Prediction Technology and Its Application for Inter-Salt Shale Oil Reservoirs

An Liu （ Shenzhen Water Planning & Design Institute Co., Ltd., Guangdong, Shenzhen 518000, China ）

Abstract

Shale oil is generally enriched in the pores or fractures of mudstone shale and is classifed as an unconventional petroleum resource. According to statistics from the U.S. Energy Information Administration (EIA), the total global shale oil and gas resources have reached 936.835 billion barrels, with recoverable reserves of 61.847 billion barrels. The Jianghan Basin is one of the main shale oil distribution basins in China. In the Qianjiang Sag, a set of salt series soil strata with a maximum thickness of 6000 meters has been deposited. Interbedded within the salt layers is a set of organic-rich fne-grained sedimentary rocks, with single layers up to 38 meters thick, which can act as both oil-generating and oil-storing layers. The shale oil resources between the salt layers in the Qianjiang Sag have great potential, with a cumulative oil production of 104,000 tons. Currently, conditions for capacity building have been preliminarily established, showing promising prospects for exploration and development.
This paper focuses on the extraction and analysis of seismic attributes for the target strata of the Qianjiang Formation in the Jianghan region, specifcally the 33x~342~41x objective layer interval. Representative post-stack geometric seismic attributes for fracture identification, such as curvature, coherence, and fracture likelihood attributes, are primarily selected. Preliminary reservoir prediction research is conducted, delineating potential locations of bedding fractures on planar maps[1]. These findings are combined with constrained sparse pulse seismic inversion results and lithology-based geostatistical seismic inversion results for a comprehensive analysis of the target reservoir interval. This dual approach serves to validate the accuracy of both shale reservoir prediction methods and to more precisely map the development of bedding fractures and other fractures. This work aims to determine the oil-bearing properties of the region, identify geological structures, and ultimately complete the prediction of inter-salt shale oil reservoir bedding fractures.

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