Gas Liberation Research Articles

Characterisation of zinc phosphate coating deposited on carbon steel wire rod using an accelerator-side and iron-side phosphating solution

ABSTRACT Accelerator-side phosphating solutions are widely used for zinc phosphate conversion coating on carbon steel wire rods to impart good lubrication and corrosion resistance during wire drawing of steel. But on the accelerator side, the use of nitrite and nitrate as accelerator agents has challenges of high process temperature, liberation of nitrous gases and high sludge generation. For these challenges, the iron-side phosphating process is used as one of the solutions where the bath is maintained at a higher iron level and aeration is done to oxidise ferrous iron instead of an accelerator. In the literature, details of different processes and bath composition are available but their effects on the characteristics of zinc phosphate coating deposited on the carbon steel wire rod are not available. In this paper, zinc phosphate coating was deposited on different grades and sizes of wire rods using accelerator-side and iron-side phosphate solutions and their effect on coating weight and other coating characteristics was studied using SEM, EDS and Tafel polarisation experiments.

Green synthesis of CoFe2O4 nanoparticles assisted with bio-waste (Gomutram): Sintering effect on the properties of structural, microstructural and vibrational bands

Synthesis of CoFe2O4 nanoparticles has been effectively accomplished by the cow-urine (Gomutram) as a chelating agent. The liberation of hazardous gases during the sol-gel synthesis process are minimized using cow-urine (Gomutram) as a chelating agent. The Energy Dispersive X-ray Spectrum offers insights on the current composition of ferrite by providing information on the stoichiometric ratio of its constituent elements. The X-ray diffraction patterns provide substantiation for the formation of the spinel phase of present ferrite system. The ferrite systems that underwent sintering at lower temperatures exhibited a more conspicuous amorphous morphology. The experimental lattice parameter (a) and average crystallite size (D) were found to be within the range of 8.0688–8.3779 Å and 3.7–9.4 nm respectively. Both a and D demonstrate an augmentation in magnitude due to the heat treatment procedure. The function of activation energy in the ripening of crystalline size during the sintering process is significant particularly in relation to grain boundary energy. The aggregation of nanoparticles into large clusters can be attributed to the strong magnetic interactions present among them. The inherent characteristics of scanning electron micrographs unambiguously demonstrate. The vibrational frequencies (υ1 and υ2) observed from Fourier Transform Infrared spectra confirm the spinel phase of the present ferrite system. The changes seen in vibrational frequencies do not offer empirical support for the association between annealing and the expansion of the lattice constant. But, offers an empirical support for the hypothetical redistribution of cations in the spinel structure.

Foamed concrete produced from CO2/N2 foam stabilized by CaCO3 nanoparticles and CTAB

Foamed concrete (FC) has garnered popularity, especially with the growing demand for energy-efficient and sustainable construction materials. The stability of the FC slurry as it sets is crucial to the uniformity of the pore structure and, subsequently, FC performance. This study investigates the stability of a novel FC produced using aqueous CaCO3 nanoparticle (NP)/hexadecyltrimethylammonium bromide (CTAB) foam. The effect of NPs and gas type (pure N2, pure CO2, and a 2:1 gas mixture of CO2/N2) on the FC dry density, compressive strength, water absorption, macro- and microstructure, hydration products, and thermal insulation is explored. The results show that the dry density of FC increases with the inclusion of CO2 owing to gas liberation during mixing with the paste leading to less voids. Using the gas mixture, CaCO3/CTAB foam increases the compressive strength of the FC by 38% compared with CTAB alone owing to enhanced uniformity of the pore structure and a denser hydrated paste skeleton. Such structure leads to less connected pores, which reduces atmospheric carbonation, and improves thermal insulation performance. A 2-fold decrease in the largest pore size and a 25% decrease in surface temperature when exposed to an open flame are also achieved in the presence of CaCO3 NPs.

