China's petroleum exploration enterprises and geological survey organizations invested more in oil and gas exploration in 2022 to cope with complicated situations like global profound changes unseen in a century and shock in international energy markets. And a lot of new exploration discoveries and breakthroughs were found and made. For the high-quality and sustainable development of China's petroleum exploration in the coming future, situations about conventional and unconventional oil and gas resources in China were expounded, main features and fresh highlights in this exploration in 2022 were reviewed, and exploration prospects in 2023 were put forward in combination with resource potential. Results show that (i) China' petroleum exploration in 2022 exhibited obvious turnaround of both capital investment and petroleum production, new discoveries mainly founded around or in the deep part of proved reservoir-forming assemblies, outstanding findings of unconventional oil and gas exploration in mature fields, and guidance of advanced geological theories and technologies to make new exploration breakthroughs; (ii) significant exploration breakthroughs have been made in fault-controlled high-energy shoal at the Ordovician of Fuman oilfield in Tarim Basin, the Permian natural gas and deeper shale gas in southeastern Sichuan Basin, and shale oil in old oilfields of east China; and (iii) China's petroleum exploration in 2023 is expected to witness novel breakthroughs in the deep or the deep waters, periphery of large petroliferous basins, as well as marine shale oil/gas and shale gas with marine-continental transitional in north China.

Although in 2022, frequent COVID-19 outbreak appeared across China, economic development faced triple pressure of pullback in demand, vulnerable supply and weaker expectation, and global oil and gas prices were on the rise due to geopolitical conflicts, China's natural gas development rolled back and forth but held stable supply and demand as well as lot of resilience. Moreover, it presents the following characters. First, major achievements were remade in gas exploration, and proved reserves kept growing at the peak rate. Second, gas production still increased like an upward arrow, but with continuous decline in growing output and rate. Third, the import price of natural gas rose whereas the imports fell; and the imports of LNG emerged as a negative growth for the first time. Fourth, its consumption dropped due to feeble demand. Fifth, the infrastructure construction of natural gas advanced energetically. Sixth, its marketization went ahead. In conclusion, in 2023, both social and economic development momentum will be enhanced in China, and natural gas development will welcome a stable and progressive year after variations of COVID-19 control and prevention strategy. It is expected that, with shale gas as the leading gas, the natural gas will exceed one trillion cubic meters of proved reserves again. Its production should move forward steadily with the output staying an increase around 10 billion cubic meters. LNG imports will continue their up trend, and those of natural gas will rebound by cooperating with Gazprom. The demand of natural gas will pick up strongly and the supply-demand market will be steady. And some latest progress will be made in system and mechanism reforms on natural gas.

Under the background of "dual carbon" goal, the industrial development of new energy resources generates the endogenous demand for the construction of talent team, and it is urgent to break the restrictions of imbalanced talent supply and demand and other problems. So, the status and difficulties in the construction of talent team were analyzed for the new resources, and the idea, model and mechanism guarantee were also made clear for this construction. Results show that (i) there exist some problems in this talent team construction, including that foreign experiences are hardly applicable to China's situations, the promotable and duplicable modeling experiences have not been formed in China, and the existing mechanisms are lack of systematic and collaborative construction and exploration; (ii) this construction shall follow the idea of keeping up with the needs of market change and industrial development, focusing on the scarce talent team and attracting multiple participants to generate the collaborative linkage effect. The construction modes include the multi-dimensional goal led planning mode, the multi-party collaboration based promoting mode, multi-advantage integrated implementing mode; and (iii) the mechanism guarantee for the construction includes four mechanisms in innovating the all-type "talent cultivation", planing the all-round" talent gathering", creating the whole-process "talent management" , and constructing the full-guarantee "talent utilization". These results provide beneficial reference for the construction of talent team in new energy sources and new functions for the development of new energy industry under new situations.

In order to accurately characterize both occurrence laws and physical parameters in multiple thin CBM reservoirs and provide guidance for CBM development, the upper Longtan Formation in Panzhihua mine of western Guizhou Province was taken as an objective to comprehensively organize some data on both mud logging and core analysis, standardize the interpretation on logging curves, and analyze a relation of physical parameters to logging curves. Then, one relation was established quantitatively by means of linear regression fitting, and a 3D geological model was built for the multiple thin CBM reservoirs through one method called facies-controlled stochastic modeling. In addition, one structural model and the other lithofacies model were developed, and the spatial distribution of physical parameters such as dry-ash-free content, permeability, density and ash was simulated. With the help of the other approach to compute CBM reserves, the original CBM in place in the upper Longtan Formation in this mine was calculated by 3.91×10⁸ m³ from the established 3D geological model. Results show that (1) taking lithofacies as the constraint of the distribution and change of physical parameters and performing variation function analysis, the multiple thin CBM reservoirs may be figured out more effectively under theoretical guidance of facies-controlled modeling, (2) the characterization on physical parameters based on logging curves can be effectively conducted through correlation analysis and linear fitting; and (3) reliable data can be gotten from the facies-controlled stochastic modeling, the modeling process is well available for the multiple thin CBM reservoirs, and the established model can provide better guidance for the following exploration and development of CBM reservoirs.

