Based on analyzing the history of shale revolution in the United States and the differences in geological and engineering characteristics of shale oil between continental basins in China and marine basins in the United States, the paper proposes ten noteworthy issues on continental shale oil revolution in China, including the application and evolution of the nomenclatures of shale oil and tight oil in U.S., the development process of shale oil/tight oil in U.S., the proposal and connotation of shale revolution, and the experience in system and mechanism that can be learned from successful shale revolution in U.S., the work pattern of shale oil in U.S., the relationship between the profit model of shale oil and investment channels, the relationship between production declines of shale oil, the concrete time when a breakthrough is made in shale oil exploration in China, the principles and standards for classification of shale oil, and the continental shale oil revolution in China. Research suggests that the concepts of shale oil and tight oil in North America are identical to some extent. The core of "shale revolution" in U.S. is to improve drilling and completion efficiency, reduce well construction costs, and increase single well production; the development stages of its work pattern is divided according to the changes in both well type and horizontal section length of horizontal well, as well as the development of hydraulic fracturing. The number of drilled and completed wells is an important indicator reflecting shale oil exploration and development. The profit models and investment channels of shale oil extraction are closely related. American companies’ pursuit of recovering investment as soon as possible to obtain profits leads to the general adoption of a production model based on pressure release, with a rapid decline in yield and an L-shaped production curve. In terms of system and mechanism, we should draw on the experience from the application of market mechanisms, the project operation model of "oil companies+lean management", as well as the establishment of shared and open databases. From the perspective of resource base, engineering and technological capabilities, and production expectations, China has the basic conditions for the success in the continental shale oil revolution. All efforts should be made to promote the marketization, technological and management transformation of shale oil exploration and development, highlight the "qualitative development and quantitative breakthrough" of shale oil, and effectively transform resources into reserves and then into beneficial production, which can ensure the victory of shale oil revolution.

China has a complete range of coalbed methane (CBM) resources, which are extremely rich and relatively reliable. The resource foundation can completely form an emerging industry with an annual gas production of hundreds of billions of cubic meters. With strong national support, after 30 years of arduous efforts, China has made significant progresses in the exploration and development of coalbed methane, forming an industry with an annual production of 10 billion cubic meters. However, this is too far from the goal of 100 billion cubic meters of coalbed methane annually, and the national task has not been completed for three consecutive Five-year plans. At the same time, China CBM industry has lost its clear development direction. Only a small contribution can be made to the urgently needed natural gas industry in China. The fundamental reason is that the theory and technology of CBM exploration and development established domestically and internationally over the past 30 years can not fully reflect the composition and pore structure characteristics of coal, as well as the occurrence state of methane mainly in an adsorbed state, which is not fully in line with the mechanism of CBM production, of which applicability is too small to be universal. On the basis of in-depth analysis of the mechanism of coalbed methane production, it is proposed that only the integration of coal mine gas and natural gas development disciplines can establish scientific and practical theories and technologies for CBM exploration and development. Then, four types of CBM resources are divided. Moreover, each CBM resource can be established with scientific and practical theories and technologies to achieve efficient exploration and effective development. This article discusses the possibility and implementation path of building a 100 billion-cubic-meter-scale CBM industry in China from aspects such as the status of CBM resources, progress in oil and gas exploration and development technology, occurrence and migration laws of methane in coal. This article proposes to rely on the cross integration of coal and oil and gas industries, strengthen basic research, establish a theoretical and technical system suitable for efficient exploration and effective development of various types of coalbed methane reservoirs, generate a new discipline (direction), form a new production, technology, and industry field, and build a path of a large industry, To achieve the development strategy of forming an emerging coalbed methane industry supported by original theories and technologies of coalbed methane exploration and development, and to ensure the rapid formation of China's annual production of a 100 billion-cubic-meter-scale CBM industry, in order to significantly reduce China's dependence on external natural gas.

Oil and gas are generated from organic matters in the rocks of sedimentary basins. Through an intensive and systematic study of global petroliferous basins, it is recognized that the distribution of global oil and gas fields is highly uneven, and most of oil and gas are enriched and accumulated in a few strata of sedimentary rocks. The distribution of oil and gas is significantly controlled by source rock, so that it is necessary to search for the source rocks initially before discovering new petroliferous basins. The nutrients required for biological growth in the sedimentary basins primarily come from rivers, and the nutrients flowing from rivers into the sedimentary basins control the degree of biological reproduction, and then control the abundance of organic matters in the source rocks, which decides the amount of oil and gas generated and the degree of enrichment of oil and gas resources in the sedimentary basins. Oil and gas are mainly distributed in the three systems on the earth, i.e., the river-lake system, river-gulf system and river-delta system. Specifically, the river-lake system is an important oil-bearing area on the earth. Lacustrine oil is mainly produced by sedimentary organic matters from the algae died in lakes. The growth of algae depends mainly on the nutrients that come from the rivers and flow into the lakes, and these nutrients can facilitate the growth of algae in the rift period and provide a guarantee for the formation of high-quality source rocks. The river-gulf system is the main distribution location of global marine oil. Gulfs are the estuary of rivers, which brings abundant minerals for rivers to promote the growth and proliferation of algae and other aquatic organisms; moreover, the gulfs are relatively isolated, which are conducive to the preservation of organic matters. In fact, boasting of the biggest reserves, the coal-type gas generated from coal-measure source rocks is the most widely distributed in the world and is mainly distributed in the river-delta system. The sediments brought by the river provide fertile soil for the growth of higher plants, and the native higher plants on the river-delta plain provide a solid material basis for the formation of coal-measure gas source rocks. The delta stratum reservoir is well developed with good reservoir-caprock configuration, which is beneficial for natural gas enrichment and accumulation.

