Journal of Natural Gas Science and Engineering

Article	Citations
External corrosion of oil and gas pipelines: A review of failure mechanisms and predictive preventions	134
A new hybrid algorithm model for prediction of internal corrosion rate of multiphase pipeline	99
Superhydrophobic coatings for steel pipeline protection in oil and gas industries: A comprehensive review	94
Use of existing steel pipeline infrastructure for gaseous hydrogen storage and transport: A review of factors affecting hydrogen induced degradation	93
A review of the features and applications of ZIF-8 and its derivatives for separating CO2 and isomers of C3- and C4- hydrocarbons	92
The role of storage systems in hydrogen economy: A review	72
Daily natural gas load forecasting based on the combination of long short term memory, local mean decomposition, and wavelet threshold denoising algorithm	66
Natural gas consumption forecasting: A discussion on forecasting history and future challenges	65
Prediction of the internal corrosion rate for oil and gas pipeline: Implementation of ensemble learning techniques	60
Numerical study of depressurization and hot water injection for gas hydrate production in China's first offshore test site	60
Liquid nitrogen fracturing efficiency as a function of coal rank: A multi-scale tomographic study	60
Characteristics of methane adsorption/desorption heat and energy with respect to coal rank	59
Experiences and lessons learned from China's shale gas development: 2005–2019	58
Accurate characterization of coal pore and fissure structure based on CT 3D reconstruction and NMR	58
A comprehensive review of proppant transport in fractured reservoirs: Experimental, numerical, and field aspects	58
Machine learning-based production forecast for shale gas in unconventional reservoirs via integration of geological and operational factors	57
Quantitative visualization and characteristics of gas flow in 3D pore-fracture system of tight rock based on Lattice Boltzmann simulation	56
Insights into the application of surfactants and nanomaterials as shale inhibitors for water-based drilling fluid: A review	54
Permeability and porosity prediction using logging data in a heterogeneous dolomite reservoir: An integrated approach	53
Hydrogen in pipeline steels: Recent advances in characterization and embrittlement mitigation	53
Hydrogen-induced cracking and blistering in steels: A review	52
A review on non-aqueous fracturing techniques in unconventional reservoirs	52
Integrated sedimentological and petrophysical characterization for clastic reservoirs: A case study from New Zealand	52
CFD-DEM simulation of proppant transport by supercritical CO2 in a vertical planar fracture	50
Aminoantipyrine derivatives as a novel eco-friendly corrosion inhibitors for P110 steel in simulating acidizing environment: Experimental and computational studies	49

Particle size effect on pore structure characteristics of lignite determined via low-temperature nitrogen adsorption	49
Study on the mechanical properties of man-made salt rock samples with impurities	48
Evaluation of the gas production enhancement effect of hydraulic fracturing on combining depressurization with thermal stimulation from challenging ocean hydrate reservoirs	48
A review on gas hydrates and kinetic hydrate inhibitors based on acrylamides	47
Neural network application to petrophysical and lithofacies analysis based on multi-scale data: An integrated study using conventional well log, core and borehole image data	47
Oxidative coupling of methane (OCM): An overview of the challenges and opportunities for developing new technologies	45
Assessment of rock-hydrogen and rock-water interfacial tension in shale, evaporite and basaltic rocks	45
Water-soluble polymers for high-temperature resistant hydraulic fracturing: A review	44
Erosion simulation and improvement scheme of separator blowdown system ——A case study of Changning national shale gas demonstration area	44
A comprehensive review of proppant embedment in shale reservoirs: Experimentation, modeling and future prospects	44
Differential enrichment mechanism of organic matters in the marine-continental transitional shale in northeastern Ordos Basin, China: Control of sedimentary environments	43
Improving the shale stability with nano-silica grafted with hyperbranched polyethyleneimine in water-based drilling fluid	43
A review on gas hydrate production feasibility for permafrost and marine hydrates	43
Flow modeling in shale gas reservoirs: A comprehensive review	42
Review of methods and applications for promoting gas hydrate formation process	42
A review of foam-based fracturing fluids applications: From lab studies to field implementations	42
Pillared cloisite 15A as an enhancement filler in polysulfone mixed matrix membranes for CO2/N2 and O2/N2 gas separation	42
A review of laboratory studies and theoretical analysis for the interaction mode between induced hydraulic fractures and pre-existing fractures	41
