Development,challenges and strategies of natural gas industry under carbon neutral target in China

In the mid-21st century,natural gas will enter its golden age,and the era of natural gas is arriving.This paper reviews the development stages of global natural gas industry and the enlightenment of American shale gas revolution,summarizes the development history and achievements of the natural gas industry in China,analyzes the status and challenges of natural gas in the green and low-carbon energy transition,and puts forward the natural gas industry development strategies under carbon neutral target in China.The natural gas industry in China has experienced three periods:start,growth,and leap forward.At present,China has become the fourth largest natural gas producer and third largest natural gas consumer in the world,and has made great achievements in natural gas exploration and development theory and technology,providing important support for the growth of production and reserves.China has set its goal of carbon neutrality to promote green and sustainable development,which brings opportunities and challenges for natural gas industry.Natural gas has significant low-carbon advantages,and gas-electric peak shaving boosts new energy development;the difficulty and cost of development are more prominent.For the national energy security and harmonious development between economy and ecology under the carbon neutral goal,based on the principle of"comprehensive planning,technological innovation,multi-energy complementarity,diversified integration,flexibility and efficiency,optimization and upgrading",the construction of the production-supplystorage-marketing system has to be improved so as to boost the development of the natural gas industry.First,it is necessary to strengthen efforts in the exploration and development of natural gas,making projects and arrangement in key exploration and development areas,meanwhile,it is urgent to make breakthroughs in key science theories and technologies,so as to increase reserve and production.Second,it should promote green and innovative development of the natural gas by developing new techniques,expanding new fields and integrating with new energy.Third,there is a demand to realize transformation and upgrading of the supply and demand structure of natural gas by strengthening the layout of pipeline gas,liquefied natural gas and the construction of underground gas storage,establishing reserve system for improving abilities of emergency response and adjustment,raising the proportion of natural gas in the primary energy consumption and contributing to the transformation of energy consumption structure,realizing low-carbon resources utilization and clean energy consumption.

Characteristics and Insights of Offshore Oil and Gas Exploration and Development Investment

The oceans'vast expanse has given rise to copious oil and gas resources,with recent years witnessing a steady unlocking of offshore oil and gas potential,positioning them as a key successor in global energy reserves.Currently,offshore oil and gas extraction constitutes nearly a third of the world's oil and gas output.This segment has evolved into a mutually beneficial ecosystem where operators and service providers collaborate closely around exploration and development activities.Investment in offshore oil and gas typically follows a dual "one-third’"pattern,reflecting high upfront costs but promising returns.It also underscores the stark variations in project viability and regional economic efficiency,with monopolistic traits seen at both national and corporate levels.Collaboration has emerged as a key tactic for resource-rich countries and oil companies to advance their offshore ventures.Given the distinct nature of offshore oil and gas development,Chinese oil companies are advised to seize opportunities in marine exploration,emphasize the coordination and planning abilities of the global supply chain,focus on the reserves of offshore oil and gas development technologies,as well as the capabilities of commercial talents and other forms of support,courageously pursue significant offshore assets,and effectively utilize global technology,equipment,and expertise,and rapidly build a competitive edge in offshore oil and gas projects.

Effect of fracture fluid flowback on shale microfractures using CT scanning

The field data of shale fracturing demonstrate that the flowback performance of fracturing fluid is different from that of conventional reservoirs,where the flowback rate of shale fracturing fluid is lower than that of conventional reservoirs.At the early stage of flowback,there is no single-phase flow of the liquid phase in shale,but rather a gas-water two-phase flow,such that the single-phase flow model for tight oil and gas reservoirs is not applicable.In this study,pores and microfractures are extracted based on the experimental results of computed tomography(CT)scanning,and a spatial model of microfractures is established.Then,the influence of rough microfracture surfaces on the flow is corrected using the modified cubic law,which was modified by introducing the average deviation of the microfracture height as a roughness factor to consider the influence of microfracture surface roughness.The flow in the fracture network is simulated using the modified cubic law and the lattice Boltzmann method(LBM).The results obtained demonstrate that most of the fracturing fluid is retained in the shale microfractures,which explains the low fracturing fluid flowback rate in shale hydraulic fracturing.

