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.

In recent years, high yield has been acquired from the Upper Ordovician Wufeng Formation-the first submember of first member of the Lower Silurian Longmaxi Formation (Long 1₁ submember) in shale gas wells, Luzhou area, revealing promising prospects in shale gas exploration and development. So, taking the organic-rich shales of Wufeng Formation-Long 1₁ submember in this area as examples, we discussed the extension of minor layers and microfacies together with the quality difference of shale reservoirs with different microfacies in an effort to better promote both efficient exploration and fine development in Luzhou area. And then, the predominant microfacies and the main controls on shale gas enrichment and high yield were made clear. Results show that, (i) Wufeng Formation-Long 1₁ submember can be subdivided into Wufeng Formation, Long 1₁¹, Long 1₁², Long 1₁³ and Long 1₁⁴, which individually represent their own characteristics in lithology, electric property and fossil; (ii) totally, there developed 9 microfacies from Wufeng Formation to Long 1₁ submember, among which, strongly reduced argillaceous siliceous shelf, strongly reduced silty siliceous shelf, and strongly reduced silty calcareous-siliceous shelf function as the most dominant microfacies, where shale features four highs in TOC, porosity, gas content and brittleness. And it is mainly developed in Long 1₁¹, Long 1₁² and Long 1₁³; and (iii) the strongly restricted setting of deepwaters is the foundation for the extension of quality shale with high yield, abnormal pressure and rich gas content as the guarantee, and effective fracturing as the key, respectively.

Drainage gas recovery, as an elemental process to improve both production and stability of tight gas in horizontal wells, is extensively used in various tight gas blocks. Thus, taking both technology and economy into consideration, an optimal and comprehensive approach was adopted for drainage gas recovery in order to improve development efficiency and economic benefits in tight gas resources. Four processes of drainage gas recovery (optimized string, foam, air lift and plunger) were verified and discussed in term of their applicability. In addition, a synthetic evaluation model was constructed by means of fuzzy mathematics theory and analytical hierarchy process. Results show that (i) it is feasible to take process flexibility, ground flow complexity, management difficulty and maintenance-free period as management indexes; (ii) the evaluation method should ponder on technical and economic factors fully; (iii) for Wubaoqian X1 well as a classic tight gas well confronted with difficulty in the production with liquid, the economic benefits are individually analyzed for the four processes. As a result, the integrated available value of both economic benefits and management is 0.92 through foam drainage gas recovery which is available for X 1 well. In conclusion, all results are is greatly significant for improving the development efficiency and benefits in tight gas resources, and provide powerful support for the development management of such fields.

Natural-gas markets in the United States boast high openness after their evolution and reform for over a century. Meanwhile this country is not only the world’s largest natural-gas consumer and producer at the moment but one of the most advanced countries in pipeline technologies. Thus, some American innovative approaches on the investment recovery mechanisms were analyzed for renovating urban-gas pipelines. Moreover, the financial subsidy plan from the federal government was discussed. In addition, And a lot of renovating successes were summarized in an effort to guide China’s renovation. Results show that (i) considered the particularity of gas industry, it’s recommended to adopt a system of floating rate to set up the reasonable rate according to the seasonal difference in gas consumption; (ii) using the way of the American government for reference, we may set up technological awards or R & D fund to encourage technological application; and (iii) public information about American pipelines may offer experience for our policy formulation, normalization, and examination and supervision in public information, and further standardize and implement this disclosure. In conclusion, learning from American innovation in the cost recovery mechanisms of gas pipelines’ renovation, we shall take their essence and combine practice application while localizing the experience absorbed, and to further find the solution in the investment return of the renovation.

At present, oil and gas exploration and development are confronted with increasingly fierce market competition, and oil companies are actively in reforms and innovations on system and mechanisms. It is urgent to intensity management innovations on purchasing construction projects in order to improve the quality and efficiency, and impel the digital transformation in purchasing business. So, taken efficiency and risks in this purchasing into account, innovative routes were proposed for tight gas exploration and development construction projects in Sichuan Basin through SWOT model and some advanced experiences. Results show that (i) there are two innovative ideas for purchasing management. The first, with problem-oriented and considerations on both symptoms and root causes, we should establish an integrated project management mode, reinforce project management of Party A, and continuously improve the business support and supervision collaborative management. The second, we should actively advance the fusion and development of new digital technologies and bidding, predict purchasing price trend, strengthen contractor and contract management, and control risks; (ii) there are four innovative strategies, such as to make countermeasure against ricks and control mechanisms to boost the achievement of the goal of governing enterprises in accordance with laws, to improve the digitalization of purchasing business in high-quality development, to invite bids in the multi-bid section form and the centralized and intensive form to ensure compliance and efficiency, and to improve the contractor management to further raise service quality; and (iii) after these management innovations, better effect has been achieved for tight gas development projects.

In order to improve the complexity of hydraulic fractures and the post-frac productivity in shale reservoirs of Longmaxi Formation, Weirong gas field, southern Sichuan Basin, the complexity in the previous 15 horizontal wells was evaluated quantitatively and fracturing controls on G function were discussed to make measures against this complexity improvement. Furthermore, parameters in the following fracturing and a temporary plugging process were determined. Results show that (i) the induced fractures in this field are mostly type II complex ones. The fluctuation coefficient of G function is in strongly positive correlation with absolute open flow (AOF). The higher the proportion and complexity of complex fractures, the better the post-frac effect; (ii) enlarging fracturing scale and displacement and performing temporary plugging are conducive to the complexity improvement; (iii) the reasonable fracturing-fluid and sanding intensity is 28 m³/m and 2.4-2.6 m³/m, respectively, and the construction displacement shall be increased to over 16 m3/min; (iv) the plugging should be carried out dominantly at the fracture opening and secondarily in the fractures; and (v) the elemental fracturing process formed has been applied to 18 horizontal wells, whose stimulation effect is remarkable with a great increase in the complexity and the AOF increased by over 20%. In conclusion, G function is better applicable to evaluating the fracture complexity and optimizing technological parameters, and can be used for references on similar gas fields.