3D microfracture network and seepage characteristics of low-volatility bituminous coal based on nano-CT	41
A review of numerical research on gas production from natural gas hydrates in China	41
CO2 geological storage: Critical insights on plume dynamics and storage efficiency during long-term injection and post-injection periods	40
Review on the accumulation behavior of natural gas hydrates in porous sediments	40
Gas hydrate formation in the presence of mixed surfactants and alumina nanoparticles	40
A proposed classification for the reservoir quality assessment of hydrocarbon-bearing sandstone and carbonate reservoirs: A correlative study based on different assessment petrophysical procedures	39
Development and application of three-dimensional discrete fracture network modeling approach for fluid flow in fractured rock masses	39
Advantages of supercritical CO2 compound fracturing in shale on fracture geometry, complexity and width	39
Insights into NMR response characteristics of shales and its application in shale gas reservoir evaluation	39
Dynamic failure behavior of buried cast iron gas pipeline with local external corrosion subjected to blasting vibration	38
Analysis of natural gas leakage diffusion characteristics and prediction of invasion distance in utility tunnels	38
The impact of supercritical CO2 on the pore structure and storage capacity of shales	38
A novel custom ensemble learning model for an improved reservoir permeability and water saturation prediction	38
Casing deformation mechanisms of horizontal wells in Weirong shale gas field during multistage hydraulic fracturing	38
Organic matter pores structure and evolution in shales based on the he ion microscopy (HIM): A case study from the Triassic Yanchang, Lower Silurian Longmaxi and Lower Cambrian Niutitang shales in Chi	38
Examining the relationship between Tmax and vitrinite reflectance: An empirical comparison between thermal maturity indicators	38
Evolution of methane ad-/desorption and diffusion in coal under in the presence of oxygen and nitrogen after heat treatment	37
A comprehensive review of laboratory, field and modelling studies on drilling mud rheology in high temperature high pressure (HTHP) conditions	37
An updated study on CH4 isothermal adsorption and isosteric adsorption heat behaviors of variable rank coals	37
The calculations of pore structure parameters from gas adsorption experiments of shales: Which models are better?	37
Analysis of the mechanical properties of methane hydrate-bearing sands with various pore pressures and confining pressures	37
Numerical study on the diffusion process of pinhole leakage of natural gas from underground pipelines to the soil	37
Thermal methods in flow assurance: A review	36
Mechanical behavior of hydrate-bearing sands with fine particles under isotropic and triaxial compression	36
Influence of pore structural properties on gas hydrate saturation and permeability: A coupled pore-scale modelling and X-ray computed tomography method	36
Synthesis and performance evaluation of a novel polymeric fluid loss controller in water-based drilling fluids: High-temperature and high-salinity conditions	35
Comprehensive review of geomechanical constitutive models of gas hydrate-bearing sediments	35
Integration of discrete fracture reconstruction and dual porosity/dual permeability models for gas production analysis in a deformable fractured shale reservoir	35
Machine learning-informed ensemble framework for evaluating shale gas production potential: Case study in the Marcellus Shale	34
Development of renewable energy system integrated with hydrogen and natural gas subsystems for cleaner combustion	34
Time-dependent coal permeability: Impact of gas transport from coal cleats to matrices	34
Modeling In-situ tectonic stress state and maximum horizontal stress azimuth in the Central Algerian Sahara – A geomechanical study from El Agreb, El Gassi and Hassi Messaoud fields	34

The characteristics and its implications of hydraulic fracturing in hydrate-bearing clayey silt	34
Exploration potential of different lithofacies of deep marine shale gas systems: Insight into organic matter accumulation and pore formation mechanisms	34
Experimental study on coal permeability and cracking characteristics under LN2 freeze-thaw cycles	33
Influence of tectonic evolution on pore structure and fractal characteristics of coal by low pressure gas adsorption	33
The effect of subcritical and supercritical CO2 on the pore structure of bituminous coals	33
Molecular insights into the kinetic hydrate inhibition performance of Poly(N-vinyl lactam) polymers	33
Impact of zinc oxide nanoparticles on the rheological and fluid-loss properties, and the hydraulic performance of non-damaging drilling fluid	33
Multi-scale reconstruction of porous media from low-resolution core images using conditional generative adversarial networks	33
