Holding the decisive essence leading to some regional variations in the carbon emission from energy consumption and taking relevant emission-reduction measures are the prerequisites for achieving the dual-carbon goal. Therefore, taken Sichuan-Chongqing area as an example, a carbon-emission inventory which regarded both fossil-fuel combustion and power allocation in different areas was constructed, and the effect of multiple influential factors was discussed on the basis of the Kaya Identity and LMDI model in order to figure out both temporal-spatial characteristics and influential factors of this emission. Results show that (i) a decreasing trend emerged in the carbon emission from energy consumption in Sichuan Province from 2015 to 2022 while an increasing trend in Chongqing City due to the endowment diversity among renewable energy resources. The emission from energy processing and conversion is rooted in thermal power generation and heating sectors. In terms of terminal expenditure, the largest emission source comes from industrial field, followed by transportation and residential life, then business and other services, and both agriculture and building industry making a small contribution to the emission. Sichuan advances the low-carbon strategy in addition to ensuring the energy's supply-demand security through transporting large amount of water and electricity resources, while Chongqing indirectly raises its carbon contribution via relying on external power output; and (ii) as an inhibiting factor, the structure of energy use makes the incremental contribution to the Sichuan's emission year by year while little impact in Chongqing. For the energy intensity as a key factor for emission reduction, its inhibition peaked in 2016-2017 due to benefits from the dual control in the energy use. The industrial structure in Sichuan is an inhibition factor as well, and its influence is slowly diminishing, while that in Chongqing increases first and then decreases with changes of secondary industries' proportion. The economic growth whose effect is on the decease each year under the new pattern of low carbon is also a critical factor in emission acceleration. The effect of population development is affected by population size, social culture, and resource allocation comprehensively.

Some investigation and professional discussion have been carried out in an effort to estimate the development potential of carbon asset from natural-gas residual pressure power generation and make this generation's methodology meeting filing requirements of the Ministry of Ecology and Environment of the People's Republic of China. Furthermore, the key to work out this methodology was analyzed according to methodological compilation needs through reference on a carbon-credit system of CDM. In addition, the decisive elements were proposed for the compilation of such generation methodology, and an additional and monitoring management was designed. Results show that (i) via the evaluation on the potential of both residual pressure power generation and carbon-asset development in different links such as oil and gasfields, long-distance pipelines, and gate stations, these two sorts of potential achieved are 145.73×10⁸ kWh/a and 811.44×10⁴ tCO₂e/a, respectively; (ii) as for the additional methodological design, baseline scenarios are made certain to contrast the additionality. And it is proposed to directly adopt exemption from demonstration based on the potential analysis on power generation and practical work; and (iii) as for the monitoring design of methodology, the principles of credibility, accuracy and conservation should be followed, and monitoring projects' boundaries are described. Parameters and data which should be relatively surveyed in not only design but implementation stages, and the method to ensure surveying quality is defined by using emission-reduction calculations.

Both hydrogen energy industry and carbon trading markets are fundamental tools for enterprises to achieve the goal of low-carbon emission and the social low-carbon transition. In order to stimulate the potential of emission reduction and make this industry in high-quality development come true, some problems about the hydrogen industry participating in the trading markets were put forward and analyzed after untangling two of them. In addition, countermeasures and suggestions were made. Results show that (i) hydrogen energy, as a kind of clean and carbon-free energy source, boasts significant prospects in carbon emission reduction, which is an essential way for profound decarbonization; (ii) its participation is confronted with shortcomings, for example, limited market coverage, imperfect industrial chain, and deficient methods to evaluate the emission; and (iii) introducing the hydrogen energy industry into the markets, consummating the industrial chain, and upgrading evaluation methods can stimulate the potential of hydrogen energy in carbon emission reduction and achieve the deep integration of both hydrogen energy industry and carbon trading markets. In conclusion, this participation is conducive to promoting their collaborative development and materializing the optimization on energy structure.