Recent demands on the innovative growth are made for audit industry when the Communist Party of China gives impetus to a self-revolution. How to bring forth novel ideas in audit ways or means and to deliver better audit services in the whole production and operation process are the burning issues for petroleum enterprises in this day and age. Therefore, a "two-stage" audit model and relative safeguards have been built and proposed for the enterprises. Results show that (i) on the basis of exclusive features of two stages, including data analysis stage and on-site verification stage in audit projects, and relied on technological and organizational reforms, this model carries on cross activity, bi-directional feedback, and following-up tracing and closed loop via adopting the required resources and plausible approaches; (ii) four safeguards proposed in this model are to set up the organizational framework, the pre-audit working standards, the requirements on rectified and improved problems, and the digital command center; and (iii) five major achievements are made after its application to an enterprise, such as full-coverage focus, standardization guarantee, efficient convoy, quality and performance promotion, and scientific and technological drive. In conclusion, with superior quality and efficiency in audit services, the "two-stage" model is contribute to the modernization of governance system and ability in these petroleum enterprises.

Green supply chain has been showing the value in recent years. Taking the construction of the world-class material supply chain management system as a strategic goal, petroleum enterprises are accelerating two sorts of transformation, from procurement management to chain management and from minimum procurement costs to minimum total costs in all life cycle. So, some problems on the quality management of material procurement in the supply chain were discussed after studying the chain management in order to explore measures of procurement quality beneficial for the chain construction, to promote the cooperation, sharing, all-win and mutual benefits among the enterprises in the supply chain. Then, suggestions and measures were put forward for cost reduction and benefit increase to further realize high-quality development. Results show (i) to optimize the organization structure, and advance the value evaluation of quality management posts; (ii) to define the quality work interface, and sort out the management process; (iii) to attach importance to the training of quality control personnel; (iv) to establish the quality improvement mechanisms for supplier, and (v) to continuously consummate the quality management system of material supply.

Using reservoir engineering approaches, we dynamically discussed an actual operation in Wen 96 underground gas storage (UGS) from two aspects of water invasion and small range in pressure run constraining both storage capacity and production achievement. And several countermeasures were also made for this achievement. Results show that (i) four technologies, which are conducive to achieving both storage capacity and production in this UGS, contain edge water control, well pattern control, injection-production engineering without tripping tubing string, and pressure enlargement. The injection-production well pattern is further improved by the newly drilled adjusting and renewal wells to draw upon not only working gas volume at the late injection-production period but marginal uncontrolled reserves in the upper submember of the Paleogene Shahejie 3 Member. As a result, the incremental working gas volume is 0.35×10⁸ m³; (ii) mechanisms on production run are optimized to condition the edge-water invasion after core experiments to evaluate this invasion affecting both storage capacity and working gas volume; (iii) some injection-production measures are taken to solve liquid accumulation and salt precipitation so as to improve injection-production capacity; and (iv) the injection-production pressure range is enlarged to meet the UGS's run under the designed maximum and minimum pressure of 27 MPa and 12.9 MPa on maximizing the recoverable production. It is concluded that the stated results contribute to expanding the capacity on the basis the capacity achievement to ultimately improve the working gas volume.

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

In order to safely and efficiently develop coal-rock gas reservoirs of the Permian Longtan Formation in Sichuan Basin and ensure the effective substitute of natural gas in Sichuan-Chongqing area, it is necessary to ascertain development difficulties in coal-rock gas wells with this formation as the target and to solve frequent accidents and complexities. Thus, taking JT1H well, a key exploration one deployed by PetroChina Southwest Oil & Gasfield Company as an objective, we discussed its sticking points in engineering and geology, including fractures developed within coal rocks, poor drillability resulted from complex lithology, large variation in wellbore trajectory, and inconvenient control on drilling-fluid performance. Then, complexity treatment was analyzed from four aspects of wellbore trajectory, drilling-fluid system, drilling parameters, and precise sticking prevention. Results show that (i) the five-stage trajectory is adopted, which reduces the dogleg degree with effect to satisfy the need of safe drilling for a horizontal interval over 1000 m long; (ii) giving full play to the geology-engineering integration and predicting coalbed thickness, downhole lithology and formation dip can help optimize engineering measures and lesson complexities; (iii) a method which may control the key drilling parameters in horizontal intervals like weight on bit (WOB), rotation speed and displacement is established to diminish coalbed scour and formation collapse; and (iv) lithologic elements are analyzed to detect high-density and high-hardness coal gangue in time and avoid sticking. In conclusion, the compound drilling technologies of efficient PDC bit + rotary steering tool + screw improve the rate of penetration and ensures the drilling rate. With the cumulative thickness of 219 m and the horizontal interval of 1160 m, there are 6 coalbeds of Longtan Formation safely drilled in JT1H well by virtue of these technologies. To deal with abnormality in drilling parameters, to adopt shale shaker, all-in-one machine and centrifuge with effect, and to develop coal-ash mechanical defoaming may cut down pipe sticking. In addition, promoting safe drilling technologies is of guiding significance for the further study on coal-rock gas development in Sichuan-Chongqing area.

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.

