Lost circulation in fractured formations remains a persistent challenge in drilling operations, causing substantial economic losses and increased operational risk. Conventional granular bridging packs are mechanically fragile and can be destabilized by pressure fluctuations, limiting one-trip plugging efficiency. This study incorporates a thermosensitive adhesive resin into bridging assemblies to enhance plug integrity by promoting interparticle adhesion and particle-wall coupling after thermal activation. Oscillatory temperature-sweep rheometry is used to quantify the temperature-dependent viscoelastic response of resin-particle composites. A wedge-shaped fracture analogue with photoelastic visualization is used to monitor force chain development and uniformity during progressive loading. Discrete element method simulations in Particle Flow Code, using a linear parallel-bond contact model, resolve mesoscale load-transfer pathways and isolate the contribution of adhesive interactions. Results indicate that thermosensitive adhesive resin increases assembly coherence, promotes a stable load-bearing skeleton, and suppresses stress localization that typically precedes plugging failure. The strengthening trend is governed by particle rigidity and surface characteristics, yielding consistent load-transfer patterns across experiments and simulations. These findings demonstrate that thermally activated adhesion can transform unconsolidated granular packs into mechanically stable plugging zones, providing a mechanistic basis for designing high-stability lost circulation control systems in fractured formations.

CO₂-energized fracturing holds great potential for enhancing fracturing fluid flowback and enabling effective CO₂ sequestration, while the effect of the choice of CO₂ energization strategy on these processes is not yet fully understood. This study experimentally investigated three representative CO₂ energization methods: Pre-fracturing injection, foam injection, and co-injection. Nuclear magnetic resonance techniques were applied to systematically analyze the influence of various CO₂ injection parameters on fracturing fluid flowback behavior and CO₂ storage in tight formations. The results showed that CO₂ pre-fracturing increases displacement pressure and significantly improves flowback efficiency, with optimal performance achieved at a moderate injection volume. Reducing the injection rate and increasing the volume further enhanced the CO₂ storage ratio. Foam injection facilitated flowback by improving foam quality, particularly in macropores. Co-injection achieved a favorable balance between high flowback efficiency and substantial CO₂ retention. Furthermore, the three energization strategies were shown to lead to distinct fluid redistribution patterns within porous media: Pre-fracturing promoted CO₂ retention in micropores and mesopores, foam injection reduced retention in macropores, and co-injection provided the most balanced performance in mesopores. These findings provide new insights into CO₂-energized fracturing and sequestration mechanisms and offer technical guidance for optimizing CO₂-based stimulation strategies in deep unconventional tight gas reservoirs.

Acid fracturing is the most widely applied technology for stimulating carbonate reservoirs. Meanwhile, the effectiveness of this method largely depends on factors such as acid penetration distance, fracture morphology and conductivity, all of which are closely governed by acid flow behavior. A wealth of numerical simulations have been conducted to characterize acid flow during fracturing, whereas the coupled effects of acid rheological properties and fracture surface roughness on the acid flow behavior remain underexplored. In this work, a three-dimensional numerical model of acid etching fracture was developed by coupling an acid-rock reaction model with computational fluid dynamics methods, which comprehensively incorporates the rheological property of acid and fracture surface roughness. Validation against experimental data showed a deviation of 11.15% in dissolved mass, with errors within 10.00% for most roughness parameters, confirming the numerical model's accuracy. Furthermore, the numerical model was employed to investigate the quantitative effect of the rheological index on acid transport and the spatiotemporal evolution of acid flow and dissolution. The results revealed significant interdependencies among flow velocity, shear rate, acid-rock reaction rate, and fracture width, all of which evolve dynamically over time and space. Moreover, it was found that the non-uniform distribution of flow velocity, shear rate, acid-rock reaction rate is caused by fracture surface roughness, and the degree of non-uniformity is enhanced as the shear-thinning capacity of the acid increases. This work provides a robust numerical framework for the simulation of the transport and reaction of acids with power-law characteristics in three-dimensional rough fractures, thus offers valuable theoretical insights for guiding the optimization of acid fracturing parameters and enhancing reservoir stimulation efficiency.