Dynamic gas liberation from water-immersed anthracite coal with varying wetting states under heating conditions: Unveiling the gas breakthrough phenomena

During coalbed methane recovery, the effective extraction of gas trapped in narrow pore throats encounters challenges due to the water blocking effect. To shed light on this phenomenon during thermal recovery of coalbed methane, this study investigated the breakthrough behaviors of CO2 traversing through a 0.2 mm diameter hole in water-immersed anthracite coal at varying temperatures (23 °C, 40 °C, and 60 °C). The measurements of breakthrough pressure (defined as the pressure at which the bubble achieves a semi-spherical shape with a minimum curvature radius), growth characteristics of CO2 bubbles, and coal wettability were conducted under varying thermal conditions and water immersion durations. The results showed that the breakthrough pressure initially increased continuously as water immersed into the coal and then gradually stabilized. During this process, the coal's water wettability increased, leading to a decrease in the diameter of the bubble's three-phase contact line, which in turn affected the breakthrough pressure. Moreover, higher temperatures accelerated the rate of water immersion, augmenting the coal's hydrophilicity. The elevated temperature also resulted in a decrease in water surface tension, consequently contributing to a lower breakthrough pressure. Interestingly, compared to CO2, He exhibited a faster increase in breakthrough pressure during water immersion. This disparity can be attributed to He's superior diffusion capacity and lower viscosity, enabling a swifter transformation of the coal's wetting state during water imbibition. This study revealed the dual mechanism of heating to reduce gas breakthrough pressure, as well as the effects of surface water content and gas properties. These findings highlight potential benefits of thermal treatment on coalbed methane recovery and provide valuable insights for its exploitation under different geological conditions.

A thiolated copper-hydride nanocluster with chloride bridging as a catalyst for carbonylative C-N coupling of aryl amines under mild conditions: a combined experimental and theoretical study.

Atomically precise copper nanoclusters (Cu NCs), an emerging class of nanomaterials, have garnered significant attention owing to their versatile core-shell architecture and their potential applications in catalytic reactions. In this study, we present a straightforward synthesis strategy for [Cu29(StBu)12(PPh3)4Cl6H10][BF4] (Cu29) NCs and explore their catalytic activity in the carbonylative C-N coupling reaction involving aromatic amines and N-heteroarenes with dialkyl azodicarboxylates. Through a combination of experimental investigations and density functional theory studies, we elucidate the radical mechanisms at play. The crucial step in the catalytic process is identified as the decomposition of diisopropyl azodicarboxylates on the surface of Cu29 NCs, leading to the generation of oxyacyl radicals and the liberation of nitrogen gas. Subsequently, an oxyacyl radical abstracts a hydrogen atom from aniline, initiating the formation of an aminyl radical. Finally, the aminyl radical reacts with another oxyacyl radical, culminating in the synthesis of the desired carbamate product. This detailed analysis provides insights into the intricate catalytic pathways of Cu29 NCs, shedding light on their potential for catalyzing carbonylative C-N coupling reactions.

Potential changes of regional natural gas market in China amidst liberalization: A mixed complementarity equilibrium simulation in 2030

Ensuring the continuous efficient use of natural gas is crucial for China to achieve its carbon peak goal by 2030. This study scrutinizes the prospective effects of an intensified liberalization of China’s natural gas sector in 2030. To accomplish this, a mixed complementarity equilibrium model is employed, capturing the interdependencies among relevant sectors within the industrial chain. Multiple scenarios of liberalization are simulated, encompassing variations in gas demand, pipeline capacity expansion, and the escalation of imported Liquefied Natural Gas (LNG), to identify potential modifications. Scenario results reveal that the insufficient capacity of long-distance pipeline network will significantly hinder the distribution of gas resources and cause a shortage of gas supplies in Eastern region. Furthermore, the expansion of pipeline capacity from Northwest to East is beneficial in low demand scenario, while increasing the receiving and transfer capacity of LNG in Northern and Eastern regions is crucial in face of strong demand growth. Moreover, a decline in LNG imports will put upward pressure on regional prices, and further affect the security of natural gas supply. The findings will offer critical data for policymakers and present a diversified view of natural gas liberalization market under China’s peak carbon emission target in 2030.