Porosity is a decisive parameter in the evaluation on reservoirs' physical properties. Only a little data has been acquired from drilling and coring in NC area, central Sichuan Basin. In particular, it was a direct challenge to receive this parameter. And traditional methods for porosity prediction based on conventional logging data give rise to a large error or poor accuracy. So, taken the reservoirs of Xujiahe 4 Member as examples, an improved machine-learning algorithm, namely SAO-LightGBM, was put forward to clarify the physical properties of tight sandstone reservoirs in this area. Then, the algorithm was utilized to analyze the latent relationship of porosity to logging parameters, indicating its strong correlation with acoustic time difference, density, neutron porosity, resistivity and natural gamma. Finally, a prediction model was built on account of these parameters. Results show that (i) owing to the exclusive dual swarm mechanism together with both efficient enquiry and utilization strategy, SAO algorithm can quickly search an optimal hyper-parameter combination of LightGBM, so as to scale up this model's prediction ability; and (ii) both mean absolute error and determination coefficient of SAO-LightGBM are 3.37% and 0.92, respectively. In conclusion, boasting more reliable ability in comparison with other regular models, SAO-LightGBM can predict the porosity very well, which plays a guiding role in reservoir research and later exploitation in NC area.

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

In this study, two suites of gas reservoirs in Sichuan Basin were taken as objectives to identify controls on the productivity in tight sandstone reservoirs with underdeveloped natural fractures, including the Upper Xujiahe 2 Member in Yuanba area of northern basin and Xujiahe 5 Member in Dongfengchang area in central basin. Their geological characteristics, drilling techniques and fracturing stimulation were discussed to ascertain the productivity controls. Results show that (i) vastly enriched in natural gas, both ancient and current structural highs with a great possibility in big output are available for hydrocarbon migration and accumulation. While there exists a poor effect in structural lows; (ii) the better the reservoirs' physical properties, the higher the enrichment in the reservoir-forming process, and the stronger the flowing rate in the production process, also implying the thicker the developed reservoirs with high quality, the higher the output; (iii) it is essential to perform the stimulation in such reservoirs with underdeveloped fractures. Especially, to expand fracturing scale may create an obvious stimulation effect in the developed quality reservoirs; (iv) not all of tight sandstone reservoirs are developed everywhere, creating more quality ones encountered in horizontal wells. So, an evidently incremental production can be attained in vertical wells; and (v) reservoir protection shall be stressed because some reservoirs with poor to moderate physical properties are contaminated by barite in drilling fluid to further condition the output. In conclusion, for the porous tight sandstone gas reservoirs, the productivity is mainly influenced by ancient and current structural highs, growth of quality reservoirs, stimulation scale and well types. What's more, the priority for well deployment shall be set in some superimposed zones developed with quality source rocks, positive structures and comparatively quality reservoirs.

Gas reservoirs of Xujiahe Formation, Dongfengchang area, central Sichuan Basin, are characterized by extra low porosity and permeability, high water saturation and normal pressure, leading to terrible effects in their stimulation and stable production after the early regular fracturing. Thus, we discussed fracturing technologies via an example from the new DF109H well in order to draw on the low-grade gas reserves in this formation. Geology-engineering integration technologies were appeared through a series of research to reduce reservoir damage, speed up flowback, enlarge stimulated bulk, and realize efficient proppant placement. Results show that (i) one system of working fluid which is composed of energized prepad liquid nitrogen and water-based drag reducer can increase flowback energy in tight gas reservoirs with normal pressure, so as to advance liquid drainage and cut down reservoir damage, and to make a rapid breakthrough in deliverability; (ii) sweet spots of both mud and well logging are selected for perforating, and differential high-density fracture arrangement is conducted. Large displacement and composite temporary plugging are used to enlarge the size of hydraulic fractures, decrease flow distance and raise distal supply capacity; and (iii) that fractures remain effective for a long time is the key to stable production. Fiber and dispersing agent are injected through pulse plug during sand fracturing so that proppant is placed more uniformly. In conclusion, with fine fitness in the tight gas reservoirs, these technologies may increase the production substantially and become considerable measures for the efficient reservoir development in Dongfengchang area.

New elements induced from the development of new quality productive forces can offer pivotal support for petroleum industry in high-quality development, and are the key empowerment for this quality development too. So, based on the newly induced elements, concepts and modes from the forces, fresh empowerment ways to this industry with quality production, normalized governance, and industrial expansion were studied from technological innovations, management innovations and industrial-chain innovations in order to boost the quality development and ensure the quality of industrial reforms. Results show three problems in this empowerment, containing still room for creative level and insufficient transformation in technological achievements, unequal growth between digital and physical economy as well as imperfect growth mechanisms, and slow integration of upstream to downstream and inadequate system of industrial integration. To address these problems, some policies are put forward as follows (i) refining mechanisms in technological innovations to advance the sudden emergence of new quality productive forces, (ii) accelerating the digital-physical integration to achieve industrial transformation and upgrading, and (iii) expediting vertical fusion and perfecting optimal strategies on convergence for petroleum industry in high-quality development empowered robustly by new quality productive forces.

In this study, the full-bore soluble plug was taken as an objective to analyze its key structure for pressure bearing and main controls on temperature resistance in order to meet the need of completion under pressure for internal plugging tools in sustainably upgrading reliability and efficiency. And then a thought was put forward to resolve the contradiction between high-pressure stress concentration and material safety strength. Results show that (i) a safer and more reliable pressure-bearing plugging structure is established by means of the CAD/CAE integrated design method; (ii) in the light of experimental data on high-temperature mechanics, combined with the selected chemical formula of soluble magnesium alloy materials, the best material association is determined, and the contradiction between high-temperature mechanical strength and material solubility is resolved; and (iii) the Plasma-Enhanced Chemical Vapor Deposition (PECVD) method is used to prepare multi-layer nano-protective film, which may effectively improve the corrosive resistance of the plug and ensures its pressure-bearing stability and reliability as well as the quick dissolution in the later stage. It's concluded that this soluble plug boasts excellent temperature resistance and pressure-bearing capabilities besides outstanding corrosive resistance. Without any residue, it can be dissolved quickly after the operation is finished, which is conducive to the next work, and provides a more reliable, green and economical tool for not only completion under pressure but the efficient development of unconventional reservoirs.

