Utilization Of Shale Gas Research Articles

Utilization law of shale gas in hydraulic fracturing with the Changning–Weyuan block in China as an example

The process of extracting shale gas, particularly the study of the utilization law of shale reservoirs modified by hydraulic fracturing technology, is crucial for understanding the effective development of shale gas. This understanding can significantly influence the estimated ultimate recovery of reserves. Our study focused on Longmaxi Formation shale in the Changning–Weiyuan block. To investigate the hydraulic fracturing expansion mechanism and utilization law, we employed shale reservoir physical and mechanical characterization, indoor triaxial hydraulic fracturing experiments, and numerical simulations. The findings are as follows. The rupture pressure of hydraulic fractures increases with the peripheral pressure, and high stress is conducive to the formation of internal microfractures. Additionally, a high rate of water injection enhances fracture extensions along the direction of fluid injection. Under varying injection pressures, the length of crack extensions and number of bond damages in shale are positively correlated with the injection pressure. Conversely, under different differential ground stresses, the length of crack extensions and number of bond damages are negatively correlated with the injection pressure. The six main factors affecting the effective utilization of shale gas are as follows: the stimulated reservoir volume, number of hydraulic fracture clusters, fracture length, fracture height, number of fracture stages, and cluster spacing, accounting for 27.13%, 14.74%, 10.31%, 9.58%, 9.53%, and 9.29%, respectively, with a cumulative contribution rate of 80.58%. This study clarifies the hydraulic fracturing mechanisms of shale reservoirs and the laws governing shale gas production, providing technical support for the development of shale gas reservoirs.

ReaxFF Molecular Dynamics Study on the Microscopic Mechanism for Kerogen Pyrolysis.

Kerogen is mainly composed of carbon, hydrogen, and oxygen, which are the main components of crude oil and gas. The pyrolysis of kerogen is an efficient method to generate clean energy. In the present work, the pyrolysis reaction process of three types of kerogen is simulated using ReaxFF molecular dynamics (MD) methods to study the microscopic mechanism and the distribution of products. The results indicated that the pyrolysis products of the three types of kerogen significantly depend on the molecular structures, temperature, and reaction time. As the temperature increases, the gaseous hydrocarbon and the light and heavy oil fractions decreased, where small molecular fragments polymerized to form new molecular fragments. For an isothermal temperature, with the reaction proceeding, some component polymerization of the pyrolyzed fragments occurred, resulting in the generation of new light oils and heavy oils. Moreover, quantum chemical analysis was employed to reveal the kerogen pyrolysis mechanism. First, the weak bonds such as C-O, C-N, and C-S structures were decomposed to generate large carbon and some heavy shale oil fragments. Second, the cycloalkanes and long-chain alkanes were decomposed to generate a large amount of light shale oil and gaseous hydrocarbons. Finally, the decomposition of C═C in the aromatic ring, the secondary decomposition of light and heavy shale oils, and the further decomposition of short-chain alkanes occurred. In addition, the production of hydrogen (H2) occurred at the late stage of the pyrolysis reaction. Hydrogen radicals were formed by the decomposition of C-H bonds and subsequently collided with each other, resulting in the formation of H2 molecules. The pyrolysis and chemical analysis of kerogen can clearly determine the type and content of hydrocarbon substances, providing scientific data for exploration, development, and utilization of shale gas and shale oil.

