Influence of high horizontal stress regime on the shape of LPG caverns – A case study

2010 ◽  
pp. 869-873
Author(s):  
M Saharan ◽  
A Sinha ◽  
H Mitri
Keyword(s):  
Horizontal Stress ◽  
Stress Regime

Geomechanical Approach in Classification of Borehole Failures in Fractured Carbonates of Boca De Jaruco Field

2021 ◽  
Author(s):  
Anna Vladimirovna Norkina ◽  
Iaroslav Olegovich Simakov ◽  
Yuriy Anatoljevich Petrakov ◽  
Alexey Evgenjevich Sobolev ◽  
Oleg Vladimirovich Petrashov ◽  
...  
Keyword(s):  
Stress State ◽  
Horizontal Wells ◽  
Horizontal Stress ◽  
In Situ Stress ◽  
Vertical Wells ◽  
Stress Regime ◽  
Geophysical Information ◽  
The Republic ◽  
Maximum Horizontal Stress

Abstract This article is a continuation of the work on geomechanically calculations for optimizing the drilling of horizontal wells into the productive reservoir M at the Boca de Haruco field of the Republic of Cuba, presented in the article SPE-196897. As part of the work, an assessment of the stress state and direction was carried out using geological and geophysical information, an analysis of the pressure behavior during steam injections, cross-dipole acoustics, as well as oriented caliper data in vertical wells. After the completion of the first part of the work, the first horizontal wells were successfully drilled into the M formation. According to the recommendations, additional studies were carried out: core sampling and recording of micro-imager logging in the deviated sections. Presence of wellbore failures at the inclined sections allowed to use the method of inverse in-situ stress modeling based on image logs interpretation. The classification of wellbore failures by micro-imager logging: natural origin and violations of technogenic genesis is carried out. The type of breakout is defined. The result of the work was the determination of the stress state and horizontal stresses direction. In addition, the article is supplemented with the calculation of the maximum horizontal stress through the stress regime identifier factor.

Unexpected HTI velocity anisotropy: a wide-azimuth, low fold, 3D seismic processing case study

2014 ◽  
Vol 54 (2) ◽  
pp. 1
Author(s):  
Randall Taylor ◽  
Simon Cordery ◽  
Sebastian Nixon ◽  
Karel Driml
Keyword(s):  
Survey Design ◽  
Local Stress ◽  
Horizontal Stress ◽  
3D Design ◽  
Seismic Processing ◽  
Velocity Anisotropy ◽  
Before And After ◽  
Key Steps ◽  
Maximum Horizontal Stress

This case-study demonstrates seismic processing in the presence of Horizontal Transverse Isotropic (HTI) velocity anisotropy encountered in a low-fold land 3D survey in New Zealand. The HTI velocity anisotropy was unexpected, being suspected only after the initial poor stack response compared to vintage 2D sections in the area, and the sparse 3D design made it difficult to identify. The paper shows how anisotropy was singled out from other possible causes, such as geometry errors. We discuss the key steps of the processing flow incorporated to deal with the HTI anisotropy to attain a high quality final processed volume. In particular we show data examples after the application of azimuthally dependant NMO velocities, along with pre-stack HTI migration. Examples are shown which demonstrate the preservation of the HTI anisotropy before and after 5D trace interpolation. Maps and vertical profiles of 3D attributes are used to demonstrate the magnitude and direction of the HTI velocity field, which varies 5% to 10% between the fast and slow horizontal directions. These observations coincide with the local stress state deduced from borehole break-out studies. We conclude that the fast velocity direction corresponds to the present maximum horizontal stress direction. Finally the paper summarises the implications for processing wide azimuth 3D data in this area and suggests improvements for future 3D survey design. This paper was originally published in the Proceedings of the 23rd International Geophysical Conference and Exhibition, which was held from 11–14 August 2013 in Melbourne, Australia.

scholarly journals Structural expression of a fading rift front, a case study from the Oligo-Miocene Irbid rift of northwest Arabia

