The Experts below are selected from a list of 7272 Experts worldwide ranked by ideXlab platform
Ernesto O. Cristallini - One of the best experts on this subject based on the ideXlab platform.
-
Contemporary Stress orientations from borehole breakout analysis in the southernmost flat‐slab boundary Andean retroarc (32°44′ and 33°40′S)
Journal of Geophysical Research, 2009Co-Authors: Cecilia Griselda Guzman, Ernesto O. CristalliniAbstract:[1] Horizontal Stress directions have been determined in the southernmost flat-slab boundary Andean retroarc between 32°44' and 33°40'S within Cuyo Basin, Argentina. These directions were obtained from the borehole breakout analysis of 42 wells using four-arm caliper data. The mean Maximum Horizontal Stress (SHmax) direction for the whole region is 104.1° with a 95% confidence interval of 8.1°. The present-day Stress field has an approximately preferred E-W trend Maximum Horizontal Stress direction, consistent with the plate boundary forces (80°) and the topographic forces (near E-W). The calculated SHmax directions are near the expected values, but some local deviations were observed. The SHmax rotates from an E-W orientation in the south to a NW-SE orientation to the north of this sector of the Andean retroarc. A regional variation in the Stress field can be observed when these results for the Cuyo Basin are analyzed together with those presented in a previous study in the Neuquen Basin to the south. The Maximum Horizontal Stress varies from ∼NW-NE along this combined section of the Andean retroarc, with the ∼E-W SHmax directions in the northern Neuquen Basin consistent with those observed in the southern sector of Cuyo Basin. These variations in the Stress field orientation appear related with the topography geometry. From the analysis between the mean SHmax obtained and the acting forces, it can be concluded that the topographic control on the Horizontal Stress field seems to be dominant in the Cuyo Basin and in the north of Neuquen Basin. To the south of Neuquen Basin the Horizontal Stress field should be mainly controlled by the plate boundary forces.
-
contemporary Stress orientations from borehole breakout analysis in the southernmost flat slab boundary andean retroarc 32 44 and 33 40 s
Journal of Geophysical Research, 2009Co-Authors: Cecilia Griselda Guzman, Ernesto O. CristalliniAbstract:[1] Horizontal Stress directions have been determined in the southernmost flat-slab boundary Andean retroarc between 32°44' and 33°40'S within Cuyo Basin, Argentina. These directions were obtained from the borehole breakout analysis of 42 wells using four-arm caliper data. The mean Maximum Horizontal Stress (SHmax) direction for the whole region is 104.1° with a 95% confidence interval of 8.1°. The present-day Stress field has an approximately preferred E-W trend Maximum Horizontal Stress direction, consistent with the plate boundary forces (80°) and the topographic forces (near E-W). The calculated SHmax directions are near the expected values, but some local deviations were observed. The SHmax rotates from an E-W orientation in the south to a NW-SE orientation to the north of this sector of the Andean retroarc. A regional variation in the Stress field can be observed when these results for the Cuyo Basin are analyzed together with those presented in a previous study in the Neuquen Basin to the south. The Maximum Horizontal Stress varies from ∼NW-NE along this combined section of the Andean retroarc, with the ∼E-W SHmax directions in the northern Neuquen Basin consistent with those observed in the southern sector of Cuyo Basin. These variations in the Stress field orientation appear related with the topography geometry. From the analysis between the mean SHmax obtained and the acting forces, it can be concluded that the topographic control on the Horizontal Stress field seems to be dominant in the Cuyo Basin and in the north of Neuquen Basin. To the south of Neuquen Basin the Horizontal Stress field should be mainly controlled by the plate boundary forces.
Richard R. Hillis - One of the best experts on this subject based on the ideXlab platform.