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.

The natural-gas chemical industry in Sichuan-Chongqing region focuses on the production of basic chemicals like methanol, synthetic ammonia and carbamide. To encourage it with the high-quality and sustainable development, some research visits were conducted in relevant enterprises inside this region. Moreover, opportunities and challenges for this industry were discussed according to some analysis on policy orientation as well as domestic and international situations. Results show that (i) the state invests more in natural-gas exploration and development and is stepping up the construction of natural-gas production capacity, causing an increase in resource supply. Meanwhile, the natural-gas consumption in Sichuan-Chongqing region tends to rise evidently following the economic growth together with the support of national and local policies, which may provide guarantee of raw materials for the sustainably industrial development; (ii) the cost gap between natural gas-based and coal-based chemical enterprises is narrowing. In the natural-gas chemical industry, management is optimizing and technologies are improving in addition to complex and ever-changing international situations, which may offer opportunities to this industry with the high-quality development in the region; and (iii) the natural gas-based chemical industry in China only accounts for a smaller share and weaker discourse power of the whole chemical industry, new and expanded chemical projects are limited, and raw gas is short supply in heating seasons, which may also restrict its industrial development. It is concluded that the natural-gas chemical industry in Sichuan-Chongqing region will hold a high growth rate in the 14th Five-Year Plan period.

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.

This paper reviews some difficulties, problems and successful practices in the process of promoting natural-gas price reform in China, and puts forward policy suggestions on further deepening this reform and improving price-forming mechanisms. And some conclusions are made as follows. First, both difficulties and problems faced in this reform include the continuously increasing dependence degree of natural gas on foreign countries, the high usage cost of imported gas, the insufficient ability of domestic market to pay for imported gas, the unbalanced regional economic development, and the low final consumption rate of residents, which will be the focus to be considered in deepening China's natural-gas price reform for a long time in the future. Second, successful reform practices include establishing the price system on natural-gas production, transportation, storage and marketing with gate station price management as the core, steadily advancing with the first easy and then the difficult in accordance with the goal orientation, combining government control and market regulation, and firming up price supervision of natural monopoly links, which will be of importance for a considerable period of time in the future. Third, perfecting the gate station price management focuses on improving the release and control combined policy, reducing the scope of controlled gas, expanding the scope of non-controlled gas, as well as clarifying the scope of supply and the responsibilities and obligations of all parties. Fourth, improving the price management of natural-gas infrastructure concentrates on further reasonably determining the allowable rate of return, establishing the standard cost system, and accelerating the promotion and implementation of the two-part charging price. Fifth, making the city-gas price management better is to set this price in accordance with international practices, further reasonably ascertain the allowable rate of return and the depreciation period of pipelines when approving gas distribution prices, and establish and upgrade the upstream and downstream price linkage mechanisms. Finally, it is essential to quicken the construction of natural-gas trading hub and the encouragement of natural-gas energy metering and pricing.

A better relation among enterprises, local government and community stakeholders is one of the key elements in the great development of natural gas, Sichuan Basin, so that the government and all sectors of the community can be mobilized to serve for increasing both reserves and production in an effort to build the production-capacity base hitting 1,000×10⁸m³ and clean-energy demonstration base as well as promote the regional economy. Taken PetroChina Southwest Oil & Gasfield Company as an example, the vital function, principle ways and obtained achievements of the enterprise-locality relation were analyzed for the great development of natural gas, some solutions of both collaboration were proposed with consideration of existing problems. Results show that (i) oil and gas exploration and development activities are exactly constrained to both subsurface and surface resources. As the exploration and development technological process, technical conditions do no longer serve as bottlenecks, and non-technical contradictions between enterprises and local entities are increasingly prominent and become one of the main factors governing this great development; (ii) enterprises and local entities should be work together to set a coordination and communication platform through deliberate planning and coordination across industrial chains, the central enterprises should build joint ventures with provincial, municipal or other local entities to initially form enterprise-locality co-sharing and co-construction mechanisms; and (iii) functions of various platforms in resource allocation and interest-sharing balance will be fully activated in order to realize mutual prosperity, and an active cooperation between petroleum enterprises and local entities will be enhanced so as to bring about favorable conditions.