Role of active oxygen species in Fe-doped ZrO2 catalyst during CO2 assisted ethane dehydrogenation reaction

CO2 assisted ethane dehydrogenation provides a promising route for the utilization of shale gas and greenhouse gas. This study investigates the role and evolution of active oxygen species over Fe-doped ZrO2 catalysts in distinct dehydrogenation reactions via Mars-van Krevelen mechanism. Fe doping led to an increase in active oxygen species (from 12.9% to 23.4%) benefitted from the phase transformation of ZrO2. This enhancement significantly boosted ethane dehydrogenation activity from 5.0 to 16.1 mmolEthene/gCat/h. In the absence of CO2, the ethane conversions rapidly decreased with a deactivation rate constant (kd) of 0.930 h−1 due to the irreversible oxygen species loss and coke deposition. Although the catalytic stability of the optimal catalyst was greatly improved (kd = 0.006 h−1) after CO2 introduction, a decrease in ethane conversion occurred when CO2 could not supplement oxygen species due to the formation of coke layers. A simple O2 oxidation can effectively restore stable activity during 5 reaction-regeneration cycles for 3600 mins.

Coordinated development of shale gas benefit exploitation and ecological environmental conservation in China: a mini review

The large-scale development and utilization of shale gas is significant for achieving the “Carbon Peak and Carbon Neutrality” goals. However, addressing the ecological environmental challenges stemming from extensive hydraulic fracturing is imperative. Drawing from the successful exploration and development of shale gas in the Sichuan Basin, this paper employs a bibliometric approach and utilizes the Web of Science database as its data source to review the impact of shale gas development on the ecological environment. Furthermore, effective strategies for achieving coordinated development of shale gas benefit exploitation and ecological environmental conservation in China are identified. The findings highlight that the ecological impact of shale gas development has been a major focus of research over the past decade, primarily involving concerns such as water resources consumption, groundwater pollution, methane emissions, and waste management. These challenges can be addressed by adopting measures such as responsible water usage, maintaining well integrity, proper storage and disposal of fracturing flowback fluids, and appropriate management of drilling solid waste. The key to achieving green and efficient shale gas development in China lies in constructing a solid theoretical framework for benefit exploitation, refining environmental management standards and regulations, and promoting the development of clean production technologies specific to shale gas. Additionally, establishing a distinct exploration and development theory and fostering technical innovation for deep shale gas (buried depth > 3500m) are pivotal for enhancing and stabilizing production in China. Clarifying the theoretical logic of benefit development and improving the environmental protection law of shale gas development are of great significance for realizing the scale benefit development of shale gas and the harmonious development of ecological environment in China.

Unraveling the role of active site Rh aggregation form in tuning the catalytic performance of ethane direct dehydrogenation

Ethane direct dehydrogenation (EDH) is of great importance for shale gas utilization. However, the development of highly active and stable catalyst is still challenge in this process. Here, to guide the establishment of a desired Rh-based catalyst for EDH to ethylene, fifteen catalysts RhxM (M=Cu, Ag, Au) (x=1, 2, 3, 6, 9) are designed and their catalytic performance for EDH are systematically studied by using density functional theory calculations. The computational results disclose that the aggregation form of active Rh atoms (ensemble effect) dominates the catalytic performance, rather than the d-band center, electron transfer and the effects of the second metal substrate. The catalysts Rh1Cu, Rh1Au, and Rh2Ag show the best catalytic performance among the catalysts with different metal substrate. Typically, the low-cost catalyst Rh1Cu with surface single-atom Rh in the non-noble metal Cu not only performs improved activity and selectivity for forming ethylene but also resists the coking. Interestingly, the catalyst Rh3M (M=Cu, Ag, Au) has poor C2H4 selectivity and coking resistance due to itself ensemble effect. This study gives a theoretical guidance for regulating the catalytic performance through the ensemble effect of active site metal atoms in ethane direct dehydrogenation.