Pore formation and evolution of organic-rich shale during the entire hydrocarbon generation process: Examination of artificially and naturally matured samples	33
Artificial neural network (ANN) approach to predict unconfined compressive strength (UCS) of oil and gas well cement reinforced with nanoparticles	32
Experimental study of the influence of water-based fracturing fluids on the pore structure of coal	32
Influence of cryogenic liquid nitrogen cooling and thermal shocks on petro-physical and morphological characteristics of Eagle Ford shale	32
Pore structure typing and fractal characteristics of lacustrine shale from Kongdian Formation in East China	32
Leakage diffusion characteristics and harmful boundary analysis of buried natural gas pipeline under multiple working conditions	32
Temperature impact on linear and radial wormhole propagation in limestone, dolomite, and mixed mineralogy	31
Experimental and numerical simulation of erosion-corrosion of 90° steel elbow in shale gas pipeline	31
Hydraulic fracturing characteristics and evaluation of fracturing effectiveness under different anisotropic angles and injection rates: An experimental investigation in absence of confining pressure	31
Shale lithofacies controls on porosity and pore structure: An example from Ordovician Goldwyer Formation, Canning Basin, Western Australia	31
Energy, exergy and economic (3E) evaluation of CO2 capture from natural gas using pyridinium functionalized ionic liquids: A simulation study	31
Hybrid machine learning algorithms to predict condensate viscosity in the near wellbore regions of gas condensate reservoirs	31
Formation damage mitigation mechanism for coalbed methane wells via refracturing with fuzzy-ball fluid as temporary blocking agents	31
A critical review of breakthrough pressure for tight rocks and relevant factors	31
Safety, economics, environment and energy based criteria towards multi-objective optimization of natural gas sweetening process: An industrial case study	30
Xenon recovery from natural gas by hybrid method based on gas hydrate crystallisation and membrane gas separation	30
Damage effects on coal mechanical properties and micro-scale structures during liquid CO2-ECBM process	30
The effect of clay-swelling induced cracks on shale permeability during liquid imbibition and diffusion	30
Machine learning for drilling applications: A review	30
Analysis of corrosion failure and materials selection for CO2–H2S gas well	30
Empirical methods of decline-curve analysis for shale gas reservoirs: Review, evaluation, and application	30
Mechanisms of shale water wettability alteration with chemical groups after CO2 injection: Implication for shale gas recovery and CO2 geo-storage	30
CFD numerical simulation of standalone sand screen erosion due to gas-sand flow	30
Multi-scale modelling of gas transport and production evaluation in shale reservoir considering crisscrossing fractures	30
The development of leak detection model in subsea gas pipeline using machine learning	30
The effect of clay-swelling induced cracks on imbibition behavior of marine shale reservoirs	30
The geochemical characteristics, origin, migration and accumulation modes of deep coal-measure gas in the west of Linxing block at the eastern margin of Ordos Basin	29
Effect of roughness on fluid flow and solute transport in a single fracture: A review of recent developments, current trends, and future research	29
Numerical simulation of proppant transport in liquid nitrogen fracturing	29
Permeability changes in mining-damaged coal: A review of mathematical models	29
Integrated wireline log and seismic attribute analysis for the reservoir evaluation: A case study of the Mount Messenger Formation in Kaimiro Field, Taranaki Basin, New Zealand	29
Self-healing hydrogels and their action mechanism in oil–gas drilling and development engineering: A systematic review and prospect	29
Molecular insights into recovery of shale gas by CO2 injection in kerogen slit nanopores	28
Quantitative analysis of pore structure and permeability characteristics of sandstone using SEM and CT images	28
Machine-learning predictions of the shale wells’ performance	28
Experimental research of the surfactant effect on seepage law in coal seam water injection	28
Nonlinear finite element analysis on the sealing performance of rubber packer for hydraulic fracturing	28
Effect of sub-/super-critical CO2 and brine exposure on the mechanical and acoustic emission characteristics of shale	28
CH4 recovery and CO2 sequestration from hydrate-bearing clayey sediments via CO2/N2 injection	28
Investigating fracture propagation characteristics in shale using sc-CO2 and water with the aid of X-ray Computed Tomography	28
Microcosmic retaining mechanism and behavior of screen media with highly argillaceous fine sand from natural gas hydrate reservoir	28
A critical review of distributed fiber optic sensing for real-time monitoring geologic CO2 sequestration	28