Helium, as a kind of strategic noble gas resources closely related to national security and high-tech industrial development, plays an irreplaceable role in scientific research, medicine, aviation and other high-tech industries. However, its supply has been confronted with shortage in recent years. In order to further reduce the foreign dependence, relieve the severe situation of domestic supply, and prevent the future supply disciplined by others, helium's exploration and development fruits, productivity construction, and supply-demand situation were discussed for major helium-producing countries worldwide through extensive literature investigation and data collection. Additionally, the distribution, production, market status and problems were analyzed for foreign helium resources, and the development and challenges in China's helium industry were also put forward. Results show that (i) helium resources in China has extremely high foreign dependence and long-term dependence on imports. Most of the imported resources come from the United States, Qatar, and Australia whose market supply is absolutely dominant; (ii) the security of helium resources is quite severe in China, suggesting that oil companies should attach great importance to their potential evaluation and development feasibility study, take helium as essential supplement to existing petroleum assets, and strengthen the exploitation in helium-rich gas reservoirs at home and abroad, so that the helium industry will have promising prospects; and (iii) some suggestions are proposed, such as to build a diversified system on helium supply, to put the shortage of domestic supply at ease, to find an adequate response to changes in helium markets, and to prevent behaviors of deliberately limiting the supply.

Based on the resource base together with production and operation status in petroleum enterprises, strategic importance was discussed for the integrated development of petroleum and new energy resources in order to follow both reform and transition in energy structure and to promote the high-quality development in petroleum industry. Additionally, the mode and scenario application were explored for this integration, and the development direction and path were also studied and determined. Results show that (i) such development is of great significance for national energy in safety supply, achieving the dual-carbon goal, constructing new energy structure and expanding oil and gas industry; (ii) it's necessary to properly handle two sorts of relationship between development and emission reduction, and between short term and medium to long term, as well as sustain this industry in green transition through "stable but progressing and promoting stability through progress"; (iii) it's suggested to lay out new energy business based on petroleum business, to grow into clean energy alternatives, and to encourage the comprehensive utilization of energy resources, including oil, gas, wind, solar, heat, storage and hydrogen; and (iv) following the principles of "petroleum priority, collaboration and mutual promotion", the integrated development shall be advanced in accordance with the three-step path, namely demonstrative exploration, large-scale promotion and deep integration. Four countermeasures have been made to ensure this integrated development, such as accelerating the "policy integration" to intensify policy support and planning guidance; accelerating the "technology integration" to deepen technological R & D and integration innovation; accelerating the "smart integration" to build a novel management mode for energy resources; and accelerating the "crossover integration" to implement cross-industry teamwork, efficiency creation and mutual promotion, and to facilitate carbon reduction, green expansion, and intelligence upgrading in petroleum industry.

Energy is not only material base in the development of world economy but an important and inevitable component in global CO₂ emission reduction. So, by means of the supply-demand balance analysis, the current supply situation was investigated for China's oil and gas resources in order to promote both resource security and geological survey under the carbon-peak and carbon-neutrality goal (dual-carbon goal). Moreover, some strategies and suggestions were made to address security challenges. Results show that (i) for domestic oil, the predicted consumption will reach the peak in 2030, and the supply-demand gap will be about 5.75×10⁸ t in 2030, 0.95×10⁸ t in 2050, and 0.25×10⁸ t in 2060; (ii) for natural gas, the predicted consumption will peak around 2040, and its supply-demand gap will be about 3000×10⁸ m³ in 2030, 3500×10⁸ m³ in 2040, and 1000×10⁸ m³ in 2060; (iii) for hydrocarbon resources in China, the security is faced with four challenges, i.e. high external dependence, large consumption, improper consumption patterns, and an intolerant role of oil and gas as leverage and strategic points; and (iv) four measures made for the geological survey, containing adhering to the position, optimizing the deployment idea, balancing the decisive targets and tasks, and optimizing the assessment system, are conducive to raising survey efficiency.