-
geomechanical analysis of the naylor field otway basin australia implications for co2 injection and storage
International Journal of Greenhouse Gas Control, 2010Co-Authors: Sandrine Vidalgilbert, Eric Tenthorey, D N Dewhurst, Jonathan Ennisking, Peter Van Ruth, Richard R. HillisAbstract:Abstract A geomechanical assessment of the Naylor Field, Otway Basin, Australia has been undertaken to investigate the possible geomechanical effects of CO2 injection and storage. The study aims to evaluate the geomechanical behaviour of the caprock/reservoir system and to estimate the risk of fault reactivation. The Stress regime in the onshore Victorian Otway Basin is inferred to be strike–slip if the Maximum Horizontal Stress is calculated using frictional limits and DITF (drilling induced tensile fracture) occurrence, or normal if Maximum Horizontal Stress is based on analysis of dipole sonic log data. The NW–SE Maximum Horizontal Stress orientation (142°N) determined from a resistivity image log is broadly consistent with previous estimates and confirms a NW–SE Maximum Horizontal Stress orientation for the Otway Basin. An analytical geomechanical solution is used to describe Stress changes in the subsurface of the Naylor Field. The computed reservoir Stress path for the Naylor Field is then incorporated into fault reactivation analysis to estimate the minimum pore pressure increase required to cause fault reactivation (ΔPp). The highest reactivation propensity (for critically-oriented faults) ranges from an estimated pore pressure increase (ΔPp) of 1 MPa to 15.7 MPa (estimated pore pressure of 18.5–33.2 MPa) depending on assumptions made about Maximum Horizontal Stress magnitude, fault strength, reservoir Stress path and Biot's coefficient. The critical pore pressure changes for known faults at Naylor Field range from an estimated pore pressure increase (ΔPp) of 2 MPa to 17 MPa (estimated pore pressure of 19.5–34.5 MPa).
-
Present‐day Stresses in Brunei, NW Borneo: superposition of deltaic and active margin tectonics
Basin Research, 2010Co-Authors: Rosalind King, Mark Tingay, Richard R. Hillis, Abdul Razak DamitAbstract:The Baram Delta System, Brunei, NW Borneo, is a Tertiary delta system located on an active continental margin. Delta top regions in many Tertiary delta systems (e.g. Niger Delta) are thought to exhibit a normal-fault Stress regime and margin-parallel Maximum Horizontal Stress orientations. However, unlike in passive margin Tertiary delta systems, two present-day Stress provinces have been previously identified across the Baram Delta System: an inner shelf inverted province with a margin-normal (NW-SE) Maximum Horizontal Stress orientation and an outer shelf extension province with a margin-parallel (NE-SW) Maximum Horizontal Stress orientation. Before this study, there were few data constraining the inverted province other than in the vicinity of the Champion Fields. New data from 12 petroleum wells in the western inner shelf and onshore west Brunei presented herein confirm the margin-normal Maximum Horizontal Stress orientations of the inverted province. A total of 117 borehole breakouts, all documented in shale units, and one drilling-induced tensile fracture (in a sandstone interval) reveal a mean Maximum Horizontal Stress orientation of 117 with a standard deviation of 191. This orientation is consistent with contemporary margin-normal Maximum Horizontal Stress orientations of the inverted province described previously in the vicinity of the Champion Fields that have been linked to basement tectonics of the Crocker-Rajang accretionary complex and associated active margin. However, Stress magnitudes calculated using data from these 12 petroleum wells indicate a borderline strike-slip fault to normal fault Stress regime for the present day; combined with the absence of seismicity, this suggests that the studied part of the NW Borneo continental margin is currently tectonically quiescent.
