Both natural gas and liquefied natural gas (LNG) in the Guangxi Zhuang Autonomous Region were surveyed in an effort to optimize natural-gas resource allocation and LNG layout. Moreover, some layout suggestions on these two were made. Results show that (i) in this autonomous region, the consumption of natural gas will be concentrated around residential gas and transportation sectors in the future. And that of industrial fuel will reveal some growth, but the increase is slowly; (ii) in terms of five major gas use in urban gas, transportation, power generation, and industrial fuel, both LNG demand and transportation will become a big concern which may make up gas consumption areas that cannot be transported by pipelines; and (iii) considered LNG infrastructure in Guangxi and LNG layout of refueling stations in counties and cities and coastal terminals, the operation cost, investment scale and economic radius of logistics were analyzed by adopting LNG transportation modes and cost analysis methods. In conclusion, Guangxi's natural-gas utilization among all sorts of energy will hold a relatively advantageous growth in the future, especially with a great prospect in transportation. Optimizing LNG utilization and infrastructure layout should be of utmost importance. It is advisable to construct new LNG processing and supply bases in Baise, Guilin and Wuzhou cities where its infrastructure projects in coordination with natural-gas pipelines and coastal LNG terminals will be conducive to constructing an efficient LNG supply-demand framework around these three cities.

To thoroughly liberalize price of gas source serves as the ultimate destination in natural-gas price reforms. Thus, focusing on market-oriented reforms on natural-gas gate price, we analyzed existing problems in gate price mechanisms and pointed out next development needs so as to work on a new national unitary market and optimize efficient resource allocation. Moreover, both goal and direction were discussed for the next round of market-oriented reforms on natural gas. Results show that (i) after the comparison on two schemes of livelihood gas consumption assurance during transitional period of reforms and after price integration, it is recommended to implement one scheme of "maintaining regulated gas supply+monetary subsidy" during transitional period while the other of "stepwise pricing+gas coupon" after integration, being supplemented by moderate price adjustment fund in order to solve key problems, for instance, different pricing between upstream gas source and end users, livelihood gas consumption assurance, and price integration of regulated with unregulated gas; (ii) through the analysis on this integration's concept and strategy, it is suggested to establish a new pricing mechanism to further directly achieve the price integration; (iii) both thinking and specific pathway to price reforms have been raised to promote natural gas in quality development; and (iv) some suggestions are made to deepen these reforms step by step, perfect the people's livelihood system, and impose greater transparency and much stricter regulation on this market.

The capability of diagnosing the faults of natural gas compressor units under complex working conditions needs to be enhanced. In this paper, the traditional diagnosis techniques are investigated for their deficiencies in processing multi-source heterogeneous data, semantic understanding and real-time response, and their limitations in terms of accuracy, interpretability and real-time performance are revealed. Then, a multimodal knowledge graph-based question-answering (MMKG-QA) model is proposed, which integrates multiple data types such as text, images and timing signals and uses natural language processing and computer vision technologies to extract deep features. On this basis, a multimodal knowledge graph integrating expertise and industry standards is constructed to structurally express the semantic relationships among fault mechanisms, key components and operating parameters. The model achieves knowledge representation and reasoning through graph neural networks, supporting the understanding of complex semantics and question answering. The following results are obtained. First, the proposed model yields significantly improved accuracy of fault identification compared with traditional methods, and it is stably performed especially in multi-factor coupling scenarios. Second, the QA system is capable of fast response and real-time diagnosis. It is concluded that (1) multimodal data fusion and knowledge graph construction can effectively enhance the expression and recognition of fault features of compressor units; and (2) the intelligent QA mechanism combined with graph neural networks is conducive to enhancing the semantic reasoning and intelligent diagnosis capability of the system.

Taken C2 well in Chaganhua North subsag, Changling fault depression, Songliao Basin, as an example, two well tests on pressure buildup were conducted in an effort to figure out dynamic response features and productivity variations in volcanic gas reservoirs at the process of their development. Then, the wellbore flow regime, buildup characteristics, and dynamic evolution of physical parameters were made clear for the reservoirs by combining flow pressure and temperature testing, bottomhole static pressure and temperature gradient testing, and transient well-testing analysis. Results show that (i) the formation pressure in this well decreases to 25.39 MPa from initial 68.49 MPa as production time continues, meaning reservoir energy in sharp decline; (ii) the effective reservoir permeability drops from 0.0122 mD to 0.0062 mD, the fracture half-length from 35.2 m to 23.4 m, and the detection radius from 63.4 m to 26.8 m, respectively, representing so weak seepage behaviors near wellbore; and (iii) synchronously, two productivity indexes decline, such as one index of gas productivity index from 3,980.02 m³·d^-1·MPa^-1 to 1,320.29 m³·d^-1·MPa^-1 and the other of liquid productivity from 0.9016 m³·d^-1·MPa^-1 to 0.4156 m³·d^-1·MPa^-1, implying that the overall development effect gets worse. In conclusion, dynamic features in the volcanic gas reservoirs are dominantly under the joint influence of reservoir-stress sensitivity effect and production system. The tight volcanic reservoirs with high pressure undergo an increase in their effective stress during production, leading to fracture closure and permeability loss. What's more, optimizing production system and controlling pressure drop may be regarded as essential measures to maintain fracture conductivity or delay productivity drop.

Taken 3D geological modeling on gas reservoirs of the fourth member in Leikoupo 4 Formation (hereinafter referred to as Leikoupo 4 Member), Xinchang block, western Sichuan Basin, as an example, both difficulties and solutions were analyzed and addressed on the basis of well- and mud-logging, and seismic data, as well as basic geological characteristics in an effort to achieve these reservoirs in the efficient and rational development. Ideas and methods were determined for the modeling on carbonate gas reservoirs of tidal flat facies. Additionally, in accordance with objective geological conditions, a 3D fine model was also established. Results show that (i) developed with multi-level faults, the top of Leikoupo Formation in this block has suffered from erosion and pinchout. Guided by theories of structural geology and sequence stratigraphy, fault and bedding plane models from coarse to fine has been created by the VBM algorithm of structural framework modeling; (ii) micrite- to powder-crystalline dolomite, algae bound dolomite and calcareous dolomite are regarded as favorable reservoir lithofacies. Data volume of lithofacies, and reservoir facies and porosity inversion is optimized for hierarchical constraints. And a model of matrix porosity is built for the reservoirs by means of the sequential Gaussian random simulation which can effectively depict attribute variations between thin reservoirs and interbeds; and (iii) another model of discrete fracture network (DNF) is adopted, simulation algorithms are selected to construct small-, medium-, and large-scale fracture sheet models, and the diadochic assignment algorithm is adopted to integrate each fracture model and to set up a complete 3D fracture grid model. In conclusion, the modeling ideas and methods of "multi-level sequence + VBM algorithm controlling framework, origin + multi-attribute constraints conditioning attributes, and multi-scale DNF model integrating fracture models" can resolve difficulties in accurately describing heterogeneity and characterizing seepage behaviors in fractured-porous reservoirs, especially in the modeling on carbonate gas reservoirs of tidal flat facies, further to improve the accuracy in geological models.