As the accelerating market-oriented natural-gas reform in China, such fair and open infrastructures as pipelines and their connectivity have reinforced the competition in natural-gas upstream and downstream markets after the establishment of PipeChina. However, mechanisms to form previous segmented price is not able to mirror a competitive relation between gas price and source under market conditions. So, changes in China's natural-gas industrial chain and value chain after the pipeline network independence were investigated and the price transmission was examined from the perspectives of industrial chain and value chain. Then, integrating these two chains, a "dual-chain" mode was proposed. Furthermore, both price formula and natural-gas competitiveness analysis model (NGCAM) were constructed. At last, the competition among national and regional natural-gas markets was analyzed by this model. Results show that (i) the newly-constructed model can, to some extent, represent operating mechanisms on these markets after opening the pipeline network, imply the price transmission in the natural-gas industrial chain, and highlight the competition among gas-gas, gas-liquid and liquid-liquid in this chain; (ii) in terms of national market competitiveness, this model presents the competition among gas sources such as domestic gas, imported pipeline gas and LNG, and the distribution of preferential markets, namely, LNG resources in coastal areas gradually infiltrating into inland and unconventional gas like coal gas into mid-eastern China with the help of the pipeline network, resulting in an increasingly prominent collaborative development among gas sources; and (iii) in terms of regional market competitiveness, the model assumes competitive results among various sources and many changes of supply structure in the next markets, indicating that as a sort of flexible regulatory resources, LNG is supportive to pipeline gas each other, and its source has became more competitive than before.

In order to accelerate the exploration and development process of shale gas in Qiongzhusi Formation, Sichuan Basin, with JS103 well recently made a significant breakthrough as an example, the mineralogical, organic geochemical and reservoir characteristics were analyzed for silty shale in this formation in Jingyan-Qianwei area. Influential factors on reservoir development were explored, and some differences between the silty shale in Qiongzhusi Formation and the high-quality shale in Longmaxi Formation were determined. Results show that (i) the silty shale in the study area is characterized by low TOC and gas content, moderate porosity and high content of siliceous minerals, apparently different from the high-quality shale in Longmaxi Formation with high TOC and gas content, high porosity and high content of brittle minerals; (ii) with developed inorganic pores as the soul, the silty shale reservoirs character mesopores and macropores as the main reservoir space along with the pores primarily in inkpot and slot shapes; and (iii) the anti-compaction and dissolution of siliceous minerals and the presence of moderate and stable clay minerals are conducive to pore extension, and the cementation of carbonate minerals is an important factor affecting mineral deterioration. In conclusion, adjacent to quality source rocks, the silty shale enjoys a certain hydrocarbon-generating capacity and relatively good physical properties, creating favorable conditions for shale-gas formation and enrichment. The gas content in field, as an important parameter for evaluating marine shale reservoirs, is not at all applicable to the silty shale. The coupling between active gas-testing shows while drilling and better reservoir conditions can be taken as a critical indicator to discriminate the gas content in the silty shale now.

Most high-pressure gas wells in Kuqa piedmont of Tarim Basin possesses three-extra typical natures in drilling depth, high temperature and pressure, leading to extremely severe and complex production conditions. With the development process in this piedmont, tubing-string failures, like leakage, breakage and deformation, have increased in recent years, creating additional well-control risks. Especially, there exists high-pressure gas channeling in A-annulus to outer annulus or surface once the primary well barrier is in failure, and well-control and environmental risks are unacceptable. Consequently, workover as an exclusive tool can recover the barrier. For purpose of the safe and efficient workover in these high-pressure gas wells, the well killing and complicating workover techniques under different barrier conditions were analyzed by taking wellbore as an objective. Supporting techniques and processes were put forward, including well-killing technique, treatment of primary wellbore string and workover while operating under pressure. Results show that (i) to select a proper well-killing technique depending upon barrier conditions is the prerequisite for the successful workover; (ii) tubing-string treatment methods commonly used in Kuqa piedmont include back-off, cutting and grinding; and (iii) THT packers can be processed by means of grinding and washover. It is concluded that such killing techniques as normal/reverse-circulating squeeze well and treatment of broken/disconnected string in the shallow under pressure are effective for workover in piedmonts; tubing-string fishing after cutting is the most efficient for the primary wellbore string; and washover is the most successful and most efficient fishing technique for the THT packers.

At present, oil and gas markets grow weakly but competition is increasing. Oil and gas supply-demand situations and market pattern have undergone profound changes, petroleum enterprises also face additional challenges in production organization and production-marketing connection as well as prominent pressure to broaden sales and improve efficiency. In the context of ongoing exploration on the cost management mode of low-cost and high-quality development, this mode with low cost simply through traditional methods such as controlling cost allocation or saving consumables and reducing management expenses can no longer meet endogenous requirements on quality and efficiency improvement. It is necessary to push its upgrade forward. So, some relevant studies have been conducted in order to comprehensively promote the "low-cost" and "high-quality development" in these enterprises, achieve the goal of quality and efficiency improvement and allocate resources rationally. Results show that (i) for the petroleum enterprises, the strategic cost management mode consists of key management business, implementation path and safeguard measures; (ii) the key management business is composed of strategic cost analysis on these enterprises and some strategic costs also in the enterprises, like budget, decision-making, accounting and control; (iii) the implementation path includes five steps, namely, clarifying strategic cost management objectives, tracking strategic cost management environment, setting up management organization, performing knowledge management, and conducting performance evaluation and incentive; and (iv) the safeguard measures contain cultivating the new concept of cost management, perfecting the responsibility control mechanism of strategic goal, and improving the information disclosure mechanism.