Completion-fluid density is essential for borehole stability in deep marine openhole horizontal wells with the horizontal length over 2,000 m due to long cycle time and complex string structure highly needed for the stability whose relation to both trajectory azimuth and borehole inclination should be taken into account. Therefore, the influence of producing pressure differences on the stability was analyzed for those wells with or without fractures through numerical simulation and two Drucker-Prager criteria to estimate both strength failure and effective plastic strain. In addition, one method for density evaluation was created for stability assurance. Results show that (i) there exists the best stability in some horizontal wells without fractures along the direction of maximum principal stress, and this stability is increased with the increased inclination; and (ii) there exists the most stable wells in the others with fractures whose dip of 90° goes the maximum principal stress. The fracture strike that moves to the direction of the stress from that of minimum stress makes the stability somehow better. And this borehole stability grows with the increased dip. In fact, this method has been applied to Pz3-4D well successfully to verifying simulation ending, which may provide a novel solution for stability improvement in deep openhole horizontal wells.

Natural gas, a sort of transitional resources for energy transition, is growing rapidly. However, its storage and transportation are in the face of multiple challenges, such as poor storage facilities, not very good connectivity among pipelines, and safety and environmental risks. Therefore, the path to the high-quality development in the natural-gas storage and transportation was proposed in terms of ensuring national energy security and stable gas supply, improving natural-gas utilization, and reducing a negative impact of carbon emission. Results show that (i) this quality development driven by energy revolution should emphasize four revolutions and one cooperation, with the promotion of energy transition and upgrading as the goal, the optimal allocation and integration of storage and transportation resources as the core, the value creation as the premise, the innovation as the fundamental driving force, and the sustainability as the essential path. And it is necessary to adhere to both quality and efficiency the first, and encourage the digital, informationized, international and sustainable development of the storage and transportation; and (ii) it is essential to fix on the application and innovation of green and intelligent technologies to the storage and transportation domain, to strengthen the construction and upgrading of gas pipelines, underground gas storages and peak-shaving facilities, to make better the networking infrastructure like storage, transportation and pipelines, to build an efficient gas market monitoring system and an information exchange platform; to establish the international energy corridor cooperation and innovation mechanisms based on the Belt and Road Initiative, and actively cultivate the storage and transportation globally-oriented talents. These measures are conducive to the development of the natural-gas storage and transportation toward safety, green, information, intelligence and efficiency, so as to achieve the smooth and stable energy transition and advance the flourishing and sustainable development of energy industry.

In an effort to speed up the productivity construction of tight gas in Sichuan Basin, gas reservoirs of the first member of the Middle Jurassic Shaximiao Formation (Shaximiao 1 Member) in Zitong block of northwestern basin were taken as examples to analyze geological and development characteristics. With complex geological conditions, the Shaximiao 1 reservoirs are quite different from the same reservoirs and Shaximiao 2 reservoirs individually in adjacent Jianyang and Jinqiu blocks. So, it's necessary to make available measures on development technologies through pilot tests. Results show that (i) developed with vertically superimposed multiple-episode channel sandstone, the Shaximiao 1 reservoirs in Zitong block are characterized by poor physical properties, small thickness, and strong heterogeneity; and (ii) there exist numerous pressure systems in these reservoirs with high water saturation, leading to big incidence of water production. In conclusion, Zitong block has a great prospect in natural-gas exploration and development, and will be a remarkably new domain for enlarging reserves and production in the future. Nevertheless, a shortage of static and dynamic data and inadequate understanding on reservoir geology make it essential to conduct pilot tests. What's more, there massively extended two suits of reservoirs in Zitong block, such as No. 1 and No. 4 sandbodies superimposed in Shaximiao 1 Member. And industrial gas flow has been received. Both sandbodies are selected as the target in pilot demonstration areas to make clear gas content in them. On top of that, learned from development experience in adjacent blocks, 8 horizontal wells with big included angle have been deployed and some efficient stimulation technologies have been optimized to establish a geology-engineering integration model, among which the designed output in single well is (6-9)×10⁴ m³/d, and the predicted cumulative production also in single well of (1.06-1.30)×10⁸ m³, respectively.

In order to help PipeChina smoothly implement the "Five Optimizations and One Innovation" (including normalized design, intensive procurement, mechanized construction, digitized delivery, intelligent operation and innovative leadership), both principal framework and practices were studied for advanced technologies to predict the consumption demand on natural-gas resources in the recent decade by means of literature survey. Results show that (i) at present, the commonly used prediction methods mainly include four kinds of prediction, like empiricism, market investigation, time series, correlation, and combination model; (ii) these methods are available for different project background due to their difference in running mechanisms and data source; and (iii) both empirical and market investigation prediction methods are more suitable for judging rough development trend, while both time series and correlation prediction ones can better reveal coupling laws among model elements. And combination model is able to meet the need of multi-scenario prediction. In conclusion, prediction models have their own advantages and disadvantages, and the combination model is conducive to capturing further input information, reducing prediction errors caused by single modeling, and further improving fitting superiority under the guidance of digital technologies, so as to provide additional reference with rational decision-making and optimal planning.