Archean buried-hill zone in the western section of Bonan low salient of Bohai Bay Basin has good conditions for hydrocarbon accumulation. Bozhong26-6 oilfield is an Archaean integrated oilfield with proven reserves of crude oil exceeding 100 million tons. Based on a large number of core, thin section, well logging and geochemical data, a systematical study was performed on Bozhong26-6 oilfield. The analysis suggests that the Archean buried-hill reservoirs can be vertically divided into weathered conglomerate zone, weathered fracture zone and bedrock zone, among which the weathered fracture zone is the key reservoir development zone. The superimposed fractures formed by the Indosinian, Yanshanian and Himalayan movements provided the foundation for the development of Archaean buried-hill reservoirs. The Indosinian compression and collision and the Yanshanian strike-slip thrust were the main driving forces for the formation of fractures, and the south-north extension of the Himalayan epoch maintained the validity of earlier fractures. Under the communication of fractures, a wide area of high-quality buried-hill reservoirs is formed by the dissolution of atmospheric fresh water, and the high-quality reservoirs are developed in the zone within 420 m away from the unconformity. The mudstone of Dongying Formation with weak overpressure and strong stability overlying buried hill provides good sealing conditions for the preservation of large-scale oil reservoirs. The Archean buried hills are in direct contact with the source rocks of Huanghekou sag in the south, and are connected with the source rocks of Bozhong sag in the north by the unconformity, thus forming a multi-dimensional oil-gas migration and charging mode. In conclusion, the above findings provide a guidance for the efficient exploration of Archean high-abundance oil reservoirs in Bozhong26-6 oilfield, further improve the hydrocarbon accumulation and reservoir mode of deep Archean buried hills in Bohai Bay Basin, and are of important guiding significance for the oil and gas exploration of the Archean buried hill zone around the southwest Bozhong sag.

After nearly 40 years of exploration in Kaiping sag of Pearl River Mouth Basin, a medium to large light oil field has been discovered in deep-water Paleogene strata of Kaiping11-4 structure. To further guide oil-gas exploration in Kaiping sag, the paper deeply investigates the petroleum geological conditions such as hydrocarbon sources, reservoirs, traps, preservation and migration conditions in Kaiping11-4 structure, and summarizes the oil and gas accumulation mode. The geological structure of Kaiping sag is a detachment-type compound half-graben with faults in the north and overlaps in the south. In Kaiping sag, Wenchang Formation develops high quality semi-deep to deep lacustrine source rocks with great hydrocarbon generation potential, and the shallow-water braided delta front deposits of Enping Formation develop a favorable reservoir-cap assemblage. The traps formed under the early tectonic activities are various, including faulted block, faulted anticline and plunging anticline, while the weak tectonic activity in the late period is conducive to oil and gas preservation. The inheritance faults that cut through the source rocks provide vertical migration channels so that oil and gas can be transported through the "source-fault-reservoir" system. The reservoirs in Kaiping11-4 structure have undergone multi-phase continuous charging since 17 Ma, presenting a hydrocarbon accumulation mode with the characteristics of "hydrocarbon supplying from high-quality lacustrine sources, strongly charging through near-source faults, and enriching in multiple stages and levels". The discovery of medium to large light oil field in Kaiping11-4 structure is not only a breakthrough of the new area exploration in Kaiping sag, but also a breakthrough of the Paleogene crude oil exploration in the eastern deep-water area of the South China Sea. It shows that the deep-water area of Pearl River Mouth Basin has a broad prospect for oil and gas exploration, and is of great significance to the exploration of petroliferous basins in the northern deep-water area of the South China Sea.

