... ABSTRACT Understanding the stress state in the Cornell University Borehole Observatory (CUBO) and its relation to the orientation of main fracture clusters is significant for building reservoir models and designing stimulation plans in the proposed geothermal project. Natural fracture...

... ABSTRACT Multi-branch radial boreholes can be drilled and combined with hydraulic fracturing to efficiently stimulate tight gas reservoirs. This paper experimentally investigates how horizontal stress difference affects fracture geometry and breakdown pressure in multi-branch radial borehole...

... ABSTRACT A novel approach to study hydraulic fracture initiation and propagation inside Nuclear Magnetic Resonance core flooding system (NMR) was examined on 38 mm diameter (1.5") outcrop sandstone rock plugs. A 3.4 mm diameter and about 35 mm long borehole (two-third of the plug's length...

..., 2021;Fanhui et al, 2021). As the drilling fluid intrusion time increases, such rocks mechanically exhibit a gradual decrease in strength and hardness, which eventually leads to an increase in the collapse pressure of the rocks on the well wall, and the borehole collapses when the collapse pressure...

... ABSTRACT In this study the elastic properties of crystalline rocks – amphibolites from different boreholes were studied. We studied the depth effect on the elastic properties of mineralogically quite homogenous rocks – amphibolites. The samples were taken from three different crustal levels...

..., is imported into the DEM model. Different hydraulic fracturing preconditioning scenarios corresponding to varied locations of boreholes are studied to investigate the influence of an existing close cave on hydraulic fracture trajectories, interactions and optimum spacing. This study highlights the importance...

... and solid inertia. A set of deep well parameters were taken as the examples to calculate the near-borehole stress field and failure response compared with the poro-elastic static model. The influences of poro-elastic parameters, in-situ stress and wellbore pressure on the shear failure responses were also...

.... Comparison of the failure zone with different borehole trajectories showed that the influence of the bedding plane decreased when the relative angle between the borehole axis and the bedding normal was small. Therefore, avoiding drilling parallel to bedding planes is conducive to borehole stability...

... source. Coupled thermo-hydro-mechanical simulations were performed to predict quantitatively the brine flow into a borehole excavated in rock salt as a result of excavation, heating/cooling and damage. The rate of water release was shown to rise with any change in temperature, with the greatest increase...

... judgement. The 3D model is usually established using borehole data. The data gaps between boreholes affect the accuracy of the 3D geological model. Instead of getting additional borehole data, geophysical survey is a promisingly cost-effective method to fill the data gaps and improve the assessment...

... with flexible tools is a novel sidetrack drilling technology. This technology is capable of drilling one or more horizontal laterals oriented to one or more formations within a vertical borehole, which can penetrate the near-well contamination zone and greatly increase the drainage radius. This technology...

... intervals with 0.7 m length enclosed by a double-packer probe, either with pre-existing fractures or initially intact, in 7 boreholes crisscrossing a rock volume of 60×30×30 m 3 . The data from the injection experiments typically used to determine components of the stress tensor comprise shut-in and jacking...

...-dependent failures can occur in the vicinity of the borehole depending on the magnitude of the tripping velocity. INTRODUCTION Tripping is a frequent operation that is running pipes into or out of a well for different reasons, e.g., replacing a dull bit, replacing bottom hole assembly, running logging...

... is established. The angle of the main branch well and the borehole azimuth angle of the main branch well on the stability of the multilateral well juncture is analyzed. The three-dimensional Coulomb failure criterion is introduced to characterize the dynamic failure of the rock, and the failure range and failure...

..., enhanced geothermal systems, and unconventional hydrocarbon reservoirs. Numerical simulations were carried out using a finite-discrete element method (FDEM) code, capable of explicit consideration of rock fracturing processes and dynamic phenomena. A parametric study on the effect of borehole...

... ABSTRACT Wellbore instability is a complex problem in water-sensitive shale formation and increases the cost of drilling. The hydration expansion effect changes the mechanical and strength properties of shale and causes the stresses to redistribute around a borehole drilling through the water...

... is verified by comparing it with the blast fracturing experiment of a cement rock sample. Then, the 3D numerical simulations are carried out to study the deflagration fracture mechanism. The results indicate that methane deflagration fracturing forms complex fractures around the borehole, with shear fracture...

... ABSTRACT A series of hydraulic stimulation experiments were performed in the Bedretto Underground Laboratory for Geosciences and Geoenergies in Switzerland to answer questions about the creation of an engineered geothermal reservoir in crystalline rocks. A 400 m long stimulation borehole...

... hydraulic fracture, developing from a pressurized borehole, against the analytical Kristianovich-Geertsma-de Klerk (KGD) solution. INTRODUCTION Numerically modeling tensile fracture propagation is of great interest in reservoir engineering (Chuprakov et al., 2011; Dahi-Taleghani and Olson, 2011; Jiang...

... ABSTRACT Knowledge of rock properties and in-situ state of stress along the horizontal laterals is essential to optimize frac and stage designs for maximum recovery and avoid casing deformation during fracturing. Also, the integrity of the borehole is directly dependent on the stress profiles...