Dynamic Identification Method for Gas Migration Based on the Gravitational Differentiation Mechanism and Its Application

Guo YANG , Jie ZHONG , Su-tian WANG , Huan-cheng JI , Yong-zhong ZHENG , Chang-sheng ZHANG

Science Technology and Engineering ›› 2026, Vol. 26 ›› Issue (24) : 10374 -10383.

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Science Technology and Engineering ›› 2026, Vol. 26 ›› Issue (24) : 10374-10383 DOI: 10.12404/j.issn.1671-1815.2507231
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Dynamic Identification Method for Gas Migration Based on the Gravitational Differentiation Mechanism and Its Application
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Abstract

With the advancement of unconventional reservoir development, the gas channeling challenge in CO2 flooding processes has been identified as a critical issue, particularly in gravity-dominated displacement scenarios where accurate prediction and control are significantly complicated. The limitation of conventional gas flooding characteristic curves that neglect oil-gas gravity segregation mechanisms is systematically addressed through the development of a multi-field constrained gravity correction model. Key geological parameters including reservoir dip angle (θ), vertical permeability variation coefficient (Vk), and fluid density differential (Δρ) were computationally integrated, with concurrent refinement applied to the dimensionless gravity stability index (${G}_{\mathrm{s}}^{\theta }$) for enhanced characterization of gravity-driven channeling effects.Three methodological innovations were presented through rigorously structured implementation phases. Initially, a dip-angle-incorporated seepage model was formulated through derivation of revised material balance equations, yielding a novel inverse S-curve formulation. Subsequently, four critical parameters [Vk, δ, air drive acceleration(ag), θ] were extracted and correlated with historical production data, enabling quantitative classification of gravity-mediated channeling patterns into four distinct categories: gravitational stabilization, weak channeling, gravitational failure, and complex transitional types, each with corresponding mitigation strategies. Ultimately, a machine learning framework was established through integration of segmented inverse S-curve constraints with gravity parameters and multimodal reservoir data, implementing an (long short-term memory-generalized autoregressive conditional heteroskedasticity,LSTM-GARCH) hybrid model for intelligent channeling early-warning in structurally inclined reservoirs.Field validation in the X54 well block demonstrate operational superiority, achieving 7-day predictive capability with 40% accuracy improvement over conventional methods. A complete technical system encompassing theoretical derivation, intelligent algorithm development, and field implementation was successfully established, providing a replicable template for gas injection optimization in analogous heterogeneous reservoirs.

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gas drive characteristic curve / gravity stability index / gas-channeling prediction / LSTM-GARCH

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Guo YANG, Jie ZHONG, Su-tian WANG, Huan-cheng JI, Yong-zhong ZHENG, Chang-sheng ZHANG. Dynamic Identification Method for Gas Migration Based on the Gravitational Differentiation Mechanism and Its Application. Science Technology and Engineering, 2026, 26(24): 10374-10383 DOI:10.12404/j.issn.1671-1815.2507231

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