Large tight sandstone gas reservoirs in Tianfu gas field of Sichuan Basin were discovered in the Member 2 of Shaximiao Formation in 2019 and the Member 1 of Shaximiao Formation in 2021, respectively. The proven reserves are 1 349×10 ⁸m ³ and the production is 15.7×10 ⁸m ³ in 2022. Based on the core and geochemical analysis data, the paper investigates the sedimentary reservoir characteristics, natural gas geochemical characteristics, gas reservoir types and gas reservoir formation conditions of Shaximiao Formation in Tianfu gas field. In the study area, shallow-water deltaic and lacustrine deposits are found in the Member 1 of Shaximiao Formation, while fluvial deposits are found in the Member 2 of Shaximiao Formation. The lithologies of the reservoir are mainly composed of feldspathic litharenite and lithic arkose, and the reservoir spaces are mainly occupied by residual intergranular pores, followed by feldspar dissolution pores. The natural gas source of reservoir is mainly from the Triassic Xujiahe Formation. The natural gas in the Member 1 of Shaximiao Formation and the 6th, 8th and 9th sand groups of 1st submember of Member 2 of Shaximiao Formation is dominated by coal-type gas with a small amount of mixed gas, while the gas in the 7th sand group of 1st submember of Member 2 of Shaximiao Formation is characterized by the occurrence of both mixed gas and oil-type gas. The gas reservoir in Shaximiao Formation of Tianfu gas field is a large lithologic gas reservoir with accumulation regularity of dual-source and multi-phase charging, fault and sandbody transport, accumulation around the source, and differential enrichment at the channel. A series of key exploration and development technologies have been developed by tackling the key exploitation problems of large tight sandstone gas reservoirs in Shaximiao Formation of Tianfu gas field, i.e., (1) technology of precisely choosing layers under the constraint of high-precision isochronous stratigraphic framework, (2) technology of finely characterizing sand bodies and precisely predicting target based on 3D seismic survey, (3) supporting technology to accelerate exploration and production based on horizontal well and volume fracturing, (4) processing technology of exploitation and transportation on the ground for the purpose of fast construction, investment, optimization and simplification, (5) integrated technical and economic template for scale and cost-effective development. The discovery of Tianfu gas field has improved the exploration and development of tight sandstone gas in China, and enriched the exploration methods of tight sandstone gas, and effectively promoted the exploration and development process of tight sandstone gas in Sichuan Basin.

In Qiongdongnan Basin, Baodao sag is considered as the one where the strongest Cenozoic tectonic activity occurred. In 2022, China's first large deep-water and deep-layer gas field, i.e., Baodao 21-1 gas field, was discovered in Baodao 21 transition step-fault zone, thus verifying the potential of natural gas resources of Baodao sag. Based on the understanding of the basic geological characteristics of Baodao 21-1 gas field, the paper systematically analyzes the enrichment and hydrocarbon generation mechanism of source rocks, the reservoir-trap formation mechanism, the migration and accumulation mechanism of fault system, and the accumulation stages and accumulation models of natural gas of the gas field, and summarizes the groundbreaking and innovative geophysical and testing technologies for deep-water and deep-layer gas fields. Baodao 21-1 structure develops "double source" organic matter enrichment, and the intense crustal thinning leads to high heat flow in the structure, as well as accelerated thermal evolution and high gas generation intensity of source rocks; the provenance of the uplift is injected into the sag along the transition slope, forming a tectonic and lithologic trap controlled by large delta lobes; large-scale tectonic ridges are conducive to natural gas accumulation, and the differential activities of main faults and delta sandstones constitute an efficient transport system, which can provide a geological foundation for the formation of large-scale gas fields. Baodao 21-1 gas field has multi-stage oil and gas charging, proving that the transition step-fault zone develops a natural gas accumulation and enrichment mode of "enrichment in semi-enclosed environment/accelerating hydrocarbon generation at high temperature for source control, relay ramp for trap control, long-term active fault for controlling hydrocarbon migration, late multi-stage strong charging, and weak active fault for controlling accumulation". This study develops the key technologies for deep layer oil and gas geophysical exploration in the rugged seabed area of deepwater steep slope land, thus achieving the fine construction of structure and successful prediction of gas-bearing properties, and creates key technologies for safety control of flowing of deepwater and deep layer complex fluid and capacity release, thus guaranteeing the release of real production capacity of the formations. The discovery of the large gas field Baodao 21-1 has confirmed the oil and gas accumulation and enrichment mode of passive epicontinental basin with strong activity. It is believed that the relatively stable strike slope type transition zone is the "golden zone" for enrichment in medium- and large-scale gas fields. The relevant research and understanding point out the direction for natural gas exploration in Baodao sag, and have important reference and enlightenment significance for natural gas exploration in Qiongdongnan Basin, the northern and central-southern South China Sea.