Combined one model of virtual nozzle with the other dynamics model of leakage from high-pressure vessels, a calculation method for leakage parameters has been developed for high-pressure hydrogen cylinders in order to ascertain hydrogen enriched in indoor garages during hydrogen leakage from the vessels in hydrogen-powered vehicles. In addition, some changes of parameters like pressure and leakage rate with volume of 120 L and storage pressure of 70 MPa were calculated using the Matlab during the leakage. They were served as boundary conditions projected in the Fluent numerical simulator. Finally, the numerical model on hydrogen leakage and dispersion from onboard hydrogen storage cylinders with high pressure was established to simulate hydrogen concentration in indoor environment for the cylinders with different size of leakage hole, vehicle parking location and flow regime at the hole. Results show that (i) the indoor combustible hydrogen cloud may reach the peak bulk and then decrease gradually in the leakage process. The larger the hole's diameter, the heavier the hydrogen capacity, and the longer the aggregation time; (ii) when this leakage in the garage corner, the average concentration of hydrogen cloud is the highest whereas the capacity is the smallest; (iii) when hydrogen at the leakage hole is dominated by buoyancy, it may disperse along the ceiling in the arched shape, which is favorable for the arrangement of both hydrogen sensors and leakage source. When hydrogen is dominated by momentum, its bulk is the heaviest, and large amount of hydrogen may gather underneath vehicle chassis.

In this study, the carbon resource distribution, recycling challenges, and domestic carbon dioxide (CO₂) recycling technologies were analyzed in order for recycling carbon resources in natural-gas purification plants. Moreover, the recycling range, methods and process were determined, and application prospects of this resource utilization were been predicted. Results show that (i) these purification plants boast abundant carbon resources, including CO₂ accompanied in raw gas and the other generated from natural-gas combustion during production runs; (ii) most carbon in the plants are recoverable, for example CO₂ in gas products, CO₂ emitted in recycling and generated from the gas combustion in industrial furnace; and (iii) the priority shall be given to the chemical absorption based on alcohol amine solution to this recycling. Combined with the status quo of process units in the purification plants, five prospects are put forward, namely reducing CO₂ removal rate while improving commercial gas ratio, replacing nitrogen to be as purge or protective gas, CO₂ products, taking CO₂ as raw materials to manufacture chemical products and carbon-emission trading and CO₂ storage.

Carbon neutrality has now become global consensus and the world is accelerating its energy structure developing into low carbonization. China's energy evolution has gotten into a new era, and the "dual-carbon" goal is proved to be the fundamental compliance in economic and social growth. Energy industry, as the main carbon-emission source, strives to implement a green and low-carbon strategy. However, to attain this goal, it is essential to setup a uniform and standard system for emission calculation and scientific prediction. So, some calculation and prediction methods in natural-gas enterprises were taken as objectives. Based on entire production chain in these enterprises, carbon-emission characteristics from natural-gas exploration, development, treatment to transmission were fully made clear. Four major sources were categorized, including emission from fossil fuel combustion, flare combustion, process venting and hidden power consumption. Moreover, both calculation and prediction methods were created, which have been applied to conventional gas, shale gas, and high sulfur gas reservoirs in Sichuan Basin. Results show that (i) considering great difference between emission intensity and structure in various reservoir development, emission calculation and prediction should be classified, especially for those enterprises involving with multiple reservoir development, to ensure the reliability of calculation and prediction results. Meanwhile, basic data statistics and monitoring should be strengthen; (ii) under such dual-control transition from energy consumption to carbon emission, one indicator of emission intensity should be the core and supplemented by the other of emission when establishing emission dual-control indicators in order to promote petroleum industrial growth with high quality, and different standards on the intensity should be established for each type of gas reservoirs; and (iii) gas enterprises, as not only the main methane producers but emitters, should expand their researches on methane's emission reduction and make countermeasures. It is concluded that the results may provide references for the natural-gas industry to establish more scientific and reasonable carbon-emission calculation and prediction methods.