Modified open-system hydrous pyrolysis

As an alternative to classic batch hydrous pyrolysis experiments, this proof-of-concept study presents a version of open-system hydrous pyrolysis (OSHP) in which the design of the apparatus allows for a small, continuous flow of only liquid-phase water to pass through the reactor during artificial maturation. This allows volatile, liquid, and soluble materials to migrate freely through and out of the system, whereas insoluble mineral matter and kerogen remain within the reactor. This apparatus differs from previous OSHP designs in the ability to maintain true open-system conditions, thus minimizing any cracking or back reaction of the products with the residual kerogen.Using the OSHP apparatus, immature Anna Shale (Pennsylvanian age, Illinois Basin) containing Type II marine kerogen was matured artificially at experimental temperatures ranging from 300 to 360 °C for up to 72 h. Petrographically, the immature Anna Shale is dominated by a micrinitic groundmass, and contains lesser amounts of vitrinite (both collotelinite and collodetrinite), inertodetrinite, bituminite, solid bitumen, and alginite. Under run conditions, mean random reflectance increased from 0.46 to 1.81% for vitrinite and from 0.66% to 1.50% for solid bitumen. Alginite fluorescence changed from a bright yellow to dull red-orange and decreased in intensity until all fluorescence was lost in shales pyrolyzed at temperatures ≥350 °C. Rock-Eval Tmax increased from 425° to 520 °C, TOC decreased (e.g., from 12.5% to ∼9% at a run temperature of 360 °C), S1 decreased from 0.71 to ∼ < 0.1 mg HC/g shale, S2 decreased from ∼40 to <1.0 mg HC/g shale, and HI decreased from ∼300 to <10 mg HC/g TOC. These changes are consistent with the maturation of the immature shale through the oil window and into the gas window. With increased maturity, the shale showed a loss in mass: shorter runs (≤ 24 h) typically lost <10%, whereas longer runs (72 h) lost 12–20%. These losses were likely due to the loss of moisture, liberation of hydrocarbons and other gases, and depletion in total sulfur from 2.03 to ∼0.1 wt% (much of which was pyritic sulfur); higher mass losses may have included retention of material in the reactor, tubing, or frits. Petrographic observations revealed that pyrite framboids, which were abundant in the immature shale, decreased in samples pyrolyzed at temperatures >330 °C and showed evidence of alteration to hematite.The OSHP design was intended to mimic normal burial maturation. However, based on the significant depletion in sulfur (i.e., pyrite), the current design and run parameters may more closely replicate conditions associated with hydrothermal alteration, possibly those associated with intrusion of organic-rich rocks. It is also possible that the OSHP approach could lead to a better understanding of organic-mineral interactions and mobility of elements, especially trace elements, during maturation.

A Methodology for In-Well Multiphase Flow Measurement with Strategically Positioned Local and/or Distributed Acoustic Sensors.

A new three-phase downhole flow measurement methodology is developed based on measurements of speed of sound at different locations along the well, where the pressure is greater than the bubble-point pressure at the first location and smaller at the second location. A bulk velocity measurement is also required at the second location. The fluid at the first location is a mixture of two phases, but becomes a mixture of three phases at the second location due to the liberation of gas from the oil phase. The flow equations are first solved for two-phase flow at the first location to obtain the first phase fraction, water-in-liquid ratio, and then this information is fed into the flow equations after adjustment to the local pressure and temperature conditions to solve for three-phase flow at the second location to obtain the second phase fraction, namely the liquid volume fraction. These two phase fractions along with the bulk velocity at the second location are sufficient to calculate the three-phase flow rates. The methodology is fully explained and the analytical solutions for three-phase flow measurement is explicitly provided in a step-by-step process. A Lego-like approach may be used with various sensor technologies to obtain the required measurements, although distributed acoustic sensing systems and optical flowmeters are ideal to easily and efficiently adopt the current methodology. This game-changing new methodology for measuring downhole three-phase flow can be implemented in existing wells with an optical infrastructure by adding a topside optoelectronics system.

Analytical Relation between b-Value and Electromagnetic Signals in Pre-Macroscopic Failure of Rocks: Insights into the Microdynamics’ Physics Prior to Earthquakes

Field measurements in subduction regions have revealed the presence of non-seismic pre-earthquake signals such as electromagnetic or acoustic emission, gas liberation, changes in Earth’s surface temperature, changes at the ionospheric level, or fluid migration. These signals are commonly associated with impending earthquakes, even though they often rely solely on temporal and spatial correlations in impending earthquake zones without a comprehensive understanding of the underlying lithospheric processes. For example, one criticism is the measurement of increasing electromagnetic signals even in the absence of observable macroscopic stress changes, which challenges the conventional understanding that macroscopic stress changes are the primary energy source for non-seismic pre-earthquake signals. To address this gap, rock experiments provide valuable insights. Recent experiments have shown that rocks can become electrified under constant macroscopic stress changes, accompanied by a decrease in the b-value, indicating multiscale cracking. This suggests the existence of small-scale dynamics that generate electromagnetic signals independently of large-scale stress variations. In that sense, multiscale thermodynamics offers a valuable perspective in describing this multiscale phenomenon. That is why the main goal of this work is to demonstrate that the electromagnetic signals before macroscopic failures are not independent of the cracking generation because the origin of both phenomena is the same. In particular, we present analytical equations that explain the physical connection between multiscale cracking, the generation of electromagnetic signals, and its negative correlation with acoustic emission before the macroscopic failure of rocks even when the macroscopic load is constant. In addition, we also show that the thermodynamic fractal dimension, which corresponds to the global parameter that controls the cracking process, is proportional to the b-value when the large-scale crack generation is considerably larger than the small-scale cracks. Thus, the decreases in the b-value and the increases in the electromagnetic signals indicate that rocks irreversibly prepare to release energy macroscopically. These findings could be related to the dynamics at lithospheric scales before earthquakes.