2018 ◽  
Author(s):  
Reli Wald ◽  
Amit Segev ◽  
Zvi Ben-Avraham ◽  
Uri Schattner
Keyword(s):  
Thermal Response ◽  
Dead Sea ◽  
Fault System ◽  
Structural Development ◽  
Stress Regime ◽  
Basin Subsidence ◽  
Continental Rifts ◽  
Severe Erosion ◽  
Geophysical Imaging

Abstract. Not all continental rifts mature to form a young ocean. The mechanism and duration of their cessation depend on the crustal structure, modifications in plate kinematics, lithospheric thermal response, or intensity of sub-crustal flow (e.g., plume activity). The cessation is recorded in the structure and stratigraphy of the basins that develop during the rifting process. This architecture is lost due to younger tectonic inversion, severe erosion or even burial into greater depths that forces their detection by low-resolution geophysical imaging. The current study focuses on a uniquely preserved Oligo-Miocene rift that was subsequently pirated by a crossing transform fault system and as a result died out. We integrate all geological, geophysical and results from previous studies from across the Southern Galilee to unravel the structural development of the Irbid failing rift, of Northwest Arabia. Despite tectonic, magmatic and geomorphologic activity postdating the rifting, its subsurface structure is preserved at depths of up to 1 km. Our results show that a series of basins subsided at the rift front, across the southern Galilee. We constrain the timing and extent of their subsidence into two main stages, based on facies analysis and chronology of magmatism. Between 20–9 Ma grabens and half-grabens subsided within a larger releasing jog, following an NW direction of a deeper presumed Principal Displacement Zone. The basins continued to subside until a transition from the Red Sea to Dead Sea stress regime occurred. With the transition, the basins ceased to subside as a rift, while the Dead Sea Fault split the jog structure. Between 9–5 Ma basin subsidence accentuated and an uplift of their margins accompanied their overall elongation to the NNE. Our study provides for the first time a structural as well as tectonic context to the southern Galilee basins. Based on this case study we suggest that the rift did not fail but rather faded and was taken over by a more dominant stress regime. Otherwise, these basins of a failing rift could have simply died out peacefully.

scholarly journals Evaluation of the Influence of In Situ Stress on the Stability of Mine Pit Walls: A Case Study of Songwe Mine

2021 ◽  
Vol 4 (2) ◽  
pp. p1
Author(s):  
Dyson Moses ◽  
Hideki Shimada ◽  
Takashi Sasaoka ◽  
Akihiro Hamanaka ◽  
Tumelo K. M Dintwe ◽  
...  
Keyword(s):  
Active Regions ◽  
Horizontal Stress ◽  
In Situ Stress ◽  
Slope Instability ◽  
Open Pit ◽  
Stress Regime ◽  
Tectonically Active ◽  
The Stability ◽  
The Impact

The investigation of the influence of in situ stress in Open Pit Mine (OPM) projects has not been accorded a deserved attention despite being a fundamental concern in the design of underground excavations. Hence, its long-term potential adverse impacts on pit slope performance are overly undermined. Nevertheless, in mines located in tectonically active settings with a potential high horizontal stress regime like the Songwe mine, the impact could be considerable. Thus, Using FLAC3D 5.0 software, based on Finite Difference Method (FDM) code, we assessed the role of stress regimes as a potential triggering factor for slope instability in Songwe mine. The results of the evaluated shearing contours and quantified strain rate and displacement values reveal that high horizontal stress can reduce the stability performance of the pit-wall in spite of the minimal change in Factor of Safety (FoS). Since mining projects have a long life span, it would be recommendable to consider “in situ stress-stability analyses” for OPM operations that would be planned to extend to greater depths and those located in tectonically active regions.

scholarly journals In Situ Stress and Stress Regime in the Onshore Part of the Northeast Java Basin