China is abundant in heavy oil resources. At present, heavy oil development mainly relies on thermal recovery techniques, including cyclic steam stimulation(CSS), steam flooding, steam assisted gravity drainage (SAGD) and insitu combustion(ISC). Based on summarizing the current situation of four thermal recovery techniques for heavy oil in China, CSS accounts for more than 50% of heavy oil production. And CSS production are generally in the middle and late stages of development, and it is urgent to change the development methods. In recent years, steam flooding, SAGD, ISC techniques have achieved significant advancement, but still need to be improved and upgraded. The results of carbon emissions per ton of heavy oil measured for different development techniques show that under "Carbon Peaking and Carbon Neutrality" targets in China, thermal recovery techniques for heavy oil characterized by "high energy consumption and high carbon emissions" are confronting double challenge from quality and efficiency improvement as well as energy conservation and emission reduction. Through analyzing the key features of heavy oil in main oilfields and assosicated downstream industry chain and value chain, it is deemed that naphthenic-based heavy oil is mainly treated as raw materials for chemical products. The intermediate products play important and irreplaceable part in downstream industry chain in China. Therefore, it is essential to keep stable heavy oil production in China during the "14th Five-Year Plan" period(2021-2025) and in the future. To achieve the "Carbon Peaking and Carbon Neutrality" targets of the state and oil companies and cope with the double challenge, the paper proposes countermeasures and suggestions for future heavy oil development. Specifically, at the policy level, it is recommended to push the upgrading of heavy oil processing industry, enhancing the development of heavy oil products, and adjusting the heavy oil pricing strategy accordingly to make heavy oil more representative of raw materials for chemical products. At the technical level, it is recommended to continuously improve the existing thermal recovery techniques and optimize and adjust the production from various thermal recovery techniques, promopt the study of limited thermal recovery techniques and low carbon steam generation technique; intensify efforts to research and develop efficient cold production techniques for heavy oil, such as heavy oil polymer flooding and emulsion water flooding.

The genetic method with basin modeling as the core has been widely used in hydrocarbon exploration and production. China’s basin modeling theory and research are in the front ranks of countries of the world, but the application software development lags far behind other countries. According to statistics, 75 % of the 39 pieces of basin modeling software or algorithms available in China are developed by foreign companies, and 100 % of the popular software on the international market are developed by overseas companies. At present, the main challenge faced by basin modeling research is that the classical petroleum system theory widely applied in the past cannot effectively evaluate unconventional oil-gas resources. In this study, whole petroleum system theory is adopted to address the current challenges. Firstly, the basic characteristics, genetic mechanism and distribution regularities for the joint coexistence of conventional and unconventional oil-gas resources are elaborated based on the whole petroleum system theory, providing theoretical and methodological guidance for the prediction and assessment of conventional and unconventional oil-gas resources. Secondly, key technologies for predicting and assessing conventional, tight and shale oil-gas resources have been developed by establishing a combined genetic model for conventional and unconventional oil-gas reservoirs and a material balance relationship between total hydrocarbon generation and hydrocarbon resources. Thirdly, this paper establishes five sets of material balance equations between the total hydrocarbon production and the evolution and productivity of the whole petroleum system, analyzes the key geological parameters such as primitive hydrocarbon production ratio, migration-accumulation coefficient, movable hydrocarbon ratio and oil recovery, and proposes 12 key technologies of three categories for basin modeling. The new generation basin modeling system based on the whole petroleum system theory and modern information technology is expected to achieve quantitative, automated and intelligent assessment of oil-gas resources, increase the total amount of resources as the study objects by 5 to 8 times, deepen the research of predicted and assessed resources by more than 3 times, significantly improve the reliability of the predicted and assessed results, and solve the existing bottleneck problem.

The injection-production alternation of gas reservoir-type gas storage leads to caprock deformation and pore pressure change, which further results in different degrees of dynamic changes in the geostress field of caprock, thus affecting the mechanical integrity and sealing performance of the caprock. Combined with the principle of effective stress and 3D caprock thin bending plate theory, an analytical model of caprock pore pressure and geostress is established, the results of which are compared with the numerical simulation results, thus verifying the rationality of the analytical model. On this basis, the paper investigates the change law of the caprock stress magnitude and geostress mechanism of S gas storage in China in the depletion-injection-production process. Results show that the farther away from the reservoir, the less obvious the disturbance of pore pressure and geostress is in the caprock, and the stress state of the strata suffering from obvious injection-production disturbance will change in the reverse, strike-slip, and normal fault mechanism. Based on caprock stress analyses, it is concluded that the dynamic mechanical integrity of caprock is in a critical state when the upper limit pressure coefficient of S gas storage is 1.5 (about 18 MPa). Finally, the scheme of multi-condition alternating mechanical test suitable for S gas storage is explored and proposed, thus providing a reference for laboratory tests of similar projects.

