Oil and gas resources serve as the foundation of the oil and gas industry and are vital to the sustained and healthy development of the national economy. Since the implementation of the "Continuously Intensifying Domestic Oil and Gas Resource Exploration and Development" initiative in 2019, domestic natural gas reserves and production have shown rapid growth. The medium- to long-term domestic natural gas consumption demand will continue to rise, making the mission of strengthening domestic self-sustained natural gas supply security both critical and urgent. Based on the progress in natural gas exploration and new geological insights since the 14th Five-Year Plan, a systematic reassessment of conventional and unconventional natural gas in-place resources in 27 onshore basins including Sichuan, Ordos, and Tarim, revealed a total of 191.90 trillion cubic meters, with a proven rate of only 12.7%, indicating a solid resource foundation for the future rapid development. The proven rate of conventional natural gas in-place resources is 16.3%, with remaining unproven resources amounting to 58.48 trillion cubic meters. The foreland and deep layers of three major cratonic basins, i.e., Sichuan, Tarim, and Ordos in central and western China, will continue to be the key targets for future conventional natural gas exploration, with an estimated 5.0-7.0 trillion cubic meters of additional reserves potential over the next five to ten years. The remaining unproven resources of unconventional tight gas is 26.52 trillion cubic meters, with exploration efforts concentrated in the Sichuan and Ordos basins, and an estimated 1.9-2.5 trillion cubic meters of additional reserves potential over the next five to ten years. The remaining unproven resources of unconventional shale gas is 48.50 trillion cubic meters, primarily distributed in the Paleozoic Strata of the Sichuan Basin, with an estimated 2.5-3.0 trillion cubic meters of additional reserves potential. The proven rate of coalbed methane is only 3.9%, with remaining unproven resources amounting to 33.80 trillion cubic meters. Basins such as Ordos, Qinshui, Junggar, Sichuan are key targets for future coalbed methane exploration, with an estimated 4.0 trillion cubic meters of additional reserves potential.

Ultra-deep（burial depth ≥6 000 m）exploration is a distinctive feature of petroleum exploration in the Tarim Basin. Since the implementation of the 14th Five-Year Plan, Tarim Oilfield Company has focused on exploration in ultra-deep new regions and new fields, achieving a series of major breakthroughs and discovering multiple new reservoir-cap rock combinations. This study deeply analyzes the geological conditions for ultra-deep hydrocarbon accumulation in continental oil and gas system of the Kuqa area, marine oil and gas system in platform-basin areas, and marine-continental transitional facies oil and gas system in piedmont areas of the Southwest Tarim. It is concluded that in the Tarim Basin, ultra-deep reservoir-cap rock combinations are either adjacent to or interbedded with source rocks, and trap formation occurred either earlier than or concurrently with the peak gas generation period of the source rocks. Therefore, the conditions for natural gas accumulation are favorable, leading to the development of multiple ultra-deep natural gas accumulation models. This study calculates the natural gas resources of the basin by using multiple methods. The in-place natural gas resources are 18.47 ×10¹² m³, and the ultra-deep in-place natural gas resources with a depth of ≥6 000 m reach 13.40×10¹² m³. The ultra-deep natural gas is predominantly distributed in the Cretaceous-Jurassic strata of Kuqa area, Carboniferous-Permian strata in the piedmont area of Southwest Tarim, and the Ordovician-Cambrian strata in the platform-basin region. Favorable exploration zones for ultra-deep natural gas include the Kelasu Structural Belt, eastern segment of the Northern Structural Belt, Zhongqiu-Di'na section of the Qiulitag Structural Belt, periphery of the Kekeya area in the West Kunlun Thrust Belt, Wuqia Structural Belt in the West Tianshan Thrust Belt, eastern part of the Lunnan-Aman Transition Zone, and western margin of the Yingmaili Low Uplift.

The Lower-Middle Jurassic tight sandstone gas reservoirs in the Turpan-Hami Basin exhibit substantial resource potential, representing a crucial exploration field for natural gas reserve growth and production enhancement. However, due to complex geological conditions, the hydrocarbon accumulation mechanisms remain unclear, which hinders resource potential evaluation and the optimization of exploration directions. Through systematic analysis of source rock characteristics, reservoir characteristics, and preservation conditions, this paper establishes an accumulation model and identifies three key controlling factors for tight sandstone gas accumulation: (1) effective hydrocarbon kitchens control the lateral distribution of hydrocarbons; (2) high-quality reservoir facies belts determine the degree of hydrocarbon enrichment; (3) stable tectonic settings are conducive to the preservation of large-scale gas reservoirs. Integrated resource evaluation employing the small-bin volume method, resource abundance analogy, and Monte Carlo simulation was conducted for three main target intervals: the third member (J₂x³) and first member (J₂x¹) of the Xishanyao Formation, and the second member (J₁s²) of the Sangonghe Formation. Results show that the total geological resource of tight gas in Taibei Sag amounts to 6 793.02×10⁸ m³, exhibiting stepwise increase with burial depth. Specifically, the J₂x³, J₂x¹, and J₁s² members contain 1 783.51×10⁸ m³, 1 923.53×10⁸ m³, and 3 085.98×10⁸ m³, respectively. Resource classification reveals: Type Ⅰ resources (1 596.36×10⁸ m³) are concentrated in the northeastern slope of the Shengbei Sag, Baka structural belt, southern slope of the Qiudong Sag, and southern slope of the Xiaocaohu Sag, serving as priority targets for near-term exploration breakthroughs; Type Ⅱ resources (2 560.97×10⁸ m³) are mainly distributed in the Gedatai-Hongtai structural belt and Qiudong-Xiaocaohu piedmont zones, representing favorable directions for medium- and long-term exploration expansion. These findings provide a scientific basis for efficient tight gas exploration in the basin.