Taken gas reservoirs of the first member in the Middle Permian Shihezi Formation (Shihezi 1 Member), Xinzhao block, Dongsheng gasfield, as examples, geological and engineering parameters, characteristics of induced fractures with single factor, and fracture monitoring data were analyzed for different reservoirs in an effort to figure out characters of induced fractures from horizontal-well fracturing in tight sandstone reservoirs with high heterogeneity. And with various fracturing scale, the induced fractures in Shihezi 1 reservoirs were analyzed. Results show that (i) the better the physical properties are in Shihezi 1 reservoirs, the lower the Poisson's ratio, Young's modulus and in-situ stress, and the higher the brittleness index; (ii) given the same fracturing parameters, such fractures possess following characters: the lower the fractures and the smaller the fracture half-length for the better physical properties, the higher the fractures and the smaller the fracture half-length for the thicker reservoirs, and the lower the fractures and the larger the fracture half-length for the larger the stress difference between reservoir and interlayer; (iii) under the same geological conditions, the higher the injection flow rate is and the greater the net liquid volume injected is, the larger the fracture height, the larger the fracture half-length, and the larger the fracturing extent. Moreover, the larger the number of perforation cluster is, the greater the spread width of fracture and the smaller the fracture half-length under the same geological and fracturing parameters; and (iv) the net liquid volume is the main influential factor to expand fracturing extent in tight sandstone gas reservoirs with high heterogeneity. It is concluded that the induced fractures in such reservoirs are jointly affected by geological and engineering factors. Depending on reservoir properties at one fracturing site, the designed fracturing parameters should be differential so as to attain the expected fracture half-length and height.

For natural gas, its energy pricing must be enforced. And to implement this pricing is accelerating in China, while the implementing difficulty lies in how to handle the interests of all parties. Moreover, the critical issue is to convert the volume price currently applied in each link of industrial chain into the energy price, which directly affects the interests of all parties in the chain and gets concerns of all parties. Thus, some relevant issues were discussed for promoting this pricing, and suggestions and specific methods were made and set up to resolve conflicts of interest among all parties. Results show that (i) it is not essential to convert the existing volume price into the energy price based on a unified reference calorific value, but adopt different calorific values for different situations; (ii) the higher calorific value is recommended, which is consistent with national standard; and (iii) the key solution to the implementation difficulty is to respect the interests of all parties, make suggestions to resolve interest conflicts, and provide specific methods of converting from volume price to energy price for the price complying with government pricing and guidance price, including gas price at gate station, pipeline transportation price, gasification expense at LNG-receiving stations, and urban gas price.

To assess exactly the effect of natural-gas price fluctuation on the energy, economy, and environment (3E) system is an essential prerequisite to expedite the market-oriented mechanism reform. Therefore, taken Sichuan province of the "Daqing-scale gas province" in China as an example, a model of computable general equilibrium (CGE) was constructed for this fluctuation in terms of production, trade, households, and environment sectors. Moreover, affected by distinct fluctuation, the regional macroeconomic development, economic benefits in individual department, energy consumption structure, and CO₂ emission from energy utilization were assessed. Results show that (i) stemmed from both reduction and expansion in government subsidies, the fluctuation of natural-gas price may induce resource reallocation by altering actual consumer demand to exert a heterogeneous effect on economic output in several sectors; (ii) the fluctuation may initiate some changes in energy supply and demand through a substitution effect whose degree is sorted from big to small: natural gas, coal, oil, and electricity and heating power, reflecting that gas industry exhibits monopolistic character, while a little fluctuation in other energy resources regulated or controlled by the "invisible hand" of market; (iii) CO₂ emission from both agriculture and construction industry is less correlated to gas price because of their small dependence on energy; (iv) light and service industries are somewhat related to this price, but it is essential to prevent resource waste from price drop; (v) CO₂ emission from transportation industry varies with the price due to the substitution effect stimulated by the dual-carbon goal and cost effect; (vi) it is difficult for heavy industry to separate from coal and oil consumption under existing technologies, resulting in a minor effect of gas price fluctuation; and (vii) apparently, chemical industry has something to do with this fluctuation since natural gas serves as not only a chemical raw material but a type of fuel.

Taking tight sandstone gas reservoirs of the second member in Xujiahe Formation (hereinafter referred to as Xujiahe 2 Member), Zhongba gasfield, northwestern Sichuan Basin, as examples, we analyzed reservoir rocks in terms of mineral composition, pore types and micro characteristics by means of several experimental ways, such as core observation, X-ray diffraction, cast-thin section, nano-CT scanning, high-pressure mercury injection, and nuclear magnetic resonance (NMR), in order to optimize reservoirs' development effect and improve their ultimate recovery factor. In addition, the main factors affecting the difference among physical properties were discussed for these reservoirs. And both development prospect and technical direction were also pointed out for these low-quality reservoirs through some stimulation practice. Results show that (i) Xujiahe 2 reservoirs can be classified into three types. Among which, both type I and II reservoirs are dominated by residual intergranular pore and intergranular dissolved pore. In type III, the proportion of feldspar and lithic intragranular dissolved pore increases significantly, and pore structure becomes more complicated; and (ii) these three types are similar in distribution interval of main pore radius while great division in throat structure. The pore-throat radius is mainly in the range of 0.75-1.55 μm and 0.08-0.21 μm in type I, 0.49-0.75 μm in type II, and further decrease to 0.37-0.49 μm in type III, respectively. This radius discrepancy directly results in the reservoirs in various permeability and productivity. In conclusion, our understanding that pore-throat radius is a key factor controlling the difference among physical properties of Xujiahe 2 reservoirs in Zhongba gasfield may provide theoretical basis for formulating development strategies. What's more, production wells are dominated by type I and II reservoirs in the early development. Practice proves that sand fracturing with high intensity in type III can actively expand the effective pore-throat radius and setup hydraulic fracture network to release natural gas from intragranular dissolved pore, indicating that, with a certain development prospect, this type serves as the vital reservoirs for this field to ensure stable production further to increase.

