End-Member Mixing Model for Methane Carbon Isotope Fractionation During Shale Gas Desorption and Its Application.

Unlike conventional natural gas reservoirs, shale gas development involves systematic changes in methane carbon isotopes that cannot be effectively described by existing isotope fractionation models and mechanisms. Therefore, based on fundamental theories such as Rayleigh fractionation, mass transfer flow, and mass conservation, this study established isotopic fractionation equations for methane in adsorbed and free gas. By considering adsorbed and free gases as two end-members and using an isotope mixing model, a fractionation model for methane carbon isotopes during shale gas desorption was constructed.

Enhanced chemiluminescence resonance energy transfer using surfactant-modified AIE carbon dots.

Chemiluminescence resonance energy transfer (CRET) efficiency can be enhanced by confining CRET donors and acceptors within nanoscale spaces. However, this enhanced efficiency is often affected by uncertainties stemming from the random distribution of CRET donors and acceptors in such confined environments. In this study, a novel confined nanospace was created through the surfactant modification of carbon dots (CDs) exhibiting aggregation-induced emission (AIE) characteristics.

Research on evaluation technology system of mid-deep underground coal gasification based on researchers from China.

Underground coal gasification is of great strategic significance to the effective and clean development of coal resources and scale up production of natural gas worldwide. Selection evaluation is the foundation of the exploration and development of underground coal gasification. In this paper, the differences between mid-deep (500-2200 m) and shallow layer (<500 m) underground coal gasification are analyzed, the key parameters affecting underground coal gasification are clearly identified, and the selection evaluation technology system is established.

Factors, Mechanisms, and Kinetics of Spontaneous Emulsification for Heavy Oil-in-Water Emulsions.

In challenging reservoirs where thermal recovery falls short, cold or chemical oil recovery methods are crucial. Spontaneous emulsification (SE), triggered by gentle disturbance, significantly enhances oil recovery. In elucidating SE mechanisms and kinetics, SE processes via direct contact between oil and aqueous phases without stirring were conducted.

Paleosedimentary environmental reconstruction and mechanisms of the response to the Toarcian OAE in a lacustrine shale system.

The Lower Jurassic Ziliujing Formation in China's Sichuan Basin is a significant shale target for exploration; however, the strong heterogeneity of the properties of organic matter (OM) in shale makes it challenging to identify the target area for exploration, and the mechanism of OM enrichment is still unclear. Furthermore, the mechanisms of the response of the Da'anzhai member to the Toarcian Oceanic Anoxic Event (T-OAE) are controversial. Previous studies have focused on sedimentary facies analysis based on mineralogy and elemental abundances and have provided minimal information about organic geochemistry, which adds to the challenge of deeply understanding the influence of the T-OAE on the molecular geochemical characteristics of the Da'anzhai member.

Unrecognized extensive charge of microbial gas in the Junggar basin.

Different from the Qaidam basin with about 320 billion m microbial gas, only limited microbial gases were found from the Junggar basin with similarly abundant type III kerogen. To determine whether microbial gases have not yet identified, natural gas samples from the Carboniferous to Cretaceous in the Junggar basin have been analyzed for chemical and stable isotope compositions. The results reveal some of the gases from the Mahu sag, Zhongguai, Luliang and Wu-Xia areas in the basin may have mixed with microbial gas leading to straight ethane to butane trends with a "dogleg" light methane in the Chung's plot.

Modeling of Burial History, Source Rock Maturity, and Hydrocarbon Generation of Marine-Continental Transitional Shale of the Permian Shanxi Formation, Southeastern Ordos Basin.

The Ordos Basin is characterized by abundant natural gas resources, and the marine-continental transitional shale gas of the Permian Shanxi Formation has great exploration and development potential. However, few systematic studies have focused on the burial history, thermal maturity, and hydrocarbon generation of the shale, which limits the understanding of shale gas enrichment and resource evaluation. To reveal the shale gas resource potential, we focused on the Shanxi Formation shale in the southeastern Ordos Basin.

The preparation of gallic acid-grafted cationic chitosan as effective salt-tolerant flocculants.

In this work, gallic acid was successfully grafted onto quaternary aminated chitosan to prepare a high efficiency cationic flocculant. The mechanism of flocculation and different influencing factors were studied in detail. The prepared flocculant only needs 60 mg L to achieve a 98.

Investigation on the Nanopore Heterogeneity in Coals and its Influence on Methane Adsorption: A Multifractal Theory Study.