In recent years, driven by the reef-shoal hydrocarbon accumulation theory, it has been confirmed that the intra-platform shoals of the Changxing Formation in the eastern part of southern Sichuan Basin have good gas-bearing properties. However, the sedimentary system and reservoir distribution of the thick-bedded limestone reservoirs remain unclear, thus restricting the deployment of oil and gas exploration. Based on outcrop, thin section, and well-seismic data, this paper carries out sequence division and third-order framework construction of the Changxing Formation, identifies sedimentary facies by integrating lithofacies, logging facies, and seismic facies, and accordingly analyzes the dominant facies belts of high-quality reservoirs and their favorable distribution areas. The results show that：(1) Three sequence boundaries (SB1, SB2 and SB3) are identified in the Changxing Formation in the eastern part of southern Sichuan Basin, which can be further divided into two third-order sequences (Sq1 and Sq2) from bottom to top. In the early stage, carbonate deep-shallow ramp developed; in the middle-late stage, ramp-type carbonate platform developed. Among these, the intra-platform shoal subfacies of the open platform facies mainly developed during the Sq1-HST and Sq2-HST depositional periods, with the most extensive development occurring particularly in the Sq2-HST period. The shoal bodies exhibite a lateral migration trend in the planar distribution and are only locally superimposed vertically. (2) The reservoir lithology is predominantly bioclastic limestone, with pore spaces and fracture-vug systems serving as the main reservoir spaces. The formation of reservoirs is primarily controlled by sedimentary facies and dissolution processes, and favorable reservoir zones concentrated in the intra-platform shoal subfacies, displaying a scattered patchy distribution. (3) According to the sedimentary facies, the development location and thickness of shoal bodies, and the development thickness of reservoirs, three favorable reservoir development areas and two potentially favorable reservoir development areas are evaluated and predicted: the area around Z207-Z201-Z202 well area, the B28-B61 well area, the B24-G11 well area are classified as favorable reservoir development zones; the BH2-BH3 well area and F7-N49 well are the potential favorable reservoir development zones. The systematic study on the sedimentary facies and reservoir characteristics of the thick-bedded limestone of the Upper Permian Changxing Formation in the eastern part of southern Sichuan Basin provides strong guidance for the next step of oil and gas exploration in the reef-shoal field of this area.

The Shangganchaigou Formation (N₁) in the northwestern Qaidam Basin mainly consists of fine-grained mixed rocks deposited in a saline lake basin, representing an important field for unconventional oil and gas exploration. However, current research on cyclostratigraphy and high-precision astronomical sedimentary response characteristics in this formation remains relatively weak. By comprehensively integrating core and well-logging data, cyclostratigraphic analysis is performed on two drilling wells, identifying Milankovitch cycles including long eccentricity, short eccentricity, obliquity, and precession in the Shangganchaigou Formation, and a floating astronomical time scale is established based on the 405 ka long eccentricity cycle, thereby determining the sedimentation rate and sedimentary characteristics of the Shangganchaigou Formation. It is shown that: (1) Sedimentation time of N₁ is approximately 4 Ma, and the average sedimentation rate can reach 20 cm/ka, which is significantly higher than that of other continental lacustrine strata in China. (2) The lithofacies characteristics based on sedimentation rate analysis indicate that lithofacies are significantly controlled by the sedimentation rate. Laminated dolomitic limestone with high organic matter content mainly develops in high-rate segments, while massive argillaceous-silty dolomitic limestone with low organic matter content is dominant in low-rate segments. (3) The continuous orogenic tectonic activity during the Himalayan period control the high sedimentation rate of N₁ at a macroscopic scale, and short-term climate alternations shape the oscillatory changes in the sedimentation rate. The identification of astronomical cycles and analysis of sedimentation rates of N₁ in the the northwestern Qaidam Basin are helpful for understanding the sedimentary evolution of favorable exploration intervals in salinized lake basins and can provide new ideas for the subsequent efficient exploration and development of shale oil.