In Situ Formation of Li2SiO3-Li-NaCl Interface on Si and Its Effect on Hydrogen Evolution

Silicon has emerged as a competitive candidate for hydrolytic hydrogen production due to its high theoretical hydrogen yield, low cost, and on-demand availability. However, the hydrolysis reaction is extremely restrained by passivated SiO2, including the original one on the Si surface and the generated one during hydrolysis, and almost no hydrogen is produced in pure water. Herein, the original SiO2 surface has been effectively removed by milling micro-Si mixed with a small amount of Li metal and NaCl. An artificial soluble interface on Si has been established containing Li2SiO3, Li, and NaCl. Once micro-Si is placed into water, fresh Si surface can be exposed and a weak LiOH solution can be generated due to the fast dissolution of the interface layer, resulting in the rapid liberation of hydrogen gas. Accordingly, the modified micro-Si displays a significantly enhanced hydrogen production in pure water at 30 °C (1213 mL g-1 H2 within 3.0 h), which is 2.0 and 4.7 times higher than that observed for ball-milled Si and raw Si in 0.06 M LiOH solution, respectively. In addition, it also exhibited an outstanding operation compatibility for practical uses. This work has proposed a green, effective, and scalable strategy to promote hydrogen production from the hydrolysis of Si-based systems.

Microstructural characterization and thermal stability of He charged amorphous silicon films prepared by magnetron sputtering in helium

Sputtering of silicon in a Helium magnetron discharge has been reported as a bottom-up procedure to obtain amorphous Si films containing high amounts of gas-filled nanopores. Here we compare the microstructure and composition of Si–He nanocomposite films deposited by magnetron sputtering (MS) with 4He in DC or RF and 3He in RF operation modes. Electron microscopy (SEM and TEM), X-ray diffraction (XRD) and ion beam analysis (IBA) have been used to analyze the films and to investigate the in-situ and ex-situ thermal evolution. Depending on deposition conditions different in depth compositions, nanopore size and shape distributions, porosity and He content could be obtained. The presence of impurities (i.e. oxygen) has shown to promote He diffusivity reducing He accumulation. The start temperature of He-release varied in the range 473–723 K without films crystallization. Films grown in RF mode reached contents of 32 and 29 at% of 4He and 3He and were respectively stable up to 573 and 723 K both in vacuum and under inert gas flow. In-situ p-EBS (proton Elastic Back Scattering) allowed monitoring the He release accompanied by blistering/delamination effects visualized by SEM. These results show the potentiality of annealing to hold nano-porous structures after liberation of trapped gas.

Green and scalable electrochemical routes for cost‐effective mass production of MXenes for supercapacitor electrodes

AbstractOne of the most unique properties of two‐dimensional carbides and nitrides of transition metals (MXenes) is their excellent water dispersibility and yet possessing superior electrical conductivity but their industrial‐scale application is limited by their costly chemical synthesis methods. In this work, the niche feature of MXenes was capitalized in the packed‐bed electrochemical reactor to produce MXenes at an unprecedented reaction rate and yield with minimal chemical waste. A simple NH4F solution was employed as the green electrolyte, which could be used repeatedly without any loss in its efficacy. Surprisingly, both fluoride and ammonium were found to play critical roles in the electrochemical etching, functionalization, and expansion of the layered parent materials (MAXs) through which the liberation of ammonia gas was observed. The electrochemically produced MXenes with excellent conductivity, applied as supercapacitor electrodes, could deliver an ultrahigh volumetric capacity (1408 F cm−3) and a volumetric energy density (75.8 Wh L−1). This revolutionary green, energy‐efficient, and scalable electrochemical route will not only pave the way for industrial‐scale production of MXenes but also open up a myriad of versatile electrochemical modifications for improved functional MXenes.

Development and mechanistic investigation of the dehydrogenation of alcohols with an iron(III) salen catalyst.