As an important force for the stable energy supply in China, liquefied natural gas (LNG) has turned into a relatively complete industrial chain after years of evolvement. In order to actively cope with current challenges, such as low control of resource open, weak voice in import pricing, low independent control degree of shipping, small scale of single receiving station, and consumption scope to be expanded, it is necessary to promote both performance and safety level in this LNG industrial chain. So, some relevant strategic suggestions were made on the basis of comparison with international advanced levels and practices after systematically analyzing development status of the upstream, midstream and downstream in this chain. Results show (i) actively acquire overseas equity gas, construct a diversified, flexible and stable "overseas resource pool", and enhance control force of resources; (ii) concentrate on efforts to create a natural-gas price index, coordinate LNG procurement, and strive for discourse power of LNG pricing that matches import volume; (iii) accelerate the construction of a LNG shipping system, realize self manufacturing, management and inspection of home-made ships and self transportation of national gas, and enhance our independent control abilities in LNG transportation; (iv) strengthen overall planning and policy guidance, promote the construction of LNG receiving stations intensively and extensively, and enlarge the scale of single receiving station; and (v) further broaden the scale of LNG utilization in the fields of gas power generation along with vehicle and ship refueling, and better exert its value to the dual-carbon goal.

With abundant oil and gas resources, Central Asia has long been a prominent source for China to import natural gas. In recent years, some new situations on natural-gas markets, however, have presented in Central Asian countries. For example, these countries trim their natural-gas export to meet local demand and promote the long-term goal of carbon neutrality. Accordingly, it is predicted that the problem on insufficient gas sources will highlight in China-Central Asia natural-gas pipelines in the future. With the energy transformation and steady advancement of the "dual-carbon" goal in China, natural-gas demand presents a strong growth, which needs more much gas source support from overseas. In order to maintain China's strategic pattern of energy import diversification and satisfy the strongly growing demand, some suggestions on the "Belt and Road Initiative" energy cooperation with Central Asia have been made on the basis of extensive investigation and in-depth analysis. Results show that (i) Central Asia boasts not only superior base of renewable energy such as wind, solar and hydropower, but favorable national policies for related industries. So, promoting the cooperation with Central Asian countries in this field can seize opportunities of renewable energy markets in these countries and push their renewable energy industrial development, while restraining the local natural-gas demand to a certain extent; and (ii) Kazakhstan enjoys strong base and great potential in coalbed methane resources. Grasping chances to develop related industries through the cooperation with this country can strengthen its natural-gas base and meet its need in energy transformation, which is of great significance to firm overseas gas sources for China to import natural gas and maintain the pattern of diversified energy imports.

There are abundant natural-gas resources in Sichuan-Chongqing area, resulting in the earliest and the most mature development and utilization in urban gas. In order to promote quality development of urban gas in this area, its exploitation status and characteristics were summarized, and its industry was also systematically investigated. In addition, the main problems and shortcomings on urban-gas industry were pointed out, and relevant solutions were made for optimizing the development. Results show that (1) the urban-gas development status in Sichuan-Chongqing area is mainly characterized by abundant gas resources, high coverage of urban gasification, well-developed production, transportation and distribution network, diversified market entities, fast growth and continuous imbalance expansion of gas demand, and better business income; (2) the development of urban-gas business in the area faces some problems such as fragmented urban gas market, inadequate gas storage facilities, imperfect pricing mechanism, non-standard urban gas business and poor ability against risk. In order to continuously promote the optimal development of urban gas in Sichuan-Chongqing area, four solutions are made to continuously promote the optimal development, reinforce the governmental leadership to successively improve the urban-gas development policies, intensify the safe operation to assist enterprises to unleash their development vitality, strengthen both publicity and promotion to advance the ability of urban and rural residents to use gas safely and efficiently, and enhance the innovation drive to move forward the sustainable development of urban gas.

In order to accurately predict well-engineering investments, effectively control well-construction costs in shale gas fields and realize beneficial development of shale gas, the application of learning curves in China and abroad and their influential factors were investigated by taking the well-engineering cost in one shale gas field as an example. On this basis, learning curves of well engineering were formed and the engineering cost indicator system was established for shale gas fields. Results show that (i) since those ready-made learning curves used for shale gas in China only reflect investment changes in drilling and fracturing & gas testing with time and experiences while not mirror the changes in pre-drilling and associated engineering, they are not applicable to predicting the engineering investment to shale gas wells which covers drilling, fracturing & gas testing, and pre-drilling and associated engineering; (ii) fracturing and drilling account for about 50% and 40% in the well-engineering cost in shale gas fields, respectively, in which the fracturing cost is mostly affected by the number of fracturing segments; and (iii) a workload deviation between plan design and engineering exerts a larger effect on the cost of pre-drilling and associated engineering. In conclude, the newly-developed learning curves can vividly forecast the engineering investment containing drilling, fracturing & gas testing, pre-drilling and associated engineering; drilling-fluid cost serves as the emphasis and difficulty for cost control in drilling; and all kinds of factor should be taken into account in the design process to maximize the accuracy of plan design.