The Permian Guofeng Formation (Member) in the Yangtze Region is a set of marine organic-rich black shale series exhibiting distinct diachronous characteristics, serving as a key replacement stratigraphic unit for shale gas exploration. This paper systematically analyzes and summarizes the spatiotemporal differentiation patterns, hydrocarbon generation characteristics, reservoir characteristics, and preservation conditions of the Permian Gufeng Formation (Member) in the Yangtze Region. From west to east, the Gufeng Formation (Member) exhibits a pattern of "east-west differentiation and multi-center sedimentation" with its distribution controlled by the synergistic effects of paleo-tectonics, sea-level fluctuations, and sedimentary environments. The reservoir lithologies are dominated by siliceous and carbonaceous shales, exhibiting a mineral combination characterized by " high silica, rich calcium, and low clay content ". The content of brittle minerals is high (averaging 85%), indicating excellent fracturability. Reservoir space types are diverse, dominated by organic pores and dissolution pores, with mesopores constituting the main pore size distribution. Pore development and gas content exhibit significant regional differentiation, characterized by "better in the west, poorer in the east". In the Upper Yangtze Region, the hydrocarbon generation quality is excellent (TOC 3%-10%, Type Ⅰ-Ⅱ₁ kerogen), reservoir physical properties are good (average porosity 4.46%), gas content is high (average >4 m³/t), and preservation conditions are favorable, making it the core area for shale gas enrichment. In the Middle Yangtze Region, shallow burial depth (<2 000 m) and moderate thermal evolution provide engineering cost advantages, but reservoir heterogeneity is strong. In the Lower Yangtze Region, burial depth is moderate, but reservoir physical properties (average porosity 1.99%), gas content, and preservation conditions are generally poor, limiting exploration potential. Comprehensive evaluation indicates that the Upper Yangtze Region (Guangyuan-Bazhong-Dazhou, Fengjie-Enshi) is the most favorable Class Ⅰ exploration area, though deep engineering challenges must be overcome; the Middle Yangtze Region (Jingshan-Wuhan) is a Class Ⅱ favorable exploration area where geological-engineering "sweet spots" should be targeted; the Lower Yangtze Region (Wuwei-Xuancheng) is a Class Ⅲ potential risk zone.

The upper gas layer of the Longmaxi Formation in the Sichuan Basin represents a crucial strategic replacement field for shale gas exploration. Based on biostratigraphic methods, through systematic fine correlation of graptolite-bearing shale intervals and analysis of drilling results from typical wells, the main controlling factors for the differential enrichment and the distribution patterns of favorable areas of the upper Longmaxi gas layer have been clarified. The results show that: (1)The development of the Aeronian LM7-LM8 graptolite zones and their associated high TOC shale is a prerequisite for the enrichment of the upper Longmaxi gas layer. In the Jiaoshiba area, successful wells are predominantly located in structural highs where this specific shale unit, characterized by relatively high TOC, porosity, and gas content, is developed. In contrast, poorer results in areas like Changning and Weiyuan are primarily due to the absence or inferior quality of this shale unit. (2)Structural morphology exerts a significant control on the enrichment of shale gas in the upper gas layer. Due to higher horizontal permeability compared to vertical permeability, gas tends to migrate updip. This leads to higher enrichment degrees in structural highs of anticlines (e.g., Jiaoshiba), while synclines (e.g., Wulong) and anticlinal limbs show lower enrichment levels and generally poorer exploration results. Based on the identified controls, it is recommended to enhance research on the development characteristics of the LM7-LM8 organic-rich shale, and conduct systematic evaluation and target optimization for the upper gas layer integrating actual drilling results. These findings provide a geological basis for optimizing favorable areas and exploration deployment of the upper Longmaxi gas layer in the Sichuan Basin.

The Sichuan Basin is rich in oil and gas resources, with its basement structure controlling hydrocarbon distribution from the ultra-deep Sinian to the shallow Jurassic Strata. With the application of ultra-deep gravity-magnetic-electric-seismic joint exploration techniques since 2010, the Neoproterozoic extensional structures in the Sichuan Basin has been continuously confirmed through exploration. Based on the high-resolution gravity-magnetic-electric data and "double-high" (high fidelity and high resolution) seismic data, combined with the outcrop observations along the basin margin and borehole data from 8 wells drilled into the Sinian Doushantuo Formation, a comprehensive interpretation study is carried out. It is proposed that the Sichuan Basin has developed "western Sichuan rift", which has mainly experienced three evolutionary stages from a rift to a depression. Stage 1: Nanhua rift stage, which was dominated by multiple near NE-trending horsts and grabens. Stage 2: the intra-cratonic depression stage happened during the deposition of the Sinian Doushantuo Formation, which was formed by merging the Northwest Sichuan Depression and the Central Sichuan Uplift. Stage 3: intra-cratonic depression stage happened during the deposition of the Sinian Dengying Formation, forming a nearly SN-trending extensional trough which opens towards northwest. Further study shows that strike-slip faults could easily occur during the evolution of the western Sichuan rift. The rift provides conditions for hydrocarbon accumulation in the Nanhua-Sinian Strata where oil and gas can be generated by lower strata, transported by faults and stored by upper strata. The Nanhua-Sinian petroleum system in the western-central Sichuan area is a new potential exploration area.