Effect of stress on permeability of clay silty cores recovered from the Shenhu hydrate area of the South China Sea	28
Effects of different amin-based core-shell magnetic NPs on CO2 capture using NMP solution at high pressures	28
Liquefied synthetic methane from ambient CO2 and renewable H2 - A technoeconomic study	28
Effects of waxes and asphaltenes on CO2 hydrate nucleation and decomposition in oil-dominated systems	27
The ungrind and grinded effects on the pore geometry and adsorption mechanism of the coal particles	27
Numerical simulation of productivity improvement of natural gas hydrate with various well types: Influence of branch parameters	27
Effect of water-based working fluid imbibition on static and dynamic compressive properties of anisotropic shale	27
Modified Peng-Robinson equation of state for CO2/hydrocarbon systems within nanopores	27
Characteristics of gas chimneys and their implications on gas hydrate accumulation in the Shenhu area, northern south China sea	27
Evaluation of enhanced coalbed methane recovery and carbon dioxide sequestration potential in high volatile bituminous coal	27
Impact of reservoir, fracturing fluid and proppant characteristics on proppant crushing and embedment in sandstone formations	27
Critical factors controlling adsorption capacity of shale gas in Wufeng-Longmaxi formation, Sichuan Basin: Evidences from both experiments and molecular simulations	27
A detailed morphology investigation on the effects of mixed anionic and nonionic surfactants on methane hydrate formation and dissociation	26
Internal microbiologically influenced corrosion of natural gas pipelines: A critical review	26
Mechanical properties of remolded hydrate-bearing clayey-silty sediments	26
Coupled wellbore–reservoir heat and mass transfer model for horizontal drilling through hydrate reservoir and application in wellbore stability analysis	26
Numerical investigation of complex hydraulic fracture network in naturally fractured reservoirs based on the XFEM	26
Numerical simulation of fracture initiation, propagation and fracture complexity in the presence of multiple perforations	26
Coupling rate of penetration and mechanical specific energy to Improve the efficiency of drilling gas wells	26
An integrated 3D fracture network reconstruction method based on microseismic events	26
Stress shadow effects and microseismic events during hydrofracturing of multiple vertical wells in tight reservoirs: A three-dimensional numerical model	26
Simulation of the hydrate blockage process in a water-dominated system via the CFD-DEM method	26
Investigation on micro-surface adhesion of coals and implications for gas occurrence and coal and gas outburst mechanism	26
Towards a fundamental understanding of biopolymers and their role in gas hydrates: A review	26
Influence of clay minerals and cementation on pore throat of tight sandstone gas reservoir in the eastern Ordos Basin, China	25
Numerical reactive flow transport simulation on core samples during acid fracturing in carbonaceous shale	25
Lithofacies classification integrating conventional approaches and machine learning technique	25
Influence of sodium chloride on the kinetics of methane hydrate formation in the presence of surfactant	25
A review of micro computed tomography studies on the gas hydrate pore habits and seepage properties in hydrate bearing sediments	25
Recent advances in waterless fracturing technology for the petroleum industry: An overview	25

Carbonate rock mechanical response to CO2 flooding evaluated by a combined X-ray computed tomography – DEM method	25
Experimental and numerical investigation of the failure mechanism and permeability evolution of sandstone based on hydro-mechanical coupling	25
Construction simulating and controlling of the two-well-vertical(TWV) salt caverns with gas blanket	25
A brittleness index evaluation method for weak-brittle rock by acoustic emission technique	25
A review of recent advances and prospects on nanocellulose properties and its applications in oil and gas production	25
A three components thixotropic agent to enhance the thixotropic property of natural gas well cement at high temperatures	25
Effect of temperature on the electrochemical pitting corrosion behavior of 316L stainless steel in chloride-containing MDEA solution	25
Glutamine functionalized iron oxide nanoparticles for high-performance carbon dioxide absorption	25
Pore-scale study on methane hydrate formation and dissociation in a heterogeneous micromodel	25
Nanoconfined methane density over pressure and temperature: Wettability effect	25
Effects of temperature on the corrosion behaviour of X70 steel in CO2-Containing formation water	25
Fabrication and characterization of Pebax-1657 mixed matrix membrane loaded with Si-CHA zeolite for CO2 separation from CH4	25
Dimensionless data-driven model for optimizing hole cleaning efficiency in daily drilling operations	24