As the backbone to build a novel energy system in China, both natural gas and hydrogen energy play regulating, supporting and balancing roles in the process of green and low-carbon energy transition. Thus, based on current situation and growth trend of these two energies, the growth room was discussed for their integration to promote coordinated and quality development. From the perspective of whole industrial chain, the growth pathway towards their integration was discussed, and strategies and suggestions are formulated and made. Results show that (i) for natural gas, its supply increases steadily in China along with more and more exploration and development. The consumption sustains its growth in the near and medium term; (ii) for hydrogen energy resources, their exploitation are deepened continuously and the productivity construction is accelerated. And the resources serve as a new driving force for energy increase in China; (iii) the integration of natural gas and hydrogen energy industries has broad development prospect. And the industrial chain features, technological foundation, and institutional environment may provide support for this deep integration; (iv) the co-development and growth of limited carbon based energy and infinite zero-carbon new energy can be achieved by enhancing the collaboration and mutual promotion between industrial chain, strengthening resource sharing and complementary advantages, and deploying the utilization pathway towards the integration in upstream preparation, midstream storage and transportation, and downstream application; and (v) it is necessary to empower the value enhancement of industrial chain in terms of top-level design, industrial alliance, technological innovation, digital and intelligent transformation, and demonstration application, and sufficiently inspire the integration potential throughout the whole industrial chain, so as to inject green new momentum to advance energy transition in this country, promoting the ecological and healthy growth of carbon neutrality industry.

The emergence of foreign trading hubs with mature natural-gas markets was ascertained in order to push forward market-oriented reforms on natural gas in China and promote global impact. Furthermore, a comparative analysis was conducted on hub types and spot transaction modes, and some scenarios and suggestions to propel China's natural-gas hub pricing were made. Results show that (i) setting up China's trading hubs is important for reform push and impact promotion. Hub pricing is the future orientation in national natural-gas industry; (ii) most of China does not qualify for hub construction while the greatest potential in the Yangtze River Delta and Pearl River Delta regions; and (iii) China's natural-gas hub pricing neither uses blindly American mode nor copy European mode. Instead, it must explore a fresh mode available for its own conditions. Accordingly, some suggestions are made as follows: changing the pricing benchmark in the current mechanism from government pricing to hub pricing, establishing virtual hubs which call for pillars in both infrastructure and software, and initiating the research and design of hub pricing, as well as planning and constructing essential infrastructures, hence making hub pricing a reality as soon as possible.

Continuous tests on production profile were conducted in DS66P18H horizontal well of tight gas reservoirs with rich water, Dongsheng gasfield, Ordos Basin, so as to figure out production performance from hydraulically fractured intervals in such reservoirs. Moreover, production changes on pay zones were analyzed for all production periods. The relation of production performance was found to not only pay zones but reservoir properties, also this relation to fracturing treatment. It is pointed that these tight reservoirs are characterized high water saturation and complex seepage mechanisms. And the contribution of each pay zone to productivity is jointly conditioned by reservoir's physical properties, fracturing intensity, and working system. Results show that (i) along with the increase of production pressure difference, the principal gas-producing interval does not change its site at the same production period. However, its contribution to production deceases, while those pay zones without production in initial stage start contributing to output; (ii) the contribution of each pay zone to output is positively correlated to physical properties and gas-bearing property, that is, the better the physical properties and gas-bearing property are, the greater the contribution is; and (iii) this contribution is less affected by fracturing treatment. In conclusion, production performance in each pay zone may be made clear from production profile tests on horizontal wells in tight gas reservoirs with rich water. And production profile is of practical significance for such reservoirs in sustained, stable, quality and efficient development.

Currently, petroleum enterprises are facing challenges in the marketization of natural-gas price. Therefore, pricing mechanisms in PetroChina was made a comparison with those in Sinopec and CNOOC to analyze marketization constraints. Then, coupled with marketization process in China, the development trend of natural-gas trading and its impact on such enterprises were discussed entirely. At last, a corresponding strategy was made from aspects of transaction mode, classified pricing, secondary transaction, facility coordination, and customer management. Results show that (i) the innovated "annual or medium to long-term" contract period and the established price mechanism linked LNG index with oil price can mitigate fluctuation risks; (ii) jointly promoting gas storage facilities and production peak shaving can greatly expand both resource allocation and configuration flexibility; and (iii) classified pricing, secondary transaction mode and stable long-term contract customers can strengthen the market's buffering capacity against supply-demand imbalance. In conclusion, integrating mechanism innovation, facility coordination with precise policy implementation, petroleum enterprises need to set up an all-round response system covering price risk management, resource optimization and allocation, and market supply-demand regulation in order to remarkably advance market adaptability and stable profits, thereby contributing to the sustainable development of natural-gas industry under this price marketization.

Tight sandstone gas reservoirs feature strong interlayer and planar heterogeneity greatly impacting on the accuracy of geological modeling. Apart from the aims of cost reduction and efficiency increase, the contribution of each horizontal interval to production is unclear, and the main influential factors to restrict single-well productivity increase are ambiguous. Thus, some horizontal wells in tight sandstone gas reservoirs were taken as objectives to deeply discuss their production profile and the association with related factors by means of the method of gray correlation whose findings were introduced into this modeling to further optimize modeling. Results show that (i) as a geological factor, gas saturation is closely in correlation with gas production; (ii) based on dual constrains of actual drilling and production profile, multi-point geostatistics are adopted in the model of geological modeling correction to simulate facies boundary once more. The model accuracy in reservoir expansion can be enlarged by 15% after correction; and (iii) eventually, on the basis of gray correlation analysis, the attribute model is more accordant with dynamic production data after reservoir parameters are recorrected through the weight correction formula. In conclusion, as for the development of tight sandstone gas reservoir by horizontal wells, probing into both gas production profile and influential factors is crucial for fully understanding and optimizing productivity and development strategies. Moreover, dependent on dual constrains of actual drilling and production profile, the model of geological modeling correction and the tool to correct reservoir parameters from gray correlation analysis may amend some bias in modeling, further to provide reliable evidence for next development.

In addition to complicated regional tectonics with developed faults and fractures, the normalized implementation of synchronous platform drilling and fracturing may bring about frequent frac-hit risks during the development of shale gas in southern Sichuan Basin, further to seriously threaten drilling safety and development efficiency. Thus, based on geology-engineering integration, some technologies for risk warning, prevention, and control have been creatively put forward after analyzing regional geological characteristics, frac-hit accidents, and engineering parameters. They have gotten successful verification in field application. Results show that (i) both faults and natural fractures are the main influential factors on frac hit. And fracturing fluid is transmitted to adjacent wells 3,000 m away through fractures; (ii) two fracturing parameters (displacement ≥18 m³/min and fracturing-fluid intensity >30 m³/m) and well spacing (<3 km) are positively correlated with the risks; (iii) in combination with the WOB linkage warning mechanism, the frac-hit accidental rate dropped to 2.2% from 11.4% in 2024 through some measures, such as fracture prediction based on 3D seismic depicting technology, fracture-end temporary plugging, and dynamic drilling-fluid control; and (iv) precisely identifying geological features, optimizing fracturing parameters, and collaborative management can reduce frac-hit risks with effect, and provide technical support for shale gas in the safe and efficient development.