CO_(2)flooding in shale oil reservoir with radial borehole fracturing for CO_(2)storage and enhanced oil recovery

This study introduces a novel method integrating CO_(2)flooding with radial borehole fracturing for enhanced oil recovery and CO_(2)underground storage,a solution to the limited vertical stimulation reservoir volume in horizontal well fracturing.A numerical model is established to investigate the production rate,reservoir pressure field,and CO_(2)saturation distribution corresponding to changing time of CO_(2)flooding with radial borehole fracturing.A sensitivity analysis on the influence of CO_(2)injection location,layer spacing,pressure difference,borehole number,and hydraulic fractures on oil production and CO_(2)storage is conducted.The CO_(2)flooding process is divided into four stages.Reductions in layer spacing will significantly improve oil production rate and gas storage capacity.However,serious gas channeling can occur when the spacing is lower than 20 m.Increasing the pressure difference between the producer and injector,the borehole number,the hydraulic fracture height,and the fracture width can also increase the oil production rate and gas storage rate.Sensitivity analysis shows that layer spacing and fracture height greatly influence gas storage and oil production.Research outcomes are expected to provide a theoretical basis for the efficient development of shale oil reservoirs in the vertical direction.

Impact of Reservoir Heterogeneity on Bitumen Content in the Mackay River Oil Sands,Athabasca(Canada)

The Lower Cretaceous Manville Group of Upper Mc Murray Formation is one of the main bitumen reservoirs in Athabasca.In this study,the relationship between reservoirs heterogeneity and bitumen geochemical characteristics were analyzed through core and microscopic observation,lab analysis,petrophysics and logging data.Based on the sedimentology framework,the formation environment of high-quality oil sand reservoirs and their significance for development were discussed.The results indicate that four types lithofacies were recognized in the Upper Mc Murray Formation based on their depositional characteristics.Each lithofacies reservoirs has unique physical properties,and is subject to varying degrees of degradation,resulting in diversity of bitumen content and geochemical composition.The tidal bar(TB)or tidal channel(TC)facies reservoir have excellent physical properties,which are evaluated as gas or water intervals due to strong degradation.The reservoir of sand bar(SB)facies was evaluated as oil intervals,due to its poor physical properties and weak degradation.The reservoir of mixed flat(MF)facies is composed of sand intercalated with laminated shale,which is evaluated as poor oil intervals due to its poor connectivity.The shale content in oil sand reservoir is very important for the reservoir physical properties and bitumen degradation degree.In the context of regional biodegradation,oil sand reservoirs with good physical properties will suffer from strong degradation,while oil sand reservoirs with relatively poor physical properties are more conducive to the bitumen preservation.

A Well Productivity Model for Multi-Layered Marine and Continental Transitional Reservoirs with Complex Fracture Networks

Using the typical characteristics of multi-layered marine and continental transitional gas reservoirs as a basis,a model is developed to predict the related well production rate.This model relies on the fractal theory of tortuous capillary bundles and can take into account multiple gas flow mechanisms at the micrometer and nanometer scales,as well as the flow characteristics in different types of thin layers(tight sandstone gas,shale gas,and coalbed gas).Moreover,a source-sink function concept and a pressure drop superposition principle are utilized to introduce a coupled flow model in the reservoir.A semi-analytical solution for the production rate is obtained using a matrix iteration method.A specific well is selected for fitting dynamic production data,and the calculation results show that the tight sandstone has the highest gas production per unit thickness compared with the other types of reservoirs.Moreover,desorption and diffusion of coalbed gas and shale gas can significantly contribute to gas production,and the daily production of these two gases decreases rapidly with decreasing reservoir pressure.Interestingly,the gas production from fractures exhibits an approximately U-shaped distribution,indicating the need to optimize the spacing between clusters during hydraulic fracturing to reduce the area of overlapping fracture control.The coal matrix water saturation significantly affects the coalbed gas production,with higher water saturation leading to lower production.