The influence of CO2 and CH4 mixture on water wettability in organic rich shale nanopore	24
Effects of permeability anisotropy on coal mine methane drainage performance	24
Effects of microstructural and petrophysical properties on spontaneous imbibition in tight sandstone reservoirs	24
Pore-scale influence of methane hydrate on permeability of porous media	24
Experimental study on the anisotropy of the effective stress coefficient of sandstone under true triaxial stress	24
A review on polymer-nanofiller composites in developing coated sand proppants for hydraulic fracturing	24
Measurement and modeling of coal adsorption-permeability based on the fractal method	24
Low-permeability reservoir sample wettability characterization at multiple scales: Pore-, micro- and macro-contact angles	24
Experimental investigation and mathematical modelling of shale gas adsorption and desorption hysteresis	24
Dynamics of coalbed methane emission from coal cores under various stress paths and its application in gas extraction in mining-disturbed coal seam	24
Brittleness and microcracks: A new approach of brittleness characterization for shale fracking	24
Recent developments in model-based fault detection and diagnostics of gas pipelines under transient conditions	24
Review of recent advances in petroleum fluid properties and their representation	24
An experimental study on the effect of nitrogen injection on the deformation of coal during methane desorption	24
Enhanced gas production from clayey-silt hydrate reservoirs based on near-well reservoir reconstruction using the high-pressure jet grouting technology	24
Prediction of hydrate formation temperature using gene expression programming	24
Tectonic controls on Permian tight gas accumulation: Constrains from fluid inclusion and paleo-structure reconstruction in the Hangjinqi area, northern Ordos Basin, China	24
Petrophysical, geomechanical and depositional environment characterization of the Triassic TAGI reservoir from the Hassi Berkine South field, Berkine Basin, Southeastern Algeria	24
A new application of atomic force microscopy in the characterization of pore structure and pore contribution in shale gas reservoirs	24
Damage constitutive model of gas-bearing coal using industrial CT scanning technology	24
Comparisons of fracturing mechanism of tight sandstone using liquid CO2 and water	23
Redistribution of fracturing fluid in shales and its impact on gas transport capacity	23
Mechanism of ultra-deep gas accumulation at thrust fronts in the Longmenshan Mountains, lower Permian Sichuan Basin, China	23
Numerical simulation and laboratory experiments of CO2 sequestration and being as cushion gas in underground natural gas storage reservoirs	23
Effect of wettability of shale on CO2 sequestration with enhanced gas recovery in shale reservoir: Implications from molecular dynamics simulation	23
Cellular automata-based multi-objective hybrid grey wolf optimization and particle swarm optimization algorithm for wellbore trajectory optimization	23
A probabilistic approach to estimate the remaining life and reliability of corroded pipelines	23
Implications of geological conditions on gas content and geochemistry of deep coalbed methane reservoirs from the Panji Deep Area in the Huainan Coalfield, China	23
Hydraulic fracture propagation at weak interfaces between contrasting layers in shale using XFEM with energy-based criterion	23
Ion-exchanged ETS-10 adsorbents for CO2/CH4 separation: IAST assisted comparison of performance with other zeolites	23
Application of computed tomography (CT) in geologic CO2 utilization and storage research: A critical review	23
Reliability assessment of subsea pipelines under the effect of spanning load and corrosion degradation	23
Membrane-based gas separation accelerated by quaternary mixed matrix membranes	23
Numerical study of pipeline leak detection for gas-liquid stratified flow	23
Numerical study on the particle erosion of elbows mounted in series in the gas-solid flow	22
Controls of facies distribution on reservoir quality in the Messinian incised-valley fill Abu Madi Formation in Salma delta gas field, northeastern onshore Nile Delta, Egypt	22
Anisotropic characteristics of the energy index during the shale failure process under triaxial compression	22
A critical review on coupled geomechanics and fluid flow in naturally fractured reservoirs	22
The dilemma of soaking a hydraulically fractured horizontal shale well prior to flowback – A decade literature review	22
Deep learning approach to coal and gas outburst recognition employing modified AE and EMR signal from empirical mode decomposition and time-frequency analysis	22
Deliquification techniques for conventional and unconventional gas wells: Review, field cases and lessons learned for mitigation of liquid loading	22
Transformation of associated natural gas into valuable products to avoid gas wastage in the form of flaring	22
