scholarly journals Dike Propagation During Global Contraction: Making Sense of Conflicting Stress Histories on Mercury

2021 ◽  
Vol 9 ◽  
Author(s):  
Kelsey Crane ◽  
Allison Bohanon
Keyword(s):  
Physical Model ◽  
Compressive Stress ◽  
Propagation Distance ◽  
Flood Basalt ◽  
Horizontal Stress ◽  
Principal Stresses ◽  
Stress Regime ◽  
Making Sense ◽  
Griffith Criterion ◽  
Uppermost Layer

Thrust fault-related landforms, smooth plains units, and impact craters and basins have all been observed on the surface of Mercury. While tectonic landforms point to a long-lived history of global cooling and contraction, smooth plains units have been inferred to represent more punctuated periods of effusive volcanism. The timings of these processes are inferred through impact cratering records to have overlapped, yet the stress regimes implied by the processes are contradictory. Effusive volcanism on Mercury is believed to have produced flood basalts through dikes, the propagation of which is dependent on being able to open and fill vertical tensile cracks when horizontal stresses are small. On the contrary, thrust faults propagate when at least one horizontal stress is very large relative to the vertical compressive stress. We made sense of conflicting stress regimes through modeling with frictional faulting theory and Earth analogue work. Frictional faulting theory equations predict that the minimum and maximum principal stresses have a predictable relationship when thrust faulting is observed. The Griffith Criterion and Kirsch equations similarly predict a relationship between these stresses when tensile fractures are observed. Together, both sets of equations limit the range of stresses possible when dikes and thrusts are observed and permitted us to calculate deviatoric stresses for regions of Earth and Mercury. Deviatoric stress was applied to test a physical model for dike propagation distance in the horizontally compressive stress regime of the Columbia River Flood Basalt Province, an Earth analogue for Borealis Planitia, the northern smooth plains, of Mercury. By confirming that dike propagation distances from sources observed in the province can be generated with the physical model, we confidently apply the model to confirm that dikes on Mercury can propagate in a horizontally compressive stress regime and calculate the depth to the source for the plains materials. Results imply that dikes could travel from ∼89 km depth to bring material from deep within the lithosphere to the surface, and that Mercury’s lithosphere is mechanically layered, with only the uppermost layer being weak.

Some influences of stratigraphy and structure on reservoir stress orientation

Geophysics ◽  
1994 ◽  
Vol 59 (6) ◽  
pp. 954-962 ◽  
Author(s):  
Michael S. Bruno ◽  
Don F. Winterstein
Keyword(s):  
Principal Stress ◽  
Compressive Stress ◽  
Horizontal Stress ◽  
Oil Fields ◽  
Fold Axis ◽  
Principal Stresses ◽  
Stress Orientation ◽  
Stress Direction ◽  
Well Pattern ◽  
Maximum Horizontal Stress

The azimuth of maximum horizontal stress in a reservoir can vary significantly with depth and with position on a subsurface structure. We present and discuss evidence from field data for such variation and demonstrate both analytically and with finite‐element modeling how such changes might take place. Under boundary conditions of uniform far‐field displacement, changes in stratigraphic layering can reorient the principal stress direction if the formation is intrinsically anisotropic. If the formation stiffness is lower perpendicular to bedding than parallel to bedding (as is often the case in layered geologic media), an increase in dip will reduce the component of compressive stress in the dip azimuth direction. Folds can reorient principal stresses because flexural strain varies with depth and position. Compressive stress perpendicular to a fold axis increases with depth at the crest of an anticline and decreases with depth at the limb. When the regional stress anisotropy is weak, this change in stress magnitude can reorient the local principal stress directions. Numerical simulations of such effects gave results consistent with changes in stress orientation at the Cymric and Lost Hills oil fields in California as observed via shear‐wave polarization analyses and tiltmeter surveys of hydraulic fracturing. Knowledge of such variation of stress direction with depth and structural position is critical for drilling, completions, hydraulic fracture, and well pattern designs.

scholarly journals Study on In Situ Stress Distribution Law of the Deep Mine: Taking Linyi Mining Area as an Example

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xuelong Li ◽  
Shaojie Chen ◽  
Sheng Wang ◽  
Meng Zhao ◽  
Hui Liu
Keyword(s):  
Coal Mine ◽  
Mining Area ◽  
Horizontal Stress ◽  
Geological Structure ◽  
In Situ Stress ◽  
Distribution Law ◽  
Principal Stresses ◽  
Stress Regime ◽  
Maximum Horizontal Stress