Being a globally recognized technology to reduce carbon emission with the greatest commercial potential, carbon capture, utilization and storage (CCUS) plays an important role in helping the achievement of China's dual-carbon goal on schedule. Moreover, CCUS-enhanced gas recovery (CCUS-EGR), as a feasible path for petroleum enterprises to enhance gas recovery in old gasfields, can achieve carbon peaking and carbon neutrality simultaneously. It is of great significance to reserve and production increment as well as carbon peaking. To set up an economic evaluation method for the whole industrial chain of CCUS-EGR is the foundation for the demonstration and future industrial development of CCUS-EGR projects. So, based on this whole chain process, one economic evaluation model has been developed for this chain which is composed of five modules, such as capture & compression, transportation, injection & storage, separation & reinjection, and risk monitoring. In addition, the model was verified through one whole industrial chain project on Chongqing Hechuan Power Plant and WLH Gasfield. Results show that (i) natural-gas price, production condition, carbon-trading price and operation cost have great influences on the revenue of the whole industrial chain. Among them, production condition and carbon-trading price are the most sensitive, followed by operation cost and natural-gas price; (ii) resource earnings contributed by CCUS-EGR can substantially increase the total chain revenue; (iii) the carbon-emission right trading price is crucial to the chain revenue, and introducing the net emission reduction of CCUS-EGR into carbon-trading markets can effectively raise the return rate. Three suggestions are made in an effort to increase the whole industrial chain economic benefits of CCUS-EGR projects, including to further discuss the effective CO₂ storage, to accelerate the research and development of CCUS-EGR, and to deliver standards and policies to quantitatively certify CCUS-EGR and support this industry.

Substituting renewable energy for classical fossil energy is surely inevitable as the advancement of "dual-carbon" goal. So, development problems were summarized for these two kinds of energy in China in 2022 as well as some measures and suggestions to keep them in a complementary and advantage sharing pattern were proposed in an effort to promote their integrative development. Results show that (i) renewable energy, with the rapid growth in production and consumption proportion as well as the development and utilization in an accelerated manner, has become a new driver to the energy growth in China. In contrast, coal exhibits a decline in consumption, but still as a major energy for its production; (ii) new energy resources are usually remote and unevenly distribution, especially wind power and photovoltaic can not provide stable energy owing to their random and volatile attributes. Classical energy corresponds to high reliance on foreign sources, creating uncertainty in import price and volume to make its self-efficiency impossible. Thus, only advantageous sharing of the new and traditional energy can practically ensure the national energy security; and (iii) for sake of achieving their intergrowth and co-prosperity, the future effort will be made to deepen the market-oriented reform of energy system and mechanism, play the basic role of market in resource allocation, and boost the integrative development of renewable and classical energy.

To effectively promote the integrative development of power generation from natural gas and renewable energy, this paper analyzes both feasibility and necessity of this development, investigates its train of thought, establishes business and profit models for these two sorts of integration, and finally makes some strategies and suggestions on this integrative development. Results show that (i) the business model should give due consideration to all parties' competence and demand from aspects of capital, information and material flow, allow them to work together for the integrative development, and share these three kinds of flow to promote the development; (ii) the profit model should, on the basis of the business model, enable all parties to create values, generate benefits and share profits together while fully taking their own human, financial and material resources into consideration under the successful completion of the cost structure, income composition, and profit targets; and (iii) in an effort to advance the integrative development of power generation from natural gas and renewable energy, it is essential to thoroughly analyze external environment, pinpoint relevant development projects accurately, and agree to ascertain both business and profit models.

As the proposed "dual-carbon" goal, some low-carbon energy such as renewable resources and natural gas has become increasingly prevalent in the future energy development. There are abundant resources in Sichuan-Chongqing area with great potential and space for natural-gas development. In order to push the rapid development in this area, present situation was investigated for natural-gas industrial development, all kinds of factors affecting the industry were analyzed, and corresponding suggestions on the next development were put forward. Results show that the natural-gas industry in Sichuan-Chongqing area is mainly affected by four factors, including supply and demand of natural-gas markets, economic development tendency, planning and layout of energy industry, and national and regional energy policies. In addition, four suggestions are made according to resource status and gas market structure in this area, such as vigorously construct gas-related infrastructures, including underground gas storages, (shale) gas production bases, and demonstrative gas utilization zones; accelerate industrial innovation by digital transformation and intelligent development; actively adapt to system reform in natural-gas industry; and accelerate the transformation from traditional to integrative energy (i.e. oil, gas, hydrogen, and power), for example advancing the integration with renewable energy industry, expanding the hydrogen industrial layout, and pushing the carbon-emission reduction and efficiency improvement in natural-gas power generation and utilization.