Dolomite reservoirs have huge oil and gas exploration potential, but there are always disputes on the genesis of dolomite, which greatly affects the effective prediction of high-quality dolomite reservoirs. To further push the study of dolomite genesis, the paper systematically reviews the genetic types and traditional research methods of dolomite, as well as the research progress of non-traditional methods involving Mg isotope, clumped isotope, crystal structure and laser in-situ U-Pb dating in the past two decades, and also summarizes the existing problems. At present, there are more than 20 genetic models of dolomite, and the genetic types of dolomite can be essentially divided into primary dolomite and secondary dolomite. Through continuous exploration, the genetic theories of dolomite have been expanded, and also face challenges; among them, the emerging microbial induction theory has provided a more favorable evidence for the genesis of dolomite, and the genetic theory of some secondary metasomatic dolomite has also been expanded and challenged. The traditional analytical methods of basic petrology, cathodoluminescence, major and trace elements, rare earth elements, fluid inclusions, carbon and oxygen isotopes, and strontium isotopes have made great contributions to the exploration of dolomite genesis, laying a foundation for exploring the genesis of dolomite. The rapid development of non-traditional research methods for dolomite genesis provides more useful information for the formation and evolution of dolomite. Mg isotopes can effectively trace the source of Mg-rich fluid and reconstruct the evolution process of dolomite. Clumped isotope thermometry is of great significance for analyzing the diagenetic environment and diagenetic fluid in terms of dolomite diagenetic temperature and recovery of oxygen isotope value of dolomitized fluid. The crystal structure of dolomite has preserved the unique evidence of environment, crystallization, crystal growth and fluid in its formation process, which can be used as an effective means to study the formation environment and formation mechanism of dolomite. The absolute age determined by laser in-situ U-Pb dating is of great value for understanding the diagenesis and evolution of dolomite. However, the formation of dolomite is a multi-stage comprehensive process involving different geological conditions and different periods, and both traditional and non-traditional dolomite research methods have certain advantages and disadvantages. In many cases, it is difficult to explain the genesis of dolomite only using a single genetic model or research method. Therefore, we shall not simply apply or even abuse the genetic model in the study of dolomite genesis, and shall analyze the specific situation, combine the traditional and non-traditional dolomite analysis methods, and comprehensively consider the geological background, fluid properties, sources, dynamic and thermodynamic mechanisms, so as to give a more accurate and reasonable explanation on dolomite genesis. Through a systematic review and analysis of researches on dolomite genesis, it is expected to provide some reference and new enlightenments for the study of dolomite genesis.

Sequence stratigraphy provides not only isochronous framework for basin analysis, but also comprehensive geologic structure models for sedimentary paleogeography research as well as exploration and development of mineral deposits, and thus has been paid much attention in both academic and industry communities. Sequence stratigraphy has made rapid development in recent 30 years, especially achieving great progress in sequence formation and relevant controlled factors of continental basin, sequence stratigraphic architecture and sandbody distribution in fault depression, depression and foreland lake basin, as well as research methods of sequence stratigraphy in continental lake basin. In future, the continental lake basin stratigraphy should focus on sequence stratigraphic architecture in different types of sedimentary basins, standardized research of continental lake basin, the relations between sequence and source-sink system and shoreline migration trajectory, the relation between stratigraphic pattern and shoreline trajectory, deep sequence stratigraphy, sequence architecture, as well as numerical modelling, so as to better guide the application research on energy exploration and development.

Deep coalbed methane (CBM) will become an important field for China to increase the large-scale natural gas reserves and production in the future. It is of great significance to review the history and progress of the geological research on deep CBM propose and evaluate the existing problems and exploration directions, which can provide a reference for developing applicable exploration and development technologies. Analyses reveal that China has made three major advances in the geological research of deep CBM in the past 20 years. First, the basic concept and its scientific connotation of deep CBM have been defined. It is found that there is a critical depth for the absorbed gas content of deep coalbeds, which mainly depends on the coupling relationship between geothermal gradient and geo-stress gradient, and other geological factors can adjust the critical depth. A decrease in the adsorbed gas content may lead to an increase in free gas content, resulting in the orderly accumulation of CBM in the depth sequence and the formation of highly to super saturated reservoirs with abundant free gas in the deep coal. Second, remarkable progress has been made in research of the geological properties of deep coal reservoirs, and it has been recognized that the weakening adsorption of deep coal reservoirs and the increase of free gas content are resulted from the dynamic equilibrium between the positive effect of pressure and the negative effect of temperature. Moreover, it has been found that there is a "highly permeability window" of coal reservoirs near the transition zone of geo-stress state on the depth profile, and the formation temperature and pressure indices related to the reconstruction of deep coal reservoirs may have a threshold property, and the temperature compensation and variable pore compressibility effects may significantly lower the decay rate of permeability for deep coal reservoirs. Third, an in-depth research is gradually implemented on the accumulation and geological evaluation of deep CBM reservoirs, and the exploration on accumulation mechanism focuses on CBM gas-bearing property formed by buried depth changes, vertical permeability distribution and its geological control, thus initially revealing the "depth effect" for CBM reservoir formation. Through on-site case analysis, the relevant understandings have been deepened and expanded from basin to favorable zone, then to sweet spot and from reservoir control to production control. The analyses suggest that the organic connection and deep coupling of basic geology (reservoir-forming process), exploration geology (evaluation optimization) and development geology (dynamic process) are key directions for the geological-engineering integration in deep CBM exploration and development. Therefore, it is suggested future research should focus on "depth effect", including the systematic description of deep CBM reservoir and the characterization of gas reservoir engineering responses to geological conditions.