Attention Mechanism-Based Method for Intrusion Target Recognition in Railway

The detection of foreign object intrusion is crucial for ensuring the safety of railway operations.To address challenges such as low efficiency,suboptimal detection accuracy,and slow detection speed inherent in conventional comprehensive video monitoring systems for railways,a railway foreign object intrusion recognition and detection system is conceived and implemented using edge computing and deep learning technologies.In a bid to raise detection accuracy,the convolutional block attention module(CBAM),including spatial and channel attention modules,is seamlessly integrated into the YOLOv5 model,giving rise to the CBAM-YOLOv5 model.Furthermore,the distance intersection-over-union_non-maximum suppression(DIo U_NMS)algorithm is employed in lieu of the weighted nonmaximum suppression algorithm,resulting in improved detection performance for intrusive targets.To accelerate detection speed,the model undergoes pruning based on the batch normalization(BN)layer,and Tensor RT inference acceleration techniques are employed,culminating in the successful deployment of the algorithm on edge devices.The CBAM-YOLOv5 model exhibits a notable 2.1%enhancement in detection accuracy when evaluated on a selfconstructed railway dataset,achieving 95.0%for mean average precision(m AP).Furthermore,the inference speed on edge devices attains a commendable 15 frame/s.

Deterministic tools to predict gas assisted gravity drainage recovery factor

Naturally fractured rocks contain most of the world's petroleum reserves.This significant amount of oil can be recovered efficiently by gas assisted gravity drainage(GAGD).Although,GAGD is known as one of the most effective recovery methods in reservoir engineering,the lack of available simulation and mathematical models is considerable in these kinds of reservoirs.The main goal of this study is to provide efficient and accurate methods for predicting the GAGD recovery factor using data driven techniques.The proposed models are developed to relate GAGD recovery factor to the various parameters including model height,matrix porosity and permeability,fracture porosity and permeability,dip angle,viscosity and density of wet and non-wet phases,injection rate,and production time.In this investigation,by considering the effective parameters on GAGD recovery factor,three different efficient,smart,and fast models including artificial neural network(ANN),least square support vector machine(LSSVM),and multi-gene genetic programming(MGGP)are developed and compared in both fractured and homogenous porous media.Buckinghamπtheorem is also used to generate dimensionless numbers to reduce the number of input and output parameters.The efficiency of the proposed models is examined through statistical analysis of R-squared,RMSE,MSE,ARE,and AARE.Moreover,the performance of the generated MGGP correlation is compared to the traditional models.Results demonstrate that the ANN model predicts the GAGD recovery factor more accurately than the LSSVM and MGGP models.The maximum R^(2)of 0.9677 and minimum RMSE of 0.0520 values are obtained by the ANN model.Although the MGGP model has the lowest performance among the other used models(the R2 of 0.896 and the RMSE of 0.0846),the proposed MGGP correlation can predict the GAGD recovery factor in fractured and homogenous reservoirs with high accuracy and reliability compared to the traditional models.Results reveal that the employed models can easily predict GAGD recovery factor without requiring complicate governing equations or running complex and time-consuming simulation models.The approach of this research work improves our understanding about the most significant parameters on GAGD recovery and helps to optimize the stages of the process,and make appropriate economic decisions.

An Experimental Analysis of Gas-Liquid Flow Breakdown in a T-Junction

When a gas-liquid two-phase flow(GLTPF)enters a parallel separator through a T-junction,it generally splits unevenly.This phenomenon can seriously affect the operation efficiency and safety of the equipment located downstream.In order to investigate these aspects and,more specifically,the so-called bias phenomenon(all gas and liquid flowing to one pipe,while the other pipe is a liquid column that fluctuates up and down),laboratory experiments were carried out by using a T-junction connected to two parallel vertical pipes.Moreover,a GLTPF prediction model based on the principle of minimum potential energy was introduced.The research results indicate that this model can accurately predict the GLTPF state in parallel risers.The boundary of the slug flow and the churn flow in the opposite pipe can be predicted.Overall,according to the results,the pressure drop curves of the two-phase flow in the parallel risers are basically the same when there is no bias phenomenon,but the pressure drop in the parallel riser displays a large deviation when there is a slug flow-churn flow.Only when the parallel riser is in a state of asymmetric flow and one of the risers produces churn flow,the two-phase flow is prone to produce the bias phenomenon.