Since the first year of hydrogen energy in 2019, China's hydrogen energy industry has witnessed its sustainable and rapid development. As the COVID-19 pandemic changes, the industrial development enters a fresh stage and faces new challenges. Under the continuous promotion of dual-carbon strategy, the hydrogen energy industry presents new characteristics as follows. It is in the period of overall transformation, hydrogen energy policies are in the period of frequent release, its market in the period of accelerated cultivation, its enterprises in the window period of transformation, its technologies in the period of rapid development, and its application scenarios in the breakthrough stage, respectively. By summarizing current situations and features, it is expected that the industrial evolvement displays some trends, for example, policies will be further optimized and adjusted, the coordination degree of industrial chain development will be improved, the industrial ecology will be deeply expanded, the international cooperation will be extensively strengthened, new breakthroughs will be made in the field of transportation, and the regional industrial development gap will be further widened. Finally, it is suggested to adhere to the policy-oriented development to ensure healthy and orderly industrial development, adhere to the market-driven core force to forge a business model with market competitiveness, adhere to the innovation-driven efficient guidance to intensify industry-university-research integrated technological RD and incubation, adhere to the behavior-driven key supplement to introduce hydrogen energy into the scope of CCER carbon market, and adhere to the important grasp of internal training and external employment to promote the level of professional personnel in enterprises.

Grass-root organizations of the Communist Party of China (CPC) are battle fortress and important force in the process of fully promoting rural revitalization. To strengthen their construction in petroleum enterprises enjoys some positive effects. Thus, some promoting paths were pointed out after deeply analyzing the importance of grass-root organizations in rural revitalization. Moreover, a typical practice was analyzed, namely PetroChina Southwest Oil & Gasfield Company (the company) offering counterpart assistance to Kaizhou District of Chongqing city. Results show that (i) this importance in rural revitalization is reflected as the force for leading rural revitalization and development, the main body of organizational guarantee and implementation to promote this revitalization and the considerable front to cultivate cadres for enterprises, which can effectively deepen the rural land reform, efficiently organize and carry out targeted poverty alleviation in rural areas, and serve the cultural construction in these areas; (ii) the promoting paths include strengthening the construction of grass-root organizations and members of CPC in petroleum enterprises, giving play to these organizations in village-level governance and the entrepreneurship and employment of migrant workers, and giving play to the organizations in the construction of rural ecological civilization.; (iii) the typical practice in this counterpart assistance includes making effort to create a new situation of rural revitalization via thoroughly implementing the important speech of President Xi Jinping on rural revitalization, integrating resources and highlighting advantages to support the sustainable development of local economy with own characteristics, and intensifying safeguards and common frequency and resonance to improve the quality of rural revitalization continuously.

Such blowout out of control is a disastrous accident of serious nature and heavy loss in petroleum domain. Especially, when a "three-high" well (high pressure, high production rate and high sulfur content) is on fire due to blowout out of control, intense flame at wellhead, and strong heat radiation and fluid shock require rescue technologies and equipment together with job safety to reach the highest level, resulting in a complex and endless disposal process. So, some rescue skills from blowout out of control and fire burning were analyzed in terms of their development history, status and direction in order to sufficiently figure out disposal difficulties in this sort of "three-high" wells. In addition, a full set of technological innovations on rescue from onshore blowout was made from aspects of reconnaissance, cooling shield, and cleaning-out & cutting to wellhead resetting. Results show that (i) domestic emergency rescue technologies have been iteratively upgraded to the unmanned operation in high-risk areas near wellhead from the insufficient professional skill and equipment in the early stage; (ii) the innovations can meet the demand of out-of-control rescue wells with high pressure of 105 MPa and production of 1,000×10⁴ m³/d, respectively; and (iii) numerous well-control accidents at home and abroad, such as blowout out of control, fire burning and wellhead leakage, have been successively disposed by virtue of these technologies which have attained to an international advanced level. In conclusion, domestic rescue technologies from blowout out of control and fire burning in onshore wells have been improved a lot. However, it is essential to tackle on their visualization, intelligence and information in the future, and to push them to a new step.

