Laser-Raman Analysis of Individual Fluid Inclusions and Hydrocarbon-Fluid Evolution in the Marine–Terrestrial Transitional Longtan Formation Shale, Southern Sichuan Basin
Source abstract
Abstract
This study integrates microthermometry and laser-Raman spectroscopy of individual fluid inclusions with basin modelling to reconstruct the hydrocarbon-fluid evolution and multistage re-mobilisation of the Permian Longtan Formation transitional marine–terrestrial shale in the YJ-LJ area, southern Sichuan Basin. Systematic analysis of aqueous two-phase, methane-rich, and associated bitumen inclusions hosted in fracture-fill veins and sandy partings identifies four fluid episodes, enabling subdivision of petroleum evolution into five stages. Results show trapping pressure increasing with temperature to a maximum of 107.77 MPa, equivalent vitrinite reflectance (EqVR) between 1.49% and 2.49%, and formation-water salinity that first rises then falls, remaining within the high-salinity continental-leaching brine field. Coupled with thermal-history modelling, shale-oil/gas evolution is divided into: (1) low-pressure slow burial, (2) over-pressured rapid burial, (3) sustained over-pressured deep burial, (4) high-pressure uplift adjustment, and (5) late uplift adjustment. The study demonstrates that over-pressure has been partially preserved, providing critical palaeo-fluid and pressure evidence for exploring transitional marine-terrestrial shale gas.
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Research context
OpenAlex topics: Hydrocarbon exploration and reservoir analysis · Petroleum Processing and Analysis · Enhanced Oil Recovery Techniques
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
School of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China
Institute of Porous Flow and Fluid Mechanics, Chinese Academy of Sciences, Langfang 065007, China
Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China
PetroChina Hangzhou Research Institute of Geology, Hangzhou 310023, China
School of Energy, China University of Geosciences (Beijing), Beijing 100083, China
Funding
In-Depth Study on the Development Potential of the Permian Longtan Formation Coal-Shale System in the Sichuan Basin
References (76)
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