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Widespread submarine hydrocarbon seepage can form complex fluid seepage characteristics, with submarine sediment geochemistry effectively recording seepage activities and fluid component changes due to hydrocarbon seepage. This is crucial for offshore oil and gas exploration and understanding global climate change. Therefore, using the geochemical information of submarine sediments to trace hydrocarbon seepage activities is of great significance. In order to identify the geochemical anomaly characteristics and genetic types of acid-hydrolyzed hydrocarbons in submarine sediments in the Yantai Depression of the South Yellow Sea Basin, Eastern China, and to explore the relationship between these anomalies and deep oil and gas, geochemical columnar samples were taken at 100 stations in the study area. A total of 100 sets of acid-hydrolyzed hydrocarbon data and 26 sets of carbon isotope data were analyzed. The results show that the content of acid-hydrolyzed hydrocarbons at each station is in the following order: methane (AC1) > ethane (AC2) > propane (AC3) > butane (AC4) > pentane (AC5). The determination coefficient between the saturated hydrocarbon indicators exceeds 0.9, indicating that these components have the same source. Data analysis reveals that the genetic type of hydrocarbon gases in the study area is generally thermogenic, with limited microbial contribution to saturated hydrocarbons, indicating deep oil and gas characteristics. The coincidence between the anomalous areas and geological structures indicates that the distribution of these anomalies is closely related to fault distribution. [ABSTRACT FROM AUTHOR]

The East China Sea Basin (ECSB) is an integral part of the Western Pacific tectonic system. Its development is linked to the Kula–Pacific Plate and the formation and expansion of the Philippine Sea Basin. Recent advancements in exploration technologies and theory have been applied to Mesozoic basins in the East China Sea. Researchers have posited that the southern basin has great oil and gas exploration potential. However, the characteristics and evolution of fault structures and their influence on hydrocarbon accumulation remain unclear. Here, in-depth geometric and kinematic analyses of Mesozoic fault structures in the southern ECSB were conducted using the latest interpretations of 2D seismic data and structural analysis theory. The findings revealed that the fault system was well developed and predominantly exhibited multiphase extensional and extensional-torsional features. Based on their lateral distribution and morphology, faults were categorized into three structural styles and seven combinations. According to their developmental timing, periods of active faulting were attributed to the Yanshan and Himalayan epochs. Multiphase fault activities strongly controlled the formation of traps and thus hydrocarbon accumulation, while earlier NE-trending faults controlled the formation of structural belts and hydrocarbon source areas. [ABSTRACT FROM AUTHOR]

To analyze the impact of volcanic rocks in the Offshore Indus Basin on hydrocarbon reservoir formation, seismic data interpretation, seismic data inversion, and sea–land correlation analysis were carried out. The results show that, longitudinally, volcanic rocks are mainly distributed at the top of the Cretaceous system or at the bottom of the Paleocene, and carbonate rock platforms or reefs of the Paleocene–Eocene are usually developed on them. On the plane, volcanic rocks are mainly distributed on the Saurashtra High in the southeastern part of the basin. In terms of thickness, the volcanic rocks revealed by drilling in Karachi nearshore are about 70 m thick. We conducted sparse spike inversion for acoustic impedance in the volcanic rock area. The results show that the thickness of the Deccan volcanic rocks in the study area is between 250 and 750 m which is thinning from southeast to northwest. Based on sea–land comparison and comprehensive research, the distribution of volcanic rocks in the Indian Fan Offshore Basin played a constructive role in the Mesozoic oil and gas accumulation in the Indus offshore. Therefore, in the Indian Fan Offshore Basin, attention should be paid to finding Mesozoic self-generated and self-stored hydrocarbon reservoirs and Cenozoic lower-generated and upper-stored hydrocarbon reservoirs. [ABSTRACT FROM AUTHOR]

Deepwater regions have emerged as pivotal domains for global oil and gas exploration and development, serving as strategic alternatives to conventional resources. The Silk Road region is distinguished by its abundant oil and gas reserves and stands as a leading arena for worldwide exploration and development in the oil and gas sector. Since 2012, a series of atmospheric fields have been discovered in the deep sea of the Luwuma Basin and the Tanzania Basin, with cumulative recoverable reserves reaching 4.4 × 1012 and 8.3 × 1011 m3, including multiple oil and gas fields ranking among the top ten global discoveries at that time. Profound advancements have been achieved in the exploration of deepwater oil and gas reserves along the Silk Road. However, deepwater oil and gas exploration presents challenges, such as high development costs and risks, leading to certain areas remaining underexplored and exhibiting a relatively low level of exploration activity, thereby hinting at considerable untapped potential. Deepwater sedimentary basins along the Silk Road predominantly adhere to a distribution pattern characterized as "one horizontal and one vertical". The "horizontal" dimension refers to the deepwater basin grouping within the Neo-Tethys tectonic domain, primarily extending from east to west. Conversely, the "vertical" dimension denotes the deepwater basin grouping along the East African continental margin, predominantly extending from north to south. Recent discoveries of deepwater oil and gas reserves validate the presence of foundational elements within Silk Road basins conducive to the formation of substantial oil and gas reservoirs and the establishment of efficient migration pathways. Despite these achievements, exploration activities in deepwater oil and gas resources along the Silk Road remain relatively limited. Future exploration endeavors in deepwater regions will predominantly focus on identifying structural and lithological traps. In the deepwater areas of the Bay of Bengal, the emphasis is on lithological traps formed by Neogene turbidite sandstone deposits. In the deepwater regions of Pakistan, the focus shifts to lithological traps emerging from Neogene bio-reefs and river-channel sandstone accumulations. Along the deepwater coastline of East Africa, the focus is on lithological traps formed by nearshore Mesozoic–Cenozoic bio-reefs and seafloor turbidite sandstone formations. Within the deepwater regions of Southeast Asia, the primary objective is to locate large structural-type oil and gas fields. Analyzing the characteristics of oil and gas discoveries in deepwater areas aims to enhance the theory of the control of the formation of deepwater oil and gas, providing valuable insights for predicting future exploration directions. [ABSTRACT FROM AUTHOR]