China's deep coalbed methane (CBM) resources, with the burial depths exceeding 1 500 m, are abundant and coexist with adsorbed and free gases. The occurrence state, accumulation characteristics, and development laws of deep CBM differ significantly from those of mid-shallow CBM, and the unclear evolution patterns have restricted its efficient exploration and development. Taking the No.8 deep coal seam in Daning-Jixian block on the eastern margin of Ordos Basin for example, this study finely characterizes the accumulation characteristics of deep CBM and simulates the burial evolution history, thermal evolution history, and hydrocarbon generation history of deep coal seams, thus improving the deep CBM enrichment and accumulation laws and patterns; moreover, the targeted exploration and development strategies are proposed. The results show that the No.8 deep coal seam is widespread in Daning-Jixian block, with high organic matter thermal maturity and Type III kerogen. This indicates significant hydrocarbon generation potential, with the total hydrocarbon intensity of (20.2-34.7) ×10 ⁸m ³/km ². The deep coal reservoir develops cleats, fractures, texture pores, cell pores, gas pores, intergranular pores, and dissolution pores, providing favorable conditions for the accumulation of deep free-state CBM. The structural-lithologic-hydrodynamic coupling closure is favorable for the preservation of deep CBM. The evolution stages of hydrocarbon accumulation in deep coal seams in the study area include the initial hydrocarbon generation stage (Stage I, 306-251 Ma), the first thermal hydrocarbon generation stage (Stage II, 251-203 Ma), the decreasing stage of organic matter thermal evolution (Stage III, 203-145 Ma), the hydrocarbon generation peak stage (Stage IV, 145-130 Ma), and the final formation stage of the oil/gas accumulation pattern (Stage V, 130 Ma to present). The deep CBM under free and adsorbed states coexist in the study area. On this basis, the paper proposes the hydrocarbon enrichment and accumulation pattern of "wide covering hydrocarbon generation, box-type closure, microstructure adjustment, self-generation and self-storage, and blanket-type accumulation", and establishes three types of deep CBM accumulation models:microfold and physical property coupling control (Type I), microfault monocline and hydrodynamic force coupling control (Type II), and physical property and hydrodynamic force coupling control (Type III) on reservoir accumulation. These understandings can effectively guide the selection of favorable areas for deep CBM exploration in Daning-Jixian block, establish an evaluation index system for favorable areas in deep coal reservoirs, propose differentiated development plans for exploration areas with different accumulation models, and help achieve the truly efficient and low-cost development of deep CBM in the study area. The research findings have important reference significance for carrying out deep CBM exploration and development in other blocks in China.

The control of tectonic dynamics on reservoirs is one of the most critical factors for the development of intracontinental thrust belts. In order to clarify the impact of tectonic thrust nappe activity on the diagenetic response characteristics of ultra-deep sandstone reservoirs in intracontinental foreland thrust belt during the Himalayan period, a study was performed on rock responses to tectonic dynamics and the genetic model of large-scale reservoirs based on extensive experimental analysis and multi-scale diagenetic physical modeling. The results show that the thrust nappe tectonic activity of Tianshan thrust belt was strong during the Himalayan period, and gradually weakening from the basin margin to the interior basin. Under the action of tectonic compression, there are three main responses of sandstone. intensification of reservoir matrix densification due to compaction and porosity reduction, intensification of reservoir heterogeneity due to fracturing and permeability increase, and increased effectiveness of fluid-rock interactions due to abnormal pressurization. The modeling of large-scale tectonic nappe and compression effects shows the following characteristics. The rock stress and strain concentration areas of gypsum/salt-bearing strata under tectonic nappe activity are mainly located in the pre-salt imbricated thrust belt, and the rock stress is significantly weakened towards the thrust propagation belt. The rock stress and strain concentration areas of coal-bearing strata under tectonic nappe activity are mainly located in the ultra-thick sandstone of the imbricated belt, and the strain is obviously weakened towards the nappe propagation belt. In particular, the rock stress and strain in the interbeds of coal seam and sand-mudstone are weak, but the fold structure is well developed. Under high temperature and pressure, the dissolution of organic acids along the fracture network is enhanced, and the connectivity of fractures, pores, and throats is significantly enhanced. The ultra-deep strata of Tianshan thrust belt mainly develop large-scale reservoirs with two genetic models. Within the depth of 10 kilometers, the porosity of fracture-pore type reservoirs in strong tectonic compression areas can reach 5% to 8%, and the porosity of pore type reservoirs in weak tectonic compression areas can reach 7% to 12%. The favorable exploration area is 3.76×10 ⁴km ², which proves that this thrust belt is a favorable field worth paying attention to in recent efficient exploration of ultra-deep reservoirs.