Evaluating a natural gas pipeline steel for blended hydrogen service	22
A review on the selection criteria for slow and medium kinetic solvents used in CO2 absorption for natural gas purification	21
Numerical evaluation on the effect of horizontal-well systems on the long-term gas hydrate production behavior at the second Shenhu test site	21
A note on dynamic rock typing and TEM-function for grouping, averaging and assigning relative permeability data to reservoir simulation models	21
Study of natural gas emission from a hole on underground pipelines using optimal design-based CFD simulations: Developing comprehensive soil classified leakage models	21
Hydraulic Fractures from Non-Uniform Perforation Cluster Spacing in Horizontal Wells: Laboratory Testing on Transparent Gelatin	21
Experimental study on methane hydrate formation in quartz sand under tri-axial condition	21
A new model to estimate permeability using mercury injection capillary pressure data: Application to carbonate and shale samples	21
Quantification of pore modification in coals due to pulverization using synchrotron small angle X-ray scattering	21
Thermodynamic characteristics of methane adsorption about coking coal molecular with different sulfur components: Considering the influence of moisture contents	21
Coupling of transient matrix diffusion and pore network models for gas flow in coal	21
Detection of gas chimney and its linkage with deep-seated reservoir in poseidon, NW shelf, Australia from 3D seismic data using multi-attribute analysis and artificial neural network approach	21
Thermochemical acid fracturing of tight and unconventional rocks: Experimental and modeling investigations	21
Experimental study of advantages of coalbed gas bioengineering	21
Flow behavior characteristics and residual trapping of supercritical carbon dioxide in tight glutenite by MRI experiments	21
A discrete element simulation considering liquid bridge force to investigate the mechanical behaviors of methane hydrate-bearing clayey silt sediments	21
Numerical analysis on gas production from silty hydrate reservoirs in the South China sea by depressurizing: The effect of permeability reduction caused by pore compression	21
Experimental investigation of using combined CH4/CO2 replacement and thermal stimulation methods for methane production from gas hydrate in the presence of SiO2 and ZnO nanoparticles	21
Innovative experimental method for particle bridging behaviors in natural fractures	21
Role of salinity in clathrate hydrate based processes	21
Enhancing tight oil recovery using CO2 huff and puff injection: An experimental study of the influencing factors	21
Key factors controlling the occurrence of shale oil and gas in the Eagle Ford Shale, the Gulf Coast Basin: Models for sweet spot identification	21
Numerical analysis on gas production from heterogeneous hydrate system in Shenhu area by depressurizing: Effects of hydrate-free interlayers	20
Simultaneous determination of the effective stress coefficients for permeability and volumetric strain on a tight sandstone	20
Experimental and numerical analysis of effective enhancement of wellbore stability in shales with nanoparticles	20
Temperature dynamics and its effects on gas influx handling during managed pressure drilling operations	20
Experimental features of cation exchange capacity determination in organic-rich mudstones	20
Variation in pore systems with tectonic stress in the overthrust Wufeng-Longmaxi shale of the southern Sichuan Basin, China	20
Prediction of interactive effects of CBM production, faulting stress regime, and fault in coal reservoir: Numerical simulation	20
Unraveling the effect of H2S on the corrosion behavior of high strength sulfur-resistant steel in CO2/H2S/Cl− environments at ultra high temperature and high pressure	20
Ultra-light weight proppant: Synthesis, characterization, and performance of new proppants	20
Different methods of permeability calculation in digital twins of tight sandstones	20
Analysis of the hydraulic fracturing mechanism and fracture propagation law with a new extended finite element model for the silty hydrate reservoir in the South China Sea	20
A critical review of synthetic natural gas production techniques and technologies	20
Numerical simulation of sectional hydraulic reaming for methane extraction from coal seams	20
Impact of shut-in time on production after hydraulic fracturing in fractured shale gas formation: An experimental study	20
LNMR experimental study on the influence of gas pressure on methane adsorption law of middle-rank coal	20
Influence of surface roughness on methane flow in shale kerogen nano-slits	20
An outlook into recent advances on estimation of effective stimulated reservoir volume	20
Hydraulic diffusivity estimations for US shale gas reservoirs with Gaussian method: Implications for pore-scale diffusion processes in underground repositories	20