Shale gas production evaluation framework based on data-driven models

Increasing the production and utilization of shale gas is of great significance for building a clean and low-carbon energy system. Sharp decline of gas production has been widely observed in shale gas reservoirs. How to forecast shale gas production is still challenging due to complex fracture networks, dynamic fracture properties, frac hits, complicated multiphase flow, and multi-scale flow as well as data quality and uncertainty. This work develops an integrated framework for evaluating shale gas well production based on data-driven models. Firstly, a comprehensive dominated-factor system has been established, including geological, drilling, fracturing, and production factors. Data processing and visualization are required to ensure data quality and determine final data set. A shale gas production evaluation model is developed to evaluate shale gas production levels. Finally, the random forest algorithm is used to forecast shale gas production. The prediction accuracy of shale gas production level is higher than 95% based on the shale gas reservoirs in China. Forty-one wells are randomly selected to predict cumulative gas production using the optimal regression model. The proposed shale gas production evaluation framework overcomes too many assumptions of analytical or semi-analytical models and avoids huge computation cost and poor generalization for numerical modelling.

Rivet of cobalt in siliceous zeolite for catalytic ethane dehydrogenation

•A catalyst with isolated cobalt in siliceous zeolite was prepared •This catalyst catalyzed the EDH at thermodynamically limited conversion levels •Superior productivity of ethylene was achieved •The catalyst was coking resistant with constant performances over a long period Catalytic dehydrogenation of ethane (EDH) is promising for the utilization of shale gas to produce ethylene, but the current processes mostly exhibit space-time productivity of ethylene lower than 1.5 KgC2H4 Kgcat−1 h−1 because of the insufficient catalyst activity in the non-oxidative route. We reported a catalyst with isolated cobalt in siliceous zeolite derived from a mechanically assisted spontaneous dispersion. This material can operate as a non-oxidative EDH catalyst at thermodynamically limited conversion levels under rapid gas feeding, resulting in ethylene productivity at 13.4 KgC2H4 Kgcat−1 h−1. This result is superior to that of the previous non-noble metal catalysts and even outperforms the precious PtSn/Al2O3 catalyst. The isolated cobalt sites are preserved upon calcination at high temperatures and during EDH operation under harsh conditions, resulting in superior durability in a long reaction period with negligible coke formation. Catalytic dehydrogenation of ethane (EDH) is promising for the utilization of shale gas to produce ethylene, but the current processes mostly exhibit space-time productivity of ethylene lower than 1.5 KgC2H4 Kgcat−1 h−1 because of the insufficient catalyst activity in the non-oxidative route. We reported a catalyst with isolated cobalt in siliceous zeolite derived from a mechanically assisted spontaneous dispersion. This material can operate as a non-oxidative EDH catalyst at thermodynamically limited conversion levels under rapid gas feeding, resulting in ethylene productivity at 13.4 KgC2H4 Kgcat−1 h−1. This result is superior to that of the previous non-noble metal catalysts and even outperforms the precious PtSn/Al2O3 catalyst. The isolated cobalt sites are preserved upon calcination at high temperatures and during EDH operation under harsh conditions, resulting in superior durability in a long reaction period with negligible coke formation.

Mercury Isotopes in Shale Gas From Wufeng-Longmaxi Shale Formation of Sichuan Basin, Southern China: A Preliminary Investigation

A series of investigations have been conducted concerning the study of traditional stable isotopes and rare gas stable isotopes in natural gas. However, little is known regarding non-traditional stable isotopes of mercury in natural gas, especially in the development and utilization of shale gas in recent years. In fact, the presence of mercury in natural gas (including shale gas) provides a basis for research on mercury isotopes. Mercury was extracted from shale gas at the Wufeng-Longmaxi Formation in the YS108 block of the Zhaotong National shale gas demonstration area in the Sichuan Basin by using an acid potassium permanganate solution, followed by the analysis of mercury content and stable isotope composition. The mercury content in the marine shale gas at the Wufeng-Longmaxi Formation ranged from 171 to 2,906 ng/m3, with an average of 1,551.08 ± 787.08 ng/m3 (n = 37, 1 SD). The Δ199Hg values of mercury stable isotopes range from 02‰ to 0.39‰, with an average of 22‰ ± 0.08‰ (n = 37, 1 SD); the δ202Hg values range from −1.68‰ to −0.04‰, with an average of −0.87‰ ± 0.31‰ (n = 37, 1 SD), which are significantly different from the Δ199Hg and δ202Hg information of coalbed gas, but similar to the Δ199Hg and δ202Hg information of terrestrial oil-type gas and the Δ199Hg in the main hydrocarbon-forming organic matter of lower organisms such as algae (t-test, p > 0.05). This indicates that terrestrial target strata with abundant algae or strata with positive Δ199Hg are the target strata for the exploration of terrestrial oil and gas.