Rheological study of methane gas hydrates in the presence of micron-sized sand particles

Natural gas hydrates,intricate crystalline structures formed by water molecules and small gas molecules,have emerged as a significant and globally impactful clean energy resource.However,their commercial exploitation faces challenges,particularly operational disruptions caused by sand-related blockages.Understanding the rheological properties of hydrate slurry,especially in the presence of micron-sized sand particles,is imperative for ensuring the flow assurance of subsea hydrate exploitation.This study extensively investigates the rheological properties of sand-containing hydrate slurries.The findings reveal that these slurries exhibit non-Newtonian fluid characteristics,including yield stress,thixotropy,and shear-thinning behavior.Solid-like elastic features are observed in sand-containing hydrate slurries before yielding,transitioning to viscous behavior after yielding.Even with a minimal amount of sand,both static yield stress and yield strain experience substantial changes,correlating with the increase in sand concentration.The research conclusively establishes the thixotropic nature of sand-hydrate slurries,where the viscosity decay rate is directly influenced by the shear rate.These insights aim to contribute comprehensively to the development of effective flow assurance strategies,ensuring the safe and stable operation of subsea hydrate exploitation.

Dynamic mechanical characteristics of deep Jinping marble in complex stress environments

To reveal the dynamic mechanical characteristics of deep rocks,a series of impact tests under triaxial static stress states corresponding to depths of 300-2400 m were conducted.The results showed that both the strain rates and the stress environments in depth significantly affect the mechanical characteristics of rocks.The sensitivity of strain rate to the dynamic strength and deformation modulus shows a negative correlation with depth,indicating that producing penetrative cracks in deep environments is more difficult when damage occurs.The dynamic strength shows a tendency to decrease and then increase slightly,but decreases sharply finally.Transmissivity demonstrates a similar trend as that of strength,whereas reflectivity indicates the opposite trend.Furthermore,two critical depths with high dynamically induced hazard possibilities based on the China Jinping Underground Laboratory(CJPL)were proposed for deep engineering.The first critical depth is 600-900 m,beyond which the sensitivity of rock dynamic characteristics to the strain rate and restraint of circumferential stress decrease,causing instability of surrounding rocks under axial stress condition.The second one lies at 1500-1800 m,where the wave impedance and dynamic strength of deep surrounding rocks drop sharply,and the dissipation energy presents a negative value.It suggests that the dynamic instability of deep surrounding rocks can be divided into dynamic load dominant and dynamic load induced types,depending on the second critical depth.

Formation mechanism of fault accommodation zones under combined stress in graben basin:Implications from geomechanical modeling

A fault accommodation zone is a type of structure that is defined as regulating displacement and strain between faults structure.Increasing numbers of fault accommodation zones are being identified in graben basins,indicating the potential exploration target and petroleum accumulation areas.This study aims to analyze the formation mechanism and development of fault accommodation zones under combined stress by a numerical simulation method considering geomechanical modeling.Using three-dimensional(3-D)seismic interpretation and fractal dimension method,exampled with the Dongxin fault zone,the fault activity and fault combination pattern were conducted to quantitatively characterize the activity difference in fault accommodation zones.Combined with mechanical experiment test,a geomehcanical model was established for fault accommodation zones in a graben basin.Integrating the paleostress numerical simulations and structural physical simulation experiment,the developmental characteristics and genetic mechanism of fault accommodation zones were summarized.Influenced by multi movements and combined stresses,three significant tectonic evolution stages of the Dongxing Fault Zone(DXFZ)were distinguished:During the E_(s)^(3)sedimentary period,the large difference in the stress,strain,and rupture distribution in various faults were significant,and this stage was the key generation period for the prototype of the DXFZ,including the FAZ between large-scale faults.During the E_(s)^(2)sedimentary period,the EW-trending symmetric with opposite dipping normal faults and the NE-SW trending faults with large scale were furtherly developed.The junction area of two secondary normal faults were prone to be ruptured,performing significant period for inheriting and developing characteristics of fault accommodation zones.During the Es1 sedimentary period,the high-order faults in the DXFZ exhibited the obvious fault depressions and strike-slip activity,and the fault accommodation zones were furtherly inherited and developed.This stage was the molded and formative period of the FAZ,the low-order faults,and the depression in the DXFZ.