In 2022, two key shale oil wells (Well HY1HF and Well H2CHF) were explored for Member 2 of Paleogene Funing Formation in Gaoyou sag of Subei Basin, and an industrial oil flow of 29.7 t/d and 50.5 t/d was separately obtained after fracturing in the drainage and production stage, achieving a great breakthrough in the shale oil exploration for Member 2 of Funing Formation in Gaoyou sag. Based on the observations of cores and thin sections from wells such as Well HY1, whole rock mineral composition analysis by X-ray diffraction, nitrogen adsorption analysis, nuclear magnetic resonance analysis, and organic geochemical analysis of frozen cores, in combination with the dynamic production data of Well HY1HF and Well H2CHF, the paper systematically analyzes the geological characteristics of Member 2 of Funing Formation in Gaoyou sag, and further reveals the enrichment regularities and controlling factors of shale oil from Member 2 of Funing Formation in Subei Basin. Semi-deep to deep lacustrine subfacies shale are developed in Member 2 of Funing Formation of Gaoyou sag, characterized by large thickness and wide distribution, laying the foundation for the enrichment of shale oil. Shale lithofacies control the horizontal and longitudinal distribution of "source sweet spots" and "reservoir sweet spots", among which the lithofacies with relatively high content of clay minerals correspond to good hydrocarbon generation potential, and those with high content of felsic minerals and carbonate minerals have good physical properties and pore-throat structure. According to the characteristics of lithologic association, the shale oil reservoir in Member 2 of Funing Formation can be divided into three types, i.e., self-generating and self-preserving shale oil (Type Ⅰ), mud generating and carbonate preserving shale oil (Type Ⅱ), and mud generating and silty laminae preserving shale oil (Type Ⅲ). High-quality pore-fracture system is developed in the source-reservoir combination of Type Ⅱ shale oil, characterized by good oil content and high mobility. Moreover, the existing dynamic production data indicate that Type Ⅱ shale oil reservoir has good productivity. In addition, good preservation conditions and pressurization resulted from secondary hydrocarbon generation are the key to high and stable production of shale oil. The shale oil exploration breakthrough in Member 2 of Funing Formation of Gaoyou sag indicates that the Paleogene shale oil in Subei Basin has good exploration prospects and Gaoyou sag is a key area for increasing reserves and production. These research results have important reference and guiding significance for the exploration and exploitation of shale oil in continental faulted basins in eastern China.

Waterflooding development oilfields have entered a new stage of deep and fine waterflooding exploitation due to complex relationships between injection and production, frequent dynamic changes in the displacement field, and aggravated inter-layer conflicts caused by long-term waterflooding. The waterflooding development program was adjusted based on static and dynamic engineering production data, which can help researchers master the dynamic changes in oil reservoirs and achieve effective tapping of residual oil. To realize the combination of waterflooding development program optimization and advanced separated zone waterflooding process, the paper systematically summarizes the development status of dynamic analysis technology for oil reservoirs, and mainly elaborates the core issues of waterflooding development program adjustment based on the intercombination of AI methods and reservoir engineering. Meanwhile, the cutting-edge intelligent theories and methods are used to explore and prospect the trend of intelligent and fine adjustments to future waterflooding development program, namely to make full use of the refined and intelligent separated zone waterflooding process to monitor a large amount of dynamic production data in real time. In the future, the study of waterflooding development program optimization will focus on the deep integration of "dynamic data, physical constraints, and AI algorithm"; it is also suggested to further promote the implementation of the intelligent optimization application, i.e., real-time acquisition of monitoring data of waterflooding development oilfields, real-time dynamic forecasts of oil reservoirs and real-time optimization of waterflooding program, and finally achieve the integration of reservoir and oil recovery engineering based on synchronously implementing the design and optimization of waterflooding program and the real-time adjustment of downhole separated zone waterflooding.

