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Study on critical stress of circular chamber rockburst Hot!
Research status and development trend of deep geological exploration techniques for hydraulic and hydropower engineering#br#
Study on failure mechanism of slopes induced by the underground coal mining subsidence
Time-dependent analysis of bolt-grouting support structures in deep roadways
Degradation mechanism and equivalent simulation method of shear strength of limestone stylolite under immersion
Research on spatiotemporal characteristics perception and prediction methods of shallow buried coal seam mining pressure in valley areas
The concept and technological implementation of active control for foot settlement of soft rock tunnels
Analysis of failure characteristics in delayed strain-type rock burst simulation test on granite
Deformation characteristics of rock mass under dislocation of deep-buried strike-slip fault and its influence by geostress
Physical simulation experiments on non-uniform extension of multi-cluster hydraulic fractures under complex fracturing conditions
Achieving uniform propagation of multi-cluster hydraulic fractures within shale gas reservoirs containing natural fracture zones remains challenging. This study developed a physical simulation methodology to model multi-cluster fracturing in specimens containing prefabricated natural fracture zones. The experimental setup for sample preparation and pumping allows for the distribution of liquid into multiple cluster fractures according to a predetermined sequence of extension, with independent monitoring of flow rates for each cluster. Leveraging the engineering-experimental similarity in fracture propagation characteristics, in-situ stress, and geometry, analogous relationships were derived between experimental and engineering parameters. The effects of pumping rates (0.825 and 3.3 m³/min per cluster), cluster spacing (6 and 12 m), and spatial arrangement positions (middle and side clusters) of natural fracture zones on the propagation of multi-cluster hydraulic fractures in field applications were experimentally investigated. The results showed that: (1) Low pumping rates combined with large cluster spacing enhance the uniform propagation of multi-cluster hydraulic fractures in both samples with and without natural fracture zones. Fractures adjacent to natural fracture zones tend to propagate preferentially, thereby inhibiting uniform multi-fracture propagation. (2) High pumping rates and small cluster spacing facilitate the formation of single-cluster branch fractures and promote inter-cluster fracture connectivity. Conversely, low pumping rates and large cluster spacing result in simpler, non-interfering multi-cluster fracture morphologies. When the initiation cluster is adjacent to a natural fracture zone, the morphology of hydraulic fractures exhibits connectivity between hydraulic fractures and natural fracture zones. (3) During multi-fracture propagation, each cluster of fractures sequentially receives fluid inflow, indicating that multiple hydraulic fractures extend in an alternating sequence rather than simultaneously. Clusters situated within fracture zones tend to receive fluid inflow preferentially and connect with natural fracture zones. Consequently, the pump pressure curve exhibits fluctuations prior to reaching the break pressure. (4) Based on the theories of fracture instability extension and stress shadow, this study discusses the mechanisms of single-cluster fracture instability propagation and multi-fracture complexity enhancement. A high pumping rate increases the driving force for fracture propagation, while natural fracture zones decrease fracture resistance, thereby promoting single-cluster fracture instability. Namely, these factors inhibit the uniform extension of multi-cluster hydraulic fractures. Furthermore, a combination of high pumping rates and small cluster spacing intensifies interference between fractures, leading to the generation of complex fractures. Finally, optimization suggestions for the fracturing design were proposed, focusing on achieving uniform propagation of multiple hydraulic fractures near the wellbore while promoting the formation of complex hydraulic fractures in more distant regions.
Research on rock strength prediction method based on rock fragment br upscaling theory
Development and application of a real-time high-temperature and high-stress true triaxial fracturing test system
Refined meteorological early warning for rainfall-induced landslide based on temporal probability model
Frost heave characteristics and in-situ testing analysis of carbonaceous slate tunnel surrounding rock in high-altitude cold regions
Research of rock blasting seismic energy radiation and its dependence on blasting source and free surfaces
Study on vertical cross-interface expansion and permeability characteristics of N2 foam fracturing cracks in coal measures reservoirs
Study on the effect of rock mesoscopic heterogeneity on its compressive mechanical properties based on GB-DDA method
The bearing capacity and load transfer mechanism of GFRP bar micro uplift pile
Large-scale shaking table test study on seismic performance of geocell retaining wall with tensioned tape
Study on mechanical properties and compaction quality evaluation of gravel soil subgrade based on impact load method
Study on static and dynamic shear characteristics of geotextile- residual soil interface considering wet-dry effect