The growth of compressed natural gas (CNG) in Sichuan-Chongqing area slows down in the context of the dual carbon. Thus, the main challenges in the CNG business were analyzed for this area in order to follow the energy trend and push CNG stations in the high and sustainable development. Results show that (i) the impact of new energy resources leads to fiercer industrial competition and there exists limit expansion space of CNG market in this area; (ii) for the CNG business in Sichuan-Chongqing area, its own industrial base is weak and the driving force is fatigue. Additionally, some suggestions on the development and transformation of CNG business have been made for Sichuan-Chongqing area, including to accelerate the construction of CNG filling stations, to install electricity-charging replacement and hydrogen filling in CNG stations, to expand the station refueling, and to push the sales of non-gas products. It is concluded that the transition of vehicle fuel to electricity and hydrogen is inevitable. But in Sichuan-Chongqing area boasting mature natural-gas industrial chain and promising CNG business, gas companies will certainly develop towards service providers integrating oil, gas, hydrogen, electricity and service.

China will speed up its energy structure to transform towards clean and low-carbon energy in an effort to achieve the "dual-carbon" goal. As a sort of clean energy due to "zero-carbon emission", hydrogen energy enjoys the most promising development in the 21st century. Natural gas, the cleanest fossil energy, will continue to play an important role in bridging and balancing this transformation for a long time. In view of China's development status, the co-development of two energy industries, including natural gas and hydrogen, is currently the most perfect way. So, taken Sichuan-Chongqing region as an example, the co-development necessity was analyzed and opportunities and challenges were put forward so as to promote energy revolution and scientifically formulate co-development strategies. Results show that (i) driven by the "dual-carbon" goal, the transformation of petroleum industry is inevitable; (ii) natural-gas industry has everything to do with hydrogen industry. Especially, with the growing hydrogen utilization in China, its co-development with natural gas is unstoppable; (iii) policy dividends, resource endowments, industrial foundation and location advantages contribute to this co-development; and (iv) there exist three urgent problems in this co-development, such as absence of positioning and system for hydrogen development, vertical extension and horizontal coordination of these two industrial chains, and infrastructure construction.

Carbon capture, utilization and storage (CCUS) is an all-inclusive technology for fossil energy to achieve large-scale carbon emission reduction and ultimately achieve the goal of carbon neutrality, but its problems of high cost and low income restrict the demonstration and large-scale development of CCUS industry. In order to promote the development of CCUS industry in the Sichuan-Chongqing area, this paper systematically sorts out domestic and foreign CCUS industrial development policies. Then, with a hypothetical CCUS-ERG demonstration project as an example, the investment cost is analyzed, and the project economy under different government subsidies and carbon prices is calculated, so as to provide reference for the support policy level of CCUS demonstration project in the Sichuan-Chongqing area. And the following research results are obtained. First, in the case of medium carbon price, the government subsidy level to reach the break even point is 145.50 yuan/t-285.50 yuan/t. Second, increasing the scale of geological storage is conducive to the decrease of the subsidy level. In the case of medium carbon price, the government subsidy level to reach the break even point can be reduced by 30-80 yuan/t if the CO₂ reinjection scale is doubled. Finally, in order to better promote the demonstration and large-scale development of CCUS industry, expand the scale of CCUS projects and reduce costs, three suggestions are put forward: First, Sichuan's and Chongqing's local governments shall accelerate the formulation of government subsidies, industrial funds, low interest loans and other policies to support the development of CCUS industry; Second, it is necessary to promote the link between CCUS and carbon trading market, and realize the carbon price benefits of CCUS projects through CCER or local CER; Third, it is suggested to link internal and external carbon sources and sinks through source-sink match , and expand the scale of CCUS projects to reduce costs.