Jin 30 well block in Dongheng gasfield was taken as an objective to conduct fine description on the production performance in gas wells with different liquid-gas ratio in tight gas reservoirs rich in water and further to figure out both decline types and laws in such wells. Moreover, taken the daily gas production, stable liquid-gas ratio and dynamic reserves as classification criteria, not only the decline laws in these tight gas reservoirs with rich water but also rational proration in gas wells were explored deeply through the traditional Arps decline analysis method. And a standard decline model was established by introducing the pseudo production intensity formula to assist in guiding gas wells in the proration optimization and lifecycle management. Results show that (i) high-yield wells are mainly situated in the north of channels 4 to 6 with better reservoir properties, medium-yield ones in the middle of channel 5, the north of channels 6 and 7, and low-yield gas block in the south of channels 6 and 7 and channel 3 with high water; (ii) decline laws in gas wells with different liquid-gas ratio vary significantly. Decline types in those wells with low to medium water are depletion-hyperbolic and exponential-hyperbolic decline, while types of high water are exponential-harmonic and exponential-depletion decline. Under the same water production, the decline rate in low-yield wells is the largest while the smallest for that of high-yield ones; (iii) from numerical simulation, rational proration ratio in low medium water gas wells is 1/7~1/6 open-flow capacity, and that of high water wells is 1/6~1/5 open-flow capacity, individually; and (iv) from the production, the pseudo gas-production intensity formula can eliminate the influence of strong heterogeneity, gas content, reservoir thickness and fracturing scale on production effect to a certain extent, guiding the production and management for gas wells. It is concluded that these achievements may not only guide to optimize the working system and evaluate the tapping potential in gas wells, but also provide reference for analyzing decline laws in the same type of gas reservoirs.

Driven by the deepening of natural gas marketization and regional production and marketing goals, the management of direct-supplied users is facing challenges such as the between contract rigidity and demand fluctuations, increasing pressure for gas payment recovery, and insufficient peak-load coordination. Taking urban gas, industry and chemical industry as the research object of three types of direct supply users in a certain area of Luzhou, through the Analytic Hierarchy Process (AHP), a four-dimensional evaluation system was established in terms of credit status, gas consumption level and characteristics and growth potential. Gas users were classified into core, key, and general groups. In addition, some differentiated management strategies and supporting measures were made. Results show that (i) the evaluation system not only considers both user attributes and demand characteristics but incorporates differentiated factors. And classification criteria is practical and boasts strong operability; (ii) differentiated strategies may enhance the loyalty in core users, the stable growth among key users, and the risk management for general users; and (iii) supporting measures, such as gas storage peak-shaving coordination and government-enterprise collaboration mechanisms, may mitigate contract execution deviations and difficulties in gas payment return, and improve resource allocation efficiency during market downward legs.

Natural gas, as a sort of low-carbon and clean energy resources, reveals an increasingly strategic role with the accelerating transformation of energy structure in the world. However, its producers are obliged to invest more constantly as exploration and development extend to deep-seated or unconventional gas. For full cost, as a core indicator for predicting economic benefits in such enterprises, its accuracy may directly affect the investment decision, market pricing, and national energy security. Thus, an innovative model was developed to fast predict the full cost in natural gas because traditional approaches based on complex financial models are difficult to make rapid decision. Furthermore, a theory on dual cost structure of new and old gas wells was proposed to achieve dynamic balance in cost behaviors between existing and new production wells through an algorithm of production weight coupling. Results show that (i) full cost consists of operating cost, depletion, depreciation and amortization, period expenses, as well as taxes and fees in addition to income tax. For those wells newly put into production, their full cost is basically confirmed at the time of commissioning and remains relatively stable in the coming years; (ii) coupled with cost behaviors of both new and existing wells, the dual cost structure theory can help in quick prediction on the full cost trend, further to improve short-term prediction accuracy and judge long-term tend; and (iii) relying on technological advancement, gas producers may reduce single-well investment and increase individual output in new production wells so as to control their full cost. In conclusion, the optimized prediction model is of great significance for these producers to confront with price fluctuation and policy adjustment. Prediction results from this model can be used to choose better investment direction in a planned way for cost control with effect and promote enterprises' healthy and sustainable development.

For liquefied natural gas (LNG), a major component in gas supply, its industrial chain involves several domains, including the whole process of production (import), storage, transportation, re-gasification, sales and utilization, as well as some corresponding industries, such as automobile and ship making, storage and transportation facilities, and equipment manufacturing. And its high-quality development is crucial for social and economic growth and energy supply guarantee. Thus, challenges in the expansion of China's LNG industrial chain were analyzed on the basis of chain development status and trend. And some measures and suggestions were also made to push this in the quality development. Results show that (i) LNG will turn into a dominant form of gas trading in the world, and China will step up to improve the pace of the right of speaking; (ii) its production will develop towards three tendencies: large scale, small-scale skid, and floating liquefied natural gas (FLNG); (iii) China will achieve stronger competitiveness continuously in the international market with the advancement in LNG production, storage and transportation technologies; and (iv) LNG industrial development in China faces a couple of problems influencing on the quality development, such as tight resource supply, lower marketization, insufficient discourse right in the international market, scattered procurement of domestic enterprises, adequate LNG receiving capacity at LNG receiving stations, and high construction costs of storage and transportation facilities. Four measures and suggestions are made as follows: propelling the marketization of LNG prices and setting up linkage mechanisms on international oil and gas prices; stressing cooperation with resource countries, allying with importing countries, creating regular communication mechanisms with domestic purchasers, and building a diversified resource pool pattern; scientifically planning the construction of LNG infrastructures; strengthening digital transformation and intelligent development to raise market competitiveness; and facilitating the fusion development with new energy.

