... of instability. Our observations document a transition from velocity-strengthening to velocity-weakening response when both the temperature was raised from 100 to 250 °C and the effective confining pressure was reduced from 89 to 30 MPa. Shear deformation localizes in a narrow shear zone with this increased...

... the recurring drilling incidents, it is imperative to investigate wellbore instability mechanisms within these composite salt layers and adjust related drilling fluid techniques. This paper analyzed the engineering properties of composite salt rock, carried out experiments on physical and chemical properties...

... first conducted geophysical and engineering characteristics analysis on the drilled wells that encountered the intrusions in the field, then carried out the physical and mechanical experiment with the intrusions and performed numerical simulation of the intrusions, to clarify the wellbore instability...

... exploration. Based on discrete particle theory and contact constitutive relation, a 3D model of wellbore stability of broken formation is established, and the influence of various engineering geological factors on wellbore stability is evaluated. The study reveals that wellbore instability is primarily caused...

... and logging data, the mechanism of wellbore instability near the fault is clarified, and a four-pressure profile prediction method suitable for heterogeneous strata in the fault development zone is established. The example calculation and analysis can provide reference for drilling and anti-collapse...

... of annular in case of displacing fluid denser. In P-2 pattern, the viscosity of displaced fluid is larger, and cementing fluids always form stratified structure which is caused by uneven distribution of velocity. This stratified structure tends to have K-H instability leading wavy interface and causes strong...

... in future to infer the stability state of parts of the mine, and potentially to identify some emerging instability hazards. 1. INTRODUCTION The Kiirunavaara Mine is a Sub-Level Caving (SLC) mine located in the north of Sweden, currently producing 25 Mtones crude iron ore per year. The production areas...

... instability problem and need to be dealt with as part of open pit mine closure planning, as with time and duration of exposure, major reductions in rock competence occur. This paper firstly outlines methods for assessing and characterizing degradable rock units as basis for quantitatively describing...

... these distributions. Finally, methods are presented to interpret the obtained modified stability number distribution. The first method introduces a risk tolerance factor allowing to completely determine a stable stope. The second method identifies the drivers for instability, which could be used as variables...

... technologies. Tunnelling projects frequently encounter various engineering geological hazards, including issues related to ground conditions, groundwater levels, and in-situ stress regimes. Challenges such as encountering fault and crushed zones, mixed face formations, geological and structural instabilities...

... ABSTRACT: Physical models are a sound tool for verifying some instability mechanisms. The authors apply these physical models to check the stability analysis of traditional dry granite masonry retaining walls as built in NW Spain. Unlike concrete retaining walls, dry masonry ones should...

... wells drilled were complicated, and the number of complications reached 35 times, mainly in the aspects of well leakage, well intrusion and wellbore instability. Due to the high pressure coefficient (1.44-1.74sg) of the conglomerate formation and the large geological regional variability...

... ABSTRACT: The Cretaceous Baxigai Formation and the Shushanhe Formation in the Tarim Basin are fractured water-sensitive formation. Wellbore instability is frequent during the drilling process. It's urgent to clarify the mechanism of the fractured water-sensitive formation, and to guide...

... ABSTRACT: Open-pit slope instabilities may lead to personnel injuries and/or equipment damages in some cases. However, in most cases, these events require mitigation measures like step-outs, unloading, buttressing and local slope flattening with potential impact on mine production in short...

... ABSTRACT Borehole instability in naturally fractured rocks poses significant challenges to drilling. However, the weakening of fracture strength due to mud intrusion was not considered in most existing borehole stability analyses, which may yield significant errors and misleading predictions...

... ABSTRACT The wellbore instability is a vital problem when drilling in the ultra-deep carboniferous shale formation in the southwest block of Tarim Oilfield. And, bits are frequently blocked and stuck. Unfortunately, the problems are hardly to be effectively solved by increasing the drilling...

... digital twin metals & mining real time system rock movement united states government artificial intelligence advancement virtual environment monitoring underground excavation ground condition engineer split section machine learning assessment rock mass instability monitoring...

... understand the nucleation process under idealized conditions. A particular focus has been on deriving an instability criterion for either slip-weakening or rate-and-state friction models (e.g., Campillo and Ionescu (1997); Favreau et al. (1999); Uenishi and Rice (2003); Rubin and Ampuero (2005); Ampuero...

... ABSTRACT: A number of injection operations such as CCS (carbon capture and storage), DAC (direct air capture), fluid and enhanced geothermal injections (EGS) can lead to fault-system instability which presents significant geohazard. This instability potentially can activate either slow...

... deformation wellbore design reservoir characterization instability abaqus geometry wellbore integrity annular closure scenario numerical instability diameter drilling reservoir geomechanics displacement creep plane strain model halite operation ARMA 22 191 Simulation of wellbore annular...