-
In situ Stresses and natural fractures in the Northern Perth Basin, Australia
Australian Journal of Earth Sciences, 2008Co-Authors: Rosalind King, Richard R. Hillis, Scott D. ReynoldsAbstract:Present-day Stress orientations in the Northern Perth Basin have been inferred from borehole breakouts and drilling-induced tensile fractures observed on image logs from eight wells. Stress indicators from these wells give an east – west Maximum Horizontal Stress orientation, consistent with Stress-field modelling of the Indo-Australian Plate. Previous interpretations using dipmeter logs indicated anomalous north-directed Maximum Horizontal Stress orientations. However, higher-quality image logs indicate a consistent Maximum Horizontal Stress orientation, perpendicular to dominant north – south and northwest – southeast fault trends in the basin. Vertical Stress was calculated from density logs at 21.5 MPa at 1 km depth. Minimum Horizontal Stress values, estimated from leak-off tests, range from 7.4 MPa at 0.4 km to 21.0 MPa at 0.8 km depth: the greatest values are in excess of the vertical Stress. The Maximum Horizontal Stress magnitude was constrained using the relationship between the minimum and maxim...
-
Fault reactivation potential during CO2 injection in the Gippsland Basin, Australia
Exploration Geophysics, 2006Co-Authors: P. Van Ruth, E.j. Nelson, Richard R. HillisAbstract:The risk of fault reactivation in the Gippsland Basin was calculated using the FAST (Fault Analysis Seal Technology) technique, which determines fault reactivation risk by estimating the increase in pore pressure required to cause reactivation within the present-day Stress field. The Stress regime in the Gippsland Basin is on the boundary between strike-slip and reverse faulting: Maximum Horizontal Stress (~40.5 MPa/km) > vertical Stress (21 MPa/km) ~ minimum Horizontal Stress (20 MPa/km). Pore pressure is hydrostatic above the Campanian Volcanics of the Golden Beach Subgroup. The NW-SE Maximum Horizontal Stress orientation (139oN) determined herein is broadly consistent with previous estimates, and verifies a NW-SE Maximum Horizontal Stress orientation in the Gippsland Basin. Fault reactivation risk in the Gippsland Basin was calculated using two fault strength scenarios; cohesionless faults (C = 0; m = 0.65) and healed faults (C = 5.4; m = 0.78). The orientations of faults with relatively high and relatively low reactivation potential are almost identical for healed and cohesionless fault strength scenarios. High-angle faults striking NE-SW are unlikely to reactivate in the current Stress regime. High-angle faults oriented SSE-NNW and ENE-WSW have the highest fault reactivation risk. Additionally, low-angle faults (thrust faults) striking NE-SW have a relatively high risk of reactivation. The highest reactivation risk for optimally oriented faults corresponds to an estimated pore pressure increase (Delta-P) of 3.8 MPa (~548 psi) for cohesionless faults and 15.6 MPa (~2262 psi) for healed faults. The absolute values of pore pressure increase obtained from fault reactivation analysis presented in this paper are subject to large errors because of uncertainties in the geomechanical model (in situ Stress and rock strength data). In particular, the Maximum Horizontal Stress magnitude and fault strength data are poorly constrained. Therefore, fault reactivation analysis cannot be used to directly measure the Maximum allowable pore pressure increase within a reservoir. We argue that fault reactivation analysis of this type can only be used for assessing the relative risk of fault reactivation and not to determine the Maximum allowable pore pressure increase a fault can withstand prior to reactivation.
-
PRESENT-DAY STATE-OF-Stress OF SOUTHEAST AUSTRALIA
The APPEA Journal, 2006Co-Authors: E.j. Nelson, Richard R. Hillis, Mike Sandiford, S. Reynolds, Scott D. MildrenAbstract:There have been several studies, both published and unpublished, of the present-day state-of-Stress of southeast Australia that address a variety of geomechanical issues related to the petroleum industry. This paper combines present-day Stress data from those studies with new data to provide an overview of the present-day state-of-Stress from the Otway Basin to the Gippsland Basin. This overview provides valuable baseline data for further geomechanical studies in southeast Australia and helps explain the regional controls on the state-of-Stress in the area. Analysis of existing and new data from petroleum wells reveals broadly northwest–southeast oriented, Maximum Horizontal Stress with an anticlockwise rotation of about 15° from the Otway Basin to the Gippsland Basin. A general increase in minimum Horizontal Stress magnitude from the Otway Basin towards the Gippsland Basin is also observed. The present-day state-of-Stress has been interpreted as strike-slip in the South Australian (SA) Otway Basin, strike-slip trending towards reverse in the Victorian Otway Basin and borderline strike-slip/reverse in the Gippsland Basin. The present-day Stress states and the orientation of the Maximum Horizontal Stress are consistent with previously published earthquake focal mechanism solutions and the neotectonic record for the region. The consistency between measured present-day Stress in the basement (from focal mechanism solutions) and the sedimentary basin cover (from petroleum well data) suggests a dominantly tectonic far-field control on the present-day Stress distribution of southeast Australia. The rotation of the Maximum Horizontal Stress and the increase in magnitude of the minimum Horizontal Stress from west to east across southeast Australia may be due to the relative proximity of the New Zealand segment of the plate boundary.