So far, a set of relatively mature techniques has been developed to settle drilling complexities such as sticking, broken drilling rig, and overflow. According to statistics, however, practicable solutions are still absent in some rare events, which may affect drilling schedule to further increase nonproductive time, for instance casing slip while setting casing. These events also cause even worse accidents or well abandonment. As the matter of fact, there exist difficulties in casing fishing resulted from long casing fish, high suspended weight and large lifting friction. For example, originated from downhole fish structure, damage of the fish top, and wellbore and casing size, the second-spud Ø244.5 mm casing slipped and fell into WH-3 well. And some fishing tools, including special large-headed male cone, casing circulation head, and retractable caving fishing spear, did not work. Thus, we optimized conventional casing circulation head and developed an improved circulation-head fishing tool. Results show that (i) the improved fishing tool can successfully catch the fallen fish at the first time, and reduce the frequency of drilling trips; and (ii) with circulation flushing and fastening capability, functional integration has been conducted to deal with wellbore cleaning and connection strength. It is concluded that the new fishing tool offers reusable solutions on similar accidents and provides valuable reference for studying these accidents.

As a peak-shaving power source with low carbon, environmental protection, and high quality, natural-gas power generation plays a vital supporting role in ensuring power security. However, its profitability is greatly affected by several elements, including on-grid electricity price, gas price, gas consumption for power generation, and government subsidy. Therefore, these elements and the profitability from gas-power projects that are in operation or being constructed in Sichuan and Chongqing areas were discussed so as for gas power in the rapid growth. And some suggestions were made to promote the profitable gas-power growth in these two areas. Results show that (i) the key to fuel cost reduction is to raise electricity price and further improve gas-power price linkage mechanisms, ensure stable gas supply, control gas price within a reasonable range, and lessen gas consumption in power generation; (ii) efficient and advanced H-class gas turbine equipment can actively improve power generation efficiency and overall profitability; (iii) the coordination among the five major entities related to gas power is also a fundamental way to enhance this profitability; (iv) for gas-power stations, their individual advantages, such as rapid start and stop, clean and low carbon, short construction period, low investment, and large output, can complement other peak-shaving forms to achieve integrated growth; and (v) during the 15th Five-Year Plan period, it is in urgent need to construct a batch of clean and efficient coal- and gas-power projects, and add a certain scale of regulating and supporting power sources, like new energy storage, to fill power gap and enhance regulating and supporting abilities in power system.

There exists low accuracy in predicting daily price of liquefied natural gas (LNG) because of high price fluctuation and complex periodicity. Thus, integrated the Informer architecture to the Fast Fourier Transform (FFT) frequency enhancement mechanism (Informer-FFT), a short-term dynamic prediction method have been developed. It makes use of Informer's advantages in handling long-sequence dependency and introduces FFT to extract frequency-domain characters explicitly in price sequence as auxiliary input in order to synchronously capture both time-domain dynamics and periodic patterns in price fluctuation. Some empirical study was conducted by using daily data on China's LNG factory price from 2011 to 2025. Results show that (i) the mean absolute percentage error (MAPE) from this method is 2.37% and 2.65% on both test and validation sets, respectively, much superior to that from the other two baseline models of long short-term memory (LSTM) and standard Transformer; (ii) frequency-domain analysis reveals a strong dominant period, approximately 955 days, in LNG price sequence, proving the effectiveness of introducing FFT characters in capturing non-traditional long-period patterns and obviously enhancing this model in predicting ability; and (iii) the model still takes on excellent generalization ability and robustness on the validation set containing unknown data, and the predicted curves are highly consistent with actual ones. It is concluded that this integrated method can precisely and stably predict LNG's daily price, and provide effective technical support for relevant market entities in risk management and decision-making.

For natural-gas power generation in China, its industrial chain growth is an important link in achieving the dual-carbon goal. At present, most financial evaluation methods for gas-fueled power projects attach importance to project itself. However, for petroleum companies with the entire industrial chain in gas power generation, such methods cannot thoroughly reflect the overall contribution of gas-fueled power plants to this chain. Therefore, based on the marginal contribution theory, a novel evaluation method which considers the chain's incremental value resulted from new plants in a comprehensive manner has been proposed. Results show that the proposed financial model can be used to evaluate the project's overall value in this industrial chain, discuss the impact of project on each chain to facilitate sound decision-making on project investment, contrast several projects with the same type under capital constraints, and reveal that the investment entity holding complete industrial chain may share risks of gas price fluctuation at all chain, enabling it to have higher risk resistance than independent power plants. It is deemed that the new method is of great significance for the decision-making on gas-fueled power projects, project selection, and layout of gas power generation industrial chain.

Shale gas with normal pressure is widespread around southeastern Chongqing City, like Pengshui, Wulong, Dingshan and Baitao areas with enormous resource potential. Its fracturing, however, is generally confronted with challenges, such as low formation energy, and poor flowback capacity and testing effect. Especially, for normal-pressure shale gasfield of the Lower Silurian Longmaxi Formation in Dingshan area, there exist many problems, like small volume of supporting fractures, severe non-uniform inflow in multiple clusters, and inconvenient fluid discharging after fracturing. Therefore, the integrated well building and single-cluster fracturing were creatively adopted to improve the effective support volume, flowback, and productivity. Results show that (i) propagation mechanisms of hydraulic fractures ascertain that high displacement is beneficial for increasing the support volume, complexity, and flowback, while single-cluster fracturing may maximize displacement only through a handful of clusters; (ii) single-cluster fracturing boasts high efficiency, large volume of supporting fractures, and strong flow conductivity. It is necessary to enhance the extension of fracture length and height; (iii) multi-cluster fracturing enjoys large extensional range and high coverage rate. The next step shall focus on strengthening uniform fluid injection in multiple clusters and improving flow conductivity; and (iv) from testing and practice, single-cluster fracturing is superior in flowback rate, and initial and mid-term productivity.

Management innovations in petroleum enterprises involve a huge management system of both production and operation. It is significant for these enterprises to probe into pathways and improve practice in innovation driving force. Thus, after some extensive investigation into enterprise management, both pathways and practice were discussed to enhance this driving force and establish a value-oriented management innovation system. Results show that (i) pathways towards enhancing the management innovation driving force from the perspective of new quality productive force mainly include three aspects: Strategic Control to construct the value-oriented management innovation system for the enterprises, Problem Orientation to create methods and models for evaluating innovation value, and Tool Innovation to devise the management element hierarchy for the first time; and (ii) practical achievements in force enhancement are summarized, the approval of industrial standard projects and the release of enterprise guidelines are promoted, and the economic value of innovation achievements are evaluated for representative enterprises. In conclusion, with ever-changing development strategic environment in petroleum enterprises, the methods involved in management innovation achievement value evaluation models and management element hierarchy need to be constantly optimized so as to provide inexhaustible driving force for promoting these enterprises in the sustainable development.