Can CO2-assisted alkane dehydrogenation lead to negative CO2 emissions?

Akash Neal Biswas received a BS in chemical engineering from the University of California, Los Angeles and is currently a chemical engineering PhD student in the Chen group at Columbia University. His research is focused on hybrid catalytic reaction schemes for carbon dioxide conversion to value-added products, in particular the coupling of thermochemical, electrochemical, and plasma chemical processes. Zhenhua Xie is currently a research associate of the Chemistry Division at Brookhaven National Laboratory. He is also serving as an investigator in the Synchrotron Catalysis Consortium (SCC). His research interests lay in the upgrading of carbon dioxide by shale gas or renewable hydrogen into value-added chemicals, employing combined approaches of precise synthesis, kinetic analysis, <i>in situ</i> synchrotron characterization, and theoretical calculations. Jingguang Chen is the Thayer Lindsley Professor of Chemical Engineering at Columbia University, with a joint appointment at Brookhaven National Laboratory. His research interests include fundamental understanding and techno-economic analysis of various thermocatalytic and electrocatalytic processes, including carbon dioxide conversion and shale gas utilization that are relevant to the current article.

Shinya Furukawa.

"The most important future applications of my research are the utilization of shale gas and hydrogen production. … The most important quality of a role model is ambition …" Find out more about Shinya Furukawa in his Introducing … Profile.

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The efficient conversion of light alkanes into highly value‐added products emerges as the key technique of shale gas utilization. In article number eom2.12095, Chen and co‐worker discuss the important progresses in the catalytic conversions of light alkanes with emphases on the design and preparation of novel heterogeneous catalysts, as well as the development of advanced processes in the recent 10 years. The technological challenges and perspectives on future research are provided. image

Design and tailoring of advanced catalytic process for light alkanes upgrading

AbstractThe wide and huge reservation of shale gas around the world has drastically altered the global energy and chemicals market, boosting the productions of hydrocarbons and their derivatives by providing massive light alkanes at low cost. Direct conversion of alkanes into the value‐added chemicals remains energy‐intensive and requires harsh reaction conditions due to its ultrahigh CH bond strength. Hence, the quest of alternative reaction pathway for alkane conversion into target product with high yield under mild conditions for a long‐term operation emerges as the key technique of shale gas utilization. In this review, we summarize important progresses in the catalytic conversions of light alkanes with emphases on the design and preparation of novel heterogeneous catalysts, as well as the development of advanced processes in the recent 10 years. The perspectives of potential areas for future study are also provided.image

A method for calculating loss of shale gas during coring based on forward modeling

AbstractThe loss of shale gas from conventional wells during coring directly affects the accuracy of measurement of shale gas content and the efficient development and utilization of shale gas. The existing methods to determine shale gas loss are not sufficiently accurate. This study used the forward modeling approach with consideration of the main influencing factors [FM (a, b)] to accurately calculate the volume of shale gas loss. Simulations of shale gas loss were run in an independently developed indoor experimental platform. A comparative analysis with established fitting methods showed that shale gas mainly exists in either a free state or an adsorbed state, and a pressure differential between the interior and exterior of the core is the primary cause of shale gas loss during coring. The FM (a, b) model simulations of shale gas loss showed reductions in average error of 16.77% and 4.6% compared to that of the improved US Bureau of Mines Method (USBM) and the curve fitting method, respectively. This study established a novel, highly accurate and widely applicable method of calculating the volume of lost shale gas.