2021 ◽  
Vol 44 (2) ◽  
pp. 95-105
Author(s):  
Agus M. Ramdhan
Keyword(s):  
Petroleum Industry ◽  
Horizontal Stress ◽  
In Situ Stress ◽  
Vertical Stress ◽  
Stress Regime ◽  
Severe Erosion ◽  
Tectonically Active ◽  
Minimum Horizontal Stress ◽  
Maximum Horizontal Stress

In situ stress is importance in the petroleum industry because it will significantly enhance our understanding of present-day deformation in a sedimentary basin. The Northeast Java Basin is an example of a tectonically active basin in Indonesia. However, the in situ stress in this basin is still little known. This study attempts to analyze the regional in situ stress (i.e., vertical stress, minimum and maximum horizontal stresses) magnitude and orientation, and stress regime in the onshore part of the Northeast Java Basin based on twelve wells data, consist of density log, direct/indirect pressure test, and leak-off test (LOT) data. The magnitude of vertical (  and minimum horizontal (  stresses were determined using density log and LOT data, respectively. Meanwhile, the orientation of maximum horizontal stress  (  was determined using image log data, while its magnitude was determined based on pore pressure, mudweight, and the vertical and minimum horizontal stresses. The stress regime was simply analyzed based on the magnitude of in situ stress using Anderson’s faulting theory. The results show that the vertical stress ( ) in wells that experienced less erosion can be determined using the following equation: , where  is in psi, and z is in ft. However, wells that experienced severe erosion have vertical stress gradients higher than one psi/ft ( . The minimum horizontal stress ( ) in the hydrostatic zone can be estimated as, while in the overpressured zone, . The maximum horizontal stress ( ) in the shallow and deep hydrostatic zones can be estimated using equations: and , respectively. While in the overpressured zone, . The orientation of  is ~NE-SW, with a strike-slip faulting stress regime.

Geomechanical analysis of horizontal wells in terms of stability for drilling — A case study from the Peri-Baltic Syneclise

2021 ◽  
Vol 40 (11) ◽  
pp. 805-814
Author(s):  
Michał Kępiński ◽  
Pramit Basu ◽  
David Wiprut ◽  
Marek Koprianiuk
Keyword(s):  
Horizontal Well ◽  
Oil And Gas ◽  
Horizontal Wells ◽  
Microseismic Monitoring ◽  
Earth Model ◽  
Gas Field ◽  
Horizontal Section ◽  
Stress Regime ◽  
Geomechanical Analysis

This paper presents a shale gas field geomechanics case study in the Peri-Baltic Syneclise (northern Poland). Polish Oil and Gas Company drilled a vertical well, W-1, and stimulated the Silurian target. Next, a horizontal well, W-2H, drilled the Ordovician target and partially collapsed. The remaining interval was stimulated, and microseismic monitoring was performed. A second horizontal well, W-3H, was drilled at the same azimuth as W-2H, but the well collapsed in the upper horizontal section (Silurian). A geomechanical earth model was constructed that matches the drilling experiences and well failure observations found in wells W-1, W-2H, and W-3H. The field was found to be in a strike-slip faulting stress regime, heavily fractured, with weak bedding contributing to the observed drilling problems. An analysis of safe mud weights, optimal casing setting depths, and optimal drilling directions was carried out for a planned well, W-4H. Specific recommendations are made to further enhance the model in any future studies. These recommendations include data acquisition and best practices for the planned well.