Obviously different from conventional gas, shale gas possesses its own exclusive reservoir-forming characteristics, and development modes, processes and technologies. So, there exists greater diversity in post-evaluation content between these two kinds of gas projects, bringing about new challenges to construct a post-evaluation index system for shale-gas development projects. In order to realize normalized and scientific evaluation on these projects, the post evaluation was studied on the basis of project features and unique post-evaluation features for shale gas. Results show that (i) this evaluation shall be carried out after project implementation, when production laws in shale-gas wells are basically made clear, data is complete and available, and both development and production indexes are comparable with the designed ones; and (ii) to construct this index system shall cover many evaluation indexes considering shale-gas development characteristics, such as the post evaluation on reservoir geology and engineering, drilling, completion & reconstruction, gas production and surface engineering, the project's economic evaluation, and the post evaluation on project's influence, continuity and management; and (iii) for this reason, a set of scientific and reasonable post-evaluation index system has been constructed for shale-gas development projects depending on the indexes corresponding to evaluation content. It is deemed that these endings are conducive to not only improving both efficiency and quality of post evaluation on shale-gas development projects but making these projects in good order.

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.

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.

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.

Sichuan-Chongqing area is not only a major gas production base but a considerable gas consumption area in China. Some problems and schemes about the mechanism reform of loop pipelines were analyzed for this area in order for boosting a reform on price mechanism of pipeline transmission. Moreover, both advantages and disadvantages as well as problems facing in various schemes were summed up. Many solutions were made. Results show that (i) reform thoughts on transmission price of loop pipelines in this area are put forward as follows, namely, it is necessary to implement a unified user price and a unified pricing in this area, to charge transmission fees from users for upstream enterprises at transmission ends and then to settle the receivable fees with other transmission parties. From aspects of the settlement between upstream enterprises and transmission parties, the rules of old way for old pipelines and unified transmission price for new pipelines were implemented for branch pipelines inside Sichuan-Chongqing area; and (ii) there exist some problems in the reform schemes, such as the identification of distribution problem, the acceptance of each main agent and the construction of high-cost pipelines for people's livelihood. And countermeasures are made, such as setting the minimum load rate, maintaining the original user preference, keeping the transmission price rate of old pipelines, and identifying the high-cost pipelines for people's livelihood. Two suggestions are proposed for the next reform and relevant research, at first to analyze controls on the price mechanism reform of pipeline transmission in Sichuan-Chongqing area, including the economic and social benefits to users, transmission parties, upstream enterprises and the government, and to study its effect on the development of natural-gas markets and the optimization of industrial chain; secondly to establish an evaluation system on this mechanism reform in Sichuan-Chongqing area, and formulate relevant indexes and standards, evaluate the implementation effect and problems of this reform periodically, and adjust and perfect the reform schemes and policies in time.

Natural-gas pipeline transportation industry in China has fulfilled its transformation from production-oriented enterprises to production-operation enterprises with the reform of pipeline transportation mechanisms. So, taken transportation benefits as an objective function as well as transportation route and distance as objectives, the relationship among the costs related to transportation business was analyzed to help these enterprises plan the route to transport commercial natural gas scientifically and efficiently. In addition, a model was established to calculate the benefits, and then solved and verified through real production data. Results show that (i) this established model is scientific and effective, and its calculated findings are in line with true values, which can provide these enterprises with reference and basis for decision making market development; (ii) for pipeline enterprises, the profit growth does not broaden continuously with the increase of pipeline distance. Calculated results reveal that, at the constant gas transportation volume, the profit may grow swiftly with the increasing distance when the transportation distance is less than 5,000 km, slowly when the distance exceeds 8,000 km, and begins to decline when the distance exceeds 15,000 km; (iii) when the enterprises select their own transportation route, they shall make comprehensive judgment according to production conditions and profit growth of pipelines so as to obtain the optimal pipeline transportation benefits; and (iv) mid-eastern China will be the core mounting area of pipeline transportation profit in the future, and it is recommended to expand the strength of market development and optimize both location and number of new openings in an effort to improve pipeline transportation benefits.

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.

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.

Projects on LNG gas storage and peak shaving can ensure the gas demand of civil and commercial as well as industrial enterprises with effect. Especially they exert an active peak-shaving impression in the peak natural-gas season during heating period. The projects boast great social benefits, but their construction and operation need large investment and also face certain risks. So, combined with project characteristics, a risk index system was established to evaluate their investment risks from seven aspects of policy, economy, finance, market, technical equipment, engineering construction and operation, and force majeure based on stakeholder theory. Then, the weight of each index was determined through a compound weight method according to both analytic hierarchy method and entropy weight method. And a model to evaluate the risks was built by using the fuzzy comprehensive assessment method. In addition, case study was conducted by taking an LNG gas storage and peak shaving project in Ya'an city as an example. Finally, some risk-control measures were made. Results show that (i) the principles of objectivity, integrity, effectiveness and measurability should be followed when constructing the risk index system for investment decision-making of LNG gas storage and peak shaving projects; (ii) the level of investment risks in the Ya'an project is medium, among which political and force majeure risks belong to low level, lower financial risks, medium risks in market, technical equipment, and engineering construction and operation, as well as high economic risks, respectively; and (iii) compared with actuality, the evaluation results verify both risk evaluation index system and evaluation model in scientific nature, rationality and operability at the LNG gas storage and peak shaving projects.