Molecular Investigation on the Displacement Characteristics of CH4 by CO2, N2 and Their Mixture in a Composite Shale Model

The rapid growth in energy consumption and environmental pollution have greatly stimulated the exploration and utilization of shale gas. The injection of gases such as CO2, N2, and their mixture is currently regarded as one of the most effective ways to enhance gas recovery from shale reservoirs. In this study, molecular simulations were conducted on a kaolinite–kerogen IID composite shale matrix to explore the displacement characteristics of CH4 using different injection gases, including CO2, N2, and their mixture. The results show that when the injection pressure was lower than 10 MPa, increasing the injection pressure improved the displacement capacity of CH4 by CO2. Correspondingly, an increase of formation temperature also increased the displacement efficiency of CH4, but an increase of pore size slightly increased this displacement efficiency. Moreover, it was found that when the proportion of CO2 and N2 was 1:1, the displacement efficiency of CH4 was the highest, which proved that the simultaneous injection of CO2 and N2 had a synergistic effect on shale gas production. The results of this paper will provide guidance and reference for the displacement exploitation of shale gas by injection gases.

Economic benefit of shale gas exploitation based on back propagation neural network

Under the influence of COVID-19, the economic benefits of shale gas development are greatly affected. With the large-scale development and utilization of shale gas in China, it is increasingly important to assess the economic impact of shale gas development. Therefore, this paper proposes a method for predicting the production of shale gas reservoirs, and uses back propagation (BP) neural network to nonlinearly fit reservoir reconstruction data to obtain shale gas well production forecasting models. Experiments show that compared with the traditional BP neural network, the proposed method can effectively improve the accuracy and stability of the prediction. There is a nonlinear correlation between reservoir reconstruction data and gas well production, which does not apply to traditional linear prediction methods

Molecular simulations of competitive adsorption behavior between CH4-C2H6 in K-illite clay at supercritical conditions

Methane (CH4) and ethane (C2H6) are dominating compositions in natural gas produced from shale, approximately 80~90 percent. For efficient development and utilization of shale gas, the competitive adsorption behavior between CH4 and C2H6 is considerable significance to make sure the storage and transportation mechanisms in the pore structure of shale. The adsorption behavior of CH4-C2H6 in K-illite slits is studied with wide range of aperture (1.5~5.5 nm), pressure (≤50 MPa) and temperature (320~380 K) by using Grand Canonical Monte Carlo (GCMC) simulations and molecular dynamics (MD) simulations. The adsorption isotherms, isosteric heats, density distribution and absorbed site are used to analyze the pure and binary adsorption behavior considering the effects of temperature, pressure and contents. The results indicate that the pressure has a large influence on the adsorption capacity of C2H6 and CH4. At the low pressure, the adsorption capacity of C2H6 is stronger than that of CH4. With the increasing pressure, CH4 molecule shows the stronger increasing adsorption behavior than C2H6. From the results of adsorption isotherms of pure gas, excess adsorption amounts of pure CH4 and C2H6 are decreased with broader apertures in unit volume of K-illite slits. C2H6 molecule is easier to full in K-illite slits and alkanes absorb on the site of Al-O-Si bond bridge in K-illite. The adsorption selectivity of C2H6/CH4 is more than unity. The content of CH4 suppresses the first and second adsorption peak of C2H6. This work can give some understandings about single and binary gas adsorption behavior in K-illite shales.

Modeling C–H Bond Activation and Oxidations of Alkanes over Cu–MOR Using First-Principles Methods

Direct conversion of methane to methanol can significantly boost the economic value of shale gas utilization. However, the stable C–H bond makes methane partial oxidation a challenging catalysis task. At low temperatures, C–H bond activation is kinetically sluggish. On the other hand, methane is likely oxidized fully into CO2 at high temperatures, which will lower methanol selectivity. Several Cu–oxo complexes such as mono(μ-oxo)dicopper, bis(μ-oxo)dicopper, and copper trioxo anchored in the mordenite (MOR) zeolite framework are shown to balance catalytic activity and product selectivity for the methane-to-methanol conversion. In this work, the thermodynamic stability of Cu–oxo complexes was evaluated as active centers for C–H bond activation using the BEEF-vdW functional within the density functional theory (DFT) framework, and the bis(μ-oxo)dicopper moiety was identified as the most stable configuration. The catalytic reactivity of these complexes was then tested with the activation of the first C–H bon...