Oliver Heidbach - One of the best experts on this subject based on the ideXlab platform.
-
The present-day state of tectonic Stress in the Darling Basin, Australia: Implications for exploration and production
Marine and Petroleum Geology, 2016Co-Authors: Mojtaba Rajabi, Mark Tingay, Oliver HeidbachAbstract:Knowledge of the full present-day Stress tensor and pore pressure has significant applications in the exploration and production of conventional and unconventional hydrocarbon reservoirs. The Darling Basin of New South Wales, Australia, is an old sedimentary basin (Late Cambrian/Silurian to Early Carboniferous) in which there was limited information about the present-day Stress field prior to this study. In this paper we evaluate the contemporary Stress field of the Darling Basin using a dataset from recent exploration wells and perform a geomechanical risk assessment with respect to borehole stability, fracture/fault generation and reactivation. Our interpretations of borehole failures in borehole image logs reveal a prevailing east-west orientation of the Maximum Horizontal Stress throughout the Darling Basin. The estimates of the magnitudes for the vertical, minimum and Maximum Horizontal Stress in the studied wells indicate a transition between thrust and strike-slip faulting Stress regime at 600-700 m depths, where the magnitude of vertical Stress and minimum Horizontal Stress are close to each other. However, the presence of borehole breakouts and drilling-induced tensile fractures, that we observe in the image logs at greater depths (900-2100 m) indicate a transition into a strike-slip tectonic Stress regime below a depth range of approximately 700-900 m. These findings are in agreement with overcoring Stress measurements east and west of the investigated wells. Furthermore, there are several Neogene-to-Recent geological structures in the study area that indicate thrust faulting with an east-west oriented Maximum Horizontal Stress orientation around this old sedimentary basin. The consistency between the orientation of Maximum Horizontal Stress determined from wellbore data and neotectonic structures is significant, and implies that Horizontal Stress orientations derived from very recent geological features may be valuable inputs to geomechanical models in the absence of wellbore or other data. However, the recent surface geological structures suggest a thrust faulting Stress regime that is in slight contrast to the transition between thrust and strike-slip Stress regime (SH > Sh similar to Sv) indicated by petroleum data, and highlights a potential pitfall of using neotectonic structures in geomechanical models. In particular, careful attention and verification should be made when using neotectonic structures for input, calibration or confirmation of geomechanical models, especially in intraplate tectonic settings such as Australia. (C) 2016 Elsevier Ltd. All rights reserved.
-
Statistical Stress Model Calibration
Second EAGE Workshop on Geomechanics and Energy, 2015Co-Authors: K Reiter, Oliver HeidbachAbstract:The estimation of orientation and magnitude of crustal Stresses is crucial for the design phase of technological and safe underground usage. As usually only a few in-situ data are available, Stress prediction is challenging. Geomechanical-numerical modelling is the only tool, which allows Stress prediction that takes material properties and inhomogeneities into account. The model calibration is essential to find the best-fitting Stress results. The presented workflow allows the statistically proved calibration to determine the best-fit model. Furthermore, statistic tests speed up the calibration process. The order in which model-independent data are used for model calibration pay attention to the interrelation between the Stress components. Therefore, data of vertical Stress are tested first to optimize material properties. Second, the orientation of the Maximum Horizontal Stress is used to optimize orientation of applied boundary conditions. Finally, the magnitudes of minimum and Maximum Horizontal Stress are varied to find the optimal strain, applied by the boundary conditions.