Speeding up the natural gas industrial development and increasing the natural gas proportion in primary energy consumption are essential tools to quicken the construction of clean, low carbon, safe and efficient modern energy system. The next industrial evolvement faces growing uncertainties for China is in an important period of energy transformation. In order to scientifically forecast the consumption demand of natural gas in China, this demand under three different alternative scenarios (baseline, deep emission reduction and low emission reduction) was analyzed by taking the LEAP model as the base. Results show that (1) the domestic gas consumption increases at a high speed under the three scenarios from 2020 to 2030, and the growth will slow down after 2030; (2) in the long run, there is a steady demand increase. Under the three scenarios of low emission reduction, baseline and deep emission reduction, the consumption demand will be stabilized at 4 500×10⁸ m³, 4 700×10⁸ m³ and 5 200×10⁸ m³, and will peak in 2041, 2045 and 2048, respectively; and (3) the demand structure is substantially stable also under these scenarios. In terms of the consumption in various industries, manufacturing is at the top proportion of gas consumption demand, making up around 50% of total demand, among which resource processing, mechanical and electronic manufacturing, and light and textile belong to subdivided ones with the highest demand on natural gas.

To construct a natural (shale) gas base with the production capacity of one hundred billion cubic meters (10¹²-m³-scale) in China is a great strategy for securing the energy security and supporting the rapid development of regional social economy. So, based on numerous successful practices in petroleum industry, a co-constructing and sharing mode was built for the national natural (shale) gas base with this scale, and some implementation routes were proposed. Results show that (i) this base construction involves an enormous industrial system and interest demands of plural subjects. Thus, guided by many co-constructing and sharing concepts, the mode should be established in plural subjects integrated with multiple elements; and (ii) there are five routes proposed, such as, to reinforce the top-level strategic design for this co-construction and sharing, to set up more modes between the government and enterprises, to perfect the co-constructing and sharing mechanisms among enterprises, to smooth the communication and negotiation channels for plural subjects, and to strengthen the early-warning system of this mode. It is concluded that the proposed co-constructing and sharing mode in a strategic view can plan the base construction as a whole, collaborate the benefits of plural subjects with effect, and promote not only development and utilization of natural (shale) gas but industrial chain's value, thereby driving the evolution of regional social economy and providing powerful support for advancing common prosperity.

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.

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.

As a kind of low-carbon, clean and efficient energy, natural gas has become one of the main energy sources in China. However, its supply-demand contradiction is prominent. Therefore, it is of great significance to conduct supply-demand prediction and early earning for smooth achieving the "dual carbon" goal. From four aspects of supply, demand, market and society, ten early-warning indicators were selected to construct the supply-demand prediction and early-warning indicator system. And ten indicators include reserve-production ratio, self-sufficiency degree, reserve index, consumption proportion, consumption intensity, import dependence ratio, import concentration, guarantee coefficient, carbon intensity and per capita GDP. All these indicators were predicted from the GM (1, 1) model. In addition, objectively and subjectively, both entropy and G1 methods were employed for determining the weight of each indicator, while grey correlation analysis method for the early warning. Results show that (i) there are four indicators affecting this supply and demand, reserve-production ratio, followed by self-sufficiency degree, reserve index and import concentration. And the security degree of the supply and demand shows a trend of stable increase; and (ii) the natural-gas supply and demand is in the critical security state during the 14th Five-Year Plan, i.e., at level III. And it will transit to the security state during the 15th Five-Year Plan and eventually achieve level IV. In conclusion, four active measures to ensure China's natural-gas security have been made, such as continuously promoting action plans of oil and gas reserve and production increase, constructing diversified natural-gas import systems, accelerating the construction of natural-gas storage mechanisms and speeding up both development and utilization of new energies.

As the growth in both demand of gas consumption and dependence on gas import in China, it is imperative to build the natural-gas reserve capacity enough for seasonal peak-shaving, which is an essential measure to secure the long-term, safe and stable natural-gas supply and promote the sustained and stable evolvement of China's economy. So, the necessity and feasibility of underground gas storage (UGS) constructed in offshore China were summed up and analyzed. Coupling with the current storage capacity, some offshore UGS schemes were proposed, and their construction and operation modes were discussed. Results show that (i) high-quality oil and gas reservoirs in offshore can make up shortfalls in the onshore UGS capacity. Sea conditions, project schemes, UGS construction/operation modes and other factors should be especially investigated. This construction is believed to be safe and reliable according to decades of offshore engineering technologies and management experiences in China; (ii) offshore UGSs and LNG terminals can be designed in collaboration by means of two schemes: offshore, and onshore & offshore. And offshore field development and UGS construction can be coordinated and integrated; (iii) UGS construction cost can be reduced by overall planning and stepped implementation. Through optimizing construction modes, the sort of UGSs build from large-scale gas reservoirs functions as a natural-gas running platform to interconnect with field production, LNG import and onshore pipeline gas, thus realizing a multi-source coordination for joint commissioning and delivery; and (iv) lifecycle dynamic management of production, injection, storage and withdrawal of gas reservoir UGS can drive the development of marginal fields nearby and also improve overall benefits in field development, UGS operation and natural-gas peak-shaving.

