Integrated cross-well evaluation of sweet spots in shale gas plays: Implications for large-scale energy resource potential
Author Identifier (ORCID)
Abstract
The identification of sweet spot in shale gas is critical for efficient resource evaluation and sustainable energy development. However, the heterogeneity of shale formations poses significant challenges to accuratly delineating the stratigraphic sweet spots and assessing their exploration and production potential. This study focuses on the Early Silurian Longmaxi shale in the Sichuan Basin, one of the most prospective shale gas formations, and aims to systematically characterize the distribution of sweet spots and elucidate the controlling factors of shale gas enrichment. An integrated evaluation framework combining geological, organic geochemical, petrophysical, mineralogical, and rock mechanical properties was established based on consecutive core analyses and integrated cross-well data. The results reveal that the Long-11 submember represents the most prospective interval, exhibiting generally favorable reservoir quality, with a high organic matter content (average TOC of 4.39%), high maturity (average Ro of 2.62%), favorable reservoir properties (average porosity of 4.39%, permeability of 0.014 mD), and high gas content (average 4.15 m3/t). Significant stratigraphic variations in mineral composition, lamination, TOC, in situ gas content, porosity, and brittleness were observed among different sublayers, resulting in pronounced heterogeneity in sweet spot quality. Based on the integrated evaluation, the Long-11 submember shales are categorized into three categories of sweet spots: Class I, Class II, and nonreservoir intervals. Class I represents the most favorable sweet spot, characterized by high TOC (3.51–5.24%), high porosity (4.12–6.89%), high gas content (4.30–6.43 m3/t), high brittle mineral content (42.8–58.9 wt %), and low clay content (22.3–32.7 wt %). These results demonstrate that integrating geological, geochemical, and geomechanical parameters at the cross-well scale can effectively constrain the spatial distribution and quality of shale gas sweet spots. The proposed evaluation framework provides practical insights for resource assessment, sweet spot prediction, exploration, and development of heterogeneous shale gas reservoirs, and may be applicable to other shale plays worldwide.
Keywords
shale gas, sweet spots, longmaxi shale, reservoir characterization, gas enrichment, sichuan basin
Document Type
Journal Article
Date of Publication
9-3-2026
E-ISSN
15205029
ISSN
08870624
Volume
40
Issue
35
Publication Title
Energy & Fuels
Publisher
ACS
School
School of Engineering
Copyright
subscription content
First Page
19358
Last Page
19372
Recommended Citation
Yuan, Y., Wang, M., Al-Khdheeawi, E. A., & Zhang, L. (2026). Integrated cross-well evaluation of sweet spots in shale gas plays: Implications for large-scale energy resource potential. Energy & Fuels, 40(35), 19358–19372. https://doi.org/10.1021/acs.energyfuels.6c01981