Sichuan Basin is rich in natural-gas resources whose exploitation co-construction and sharing are the only way and core strategy to ensure China's energy security, support regional economic growth, advance structural transformation of energy consumption, and assist in achieving the dual-carbon goal. Therefore, after analyzing three major stakeholders, including local government, petroleum enterprises, and consumers, and their links, hypothetical scenarios were deconstructed for the co-construction and sharing, an evolutionary game matrix was set up, and strategic stability was studied in an effort to offer theoretical reference and practical guidance on the natural-gas industry in sustainable and quality development in this basin. Results show that (i) the co-construction and sharing of natural-gas resource exploitation in Sichuan Basin are closely related to decision-making behaviors of these three stakeholders, meanwhile need every participant in multiple games and select the best tactic under the premise of long-term cooperation; (ii) local government can stimulate oil and gas enterprises in active participation by increasing benefits of co-construction and sharing moderately, and policy support also has a positive effect apparently. The government shall seek a balance between policy support and default penalty; (iii) for enterprises, safe and green production are essential in the process of their participating in the co-construction and sharing, and will greatly enhance efforts to protect both ecological environment and their own reputation; and (iv) for consumers, strong followership makes them heavily affected by local government and enterprises when they participate in the co-construction and sharing, specially gas-consuming enterprises and local residents are different in interests and demands, so not only the government but enterprises shall compensate them respectively. In conclusion, these major stakeholders shall cooperate in-depth to strengthen gas resources in Sichuan Basin in the long-term, efficient and green development. Additionally, local government should play a leading role to increase sharing benefits, optimize benefit distribution, and boost policy support. Petroleum enterprises should adhere to the equal importance of safe production and green development. Both of them should jointly safeguard the livelihood ecology as well as the legitimate rights and interests of consumers.

PipeChina has been emerged as the times require and a new pattern called one pipeline network of natural gas has also been arisen to accelerate the formation of natural-gas market system with "multi-subject and multi-channel supply of upstream resources, efficient gathering and transportation through intermediate unified pipeline network, and full competition of downstream sales markets". Thus, some implementation pathways were proposed for the coupling development of one pipeline network of natural gas and (liquefied natural gas) LNG tank containers in the context of a new business format in order to fully exert the function of one pipeline network as the transportation network and LNG tank containers with advantages in flexible storage and transportation. Results show that (i) based on PipeChina's physical foundation ("one physical network, one business network, and one dispatch network"), business rules and existing innovative services and product system, the coupling development of one pipeline network and LNG containers is not only feasible, but also conducive to broadening the multi-modal transportation modes of tank containers; (ii) this coupling development may overcome the containers in road transportation with disadvantages of multiple constraints and smaller optimal radius, while avoiding transportation difficulties caused by the lack of regulation, norms and standards related to railway and inland transportation of LNG tank containers; (iii) compared with traditional single transportation and multi-modal transportation of LNG tank containers, the coupling development of one natural-gas pipeline network and LNG tank containers is conducive to raising LNG supply subjects and channels, and helps to respond quickly to end consumer markets.

Floating features in pressure difference among gas-liquid two-phase choke flow were analyzed in order to accurately identify such flow patterns in vertical pipes and optimize downhole throttling design. Moreover, one method was proposed for pattern identification according to floating amplitude parameters. And in combination with Aziz flow-pattern chart, a discrimination logic framework was constructed. Results show that (i) the floating amplitude of pressure difference among choke flow is greatly different under three typical patterns, including slug flow, turbulent flow, and annular mist flow. With 4%-6% for slug flow while only 0.5% for annular mist flow, this amplitude confirms the correspondence between floating features and flow patterns; (ii) a quantitative criterion for pattern transformation is established by extracting the critical amplitude from slug flow to turbulent flow (4%-6% of the pressure in front of the choke); and (iii) in experiments, the choke exerts a regulating effect on pattern evolution. When the gas/water ratio attains 45 m³/m³, the pattern carries out the transition to annular mist flow steadily. Some slug flow, however, are included in the turbulent flow region by mistake due to liquid accumulation. In conclusion, this method is feasible for identifying vertical-pipe flow patterns based on floating pressure difference among two-phase choke flow. It can also effectively distinguish different flow patterns by quantitatively analyzing floating amplitude parameters, providing a new tool for optimizing downhole throttling technology.

Two problems are exposed to the large-scale efficient development of shale gas, Luzhou block, Sichuan Basin, such as vague non-technical factors and insufficient empowerment. Thus, non-technical factors were analyzed on the basis of "three-circle theory" in an effort to promote such development and construct the pattern of "co-construction, sharing and win-win" between enterprises and local government. Results show that (i) according to the theory, a framework has been conducted to analyze these factors for the large-scale efficient development of deep shale gas in Luzhou block via questionnaire survey, field investigation, literature collection, and policy analysis; (ii) influencing on this development, the factors stem from policy, mechanism, management and society, respectively; and (iii) beginning from the perspective of "government-enterprise-society" relationship, the modeling on shale-gas efficient development in Luxian County aims at setting up a new type of harmonious government-enterprise relationship to achieve cost reduction and sustainable development. Three suggestions are made to enhance the non-technical ability for the large-scale efficient development of deep shale gas, such as speeding up the construction of the Luxian model; guided by the concept of coordinated development, correctly understanding and handling the relation of corporate to local interests; and that between current and long-term development, seeking the greatest common divisor of coordinated development between enterprises and local government; setting a new type of harmonious link between enterprises and local government; and establishing management mechanisms for efficient operation within the enterprise.

Constructing natural-gas trading hubs is not only one of the key links in the China's market-oriented reform on energy resources, but crucial for forming fair and representative gas benchmark prices. Available hubs must be supported by powerful infrastructure among which gas storage facilities play an indispensable role. Compared with the development status of natural-gas markets at home and abroad, core natures in this construction and facility operation were analyzed systematically. Results show that (i) the success of mature hubs abroad to a large extent relies on gas storage facilities which serve as "physical anchor for the formation of price" to achieve decisive market function, for example seasonal arbitrage, spot liquidity support and price signal transmission; and (ii) to grow up natural-gas trading hubs must depend on the synchronous market-oriented evolution of storage facilities, that is, to boost facility transformation from peak shaving assets to market assets, from single operation to group collaboration, and from cost center to profit center. Furthermore, relevant policy implications have been put forward. In conclusion, these achievements provide theoretical reference and practical pathways towards the construction of natural-gas trading hubs with Chinese way.