Taken Dugui gas province as an example, the production traits were discussed for tight sandstone gas wells rich in water at various water/gas ratio to hold up the efficient development in such gas reservoirs. On this basis, the effect of stress sensitivity and pressure difference on the production was also analyzed. Moreover, production outcome was accessed for gas wells with different proration working systems, and differentiated proration plans and standards were proposed to condition the pressure-drop rate. Results show that (i) with the unique pore-throat assemblage dominated by micropore and fine throat, the reservoirs in the study area feature low to ultra-low porosity, low permeability and strong heterogeneity; (ii) the development in these wells is seriously affected by water production. The higher the water/gas ratio, the larger the production decline and pressure-drop rate, and the lower the elastic yield; and (iii) with the increasing division in production pressure, part of capillary water and bound-water membrane may turn into movable water. As a result, water production increases, both elastic yield and cumulative production decrease, creating further complication in stabilizing production to deteriorate the development. In conclusion, for this kind of tight sandstone reservoirs rich in water in the mode of depletion development, controlling the proration and pressure-drop rate is an important means for gas wells to prolong their stable period and improve recovery. What's more, after the proposed differentiated proration plan and pressure-drop rate control chart have been in practice, the coincidence rate achieves up to 87.5%. So, these plan and chart may be popularized to the development in similar reservoirs and provide better guidance for the efficient development.

It's increasingly difficult for conventional natural gas to scale up both reserves and production with the advancement of exploration and development in natural gas. Natural-gas exploration and development is gradually shifting from conventional to unconventional domains. However, there exists significant difference in technical and economic traits between them. Thus, the comparative analysis was conducted for China's conventional and unconventional gas based on their genesis and geological features, exploration risks and costs, and development technologies. Results show that (i) unconventional gas in our country has more complicating genesis and geological features. It's essential to figure out its geologic conditions and evolution laws through benchmarking methodology so as to reduce exploration uncertainties; (ii) for unconventional gas, the exploration and development risks are generally higher, which should be turned from "passive meeting with" to "active foresight" by means of some studies on its identification, evaluation, and management to get clear pictures; (iii) unconventional gas spends higher development costs than conventional gas on the whole. Thereupon, some measures for cost reduction should be made, such as joint exploration and production between these two domains, enlarging technological R & D to raise development efficiency, optimizing operation steps to cut down invalid costs, strengthening safety risk control to diminish accident incidence, and pushing on cost's target management; and (iv) technologies used in both conventional and unconventional gas have their own style. Technical progress can be facilitate by setting up special fund for innovative research, building up knowledge-sharing platforms for unconventional gas, and collaboratively promoting theoretical research and practical application.

During west testing, there exists large difference in single-well productivity and poor effect in stable production for gas reservoirs of the fifth member of Xujiahe Formation (Xujiahe 5 Member) in Dongfengchang area. So, the main controls on the productivity and reasons on production decline were discussed in the light of geological, dynamic monitoring and experimental data. And some countermeasures were made for stabilizing production. Results show that (i) the productivity is principally affected by both types of gas wells and extensional degree of quality reservoirs. The productivity in horizontal wells is significantly higher than that in vertical ones. The more developed the quality reservoirs, the higher the productivity; (ii) for these wells, the stabilizing effect is poor with the average stable period of 10 months, and the production decline index of 0.0017 per day on average, creating low effective permeability and finite gas supply; (iii) induced from big production pressure difference caused by high proration in the early days of development, the reservoirs feature strong stress sensitivity. Moreover, small dew-point pressure difference results that condensate oil is easy to be precipitated to cause anti condensation damage, to bringing about permeability loss, and finally the rapid productivity decline; (iv) fracturing sand’s backflow results in the decrease of the conductivity in induced fractures and these fractures accumulated near wellbore area. And it’s hard for fracturing liquid to flow back, resulting in liquid accumulation or even water flooding and well shutdown; and (v) the managed-pressure production can effectively reduce the permeability loss. And liquid nitrogen cleanup and production-string optimization are conducive to liquid drainage. As a result, the productivity decline may be put off. All results may provide important reference on technical measures made for the development of tight sandstone gas reservoirs in similar areas.

There exist many problems in drawing sedimentary-facies plans, including confused facies or facies deficiency, too simple lithological icon style, facies division in chaos, and informal color filling. So, taking drawing specifications as objectives, we analyzed the main issues in SY/T5615-2004 Drawing Specification and Pattern for Oil and Gas Geology Exploration (hereinafter referred to as Drawing Specification and Pattern), and pointed out how to make use of the relatively complex marine carbonate facies model, establish lithology pattern library through systematic rock classification, and form coloring principles by gathering colors filling in different facies zones from deep-sea basins to ancient continents. Results show that (i) three conceptual facies patterns, including the newly revised Wilson facies pattern, the carbonate platform facies pattern and the carbonate gentle-slope facies pattern, are regarded as the most important reference basis to divide relatively complex marine sedimentary facies; (ii) referring to the classification scheme of both rock icon style and rock formation in Drawing Specification and Pattern, we have established over 2,200 lithology patterns through the five-step way, which may roughly meet the current demand for drawing sedimentary-facies plans with high precision and achieve the aim of "lithology namely lithofacies"; (iii) characterization on thin-section microfacies is conducted after accurate lithologic filling, which considers not only microfacies classification but micro scale in this thin section; and (iv) coloring principles are as follows: blue towards the deep-sea, brown towards the continent, and the marine-terrigenous facies in orange, respectively. In conclusion, to properly take advantage of facies patterns may improve scientific natures in drawing sedimentary-facies plans. Setting up the lithology pattern library which meets the needs of production and scientific research is conducive to this drawing timely. Accurate lithologic filling is helpful to perform facies classification, especially for microfacies with inconsistent definition. And these principles make the plans in better versatility and pleasing to the eye.