The iron(III) salen complex (R,R)-N,N'-bis(salicylidene)-1,2-cyclohexanediamineiron(III) chloride has been developed as a catalyst for the acceptorless dehydrogenation of alcohols. The complex catalyzes the direct synthesis of imines in good yields from different primary alcohols and amines with the liberation of hydrogen gas. The mechanism has been investigated experimentally with labelled substrates and theoretically with density functional theory calculations. In contrast to the corresponding manganese(III) salen-catalyzed dehydrogenation, it has not been possible to identify a homogeneous catalytic pathway with the iron complex. Instead, poisoning experiments with trimethylphosphine and mercury indicated that the catalytically active species are heterogeneous small iron particles.

Facile Synthesis of Formaldehyde-Free Bio-Based Thermoset Resins for Fabrication of Highly Efficient Foams

Bio-based biodegradable foams were formulated from a crosslinkable network structure combining starch, furfuryl alcohol, glyoxal, and condensed tannin in the presence of p-toluenesulfonic acid (pTSA) and azodicarbonamide (AC) as a foaming agent. More importantly, the reinforcement of gelatinized starch-furanic foam using tannin, originating from forestry, resulted in an excellent compressive strength and lower pulverization ratio. Moreover, the addition of tannin guaranteed a low thermal conductivity and moderate flame retardancy. Fourier transform infrared (FTIR) spectroscopy approved the successful polycondensation of these condensing agents under the employed acidic conditions. Moreover, the catalytic effect of pTSA on the foaming agent induced liberation of gases, which are necessary for foam formation during crosslinking. Scanning electron microscopy (SEM) showed foam formation comprising closed cells with uniform cell distribution and appropriate apparent density. Meanwhile, the novel foam exhibited biodegradation under the action of Penicillium sp., as identified by the damage of cell walls of this foam over a period of 30 days.

Gas Liberation in High-Temperature Pyrolysis of Coal Wastes with Binder

Gas Liberation in High-Temperature Pyrolysis of Coal Wastes with Binder

Effect of fluid properties and boundary conditions on rod pump efficiency – Novel modeling

Among artificial lift systems, the most widely used method is sucker rod pumping. Since its inception in the oil industry, inefficiency in sucker rod pumping system due to gas interference is one of major concerns. The need for better understanding of gas interference during sucker rod pumping process is significantly required. Although, many models and techniques are available but there are many parameters, which need to be well studied and adequately addressed. This delineates the need to research all empirical parameters that could affect efficiency of conventional rod pump. The pump performance appears to be low in presence of gas which in extreme situation locks the pump and make the pump paralyzed completely. The models available in literature neglect mass transfer during suction process, which brings unreliable calculation of gas phase in pump. Models in literature on efficiency of pump and gas lock are studied to analyze the vital parameters and reasons for the inefficiency. The expedient analytical models to predict gas lock criteria and efficiency of conventional pump, based on liberation of gas during pumping, are established in this work. The models emphasize the importance of the fluids properties to be handled by pump, which affect the production rate while pumping with a gaseous phase. This new model considers free gas phase presence and mass transfer during working of pump. Sensitivity and comparative analysis of numerous parameters contributing to pump efficiency is established in this work. The study results provide some theoretical and analytical references for further advancements in system efficiency of conventional rod pump system and to improve economic benefits.

A Tripolar Model of Gas Price Formation in Germany. Does the Shale Revolution in the US Matter?

Abstract Presented analysis of gas price formation mechanism in Germany was prompted by changes brought about by technological advancements and the liberalization and harmonization of natural gas markets in the European Union after the year 2000. Because the data used in the study is generated by nonstationary stochastic processes, the cointegrated vector autoregressive model was applied as the most appropriate. The analysis pointed out that the price of natural gas, oil and the USD/EUR exchange rate influence each other in the long run and thus should be modelled together. Gas price in Germany is driven by both fundamental and financial factors, and so it rises with economic expansion, oil price increases, and the depreciation of the USD. It also reacts to changes in short-term interest rates and the volume of gas production in the US, which confirms that the shale revolution in this country has been consequential for gas prices in Europe, like any other supply shock would have been.