Numerical simulation is one of critical techniques for the quantitative characterization on remaining gas, scheme optimization of reservoir adjustment, and production prediction. For tight sandstone gas reservoirs, however, their complex geological conditions and flow behaviors make the accurate description of remaining-oil distribution impossible by using conventional simulation techniques. Thus, for fine characterization of remaining gas in tight sandstone reservoirs, Taiyuan 2 gas reservoirs of Daniudi gasfield in Ordos Basin were taken as examples to explore the effect of flow behaviors on production. Moreover, coupling with reservoir engineering and laboratory experiments, the equivalent characterization on start-up pressure gradient, water-locking effect and stress sensitivity was conducted in numerical simulation according to seepage theories in tight sandstone reservoirs. Results show that (i) due to both formation-pressure drop and another fluid or gas invasion after reservoir development, there induced stress sensitivity effect and water-locking damage in reservoir rocks, causing the decrease of effective permeability to severely restrict productivity; (ii) as the invasion of formation water and another fluid, the locking damage may also occur. Changes of irreducible to movable water are simulated by horizontal endpoint calibration of relative permeability, and the damage to gas flow in the early stage of production is simulated through vertical endpoint calibration. Furthermore, relative-permeability curves at different stages are mobilized in module of Schedule model. Large deviation in pressure matching can be avoided during the middle to late stage of production; and (iii) when the equivalent characterization on the start-up pressure gradient is considered in numerical simulation, the model's coincidence in the process of history matching increases to 85% from 45%, indicating this finding more in line with in-situ conditions. In conclusion, these results may perfect seepage theories and numerical simulation technique in tight sandstone gas reservoirs and are of theoretical and practical significance for the development of similar reservoirs with effect.

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.

Hydraulic fracturing technology is the main technology for shale gas production at home and abroad, but it faces the challenges of great water consumption, serious reservoir damage and water environment pollution. Water-free or low-water fracturing technology has attracted more and more attention in recent years for it can effectively avoid shale water lock effect and reduce reservoir damage. In order to reduce the consumption of water resources in the process of unconventional reservoir stimulation and diminish environmental risks, this paper systematically investigates the shale gas water-free fracturing technology. Then, the implementation characteristics, advantages and disadvantages of hydraulic fracturing, water-free fracturing (e.g. supercritical CO₂ fracturing) and foam fracturing technologies are summarized and analyzed by means of investigation, comparative analysis and case demonstration. Finally, the development directions of future fracturing technologies are discussed and forecast. And the following research results are obtained. First, the current water-free fracturing fluid technologies mainly include liquid CO₂ and N₂ fracturing fluid technology, supercritical CO₂ fracturing fluid technology, LPG (liquefied petroleum gas) fracturing fluid technology, and alcohol based fracturing fluid technology, all of which are characterized by good compatibility with reservoir fluid, strong fracture making ability and good stimulation effect. Second, foam fracturing fluid has good proppant bearing capacity and proppant transportation capacity, so that proppant can be distributed throughout the fracture network more effectively. Third, under the strategic background of "carbon peaking and carbon neutrality" in China, CO₂ fracturing technology can realize the resource utilization and geological storage of CO₂. When selecting fracturing technology, CO₂ emission reduction effect shall be considered comprehensively.

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.

As a sort of clean fossil energy with low carbon and high quality, natural gas serves as one of the best choices to implement low-carbon transformation, and its supply security is about energy security in China. There exist numerous large gasfields in Sichuan with abundant unconventional gas resources. And the gas demand will grow steadily in the future. In order to promote the sustainable and healthy development of Sichuan's economy and society, scientifically formulate natural-gas planning schemes, and ensure Sichuan's energy security, an evaluation index system has been developed for Sichuan' natural-gas supply security from four aspects of availability, affordability, efficiency and research & development. Furthermore, an evaluation model was also built through one approach called set pair analysis (SPA). Additionally, the security level was determined. Results show that (i) the supply security in Sichuan was evaluated as Level III in 2017, upgraded to level II in 2018, and then to Level I in 2019-2021; and (ii) the linkage degree of Sichuan's natural-gas supply security index was increased from -0.2 in 2017 to 0.219 in 2021, showing the steady growth. It is deemed that the security level of Sichuan's natural-gas supply will be gradually improved, and the effective measures for this improvement include constructing a diversified supply system, perfecting natural-gas price mechanisms, and establishing a multi-level system in gas storage and peak shaving.