To make clear both hydrocarbon source conditions and next exploration directions in the west sag of Wushi Depression, the source rocks and favorable targets in this sag were taken as objectives to perform some analog analysis on the distribution, quality and hydrocarbon-generating potential of the source rocks by means of the analog of seismic data, and sedimentary and organic facies as well as certain analysis on periphery wells. Moreover, source-rock characteristics and the next key exploration directions were summarized and pointed out. Results show that (1) there exist three sets of source rocks in the west sag, namely Eocene Liushagang 1 and Liushagang 2 Members together with Oligocene Weizhou 2 Member. An analog prediction on both sedimentary and organic facies indicates that the source rocks of both Liushagang 2 Member and Weizhou 2 Member are mainly of high quality with type C organic facies while that of Liushagang 1 Member is better with type A; (2) these three sets of principal source rocks are all mature with hydrocarbon-generating capacity up to 10×10⁸ t, and the quantity of potential resources is 1×10⁸ t in the west sag; and (3) there are multiple favorable reservoir-caprock assemblages, among which, not only Weizhou Formation but the Neogene may currently serve as beneficial sequences with shallower burial depth and better physical properties. In conclusion, these source rocks in the west sag of Wushi Depression (including Liushagang 1 and Liushagang 2 Members as well as Weizhou 2 Member) are characterized by excellent quality, wide distribution and great hydrocarbon-generating potential. What's more, a few faulted-anticline and faulted-block traps containing Wushi A and Wushi B are extended, boasting favorable reservoir-forming conditions and vast exploration prospect, which can be conducted as critical evaluation targets in the subsequent exploration.

With great advantages of cleanliness, safety, efficiency and sustainability, solar energy plays a very essential role among new China's energy systems. Constructing a clean, safe, efficient and low-carbon energy system is the key to achieve the dual-carbon (namely carbon peaking and carbon neutrality) goal. So, the photovoltaic power-generating industry was fully investigated in order for its promotion and goal achievement. And then, its role and significance were analyzed, and development trend was pointed out for power-generating technologies. Results show that (1) this environmentally friendly, safe and sustainable photovoltaic power generation will be a primary alternative of new energy power generation in the future and also a vital assurance to boost an achievement of the dual-carbon goal in China; (2) the industrial mass production technology of photovoltaic cell component is staying ahead in the world, the complete technology of photovoltaic power-generating system is optimized continuously, and the photovoltaic component recycling and treatment technology needs further encouragement; and (3) the center to advance a large-scale photovoltaic power-generation development in China is to build the photovoltaic cell of higher efficiency and lower cost as well as the photovoltaic power-generating system of high reliability and strong grid adaptability, stimulate the technological innovation of photovoltaic-building integration, construct the local and smart photovoltaic manufacturing systems, and facilitate the abandoned photovoltaic component recycling and treatment skills.

As a recycle, clean, and secondary energy source, hydrogen energy is superior in abundant resources, extensive source, and multiple uses, which becomes a substitute energy to reconstruct the modern clean energy system in China. Automobile hydrogen stations are specially set up for hydrogen-powered or hydrogen-fueled internal combustion vehicles. And they are vital carriers to popularize and use the hydrogen energy. For these stations, the key facilities contain compressor, hydrogen-storage tank, and refueling system. In order to sufficiently understand hydrogen compressors' function and role in one station, compressor selection was studied, and the key elements and measurement in this section were analyzed. Moreover, some practical selection in both West Shanghai and Zhejiang Jiaxing hydrogen stations was illustrated. It is indicated that the selected compressors from these two stations have their own advantages. Results show that the key elements to select compressors include displacement, skid design, stage ratio, design working condition, and cooling mode. In conclusion, the following suggestions are proposed, including that (1) diaphragm compressor is available in the situation with hydrogen source ranging from 5 MPa to 20 MPa; (2) diaphragm compressor is recommended at one hydrogen station where refueling volume is stable or may not change greatly, so as to reduce an investment to fixed cost; and (3) hydraulic-driven compressor is recommended under special working conditions, such as frequent start and stop, and refueling under different pressure and stages.