-
Present-day Stress orientation in the Molasse Basin
Tectonophysics, 2010Co-Authors: John Reinecker, Mark Tingay, Birgit Müller, Oliver HeidbachAbstract:The present-day Maximum Horizontal Stress orientation in the Molasse Basin is broadly perpendicular to the strike of the Alpine front, indicating that the Stress pattern is probably controlled by gravitational potential energy of Alpine topography rather than by plate boundary forces. The present-day Maximum Horizontal Stress orientations determined herein have important implications for the production of hydrocarbons and geothermal energy in the German Molasse Basin, in particular that hydraulically-induced fractures are likely to propagate N–S and that wells deviated to the north or south may have reduced wellbore instability problems
-
Present-day Stress orientation in the Molasse Basin
Tectonophysics, 2009Co-Authors: John Reinecker, Mark Tingay, Birgit Müller, Oliver HeidbachAbstract:Abstract The present-day state of Stress in Western Europe is considered to be controlled by forces acting at the plate boundaries. It is assumed that the Alpine orogen only influence the regional pattern of present-day Stress in Western Europe within the Alps themselves. We examine the present-day Maximum Horizontal Stress orientation in the Molasse Basin in the Alpine foreland in order to investigate the possible influence of the Alps on the far-field Stress pattern of Western Europe. Four-arm caliper and image logs were analysed in 137 wells, in which a total of 1348 borehole breakouts and 59 drilling-induced fractures were observed in 98 wells in the German Molasse Basin. The borehole breakouts and drilling-induced fractures reveal that Stress orientations are highly consistent within the Molasse Basin and that the present-day Maximum Horizontal Stress orientation rotates from N–S in southeast Germany (002°N ± 19°) to approximately NNW–SSE in southwest Germany and the Swiss Molasse Basin (150°N ± 24°). The present-day Maximum Horizontal Stress orientation in the Molasse Basin is broadly perpendicular to the strike of the Alpine front, indicating that the Stress pattern is probably controlled by gravitational potential energy of Alpine topography rather than by plate boundary forces. The present-day Maximum Horizontal Stress orientations determined herein have important implications for the production of hydrocarbons and geothermal energy in the German Molasse Basin, in particular that hydraulically-induced fractures are likely to propagate N–S and that wells deviated to the north or south may have reduced wellbore instability problems.
Cecilia Griselda Guzman - One of the best experts on this subject based on the ideXlab platform.
-
Contemporary Stress orientations from borehole breakout analysis in the southernmost flat‐slab boundary Andean retroarc (32°44′ and 33°40′S)
Journal of Geophysical Research, 2009Co-Authors: Cecilia Griselda Guzman, Ernesto O. CristalliniAbstract:[1] Horizontal Stress directions have been determined in the southernmost flat-slab boundary Andean retroarc between 32°44' and 33°40'S within Cuyo Basin, Argentina. These directions were obtained from the borehole breakout analysis of 42 wells using four-arm caliper data. The mean Maximum Horizontal Stress (SHmax) direction for the whole region is 104.1° with a 95% confidence interval of 8.1°. The present-day Stress field has an approximately preferred E-W trend Maximum Horizontal Stress direction, consistent with the plate boundary forces (80°) and the topographic forces (near E-W). The calculated SHmax directions are near the expected values, but some local deviations were observed. The SHmax rotates from an E-W orientation in the south to a NW-SE orientation to the north of this sector of the Andean retroarc. A regional variation in the Stress field can be observed when these results for the Cuyo Basin are analyzed together with those presented in a previous study in the Neuquen Basin to the south. The Maximum Horizontal Stress varies from ∼NW-NE along this combined section of the Andean retroarc, with the ∼E-W SHmax directions in the northern Neuquen Basin consistent with those observed in the southern sector of Cuyo Basin. These variations in the Stress field orientation appear related with the topography geometry. From the analysis between the mean SHmax obtained and the acting forces, it can be concluded that the topographic control on the Horizontal Stress field seems to be dominant in the Cuyo Basin and in the north of Neuquen Basin. To the south of Neuquen Basin the Horizontal Stress field should be mainly controlled by the plate boundary forces.
