were carried out in a Cailletet apparatus, according to the synthetic method, from low to high pressures. One hundred experimentally-measured phase equilibrium data points are presented for methane + OMCTS in the form of bubble-points. The pressure, temperature, and methane mole fraction ranges are (0.61–8.07) MPa, (287.73–368.25) K, and (0.0534–0.4038), respectively. Furthermore, phase equilibrium calculations based on the ϕ−ϕ approach were carried out to model the methane + OMCTS binary system. In this regard, the Peng-Robinson EoS (PR EoS), coupled with the classical van der Waals (vdW) mixing rule, was applied. The vdW mixing rule was used in three modes: a) with no binary interaction parameters (kij=0,lij=0), b) with one constant binary interaction parameter (kij=constant), and c) with one temperature-dependent binary interaction parameter (kij=a+bT). It was concluded that both modes (b) and (c) give accurate results for methane solubility in OMCTS, with AAD(MPa) values of 0.11 and 0.10, respectively.

Experimental Measurement and Thermodynamic Modeling of Methane Solubility in Triethylene Glycol within the Temperature Range of 343.16–444.95 K

Triethylene glycol (TEG) is widely used in the gas dehydration process. While absorbing water from the gas, some hydrocarbons may also be absorbed. Knowledge of hydrocarbon solubility in TEG is nec...

Structure and Physicochemical Properties of Water Treated under Methane with Low-Temperature Glow Plasma of Low Frequency

Our former studies delivered a strong evidence that water indirectly treated with low-temperature, low-pressure glow plasma of low frequency (GP) changed its structure depending on the atmosphere in which such treatment was performed (air, ammonia, and nitrogen) and on the time of the treatment (0 to 120 min). In every case, water of different physicochemical characteristics and interesting biological functions was produced. Therefore, the relevant studies were extended to treating deionized water with GP under methane. The resulting samples were characterized by means of ultraviolet/visible (UV/VIS), Fourier transformation infrared-attenuated total reflectance (FTIR-ATR), electron spin resonance (ESR) and Raman spectroscopies, differential scanning calorimetry (DSC), thermogravimetry, pH, conductivity, and refractive index. The generated samples of water had entirely different physicochemical properties from those recorded for water treated with GP in the air and under both ammonia and nitrogen. The treatment of water with GP under methane did not produce clathrates hosting methane molecules. Thermogravimetry delivered an evidence that the treatment with GP increased the aqueous solubility of methane. That solubility non-linearly changed against the treatment time.

Scaled charges at work: Salting out and interfacial tension of methane with electrolyte solutions from computer simulations

The solubility of methane in water decreases when a small amount of salt is present. This is usually denoted as the salting out effect (i.e., the methane is expelled from the solution when it contains small amounts of salt). The effect is important, for instance the solubility is reduced by a factor of three in a 4 m (mol/kg) NaCl solution. Some years ago we showed that the salting out effect of methane in water can be described qualitatively by molecular models using computer simulations. However the salting out effect was overestimated. In fact, it was found that the solubility of methane was reduced by a factor of eight. This points to limitations in the force field used. In this work we have carried out direct coexistence simulations to describe the salting out effect of methane in water using a recently proposed force field (denoted as Madrid-2019) based on the use of scaled charges for the ions and the TIP4P/2005 force field for water. For NaCl the results of the Madrid-2019 force field significantly improve the description of salting out of methane. For other salts the results are quite reasonable. Thus the reduction of the charge of the ions also seems to be able to improve the description of salting out effect of methane in water. Besides this we shall show that the brine-methane interface exhibits an increased interfacial tension as compared to that of the water-methane system. It is well known that electrolytes tend to increase the surface tension of liquid water, and this seems also to be the case for the interface between water and methane.

Prediction method of methane content change in cyclic hydrogen after desulfurization

The purity of circulating hydrogen after desulfurization is mainly affected by the content of inert component methane. Based on this, the prediction method of methane content in circulating hydrogen after desulfurization is studied. From the process of hydrogen facing system, it can be seen that the methane content in circulating hydrogen after desulfurization is mainly affected by methane solubility, feed oil density, new hydrogen components, reaction temperature, hydrogen consumption per ton of oil and catalyst components. In the process of predicting the change of methane content in circulating hydrogen after desulfurization, the methane content in circulating hydrogen after desulfurization was detected under different working conditions (different influencing factors) by means of spectral absorption method and methane content detection device. According to the real-time test results, the influence of different working conditions on methane content in circulating hydrogen after desulfurization was obtained. Based on this, the change of methane content in circulating hydrogen after desulfurization was predicted under the fluctuating conditions of various influencing factors. The results show that the methane content in recycled hydrogen after desulfurization increases with the increase of methane content, reaction temperature and the addition of higher active catalyst in the reactor. When the density of feed oil is 892–909 kg/m3, the change of composition is small, which has little effect on the circulating hydrogen methane content after desulfurization.