The proposal of so-called “Double Carbon” (carbon peaking and carbon neutrality) goal arises some new requirement for natural-gas industrial development. As a clean low-carbon fossil energy, natural gas plays an important transitional role, and also affects its utilization engineering, such as city gas, gas power generation, industrial fuel, and chemical raw material. In order to promote the healthy development of China's natural-gas industry and support the goal realization, domestic development status and international resource supply and demand were summarized. And four challenges in China's natural-gas industry were presented, including insufficient domestic resource, more difficult international resource acquisition, incomplete market-oriented price mechanism, and incomplete infrastructure. In addition, some suggestions beneficial to the industrial development were made. Results show that (1) focus on energy supply security. At the resource end, it's crucial to promote the reserve and production increase of domestic gas, deepen the upstream reform, encourage the development of unconventional gasfields, strengthen the cooperation with international resource countries, and construct the diversified import channels. At the consumption end, it's necessary to promote the reform of terminal market and improve the comprehensive utilization efficiency; (2) continuously deepen the market-oriented natural-gas reform, strengthen the classified user management, give play to the governmental macro-regulation and control, and make comprehensive use of administrative means to ensure the user needs concerning national economy and people's livelihood, and make full use of market's resource allocation action. As for the user needs of high marketization degree, both supplier and user shall undertake the main responsibility, the price shall be oriented by the market. The dynamically balanced supply-demand relationship shall be constructed; and (3) plan the national natural-gas infrastructure as a whole, speed up the construction of gas storage capacity, construct and operate the gas pipeline network and LNG terminal, avoid the unbalance of local resources and infrastructure between different areas, and improve the utilization efficiency of infrastructure.

Green and low-carbon transformation and development is an inevitable trend on energy development and bound to drive China's new energy development into the fast lane. Sichuan-Chongqing area is just an important and quality base with clean energy in China, and Sichuan and Chongqing governments pay much attention to implement the national strategy of “carbon peaking and carbon neutrality” (Double Carbon) and will speed up to build their own clean energy demonstration province based on resource and industrial advantages. In order to promote the green and low-carbon transformation and upgrading in this area, speed up the green industrial development, and support to realize the “Dual Carbon” goal as soon as possible, some potential in this resource base was analyzed for the integrated development of natural gas and new energy. Then, the integrated development path was put forward based on technological characteristics on natural gas as well as its positioning and role under the goal. Results show that (1) for natural gas, the lateral integrated development mode may refer to its integration with others, which highlights the complementarity and coupling between different energy, and mainly includes multi-energy integrated development mode of natural gas with hydropower, wind power, photoelectricity, and hydrogen energy; (2) the vertical mode may refer to its integration with industrial chain's extensional resources, implying the resource recycling generated, and mainly includes the integrated development mode of natural gas with residual pressure power generation, associated resources, and CCS/CCUS; and (3) in Sichuan-Chongqing area, the clean-energy industrial development can be promoted from the aspects of policy support, pilot demonstration, strategic alliance, and joint technological research so as to support the quality development.

In China, both energy production and consumption activities lead to larger emission of greenhouse gas. So, the “carbon peaking and carbon neutrality” (Double Carbon”) goal is bound to affect deeply energy industrial development. In order to calculate the low-carbon economic efficiency from the perspective of the “Double Carbon” goal, the energy, economy, and environment factors were incorporated into one system to evaluate this efficiency by using the Undesirable-Super-SBM Model. Then, based on some panel data containing more freedom and sample variability, the low-carbon economic efficiency in 2000-2018 was individually calculated for coal mining and washing industry, petroleum industry, oil, coal, and other fuel processing industry, and gas production and supply industry. Then, some specific policy and suggestion were made. Results show that (1) the low-carbon economic efficiency in China's energy industry presents an overall rising trend; (2) coal mining and washing industry depends on a great amount of labor force and has fuel burning and overflow emission, so its low-carbon economic efficiency is the lowest; (3) in petroleum industry, the efficiency declines significantly, which may be caused by low profit due to stagnant international environment and low marketization degree; (4) under the new low-carbon development pattern, the efficiency in oil, coal, and other fuel processing industry increases at high speed; and (5) the efficiency in gas production and supply industry is the highest due to clean-energy advantage and support from national policy.