Even with clean and low carbon, natural gas has its own technological and economic advantages in flexible peak shaving and high multipurpose utilization. It not only serves as beneficial complementation to new energy, but is an important impetus for the growth of clean energy in Sichuan-Chongqing area. In line with the macro strategy of the Chengdu-Chongqing dual-city economic circle, dependent on the constructing a natural-gas base with production capacity above 100 billion cubic meters in this area, to build Sunning city as the imaging of "Oriental Gas Capital" has been proposed in order to take advantage of abundant gas resources and to advance both energy transformation and green development. So, this building was analyzed using the multi-scale method from aspects of necessity and feasibility. Moreover, the collected literature concerned natural-gas exploration, storage and transportation, utilization and development planning. On top of that, growth paths of gas industry in Suining city were ascertained by lots of investigation from relevant enterprises and colleges. Results show that (i) the economic-circle construction, the carbon-peaking and carbon-neutrality goals and the development of information technology all provide opportunities for building up the "Oriental Gas Capital"; (ii) Suining city has numerous strengths in policy, location, resource and market; and (iii) through "natural gas +", this city may promote the layout and construction of the Suining-Tongnan Natural-Gas Comprehensive Utilization Industrial Park, and strengthen scientific and technological innovations to work towards the imaging of "Oriental Gas Capital".

Normal-pressure gas reservoirs in Dingshan block along the margin of Sichuan Basin are confronted with technical challenges, i.e., low fracture-induced complexity giving rise to shortage of fracture-conditioned reserves, inconvenient post-fracturing drainage creating slow productivity release, and small recoverable reserves and difficult benefit development. With three objectives of addressing these challenges, such as the adequate reserve control in stimulation areas, and the reduction of both drainage load and stimulation cost, an efficient stimulation process with low cost, which the extreme limited-entry perforation to promote equilibrium and the integrated fracturing and drainage for composite load reduction are conducted as the dominant measures, and the simple formula of "drag reducer + cleanup additive" is used for cost reduction, has been developed for the normal-pressure shale gas in this block. Results show that (i) the extreme perforation can ensure the uniform initiation of fracture clusters, enhance the coverage rate from 75% to 90% in single-stage fracturing, and make the stimulated reservoir volume (SRV) by 15% higher than before; (ii) the drainage load is released through the composite load reduction, and the intensity of both fracturing fluid and proppant is optimized to be 15-20 m³/m and 1.5-2.0 m³/m, respectively. The rapid startup and drainage after fracturing without shut-in, running tubing during the initial fracturing, and gas lift cleanup can release the productivity while SRV assurance; and (iii) the fracturing-fluid system with low damage and cost can cut down the cost under such stimulation. Practice has proven that, after the application of this new low-cost fracturing technology to normal-pressure gas reservoirs by 6 well times from 2022 to 2023, the stimulation effect is improved by 60.2% and the fracturing cost reduced by 15.3%, respectively, which may provide successful experience for the subsequent large-scale benefit development in the low-grade reservoirs with normal pressure.

Technological innovations are the core element to develop new quality productive forces, and striving to this development has set the new request to innovations on natural gas. So, in an effort to fully stimulate scientific research vigour, enhance creative ability and innovation's efficiency transformation, and provide strong impetus for natural-gas industrial development in high quality, both current status and problems were analyzed in depth for the industrial innovations, and some countermeasures were formulated from the perspective of developing these new forces. Results show that, in terms of the forces' intension and strategic highlights, there exist several problems in the gas innovations, such as still room for improving the strategic layout and overall planning, training modes of leading talents, and technological management supportability. And taken the creative strategy as the guide, the talent cultivation as the source, and the thorough structural and mechanism reforms as the safeguard, three countermeasures are made, namely insisting on the science and technology as the primary productive force to construct the "361" project layout (30% for basic projects, 60% for application ones, and 10% for technique import or promotion ones, respectively), push forward the construction of high-level R & D platforms, and build mechanisms to foster major innovations; insisting on the talented personnel as the primary resources to clarify the cultivation objects of leading talents and cultivation ways, and optimize the echelon construction of back-up personnel; and insisting on the innovations as the first driving force to follow below creative principles on the natural gas, optimize collaborative security mechanisms, perfect mechanisms on check and initiate, and advise innovative surrounding with non-salary motivation as the core.

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

For underground gas storages (UGSs), the value property to make a profit from natural-gas trade through pricing fluctuation is known as the financial value. And this value in storage capability is important for the profit made via UGS business. So, pricing discrepancies among Europe, America and China were analyzed to further discuss assessment models on the financial value in order for UGS's value promotion. Moreover, some assessment ideas about this capability, which are also applicable to different development stages in China's gas market, were put forward, and a historical pricing model was built for this assessment at low degree of marketization. Results show that (i) the pricing modes in Europe and America at high marketization are characterized by high fluctuation and mobility, while the mode in China with low characteristics; (ii) taken these low fluctuation and mobility together with future changes into account, the built historical pricing model may be used to evaluate the financial value at low marketization, and the least square Monte Carlo simulation is regarded as another evaluation model for the improved price marketization; (iii) the historical model has its own features, such as calculation only for a single curve on historical price and functionality at the variable trading cycle. The lower the marketization is, the more credible the model evaluation is; and (iv) this pricing model is able to be applied to the value assessment on China's UGSs under existing pricing mode, capture the optimal working gas capacity at the high- and low-record price, and calculate relevant cash flow.

As data resources transform towards data assets, encouraging the data in fusion application, open sharing and circulation transaction has become an important way for natural-gas enterprises to enhance their competitiveness. Thus, a management system of data assets was constructed for such enterprises in line with present situation and system theory in gas industry so as to accelerate the pace of digital transformation. Additionally, its construction direction was discussed in terms of urgency, framework design, module construction and safeguard measures. Results show that (1) this system is notable for intensifying national energy governance, driving innovations on business modes, and enhancing enterprise competitiveness; (ii) highlighting the integrity, dynamicity, and universal connectivity, its construction needs the basic framework from five elements such as goal, structure, system, mechanism and platform; (iii) this system consists of five submodules, such as strategic goal management, organization, operational function, and management platform and system; (iv) to construct the management system should continuously perfect long-term mechanisms, foster management talents and build up platforms on data assets as possible.