Preliminary research and scheme design of deep underground in situ geo-information detection experiment for Geology in Time

The deep earth,deep sea,and deep space are the main parts of the national“three deep”strategy,which is in the forefront of the strategic deployment clearly defined in China’s 14th Five-Year Plan(2021-2025)and the Long-Range Objectives Through the Year 2035.It is important to reveal the evolutionary process and mechanism of deep tectonics to understand the earth’s past,present and future.The academic con-notation of Geology in Time has been given for the first time,which refers to the multi-field evolution response process of geological bodies at different time and spatial scales caused by geological processes inside and outside the Earth.Based on the deep in situ detection space and the unique geological envi-ronment of China Jinping Underground Laboratory,the scientific issue of the correlation mechanism and law between deep internal time-varying and shallow geological response is given attention.Innovative research and frontier exploration on deep underground in situ geo-information detection experiments for Geology in Time are designed to be carried out,which will have the potential to explore the driving force of Geology in Time,reveal essential laws of deep earth science,and explore innovative technologies in deep underground engineering.

Magnificent Frigatebird Optimization: A New Bio-Inspired Metaheuristic Approach for Solving Optimization Problems

This paper introduces a groundbreaking metaheuristic algorithm named Magnificent Frigatebird Optimization(MFO),inspired by the unique behaviors observed in magnificent frigatebirds in their natural habitats.The foundation of MFO is based on the kleptoparasitic behavior of these birds,where they steal prey from other seabirds.In this process,a magnificent frigatebird targets a food-carrying seabird,aggressively pecking at it until the seabird drops its prey.The frigatebird then swiftly dives to capture the abandoned prey before it falls into the water.The theoretical framework of MFO is thoroughly detailed and mathematically represented,mimicking the frigatebird’s kleptoparasitic behavior in two distinct phases:exploration and exploitation.During the exploration phase,the algorithm searches for new potential solutions across a broad area,akin to the frigatebird scouting for vulnerable seabirds.In the exploitation phase,the algorithm fine-tunes the solutions,similar to the frigatebird focusing on a single target to secure its meal.To evaluate MFO’s performance,the algorithm is tested on twenty-three standard benchmark functions,including unimodal,high-dimensional multimodal,and fixed-dimensional multimodal types.The results from these evaluations highlight MFO’s proficiency in balancing exploration and exploitation throughout the optimization process.Comparative studies with twelve well-known metaheuristic algo-rithms demonstrate that MFO consistently achieves superior optimization results,outperforming its competitors across various metrics.In addition,the implementation of MFO on four engineering design problems shows the effectiveness of the proposed approach in handling real-world applications,thereby validating its practical utility and robustness.

Construction of Value-Creation Oriented Carbon Assets Management System of Oil Companies

As climate change draws more attention globally,the development of low-carbon economy has become an inevitable choice for mankind to achieve sustainable development.The increasingly strict control of carbon emission is making carbon emission rights a scarce resource and endowing the rights with the attributes of assets and commodities.China has announced the goal of“carbon emission peaking before 2030 and carbon neutralization before 2060”.Responding to this goal,as major carbon emitters,oil companies play the role of a driving force for green and low-carbon development.Carbon assets management is a key path for oil companies to achieve emission reduction goals and low-carbon transformation.However,the carbon assets management of China’s oil companies is still in the initial stage,with the system and regulations not yet sound,and the management process not yet closed loop.First the modes and experiences of carbon assets management in major international oil companies is introduced.Then the objective logical relationship and linkage laws between carbon assets management and enterprise value creation are comprehensively analyzed by integrating the basic theories of economics and management.On this basis,a value-creation oriented carbon assets management system for oil companies is constructed,mainly covering aspects such as enterprise strategy,control mechanisms,carbon inventory,and management modes.