Single rhodium atoms anchored in micropores for efficient transformation of methane under mild conditions

Catalytic transformation of CH4 under a mild condition is significant for efficient utilization of shale gas under the circumstance of switching raw materials of chemical industries to shale gas. Here, we report the transformation of CH4 to acetic acid and methanol through coupling of CH4, CO and O2 on single-site Rh1O5 anchored in microporous aluminosilicates in solution at ≤150 °C. The activity of these singly dispersed precious metal sites for production of organic oxygenates can reach about 0.10 acetic acid molecules on a Rh1O5 site per second at 150 °C with a selectivity of ~70% for production of acetic acid. It is higher than the activity of free Rh cations by >1000 times. Computational studies suggest that the first C–H bond of CH4 is activated by Rh1O5 anchored on the wall of micropores of ZSM-5; the formed CH3 then couples with CO and OH, to produce acetic acid over a low activation barrier.

An Investigation of the Underlying Evolution of Shale Gas Research’s Domain Based on the Co-Word Network

With the increasing shortage energy, the exploration and utilization of shale gas (SG) have greatly changed the world’s natural gas supply pattern. In this study, based on a bibliometric review of the publications related to SG, by analyzing the co-word networks during the past years, we provide comprehensive analyses on the underlying domain evolution of shale gas research (SGR). Firstly, we visualize the topical development of SGR. We not only identify the key topics at each stage but also reveal their underlying dependence and evolutionary trends. The directions of SGR in the future are implied. Secondly, we find the co-word network has small-world and scale-free characteristics, which are the important mechanisms of driving the evolution of SGR’s domain. Thirdly, we analyze China’s SGR. We find the co-word network in China’s SGR has not yet emerged obvious differentiation. Nevertheless, it has a similar self-organized evolution process with the co-word network of international SGR. Our above results can provide references for the future SGR of scholars, optimization or control of the domain and the strategy/policy of countries or globalization.

A dynamic forward-citation full path model for technology monitoring: An empirical study from shale gas industry

The utilization of shale gas has become one of the important options to transit into low-carbon economy in the world and its vigorous development relies on successful technology revolution to a great extent. Based on patent data, this paper analyzes the development trends and the status quo of technical innovation of shale gas quantitatively by means of patent maps. A new dynamic model named Forward-Citation Full Path (FCFP) is investigated to identify the key development paths in technology clusters and monitor potential breakthrough technologies on those key paths. Then we employ topic modeling and text mining for patent abstracts to explore the potential promising topics with high innovation activeness in aid of providing specific references for development and foresight of the shale gas technology. The results show that: (1) The patent center of shale gas has been transferring from North American to the Asia-Pacific region and the technological innovation is mainly driven by preferential tax policy and loose environmental regimes. (2) Current hotspots of shale gas technology are production technique including stimulation treatments, environmental protection technology of fracturing fluid and geological prospecting technology. (3) There are five potential topics with high innovation activeness identified by topic modeling and text mining which are synthetic carbon oxide, hydraulic fracturing, fracturing propping agents, horizontal well, and technologies of reservoir exploration and modeling. (4) By means of visualization of technology clusters, it is found that promising technologies are refined simulation technology for shale gas exploration, multi-interval fracturing techniques in horizontal wells with deep pay zones, water treatment and environmental protection technology in shale gas production. (5) The suggested dynamic FCFP model can effectively identify the key development paths and monitor potential breakthrough technology of shale gas.