Remarkable achievements have been made in China to actively participate in international oil and gas governance after numerous years, so that both governance role and status are enhanced evidently and greatly. In response to complex international oil and gas markets and a few uncertainties, China shall proactively propel this participation at a higher level, and further push the great growth of global oil and gas industry. Therefore, practices and achievements in China's governance over the past decade were systematically figured out, both risks and challenges were analyzed, and China's directions and key measures were predicted and made for international oil and gas governance in the future. Results show that (i) with increasing opening-up to the outside world in the past decade, China's role in multilateral mechanisms has been intensified to yield a clear and predictable international cooperation framework for the global oil and gas industry and to promote consensus and action of different countries in facilitating petroleum transformation; and (ii) China's governance is still confronted with great challenges, such as intensified oil and gas supply risks caused by uncertain geopolitics, the game between governance mechanisms and rules, differences in policy orientation among countries, environmental constraints, and pressure for low-carbon transformation. In conclusion, as for the international oil and gas governance, China should reinforce its cooperation with existing international energy platforms and organizations, promote mechanism innovations, advance market-oriented reforms in petroleum domains, collaborate with other countries to jointly build new models of oil and gas governance based on local practices, and provide Chinese solutions for the international oil and gas governance.

As a crucial institutional arrangement, the natural-gas futures market can improve the natural-gas market system, China's influence in the global energy market, and stability and competitiveness in industrial chain. Being a centralized and transparent tool for price discovery and risk management, natural-gas futures can actively diversify price fluctuation risks and optimize resource allocation efficiency through financial derivative mechanisms. Therefore, in combination with the development stage and practical foundation in domestic market, paths to promote this market constructed in China were discussed systematically by analyzing the construction experience from other natural-gas futures markets in the United States, the United Kingdom, Japan, and Singapore, Results show that (i) the development experience from foreign natural-gas futures markets demonstrates that the market construction should be coordinated with the maturity of spots markets and the process of industry system reform; (ii) in view of the resource endowment and supply-demand structure in China, the construction goals in China's market should focus on risk management, safe supply and stable price, rather than competing for international pricing dominance in the short term; and (iii) a mature natural-gas futures market is inseparable from clear supervision boundaries and effective risk prevention and control mechanisms. The selection of futures varieties is directly related to the liquidity and long-term effective operation of futures market, so the China's market construction should be advanced in stage based on domestic spots market maturity and resource structure, and international experience. Four suggestions made on variety selection and launch sequence are as follows: adhere to the basic path of "spots first and then futures"; drawing on the practical experience from Japan and Singapore, prioritize the launch of LNG futures contracts; and improving the variety system gradually with imported gas first and then domestic gas; take regional hubs as the starting point to promote the regional pilot work of pipeline gas futures construction.

Taken a core parameter, reliability of effective gas permeability, as an objective, the relation of mobility from pressure measurement in a modular formation dynamics tester (MDT) to effective permeability was analyzed for improving the accuracy to predict the productivity in offshore gas reservoirs with low permeability. In addition, a new model was proposed for quantitative conversion between mobility and effective permeability. Results show that (i) the effective gas permeability is not in a simple linear relation with mobility, and the gas-water relative permeability and temperature in reservoirs and drilling-fluid type shall be considered fully in this conversion; (ii) the key to reducing uncertainties in the effective gas permeability rests with attaining a representative average mobility. The seven-step method can obtain such mobility through multi-scale integration of different pressure measurement points, fluid difference, untested layer interpolation and plane correction; (iii) the influence of temperature and salinity on viscosity of water-based drilling fluid filtrate is small at higher formation temperature (>100℃), while large at lower temperature (<100℃), so the influence of temperature and salinity shall not be ignored in the conversion; and (iv) drilling practices in low-permeability gas reservoirs, western South China Sea, demonstrate that the effective gas permeability calculated from the model is in good agreement with actual interpretation. 13 out of total 14 wells have a relative error less than 30%, even 10 among these 13 wells with the relative error less than 20% and the mean relative error of 11.05%, respectively. In conclusion, as for productivity prediction, this quantitative model has broader applicability and higher accuracy than the mobility from traditional MDT local qualitative methods, for it considers temperature, relative permeability, and plane and vertical heterogeneity comprehensively. In addition, it can be used for reducing exploration and development risks in low-permeability gas reservoirs.

At present, greatly growing global instability and uncertainties pose grave challenges on energy supply security in China. It is increasingly urgent to ensure the security in natural-gas supply under two constraints of further implementation on dual-carbon strategy and low-carbon transformation of energy structure. Therefore, in order to improve the level of supply security insurance, the basic load of natural-gas consumption was taken as an objective to analyze the definition method of basic load, the capacity of storage facility, and the security warning system on the basis of facility capacity, total gas consumption and available resources. Moreover, the supply duration, which is corresponding to basic load and normal load based on available resources, was pointed out under the extreme thinking of resource channel failure. Results show that (i) with heavy external dependence, the natural-gas supply in China is confronted with higher risks. According to the gas consumption in 2024, the sustainable supply time will be 6.6 months and 5.7 months individually for imported pipeline gas and (liquefied natural gas) LNG under the failure in imported channels; and (ii) risks on supply shortage may be effectively alleviated by means of following measures, such as building interruptible user mechanisms, accelerating the construction of gas storage facilities and establishing a system of multi-energy complementary energy supply for important users to adjust this supply structure. It is concluded that the above-mentioned measures are conducive to reinforcing the overall resilience and emergency response to the supply system, and provide support for safeguarding national energy security.

There exists resource mismatch in portfolio decisions making on productivity projects in oil and gasfields under uncertain results and project coupling. Thus, traditional methods of portfolio optimization were analyzed in terms of drawback by taking the productivity project in S field as an objective. On this basis, a function model was created for the non-additive multi-attribute utility to nondimensionalize and probability weight evaluation attributes in this project, and then to calculate the expected utility and to quantify the uncertainty of project results. In addition, parameters were introduced to reflect decision-makers' scale preferences and characterize the impact of project coupling relationship on overall portfolio utility. And the "non-additivity" of total utility was utilized to break through the limitation of traditional models. Results show that (i) the non-additive multi-attribute utility function model can effectively characterize uncertainties in field projects and the coupling relationship among projects; (ii) from the case study of S field, the portfolio selected from this model can improve the relatively expected utility and reduce utility loss; and (iii) sensitivity analysis indicate that the project portfolio selected from this non-additive model has comparatively small replacement and strong robustness as the budget varies. In conclusion, applying the non-additive multi-attribute utility function model to portfolio optimization can promote the quality in making decisions.

