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Guanyi Lu

Publications and source records attributed to Guanyi Lu.

3 recordsLinked to original sources

Structure-Semantic Decoupled Modulation of Global Geospatial Embeddings for High-Resolution Remote Sensing Mapping

Fine-grained high-resolution remote sensing mapping typically relies on localized visual features, which restricts cross-domain generalizability and often leads to fragmented predictions of large-scale land covers. While global geospatial foundation models offer powerful, generalizable representations, directly fusing their high-dimensional implicit embeddings with high-resolution visual features frequently triggers feature interference and spatial structure degradation due to a severe semantic-spatial gap. To overcome these limitations, we propose a Structure-Semantic Decoupled Modulation (SSDM) framework, which decouples global geospatial representations into two complementary cross-modal injection pathways. First, the structural prior modulation branch introduces the macroscopic receptive field priors from global representations into the self-attention modules of the high-resolution encoder. By guiding local feature extraction with holistic structural constraints, it effectively suppresses prediction fragmentation caused by high-frequency detail noise and excessive intra-class variance. Second, the global semantic injection branch explicitly aligns holistic context with the deep high-resolution feature space and directly supplements global semantics via cross-modal integration, thereby significantly enhancing the semantic consistency and category-level discrimination of complex land covers. Extensive experiments demonstrate that our method achieves state-of-the-art performance compared to existing cross-modal fusion approaches. By unleashing the potential of global embeddings, SSDM consistently improves high-resolution mapping accuracy across diverse scenarios, providing a universal and effective paradigm for integrating geospatial foundation models into high-resolution vision tasks.

cs.CV

Rock anisotropy promotes hydraulic fracture containment at depth

We report laboratory experiments and numerical simulations demonstrating that the anisotropic characteristics of rocks play a major role in the elongation of hydraulic fractures propagating in a plane perpendicular to bedding. Transverse anisotropy leads to larger hydraulic fracture extension in the parallel-to-bedding/divider direction compared to the perpendicular-to-bedding/arrester direction. This directly promotes vertical containment of hydraulic fractures in most sedimentary basins worldwide even in the absence of any favorable in-situ stress contrasts or other material heterogeneities. More importantly, the ratio of the energy dissipated in fluid viscous flow in the fracture to the energy dissipated in the creation of new surfaces is found to play a critical role on fracture elongation, with fracture-energy dominated hydraulic fractures being the most elongated while the viscous dominated ones remain more circular. These results open the door to a better engineering and control of hydraulic fractures containment at depth in view of the competition between material anisotropy and injection parameters (fluid viscosity and rate of injection).

physics.geo-ph

Modeling the impact of thermal stresses induced by wellbore cooldown on the breakdown pressure and geometry of a hydraulic fracture

Wellbore cooldown is often employed before well stimulation and/or hydraulic fracture stress testing in EGS and high temperature petroleum reservoirs. The thermo-elastic stress resulting from heat conduction during the cooling activity can have important influence on the behavior of the hydraulic fractures. A coupled numerical model has been developed to study the thermo-mechanical effect associated with pre-injection wellbore cooldown on the wellbore pressure and geometry of the hydraulic fracture (either longitudinal or transverse to the wellbore axis). The main novelty of this numerical study is the consideration of significant near-wellbore thermal stresses in the coupled non-linear problem of hydraulic fracturing initiation and propagation, which enables investigation of the thermo-mechanical effect under different fracture propagation regimes. Simulation results show earlier fracture initiation and lower breakdown pressure caused by cooling circulation. Extensive wellbore cooling also significantly alters the evolution of wellbore pressure, as evidenced by the differences observed under various cooling conditions. Most importantly, cooling promotes the transverse initiation of hydraulic fractures in situations where the initiation would have been longitudinal in the absence of cooling. The cases most susceptible to the complete change of fracture initiation geometry are those horizontal wells drilled parallel to the minimum horizontal stress but also applicable to vertical wells in cases where the vertical stress is the lower in magnitude than either horizontal principal stress. These results combine to indicate a profound potential for cooling to impact hydraulic fracture initiation and early growth, and therefore needs to be considered in the planning and interpretation of stress testing and reservoir stimulation when cooling operations are necessary.

physics.geo-ph