Coalbed methane (CBM) reservoirs constitute a distinct class of dense organic rocks characterized by extremely low porosity and permeability. Conducting an in-depth investigation into pore heterogeneity assumes paramount importance for the exploration and development of CBM. This study focuses on the multifractal analysis of the pores with diameters below 300 nm in six coal samples sourced from the Junggar Basin and the Qinshui Basin in China.

The effect of aromatic side chains on the dilational rheological properties of -acyltaurate amphiphiles at water-decane interfaces.

To elucidate the effect of aromatic side chains on dilational rheological properties of -acyltaurate amphiphiles at the decane-water interface, the interfacial rheological properties of sodium -2-(2-naphthoxy)-tetradecanoyltaurinate (12+N-T) and sodium -2-(-butylphenoxy)-tetradecanoyltaurinate (12+4B-T) were investigated utilizing the drop shape analysis method. The effects of adsorption time, interfacial pressure, oscillating frequency, and bulk concentration on the interfacial dilational modulus and phase angle were explored. The results show that the 12+4B-T molecule with a longer hydrophobic chain shows a higher ability for reducing the interfacial tension (IFT).

Three-Dimensional Crystalline Organic Framework Stabilized by Molecular Mortise-and-Tenon Jointing.

Three-dimensional (3D) crystalline organic frameworks with complex topologies, high surface area, and low densities afford a variety of application prospects. However, the design and construction of these frameworks have been largely limited to systems containing polyhedron-shaped building blocks or those relying on component interpenetration. Here, we report the synthesis of a 3D crystalline organic framework based on molecular mortise-and-tenon jointing.

Study on the kinetics of formation process of emulsion of heavy oil and its functional group components.

Enhanced oil recovery (EOR) by in situ formation of oil-in-water emulsion in heavy oil cold production technology has received growing interest from the petroleum industry. We present an experimental study of emulsification of model oils prepared by heavy oil and its functional group compositions dissolved into toluene brought into contact with a surfactant solution. The effects of functional group composition, emulsifier concentration, temperature, pH and stirring speed on the emulsification rate of heavy oil was investigated.

Characteristics and Controlling Factors of Natural Fractures in Deep Carbonates of the Puguang Area, Sichuan Basin, China.

Understanding the types, characteristics, and controlling factors of natural fractures in deep and ultradeep carbonates is crucial for evaluating reservoir quality, optimizing well deployment, and comprehending their impact on hydrocarbon exploitation. Multiple types of natural fractures are widespread in the deep carbonates of the Feixianguan Formation in the Puguang area, northeastern Sichuan Basin, China, and the main controlling factors are complex. Based on geological, geophysical, and experimental data, this study defined fracture types and analyzed the fracture development characteristics in the deep Feixianguan carbonates.

Numerical Simulation of Proppant Transport in Major and Branching Fractures Based on CFD-DEM.

This research investigated the effect of branching fracture, proppant, and fracturing fluid on proppant transport based on the CFD-DEM coupling model. The obtained results show that the balance height of embankment in the major fracture decreases gradually with increasing angle between major and branching fractures, while it increases gradually in the branching fracture. This is because the additional resistance of fracturing fluid flow at the joint increases with increasing angle, leading to the decrease of the fracturing fluid velocity.

Distinctive volcanic ash-rich lacustrine shale deposition related to chemical weathering intensity during the Late Triassic: Evidence from lithium contents and isotopes.

The Late Triassic Carnian Pluvial Episode (CPE) witnessed enormous climate change closely associated with volcanic activity. However, the coupling relationship between volcanic activity and climate change, which may be linked to chemical weathering, has not yet been fully uncovered. We used lithium contents and isotopes of volcanic ash (VA)-bearing lacustrine shale to constrain their deposition pathways and response to climate changes, i.

Experimental and Simulation Studies of Imidazolium Chloride Ionic Liquids with Different Alkyl Chain Lengths for Viscosity Reductions in Heavy Crude Oil: The Effect on Asphaltene Dispersion.

Heavy crude oil poses challenges in terms of extraction and transportation due to its high viscosity. In the pursuit of effective methods to reduce viscosity in heavy crude oil, this study investigates the potential of imidazolium chloride ionic liquids with varying alkyl chain lengths as viscosity reducers. The experimental results demonstrate that the addition of 1-dodecyl-3-methylimidazole chloride ([C12-MIM]Cl) leads to a maximum viscosity reduction of 49.