Lithology-controlled stress variations and pad-scale faults: A case study of hydraulic fracturing in the Woodford Shale, Oklahoma

Geophysics ◽  
2017 ◽  
Vol 82 (6) ◽  
pp. ID35-ID44 ◽  
Author(s):  
Xiaodong Ma ◽  
Mark D. Zoback
Keyword(s):  
Hydraulic Fracturing ◽  
Horizontal Wells ◽  
Horizontal Stress ◽  
Strike Slip ◽  
Woodford Shale ◽  
Stress Regime ◽  
Component Content ◽  
Microseismic Events ◽  
Minimum Horizontal Stress ◽  
Stress Variations

We have conducted an integrated study to investigate the petrophysical and geomechanical factors controlling the effectiveness of hydraulic fracturing (HF) in four subparallel horizontal wells in the Mississippi Limestone-Woodford Shale (MSSP-WDFD) play in Oklahoma. In two MSSP wells, the minimum horizontal stress [Formula: see text] indicated by the instantaneous shut-in pressures of the HF stages are significantly less than the vertical stress [Formula: see text]. This, combined with observations of drilling-induced tensile fractures in the MSSP in a vertical well at the site, indicates that this formation is in a normal/strike-slip faulting stress regime, consistent with earthquake focal mechanisms and other stress indicators in the area. However, the [Formula: see text] values are systematically higher and vary significantly from stage to stage in two WDFD wells. The stages associated with the abnormally high [Formula: see text] values (close to [Formula: see text]) were associated with little to no proppant placement and a limited number of microseismic events. We used compositional logs to determine the content of compliant components (clay and kerogen). Due to small variations in the trajectories of the horizontal wells, they penetrated three thin, but compositionally distinct WDFD lithofacies. We found that [Formula: see text] along the WDFD horizontals increases when the stage occurred in a zone with high clay and kerogen content. These variations of [Formula: see text] can be explained by various degrees of viscous stress relaxation, which results in the increase in [Formula: see text] (less stress anisotropy), as the compliant component content increases. The distribution of microseismic events was also affected by normal and strike-slip faults cutting across the wells. The locations of these faults were consistent with unusual lineations of microseismic events and were confirmed by 3D seismic data. Thus, the overall effectiveness of HF stimulation in the WDFD wells at this site was strongly affected the abnormally high HF gradients in clay-rich lithofacies and the presence of preexisting, pad-scale faults.

3D Alford rotation analysis for the Diamond M Field, Midland Basin, Texas

2014 ◽  
Vol 2 (2) ◽  
pp. SE63-SE75 ◽  
Author(s):  
Oswaldo E. Davogustto Cataldo ◽  
Timothy J. Kwiatkowski ◽  
Kurt J. Marfurt ◽  
Steven L. Roche ◽  
James W. Thomas
Keyword(s):  
Vertical Component ◽  
Horizontal Stress ◽  
Compressional Wave ◽  
Carbonate Reservoir ◽  
S Wave ◽  
Stress Regime ◽  
Compressional Waves ◽  
Principal Axes ◽  
Wave Splitting ◽  
Processing Effort

The 2C by 2C S-wave survey generated significant excitement in the mid-1980s, but then it fell out of favor when S-wave splitting initially attributed to fractures was also found to be associated with an anisotropic stress regime. In general, 2C by 2C data require more expensive acquisition and more processing effort to obtain images comparable to 1C “compressional wave” data acquired with vertical component sources and receivers. Because S-waves are insensitive to fluids, and hence the water table, the effective S-wave weathering zone is greater than that for compressional waves, making statics more difficult. S-wave splitting due to anisotropy complicates residual statics and velocity analysis as well as the final image. S-wave frequencies and S-wave moveout are closer to those of contaminating ground roll than compressional waves. Since Alford’s introduction of S-wave rotation from survey coordinates to the principal axes in 1986, geoscientist and engineers retain their interest in fractures but are also keenly interested in the direction and magnitude of maximum horizontal stress. Simultaneous sweep and improved recording technology have reduced the acquisition cost to approximate that of 1C data. Alford’s work was applied to 2C by 2C poststack data. We extended the Alford rotation to prestack data using a modern high-fold 2C by 2C survey acquired over a fractured carbonate reservoir in the Diamond M Field, Texas. Through careful processing, the resulting images were comparable and in many places superior to that of the contemporaneously acquired 1C data. More importantly, we found a good correlation between our derived fracture azimuth map and the fracture azimuth log data from wells present in the field.

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