Under the background of "carbon peaking and carbon neutrality", carbon asset development is an important means to improve the energy conservation & emission reduction and the economic benefits of new energy projects, and it helps oil & gasfield enterprises achieve carbon peaking and large-scale benefit development of new energy business on schedule. In order to speed up the green and low-carbon transformation and development of oil & gasfield enterprises and assist the achievement of the "dual carbon" goal, this paper systematically sorts out domestic and foreign carbon asset development systems, analyzes key directions of carbon asset development of oil & gasfield enterprises, and proposes development paths of carbon asset. And the following research results are obtained. First, the carbon asset development of oil & gasfield enterprises mainly focuses on methane emission reduction and recycling, waste heat and pressure utilization, renewable energy/new energy utilization, and CO₂ capture, utilization and storage (CCUS) projects. Second, large-scale grid connected renewable energy projects (such as wind and solar power) can be prepared to apply for national CCER, while small-scale distributed photovoltaic, geothermal energy utilization and other renewable energy projects that are not connected to the grid, as well as self use projects (such as waste heat and pressure) and oil & gasfield emission reduction projects (such as associated gas recovery and escaping methane recovery) can apply for UER projects and VCS projects simultaneously. Third, as for the associated gas recovery and utilization projects of oil & gasfields, there is only the emission reduction methodology for oil fields. Gas mining projects need to be properly optimized. The emission reduction mechanisms and methodologies of waste pressure and heat utilization and renewable energy/new energy utilization have been well developed. As for CCUS, it is suggested to cooperate with the third party to develop new methodologies. Fourth, It is recommended that oil & gasfield enterprises figure out their exploitable resources of carbon assets in advance, establish a professional carbon asset development management team, and start the development of emission reduction projects in time according to local conditions.

Oil & gas fields are rich in pressure energy resources and have great potential to develop and utilize waste natural pressure gas for power generation. The current technologies and equipment are still not mature enough, which impacts the large-scale benefit development of waste pressure power generation project, so it is in urgent need to improve the economy of the project through carbon asset development. In order to promote the healthy and sustainable development of the waste natural gas pressure power generation industry and help oil & gasfield enterprises achieve the "dual carbon" goal as scheduled and the large-scale benefit development of new energy business, this paper evaluates the feasibility of the carbon asset development of the oil & gasfield's waste pressure power generation project, measures the impact of carbon asset development on the income of waste natural gas pressure power generation project, and analyzes the feasibility of the carbon asset development of the project. And the following research results are obtained. First, referring to the current carbon market price, the annual emission reduction income per unit installed capacity of waste natural gas pressure power generation is 188 yuan/kWh, which is much higher than that of onshore wind power and photovoltaic project, but the annual emission reduction income per unit investment is lower than that of onshore wind power project and basically the same as that of photovoltaic projects. Second, the feasibility of carbon asset development of waste pressure power generation project is demonstrated from the aspects of methodology, additionality, monitoring feasibility, emission reduction and income evaluation. Third, there is no technical difficulty in carbon asset development and monitoring management of waste natural gas pressure power generation project, but due to the small scale of the project, the development income of a single project is not economically feasible. It is suggested to design multiple project feasibility schemes as a whole and perform bundled development of carbon assets. Fourth, the carbon asset development of waste pressure power generation can be promoted by taking the following 4 measures, i.e., improving the development rules for special types of projects, establishing positive technology list suitable for China's "dual carbon" work development strategy, adopting digital management to improve development efficiency, and applying carbon financial tools.