Some exploration wells in offshore X gasfield were taken as objectives to analyze the main reservoir factors affecting post-frac productivity in offshore low-permeability gas reservoirs in order to accurately predict such productivity and quantify uncertainties related. However, traditional deterministic approaches only have single results and risks cannot be quantified. Afterwards, the relation of post-frac natural-gas open flow rate to reservoir coefficient was determined through fitting, and the method of Monte Carlo stochastic simulation was introduced to obtain productivity prediction outcome which was expressed by probabilistic. Results show that (i) the combination of productivity relation with Monte Carlo simulation can effectively quantify post-frac productivity uncertainties in these offshore wells, and the output results are expanded from a single valuation to a probability interval, so that predictions become more comprehensive and decisions get more available; and (ii) practices demonstrate that the reasonable post-frac open flow rate in the targeted field ranges in (5.08-6.36)×104 m3/d, which may provide a clear quantitative basis for risk evaluation in development plans. In conclusion, Monte Carlo method intuitively characterizes the probability distribution of productivity when geological parameters are uncertain, so it is available for solving exploration data in shortage. What's more, the P10-P50-P90 productivity estimates generated from this method can provide key risk indicators for optimizing fracturing schemes and development economic evaluation, so as to promote offshore low-permeability gasfields in the efficient growth.

Taken 10 development plans of tight gas in Sichuan Basin as samples, the main factors controlling on the unit full cost for tight gas were analyzed by using radar maps in an effort to improve economic benefits and risk management capability in tight gas fields, and achieve accurate prediction on development costs and scientific optimization on investment decision. Moreover, a probability model of unit full cost was established creatively by means of Monte Carlo method. Results show that (i) owing to joint effects of different resource endowment and high technological complexity, the unit full cost of tight gas is greatly higher than that of conventional gas, and it is 1.2-1.5 times that of conventional gas; (ii) at present, the unit full cost of tight gas is dominated by unit depreciation and depletion (accounting for 49.8%), and the operation cost mainly consists of maintenance and repair, exploitation operation, and downhole operation costs (accounting for 60.7%); (iii) six key cost factors are screened out through the analytic hierarchy process (AHP), and a Monte Carlo simulation objective function for the unit full cost is constructed on the basis of Gaussian, triangular, lognormal, and Gamma distribution to achieve comprehensive fitting analysis of multiple probability density functions; and (iv) from the perspective of fitting accuracy, the lognormal distribution function is greatly superior to other density functions. The P50 fitting result shows that the unit full cost is 1.049 yuan/m3, which is highly consistent with actual cost. In conclusion, these findings may provide reliable basis for benefit risk warning and optimal decision making.

Under the promotion of new quality productive forces, professional technical talents have grown into one of core driving forces for petroleum enterprises in the high-quality development. And their cultivation and echelon building are confronted with new opportunities and challenges. Taken enterprise needs into consideration, both path and countermeasures were discussed for the construction of technical talents in petroleum enterprises from numerous perspectives, such as echelon planning, training path design, technical standard system construction, and incentive mechanism optimization. Results show that (i) the system of "conventional oil and gas + unconventional oil and gas + new energy" integrated with "major energy discipline" can break through disciplinary barriers, promote cross-field collaborative innovation, and enhance technical skills and talent cultivation level for such enterprises; (ii) the design and completion of professional technical honor scheme based on job requirements and development stages, and the construction of development channel from "basic talents" to "strategic leaders" can strengthen talent motivation and promotion mechanisms; (iii) not only systematic hierarchical training path but standardized technical performance evaluation system will promote standard and scientific talent selection, promotion, utilization and motivation; and (iv) enhancing the integration of education and training, practical training, and lifelong learning, which combines with enterprise-school cooperation, scientific research innovation, and academic exchange, can setup a diversified talent cultivation ecosystem. In conclusion, these measures will stimulate the innovative potential of talents, promote the driving force of technological innovation, and build up a high-quality talent echelon that meets requirements of new quality productive forces, so as to provide strong support for petroleum enterprises in both technological advancement and core competitiveness enhancement, and solid talent guarantee for national energy security, and industrial transformation and upgrading.

While deepening the "X+1+X" market-oriented natural-gas reform and accelerating the construction of a new pattern of production, transportation, storage and sales in China, all natural-gas supply and use enterprises shall improve their contract awareness and risk management skills. Based on the basic theory of modern contract economy, characteristics were pointed out for medium- and long-term natural-gas purchase and sales contracts, and the significance, principles, terms and measures were discussed for domestic supply and use enterprises to sign and execute medium- and long-term contracts, so as to provide theoretical support and practical reference for promoting China's natural-gas markets in the long-term sustainable development. Results show that (i) these contracts signed by these enterprises are mainly characterized by indefinite terms, openness and inclusiveness, and moderate flexibility; (ii) the main signing and executing principles are to comply with market rules, scientific allocation, supply and use bottom line, unified quantity and price, and voluntary selection; and (iii) the primary signing contents include dynamic workload allocation model, differentiated pricing model, default compensation agreement, and other clause agreement. To promote domestic natural-gas supply and use enterprises to flexibly sign and execute medium- and long-term purchase and sales contracts, it is recommended to ascertain the supply and use pattern, reinforce the publicity and guidance in effect, prepare purchase and sales contracts in a scientific mode, select signing and executing objects thoroughly, and organize the signing and executing in an orderly manner.

With the rapid growth of China's economy and the transformation of energy structure, natural gas, being a kind of clean energy resources, continuously increases in its proportion in energy consumption. Especially, shale gas serves as the key alternative energy resources for low-carbon transformation. And to evaluate scientific benefits in its green development is a core proposition for coordinating energy security and ecological protection. The current evaluation of shale-gas benefits mostly highlights single-dimension benefit calculation, but ignores the nonlinear correlation between indicators and the impact of policy and market uncertainties, resulting in evaluations deviating from actual values. Therefore, an integrated evaluation framework, which depends on principal component analysis (PCA), Gaussian Copula function and Monte Carlo simulation, has been created. And comprehensive benefits in green shale-gas development were evaluated from four dimensions of economy, environment, society and technology. In addition, the multi-scenario simulation was built. Results show that (i) both environmental dimension (weight 29.28%) and technological dimension (28.35%) jointly contribute over 57% of the weight, indicating that green application and ecological governance have become the principal drivers of efficiency increase; (ii) the comprehensive benefit score of the optimized scenario is 0.567, which is 22.11% higher than that of traditional models (0.465), and its 90% confidence interval is [2.13%, 46.03%], revealing the statistical robustness of benefit advantage; and (iii) the sensitivity analysis demonstrates that marginal benefits of governance indicators such as compliance rate of hazardous waste disposal (impact coefficient 0.920) and resolution rate of community conflict (0.356) far exceed such traditional economic indicators as gas price and production, verifying the leverage effect of "bottom line management" on the green development. In conclusion, this study creatively combines statistical models with uncertainty quantification, so as to provide not only a replicable interdisciplinary tool for evaluating development benefits in unconventional resources, but also public services and oil and gas enterprises with decision-making basis from aspects of governance mechanism optimization and technical standard iteration.