-
contemporary Stress orientations from borehole breakout analysis in the southernmost flat slab boundary andean retroarc 32 44 and 33 40 s
Journal of Geophysical Research, 2009Co-Authors: Cecilia Griselda Guzman, Ernesto O. CristalliniAbstract:[1] Horizontal Stress directions have been determined in the southernmost flat-slab boundary Andean retroarc between 32°44' and 33°40'S within Cuyo Basin, Argentina. These directions were obtained from the borehole breakout analysis of 42 wells using four-arm caliper data. The mean Maximum Horizontal Stress (SHmax) direction for the whole region is 104.1° with a 95% confidence interval of 8.1°. The present-day Stress field has an approximately preferred E-W trend Maximum Horizontal Stress direction, consistent with the plate boundary forces (80°) and the topographic forces (near E-W). The calculated SHmax directions are near the expected values, but some local deviations were observed. The SHmax rotates from an E-W orientation in the south to a NW-SE orientation to the north of this sector of the Andean retroarc. A regional variation in the Stress field can be observed when these results for the Cuyo Basin are analyzed together with those presented in a previous study in the Neuquen Basin to the south. The Maximum Horizontal Stress varies from ∼NW-NE along this combined section of the Andean retroarc, with the ∼E-W SHmax directions in the northern Neuquen Basin consistent with those observed in the southern sector of Cuyo Basin. These variations in the Stress field orientation appear related with the topography geometry. From the analysis between the mean SHmax obtained and the acting forces, it can be concluded that the topographic control on the Horizontal Stress field seems to be dominant in the Cuyo Basin and in the north of Neuquen Basin. To the south of Neuquen Basin the Horizontal Stress field should be mainly controlled by the plate boundary forces.
Takeshi Tsuji - One of the best experts on this subject based on the ideXlab platform.
-
in situ Stress state from walkaround vsp anisotropy in the kumano basin southeast of the kii peninsula japan
Geochemistry Geophysics Geosystems, 2011Co-Authors: Ryota Hino, Yoshinori Sanada, Jinoh Park, Nathan L Bangs, Takeshi Tsuji, Tetsuo No, Eiichiro Araki, Kiyohiko Yamamoto, Roland Von HueneAbstract:To reveal the Stress state within the Kumano basin, which overlies the Nankai accretionary prism, we estimated seismic anisotropy from walkaround vertical seismic profiling (VSP) data recorded at Site C0009 during Integrated Ocean Drilling Program (IODP) Expedition 319. We obtained the following anisotropic parameters: (1) P wave velocity anisotropy derived from azimuthal normal moveout (NMO) velocity analysis, (2) P wave amplitude variation with azimuth, and (3) axes of symmetry of S wave splitting. Azimuthal variations of P wave velocity by ellipsoidal fitting analysis showed that P wave velocity anisotropy within sediments of the Kumano basin was ∼5%. Both the directions of fast P wave velocity and strong amplitude are aligned with the convergence vector of the Philippine Sea plate. Furthermore, S wave splitting analysis indicated that S wave polarization axes were parallel to and normal to the direction of plate subduction. These results indicate that the Maximum Horizontal Stress at Site C0009 in the Kumano basin is in the direction of plate subduction. The Horizontal differential Stress estimated from the P wave velocity anisotropy (2.7∼5.5 MPa) indicates that the Maximum Horizontal Stress is similar in magnitude to (or a little higher than) the vertical Stress.