About the “Heat Shock” Phenomenon

At present, depletion and diminished performance of oil formations take place. Operation of low production wells is carried out using ESP units at the rate of max. 35 m3/per day under low suction pressure of centrifugal pumps. The drop of the centrifugal pump suction pressure below the saturation pressure leads to liberation of free gas in the pumped mixture. Operation of a centrifugal pump during pumping of gas-cut mixtures results in reduction of the ESP unit efficiency. The loss of the pump efficiency leads to the fact that the substantial part of energy is consumed on heating and temperature rise of the centrifugal pump. Operation of a centrifugal pump at elevated temperatures results in frequent faults of the ESP units and in salt deposition. In some cases, faults of the ESP units may occur out of the blue due to the uncontrolled heat release and temperature rise. Let us call a sudden uncontrolled heating of a centrifugal pump a “heat shock”. The pump failure as a result of a heat shock is normally classified as the “wrongdoing of the oil producing organization personnel”. This article addresses the possibility of detection and elimination of the “heat shock” moment - a sudden ESP failure. Solution of this problem will be useful for design engineering of the pump automatic control.

Unravelling the pore templating effect on CO2 adsorption performance of alkali metal nitrates promoted MgO pellets

Alkali metal salts (AMS) promoted MgO with high CO2 uptakes represents a promising adsorbent candidate for CO2 capture. The AMS-MgO composite adsorbents are facing the challenges of increased pressure drop or elutriation when employed in dual fixed-bed reactor or twin circulating fluidized-bed configurations. Granulation by the extrusion-spheronization technique represents an effective problem-solving strategy. However, textural properties and CO2 uptakes of MgO-based adsorbent pellets might be adversely affected by the granulation process. In this work, AMS-MgO composite adsorbent pellets were prepared by the extrusion-spheronization method. Citric acid (CA), ammonium bicarbonate (AB), urea (UA) and microcrystalline cellulose (MC) were employed as pore-forming templates to improve the porous structures and CO2 uptakes of the AMS-MgO pellets. CO2 uptakes and adsorption kinetics of the adsorbent pellets were studied using a fixed-bed reactor. Effects of granulation and pore templating on the structure-performance relationships of the AMS-MgO pellets were unraveled. Granulation had resulted in the remarkable decrease in CO2 uptake from 10.87 to 4.24 mmol CO2/g due to the impaired textural parameters. The employed sacrificial templates endowed the AMS-MgO pellets with enhanced CO2 uptakes and improved carbonation kinetics. This was associated with extended surface area and expanded pore structures due to gas liberation in the pyrolysis of templates, which had facilitated the kinetics of CO2 bulk diffusion. The desired AMS-MgO-MC pellet modified with MC template showed a high CO2 uptake of 7.54 mmol CO2/g in 50%CO2 at 340 °C, and its CO2 uptake was stabilized around 5.0 mmol CO2/g within 20 cycles. Besides, the AMS-MgO-MC pellet also exhibited good mechanical properties. The results will guide the rational design of highly efficient and robust MgO-based adsorbent pellets for CO2 capture applications.

Water Liberating/Sealing effects on shale gas Extraction: A fully coupled multidomain and multiphysics model

Whether the gas in kerogen is liberated/sealed by water, is a crucial issue for successful shale gas reservoir exploitation. Although this issue has been recognized, no tools are developed to evaluate the impact of this gas liberation/sealing on gas production under in-situ conditions. In this work, a concept named kerogen threshold differential pressure (KTP) is proposed to describe the mass transport influenced by the wettability at the heterogeneous kerogen interface with external/connate water. KTP is defined as a critical pore pressure difference between inside and outside of kerogen pores. It corresponds to the energy barrier needed to remove the liquid film at the kerogen surface so that the gas in kerogen can flow out. Based on this definition, whether kerogen supplies gas to its surroundings or not is controlled by an on/off mechanism which is incorporated into a fully coupled, multidomain, and multiphysics model to simulate gas extraction from stimulated shale reservoirs. Gas flow in kerogen, gas–water-two-phase flowback in inorganic matrix and fractures, shale deformation, and gas sorption are considered in the model. The proposed model is verified against a set of gas production data from the field and the simulation results published by a previous study. Furthermore, a sensitivity analysis is performed to investigate the effects of important influencing factors on gas and water production. The results suggest four main findings: (1) Shale gas production behaviour is dependent on the combination of gas-supplying capabilities of the different components in different domains of shale reservoir. (2) Water influences shale gas extraction in two aspects including two-phase flow and on/off gas supplying mechanism. The former aspect affects the gas flow in inorganic matrix and fractures, while the latter aspect controls the gas liberation from kerogen and thus, the sustainability of gas extraction. (3) The shapes of the gas/water relative permeability curves of different components of shale reservoir are influenced by formation damage and stimulation operation. They mainly affect early-period water production. (4) Gas recovery is enhanced by decreasing KTP, which can be achieved by using appropriate surfactants and/or water-free fracking fluids to alleviate/eliminate formation damage.