Rich in natural-gas resources, Sichuan Basin where above 2×10¹² m3 of the proved reserves in place had been submitted cumulatively from 2019 to 2023 is one of the most abundant areas in China, which makes the development of natural gas access to the critical era of high quality. Nowadays, shifting to deep or ultra-deep targets, our exploration on conventional gas calls upon advanced drilling and completion technologies as well as better investment guarantee. And for tight gas, with strong heterogeneity in its reservoirs and numerous reservoir types, it's also urgent to upgrade low-cost matching technologies. In addition, as an emerging unconventional energy, shale gas will evolve into an elemental alternative domain for the coming large-scale reserve and production increase. So, confronted with ever-growing hardships in investment control, a management mode of technological and economic integration was discussed to address several issues throughout the natural-gas development and management in this basin, such as investment and unequal benefits, technology and disconcordant economy, and follow-up tracing and adjustment. Results show that (i) linking the entire integration process, a three-level management system is constructed to accomplish closed-loop control across all life cycle; (ii) management is the integration pivot. Employed the three-stage workflow and the five-point closed-loop means, a sort of work environment is set up for the integration to maximize economic profits; and (iii) intensifying organization security, consummating necessary system, fostering talents and building up intelligentization platforms will make the integration come true. It's concluded that, with the brand development of natural gas in Sichuan Basin, this discussion on the management mode of technological and economic integration may provide not only guidance for the cost control in natural-gas development and optimum benefits but reference for both development and management in some other oil and gasfields.

In Daniudi gasfield, Ordos Basin, production differs greatly in porous carbonate reservoirs even after hydraulic sand fracturing due to strong reservoir heterogeneity. Thus, a model was established to compute the production contribution of each layer, and a heat map matrix chart was created on both geology-engineering parameters and production data. Moreover, the major geology-engineering factors influencing on the production were analyzed to evolve into a formula for evaluating double sweetspots and calculating productivity. Results show that (i) the production contribution in fifth submember of Majiagou 5 Member (Ma 5⁵, hereinafter same) negatively correlates with gamma ray and positively with interval transit time, bulk density and gas saturation. While that of Ma 5⁶⁺⁷ is positively correlated with reservoir thickness, bulk density and neutron porosity; (ii) the production in Ma 5^5-7 is in high correlation with reservoir thickness, maximum total hydrocarbon, porosity, gas saturation, and injected fracturing-liquid, and acid proppant volume; (iii) the established double-sweetspot index calculation model for Ma 5^5-7 is dependent on multiple factors, and the calculated index has the correlation of 0.937 5 with the production; and (iv) the created production prediction model is on the basis of the double-sweetspot index, and the error between the predicted and actual production is less than 2%. In conclusion, with high coincidence with reality, both geology-engineering sweetspot and productivity prediction models which provide active guidance for selecting staged fracturing and designing optimal fracturing are worth popularizing.

The gas storage peak-shaving has turned into a universal technology to alleviate consumption summit as the shortage of gas source during peak gas consumption becomes increasingly serious. And rationally selecting the peak-shaving mode is the primary prerequisite for ensuring safe and stable gas supply. In order for better cost sharing in LNG storage and peak shaving projects, one item in Ya'an city of Sichuan province was taken as an example to predict its efficiency after some analysis on the status quo at home and abroad. Moreover, this item was optimized and improved to address the problem on its economic indicators not meeting standards. The affordable price was analyzed for gas enterprises by means of questionnaire over their price in peak-shaving services. Combined the questionnaire with real calculation, the sharing proportion was recommended for the peak-shaving costs. Finally, three cost-sharing schemes were individually made for relevant government departments, gas enterprises and end users based on the calculated results. It is demonstrated that (i) governments should reasonably differentiate between basic and nonbasic demands, fully think over upstream and downstream industries, enterprise development, livelihood security, economic benefits, and social fairness and justice, complete livelihood protection very well, improve policies on subsidy for disadvantaged groups, and ensure the groups' living gas unaffected by price linkage; (ii) gas enterprise should ensure their reasonable profits through reasonable sharing of LNG storage peak-shaving costs with end users, which embodies their responsibility as the main part of supply guarantee and the social attribute which gives priority to ensuring people's livelihoods; and (iii) end users should thoroughly consider the economic burden capability in needy families to eliminate individual spending as possible while keeping the normal production during peak consumption periods and seasons, ultimately to achieve mutual benefits and wins for multiple sides. In conclusion, the recommended sharing proportion may provide reference for similar projects.

Most coalbed methane (CBM) directional wells in Zhijin block are confronted with challenges, such as significant difference in the productivity, short time in the stable production, and unclear productivity controls. So, 23 directional wells deployed at large and small well groups in the study area were taken as examples to analyze the effect of both geological conditions and operational parameters on the productivity. Moreover, the influential degree of different geological conditions and technological measures on the productivity was pointed out for these wells. Results show that (i) the controls mainly include desorption pressure, coal seam thickness, working-fluid volume, lead volume and displacement; (ii) geologically, the average development horizons in large well groups are about 4 times those in small ones. And No. 16, 17 and 21 coal seams are better than others in terms of sedimentary environment, preservation conditions and reservoir structure; and (iii) the working-fluid volume, lead volume and displacement have a great impact on fracturing stimulation. Practical data indicates that, at a certain displacement, the stimulation effect is better when the working-fluid volume is about 5 times of the lead volume. Two conclusions are made. In addition to great in quantity, the coal seams in Zhijin block feature small in thickness, layer spacing and heterogeneity difference in vertical. Thus, a better effect may been achieved from multilayer commingled production by directional wells, and the overall effect in the lower to middle coal groups is better than that in the middle to upper groups. What's more, various stimulation scale and methods have a great impact on the productivity. For the Zhijin coal seams which are provided with high coalification and less brittle than the other seams or shale reservoirs, to raise the proportion of lead volume is helpful to induce fractures better, thus to scale up the stimulated reservoir volume.

