Abstract:

The Subei Basin is characterized by a complex structure and well-developed faults. The shale in the second member of the Funing Formation has relatively low organic matter abundance, with a total organic carbon (TOC) generally below 1.5%. This shale exhibits diverse lithofacies types, complex pore structures, strong reservoir heterogeneity, and significant lateral variations in pressure coefficients. Using the shale oil reservoir in Block H of the second member of the Funing Formation in the Subei Basin as an example, this paper analyzed the characteristics of regional logging responses based on the results of rock physics experiments. By integrating conventional and specialized logging methods, a logging interpretation model was developed to evaluate the lithology, reservoir properties, oil content, mobility, and fracability of the shale oil reservoir. The model’s calculations aligned well with core analysis results. Building on this, sensitive parameters were optimized to establish evaluation and classification standards for the shale oil reservoirs in the block, and a comprehensive “sweet spot” evaluation of the reservoir was conducted. Exploration practices involving multiple wells have verified that this logging evaluation technology is regionally adaptable. It effectively classifies shale oil reservoir types, supports the optimal selection of “sweet spots”, and provides reliable technical support for the exploration and development of shale oil in the Subei Basin.

Key words: Subei Basin, the second member of Funing Formation, shale oil, well logging, reservoir parameters, “sweet spot” evaluation