The frontal uplift of Kuqa foreland basin is located at the southern end of the basin, which is rich in oil and gas resources. It is an important field for oil-gas exploration in Kuqa foreland basin. At present, oil and gas discoveries have been made in exploration of both marine cratonic tectonic strata and continental foreland tectonic strata in the lower and upper parts of the frontal uplift, respectively. The complex geological background leads to significant differences in oil and gas accumulation characteristics between the two sets of tectonic strata, thus restricting the further oil-gas exploration. Based on the data of drilling, rock thin section and source rock tests, reservoir property analysis, and hydrocarbon assay, this paper systematically investigates the oil and gas source, hydrocarbon accumulation period, oil and gas migration direction, and transport system characteristics of the western section of the frontal uplift of Kuqa foreland basin, and clarifies the hydrocarbon accumulation conditions of the western section of the frontal uplift. Further, in combination with the analyses of typical reservoirs, the types and distribution characteristics of reservoirs in the study area are determined. The findings show that:(1) The oil and gas in the western section of the frontal uplift of Kuqa foreland basin are mainly originated from the Triassic-Jurassic lacustrine source rocks and coal-measure source rocks in the northern part of the basin; (2) Mesozoic-Cenozoic sand body and tectonics co-controlled reservoirs and marine paleoweathering crust dominated buried hill reservoirs are developed in the study area; according to the differences of depositional setting and lithology, the latter can be further divided into marine carbonate paleoweathering crust type buried hill reservoirs and marine clastic paleoweathering crust type buried hill reservoirs; (3) Based on various hydrocarbon accumulation factors, the favorable exploration area of marine palaeoweathering crust buried hill reservoirs (Type I), that of the Paleogene basal sandstone sand body and tectonics co-controlled reservoirs (Type II), and that of the Cretaceous Baxigai Formation sandbody-structure co-controlled reservoirs (Type III) are optimized in the study area, aiming to provide theoretical guidance for further oil-gas exploration.

The ultra-deep oil and gas resources are abundant in China’s superimposed basins, which are an important strategic replacement field. The exploration and research work has revealed that there is a dichotomy of accumulation conditions for ultra-deep oil and gas reservoirs; favorable accumulation conditions only exist in specific basin environments, characterized with regionality, while the unfavorable accumulation conditions are inherent attributes of ultra-deep layers, characterized with universality. The decisive factors determining whether ultra-deep layers have exploration value are the effectiveness and scale of source kitchens, the effective reservoir and its scale, as well as the spatial combination and effectiveness of source, reservoir, and cap. The basins with exploration potential in ultra-deep layers have the following characteristics: (1) there is differential subsidence evolution in cratons, which have not been deeply buried during a long geological history, and where source kitchens are developed and still in an effective hydrocarbon-generation window to this day; (2) sedimentary strata mainly composed of carbonate rocks are developed, with granular platform marginal-platform shoals and intraplatform shoals, and have undergone constructive diagenesis and modification, or have experienced groundwater dissolution and leaching during geological history, as result of which reservoirs with pores in ultra-deep layers (including fractures and caves) are developed and have been effective till today; (3) the development of clastic rock, basement, or volcanic reservoirs requires a combination of single or multiple factors, such as long-term shallow burial and later deep burial with a short burial time, the presence of structural bridges for supporting effect, less compaction, the generation of fractures by tectonism, or long-term weathering for constructive reformation of crystalline rocks; (4) the basin generally presents a medium to low geothermal field, or there is no excessive radioactive material in the environment during the development of source rock, and the large-scale hydrocarbon generation is not accelerated. The reasons for the occurrence of unfavorable accumulation conditions in ultra-deep layers include: (1) mechanical compaction and high temperature and pressure result in strong diagenesis and increased plasticity of rock particles in ultra-deep layers, which is not favorable to the preservation of reservoir pore space; (2) most source rocks in ultra-deep layers have lost their hydrocarbon-generation potential, and the effectiveness of source kitchens is limited due to deep burial and long burial history; (3) there is a low probability for forming an effective combination of source-reservoir-seal-trap, and the probability of economic resource mineralization is reduced. China has abundant oil and gas resources and great exploration potential in ultra-deep layers, but large-scale exploration faces challenges in terms of the hydrocarbon accumulation theory to be perfected and engineering technology, and it is urgent to carry out researches to achieve relevant breakthroughs.

With the deep integration of informatization and industrialization, an intelligent and digital cyber-physical system has been developing for traditional oil and gas storage and transportation. The computing, communication and control technologies empower the oil and gas storage and transportation industry, and also bring the information security issues, which will be developed into complex issues regarding comprehensive cyber-physical system safety, resulting in problems such as unclear superimposed risk mechanism and difficulties in comprehensive state evaluation. Therefore, it is urgent to change from the traditional physical safety analysis of engineering failures to the comprehensive risk analysis of cyber-physical integration. For this reason, this paper analyzes the current safety status and connotation of the cyber-physical system of oil and gas storage and transportation, establishes the cyber-physical safety theory and technology system for oil and gas storage and transportation focusing on the heterogeneous integration of functional safety and information security, explores the risk formation and evolution mechanism and risk characteristics of cyber-physical system, puts a focus on the research and application of key technologies such as fusion modeling, situation awareness, collaborative assessment, anomaly alert, and security defense, and outlook the trending study of cyber-physical system safety, thus providing a reference for pushing the research of cyber-physical system safety.