Dynamics of green economic development in countries joining the belt and road initiative: Is it driven by green investment transformation?

Green investment transformation is the main interval difference of the Belt and Road Initiative, however, its actual effects are still uncertain. Finding out its utility, mechanism and improvement on green economy may accelerate green development. In this paper, Slack Based Measure model is used to obtain original results, Super-Efficiency model is used to sort effective decision-making units for stronger efficient frontier and Minimum Distance to Strong Efficient Frontier model is used to narrow gaps between non-effective ones and real situations.

Modeling Permeability Using Advanced White-Box Machine Learning Technique: Application to a Heterogeneous Carbonate Reservoir.

From exploration to production, the permeability of reservoir rocks is essential for various stages of all types of hydrocarbon field development. In the absence of costly reservoir rock samples, having a reliable correlation to predict rock permeability in the zone(s) of interest is crucial. To predict permeability conventionally, petrophysical rock typing is done.

Organic Geochemical Characteristics and Organic Matter Enrichment of the Upper Permian Longtan Formation Black Shale in Southern Anhui Province, South China.

Although previous studies have yielded valuable insights into shale gas reservoirs, a comprehensive understanding of the organic geochemical characteristics and organic matter enrichment of marine-continental transitional shale has yet to be achieved. The Longtan Formation transitional shales were extensively deposited in Southern Anhui Province, South China, during the Late Permian. Our analysis of twenty-two rock samples from one core (Gangdi-1 well) and two outcrops (Daoshanchong outcrop and Changqiao outcrop) revealed that the Longtan Formation shale extracts exhibit a wide range of C-C-alkanes and acyclic isoprenoids, with unimodal, bimodal, and multimodal distributions.

Fracability Evaluation Method of a Fractured-Vuggy Carbonate Reservoir in the Shunbei Block.

The fracability of carbonate reservoirs is a key indicator for evaluating whether reservoirs can be effectively fractured. Taking the fractured-vuggy carbonate reservoir in the Shunbei block as an example, the microscopic characteristics and mechanical properties of this reservoir were analyzed. The test results showed that the core microstructure is relatively dense, the micropores and microfractures are developed, and the mineral composition is characterized by "high carbonate and few impurities".

Mercury isotopes show vascular plants had colonized land extensively by the early Silurian.

The colonization and expansion of plants on land is considered one of the most profound ecological revolutions, yet the precise timing remains controversial. Because land vegetation can enhance weathering intensity and affect terrigenous input to the ocean, changes in terrestrial plant biomass with distinct negative ΔHg and ΔHg signatures may overwrite the positive Hg isotope signatures commonly found in marine sediments. By investigating secular Hg isotopic variations in the Paleozoic marine sediments from South China and peripheral paleocontinents, we highlight distinct negative excursions in both ΔHg and ΔHg at Stage level starting in the early Silurian and again in the Carboniferous.

Simple Co-Precipitation of Iron Minerals for the Removal of Phenylarsonic Acid: Insights into the Adsorption Performance and Mechanism.

In this study, three kinds of iron minerals, ferrihydrite, hematite, and goethite, were prepared by a simple coprecipitation method for the adsorption and removal of phenylarsonic acid (PAA). The adsorption of PAA was explored, and the influences of ambient temperature, pH, and co-existing anions on adsorption were evaluated. The experimental results show that rapid adsorption of PAA occurs within 180 min in the presence of iron minerals, and the adsorption process conforms to a pseudo-second-order kinetic model.

Synthesis of 3-Oxo Quinolines by Cyclization Using Lignin Models and 2-Aminobenzyl Alcohols.

Phenoxy acetophenones were usually employed as β-O-4' lignin models for chemical conversion. Herein, an iridium-catalyzed dehydrogenative annulation between 2-aminobenzylalcohols and phenoxy acetophenones was demonstrated to prepare valuable 3-oxo quinoline derivatives, which are hard to prepare using previous methods. This operationally simple reaction tolerated a wide scope of substrates and enabled successful gram-scale preparation.

Pore Structure and Gas Content Characteristics of Lower Jurassic Continental Shale Reservoirs in Northeast Sichuan, China.

The Jurassic shale in the northeastern Sichuan Basin is one of the main target intervals for continental shale gas exploitation. Research on the pore structure and gas-bearing properties of shales is the key issue in target interval optimization. Through core observation, geochemistry, bulk minerals, scanning electron microscopy, nitrogen adsorption, and isothermal adsorption experiments, various lithofacies with different pore structure characteristics were clarified.