... this temperature. These results also suggest that the dominant deformation mechanisms may evolve from frictional granular flow with intergranular pressure solution at low temperatures to grain boundary sliding (GBS) with solid-state diffusion creep at high temperatures. INTRODUCTION Induced seismicity...

... ABSTRACT Rocks exhibit time-dependent creep behavior under constant stress conditions. This can cause damage, instability, and failure of rocks depending on the applied stress levels. Creep behavior is defined by three stages: primary (decelerating), secondary (steady-state), and tertiary...

... ABSTRACT Casing damage is the main form of wellbore integrity failure, severely affecting oil and gas production. The mudstone has rheological properties under the high temperature and pressure of the formation, and creep deformation of the formation leads to increased external pressure...

... is developed. The effects of creep time, eccentricity distance, cement sheath modulus of elasticity and internal casing pressure on wellbore stress were investigated using the finite element method. The results show that for a given eccentricity, the stress on the wellbore increases with creep time, affecting...

... ABSTRACT Shale is considered a suitable host rock for geological nuclear waste repositories due to its low permeability and tendency to reduce stress concentrations via creep. However, such a claim has not been carefully examined from the perspective of shale anisotropy caused by its bedding...

... ABSTRACT Shale oil and gas reservoir is a new hotspot of oil and gas exploration and development. It is very important for fracturing production to produce artificial fractures with sufficient conductivity. Shale clay and organic matter content is high, which is easy to creep, and it makes...

... ABSTRACT Time-dependent processes in rock govern its long-term behavior hence understanding of these processes is of great importance especially for long-lasting surface and underground structures. Results from conventional creep experiments have shown that three stages of creep (trimodal...

...-element analysis considers an uncemented annulus, a fully cemented annulus, and a partially cemented annulus with a channel covering 20%, 50% and 80% of the pipe circumference. No pressure build-up was considered. Commonly applied to Brazilian salts, a double-mechanism creep law is adopted, and strain...

... lead to rock failure in the long-term perspective, even if the effective stress state is not changing. Pore fluid could significantly affect the inelastic response and makes brittle creep in rock more pronounced. Triaxial creep tests are performed on dry and oil-saturated Berea sandstone specimens...

.... Simulations of multi-stage constant stress tests showed that only combined hardening could qualitatively represent reverse (inverse transient) creep, as well as the large transient strains experimentally observed upon switching from axisymmetric compression to axisymmetric extension. Simulations of a gas...

... is used to explain the elastic behavior of the sample. The force-time curve is obtained from the holding stage, which is used to analyze the creep behavior (viscoelasticity) of the sample. The loading stage can be used to analyze the elastoplastic behavior. reservoir geomechanics viscosity young...

... ABSTRACT: From 1996 to 2021, uniaxial creep tests were performed on salt samples in dead-end drifts of the Varangéville (France) and Altaussee (Austria) mines to take advantage of constant temperature and hygrometry. The applied loads were from 0.05 MPa (relative) to 4.5 MPa, i.e., much...

... of the sample composite. The aim of this study is to investigate the link between microstructural evolution and creep behavior of shale rocks subjected to chemo-mechanical loading through modeling time-dependent deformation induced by the dissolution-precipitation process. The model couples the microstructural...

... ABSTRACT: This study investigates the effect of shale creep on the stress evolution of a generic nuclear waste repository. Thermo-hydromechanically (THM) coupled simulations were carried out with the TOUGH-FLAC simulator to model temperature/pore pressure/stress changes due to the decay...

... ABSTRACT: Numerous observations have shown that shale formations may creep in and close the annulus between rock and casing in deep wells, thus effectively sealing off the well sections in a natural way. This movement of the rock is partly controlled by strain and partly by stress, and parts...

... ABSTRACT: During drilling operations in cold regions, the frozen soil obtains strong creep characteristics, which will result in wellbore shrinkage. An unreasonable drilling fluid density may cause engineering accidents, such as blocking and stuck drills. To solve this problem, a drilling...

... ABSTRACT: Microscale grain deformation and reorganization, fracturing, and pressure solution at interfaces have been identified as the mechanisms for the creep of salt at larger scales. However, it remains uncertain how each mechanism quantitatively impacts creep in granular salt...

... ABSTRACT: Rock salt, mainly comprised of NaCl, exhibits inherent softness and has a good rheology property, resulting in complex creep patterns and fracture evolution for wellbore stability. They are, even coming from underground, facing weathering and dissolution & precipitation process...

... ABSTRACT: Wellbore construction through salt formation remains a great challenge in drilling engineering in many oil provinces around the world due to its unique mechanical properties, in particular, its high creep mobility under downhole conditions. However, once the casing is defined...

... a standard suite of material tests. These include creep, dilation and tensile tests. The model effectively captures these test results without resort to more elaborate phenomenological constitutive models. Fitting exercises are provided for each aspect of the constitutive model based upon the material tests...