Analysis and Development Proposals of Aronia mealnocarpa Planting Industry in Heilongjiang Province

Aornial mealnocarpa Elliot is a rare tree species that combined edible,medicinal,ornamental and ecological values. This article analyzes the economic value,domestic research and development status and development trend of A. mealnocarpa. Heilongjiang Province has been hurried to introduce A. mealnocarpa,lack of understanding of the characteristics of the tree species,resulting in serious cold damage and great economic losses. For these issues,proposals are put forward to promote the development of A. mealnocarpa planting industry.

Modeling texture development during cold rolling of IF steel by crystal plasticity finite element method

With the consideration of slip deformation mechanism and various slip systems of body centered cubic （BCC） metals, Taylor-type and finite element polycrystal models were embedded into the commercial finite element code ABAQUS to realize crystal plasticity finite element modeling, based on the rate dependent crystal constitutive equations. Initial orientations measured by electron backscatter diffraction （EBSD） were directly input into the crystal plasticity finite element model to simulate the develop- ment of rolling texture of interstitial-free steel （IF steel） at various reductions. The modeled results show a good agreement with the experimental results. With increasing reduction, the predicted and experimental rolling textures tend to sharper, and the results simulated by the Taylor-type model are stronger than those simulated by finite element model.＇Conclusions are obtained that rolling textures calculated with 48 { 110} 〈 111 〉＋ { 112 } 〈 111〉＋ { 123 } 〈 111 〉 slip systems are more approximate to EBSD results.

Core Competitiveness as the Fundamental Guarantee for Sustainable Development of Geo-parks

With the booming development over the past years,geo-parks have achieved impressive progress together with a series of problems.Most importantly,geological tourism is not in prosperity.How to prosper geological tourism and achieve the sustainable development of geoparks is the top concern of workers engaged in tourism geology in China.This article discusses the problem from the perspective of core competitiveness of geo-parks,particularly from three aspects of subject,object and medium,and puts forward methods to form the core competitiveness.

Developing Situation and Trend Analysis of Combined Well Pattern of Horizontal Well in Low Permeability Reservoir:Case in Yushulin Horizontal Wells in the Development Block

1 Introduction Now, the key of oil-field＇s increase production is the development technology for extra-low permeability reservoirs whose porosity is less than 5% and permeability less than 5 mD. The technologies of horizontal well, fracturing and gas driving are the advanced means of improving recovery.

The Geoscience Frontier of Gulong Shale Oil:Revealing the Role of Continental Shale from Oil Generation to Production

The clay mineral content of Daqing Gulong shale is in the range of about 35%–45%,with particle sizes less than 0.0039 mm.The horizontal fluidity of oil in Gulong shale is poor,with near-zero vertical flowability.As a result,Gulong shale has been considered to lack commercial value.In recent years,however,interdisciplinary research in geoscience,percolation mechanics,thermodynamics,and surface mechanics has demonstrated that Gulong shale oil has a high degree of maturity and a high residual hydrocarbon content.The expulsion efficiency of Gulong shale in the high mature stage is 32%–48%.Favorable storage spaces in Gulong shale include connecting pores and lamellar fractures developed between and within organic matter and clay mineral complexes.The shale oil mainly occurs in micro-and nano-pores,bedding fractures,and lamellar fractures,with a high gas–oil ratio and medium–high movable oil saturation.Gulong shale has the characteristics of high hardness,a high elastic modulus,and high fracture toughness.This study achieves breakthroughs in the exploration and development of Gulong shale,including the theories of hydrocarbon generation and accumulation,the technologies of mobility and fracturing,and recoverability.It confirms the major transition of Gulong shale from oil generation to oil production,which has extremely significant scientific value and application potential for China’s petroleum industry.