With rich water, some tight reservoirs in Dongsheng gasfield along the northern margin of Ordos Basin were studied to ascertain production performance in commingled-producing wells and further guide the highly efficient development. This performance was individuality analyzed for single and commingled wells at various development stages, in different well areas or in the vertical. And controls of gas-bearing property between layers on the performance were discussed for the commingled ones. Results show that (i) such commingled ones have characteristics of high initial pressure and production, but their overall performance is correlated with both gas-bearing property and water production in the tight reservoirs; (ii) after parameter comparison, the performance in payzones has clearly positive correlation with physical properties and gas-bearing property, and the property difference between payzones also affects this performance; and (iii) the critical liquid-carrying (with foam) flow rate during stable production period is certainly related to water/gas ratio. It is concluded that, for the commingled-producing wells with relatively high initial pressure and production, their overall performance, however, is poor in somewhere with low gas saturation (high water/gas ratio). The interlayer production in the vertical is still evolving as the development time goes on. The better the physical properties and gas-bearing property are, the better the production performance is. The physical properties are dominant. Nevertheless, if there is large difference in the gas-bearing property between layers, gas and liquid are highly prone to severe backflow, resulting in not good overall performance. The higher the water/gas ratio is, the greater the critical liquid-carrying flow rate is.

The global energy structure has been optimized all along, and the low-carbon transformation is forging ahead. New quality productive forces serve as the recent dynamic for economic and social growth. Their expansion is of great significance for traditional petroleum industry in sustainable development. Thus, the forces' intension and features were discussed for traditional petroleum enterprises whose opportunities and challenges were analyzed in the context the present situation. In addition, paths towards the industrial high-quality development were discussed from aspect of new quality productive forces. Results show that (ⅰ) aimed at weak oil and gas import channels, both channels of import source and diversified transportation should be broadened to mitigate supply risks; (ⅱ) the principal activities in oil and gas markets should be stimulated through innovations on market mechanisms in an effort to address one problem about low dominance of Chinese market; (ⅲ) for these enterprises also as information intensive ones, information-sharing platforms should be utilized to tackle longer production chains, mutually independent institutional sectors, and poor information exchange; (ⅳ) because of capital as the essential guarantee for new quality productive forces, the green finance and investment in combination with financing should be conducted for the enterprises with pressure reduction; (ⅴ) oil and gas resources will be surely the main part of energy consumption for a long time. As a result, exploration should be strengthened, and both emerging and future industries should be in continuous cultivation; and (ⅵ) given talents as the fundamental for the forces, both creative surrounding and innovation intensity should be improved and enlarged to nurture highly qualified talents as many as possible.

To figure out the lithofacies distribution, main controls on reservoir extension, and reservoir-forming modes of volcanic rocks in eastern Sichuan Basin, both forming modes and hydrocarbon accumulation were analyzed for the Permian volcanic rocks in this area according to outcrop, drilling, logging and experimental data. Moreover, favorable exploration belts were pointed out. Results show that, affected by the Emei taphrogenesis, there developed two sets of favorable volcanic reservoirs in the Middle Permian Maokou Formation and the Upper Permian Wujiaping Formation of eastern basin. Mainly located in Dazhu-Liangping-Xinglongchang effusive-facies block of northern Fuling area, the volcaniclastic lava reservoirs around volcano seat are developed at the middle and upper parts of the third member of Maokou Formation (Maokou 3 Member). And they are 10 m to 35 m in thickness and their logging-interpreted porosity between 3.4% and 8.0%, respectively. Situated in Puguang-Fuling North-Jiannan area, the volcanic-sedimentary clastic reservoirs, also as the compound deposition of volcanic ash and regular sediments, far away from the seat, are developed at Maokou 3 Member bottom and in Wujiaping Formation. And their thickness varies from 16 m to 35 m. These volcanic-sedimentary clastic rocks are regarded as not only reservoirs but also quality source rocks. For sake of their own natures in high porosity and TOC, self-generation and self-storage, and massive and successive extension, it is possible to form reservoirs inside source. The volcaniclastic lava reservoirs of Maokou 3 Member are trapped by the source rocks of both underlying Maokou 3 Member bottom and overlying Wujiaping Formation, forming one source-reservoir assembly like a sandwich available for reservoirs near source. It is concluded that (i) in northern Fuling area, as the favorable exploration belt for the volcaniclastic lava reservoirs, old wells' resurvey and retesting or deploying exploration wells at advantageous structural points can be carried out; and (ii) surrounding Kaijiang-Liangping continental shelf, Puguang-Fuling North-Jiannan area is believed as the favorable belt for the volcanic-sedimentary clastic reservoirs. Unconventional thinks may be adopted, for example bypassing high-steep structural belts or selecting sweet spots with better preservation and buried depth less than 6,000 m for in-depth exploitation.

The state has been strengthening the "baton" role of performance evaluation in guiding central enterprises to hoist their capability in value creation. How to make flexible and good use of this evaluation to leverage more value output is essential to deepen the reform and development in petroleum enterprises. Thus, three evaluation aspects were discussed, including index system, both mode and tool selection, and result application. Results show that (i) guiding index policies on the enterprise head, such as "two-profit and three-rate" to "two-profit and four-rate" and then to "one-profit and five-rate", these enterprises establish multiple index systems emphasizing some core indexes of benefit, operation and control based on production practice; (ii) the performance evaluation mode is developing toward differentiation, target and precision, and the evaluation tool tends to diversification; and (iii) the evaluation results are mainly applied to salary distribution, and more attention is paid to their application to performance execution, guidance, monitoring and warning, and feedback.