The variation of the in situ stress state is closely related to various factors. In situ stress state is also an important indicator to guide mining production. The study of in situ stress measurement and its distribution characteristics has always been a basic and very important work in mine production. In this study, the deep mines of Linyi Mining Area were considered as the research object. In this regard, the stress distribution law of each mine was studied. We found that the relationship between principal stresses was σH >  σ v  > σh, which belongs to the strike-slip stress regime. In this stress regime, the lateral Earth pressure coefficient was greater than one, and the magnitude of the three principal stresses all showed an increasing trend with the increase of depth. The maximum horizontal stress direction of the Gucheng Coal Mine, Guotun Coal Mine, and Pengzhuang Coal Mine was NW-SE under the influence of regional geological structure, while the maximum horizontal stress direction of Wanglou Coal Mine was NE-SW under the influence of local geological structure. Besides, the relationship between mine in situ stress and mine geological structure, the impact of original rock stress on stope stability, and the effect of original rock stress on floor water inrushing were also investigated. We believe that the research results are beneficial to mine disaster prevention and safety production.

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.

The Effect of Well Azimuth or Don't Let Your Landman Plan Your Well Path!

2015 ◽  
Author(s):  
Fen Yang ◽  
Larry K. Britt ◽  
Shari Dunn-Norman
Keyword(s):  
Horizontal Well ◽  
Oil And Gas ◽  
Horizontal Wells ◽  
Horizontal Stress ◽  
Well Performance ◽  
Gas Reservoirs ◽  
Principal Stresses ◽  
Lateral Direction ◽  
Well Completion ◽  
Stimulation Of

Abstract Since the late 1980's when Maersk published their work on multiple fracturing of horizontal wells in the Dan Field, the use of transverse multiple fractured horizontal wells has become the completion of choice and become the “industry standard” for unconventional and tight oil and tight gas reservoirs. Today approximately sixty percent of all wells drilled in the United States are drilled horizontally and nearly all of them are multiple fractured. Because a horizontal well adds additional cost and complexity to the drilling, completion, and stimulation of the well we need to fully understand anything that affects the cost and complexity. In other words, we need to understand the affects of the principal stresses, both direction and magnitude, on the drilling completion, and stimulation of these wells. However, little work has been done to address and understand the relationship between the principal stresses and the lateral direction. This paper has as its goal to fundamentally address the question, in what direction should I drill my lateral? Do I drill it in the direction of the maximum horizontal stress (longitudinal) or do I drill it in the direction of the minimum horizontal stress (transverse)? The answer to this question relates directly back to the title of this paper and please "Don't let your land man drive that decision." This paper focuses on the horizontal well's lateral direction (longitudinal or transverse fracture orientation) and how that direction influences productivity, reserves, and economics of horizontal wells. Optimization studies using a single phase fully three dimensional numeric simulator including convergent non-Darcy flow were used to highlight the importance of lateral direction as a function of reservoir permeability. These studies, conducted for both oil and gas, are used to identify the point on the permeability continuum where longitudinal wells outperform transverse wells. The simulations compare and contrast the transverse multiple fractured horizontal well to longitudinal wells based on the number of fractures and stages. Further, the effects of lateral length, fracture half-length, and fracture conductivity were investigated to see how these parameters affected the decision over lateral direction in both oil and gas reservoirs. Additionally, how does completion style affect the lateral direction? That is, how does an open hole completion compare to a cased hole completion and should the type of completion affect the decision on in what direction the lateral should be drilled? These simulation results will be used to discuss the various horizontal well completion and stimulation metrics (rate, recovery, and economics) and how the choice of metrics affects the choice of lateral direction. This paper will also show a series of field case studies to illustrate actual field comparisons in both oil and gas reservoirs of longitudinal versus transverse horizontal wells and tie these field examples and results to the numeric simulation study. This work benefits the petroleum industry by: Establishing well performance and economic based criteria as a function of permeability for drilling longitudinal or transverse horizontal wells,Integrating the reservoir objectives and geomechanic limitations into a horizontal well completion and stimulation strategy,Developing well performance and economic objectives for horizontal well direction (transverse versus longitudinal) and highlighting the incremental benefits of various completion and stimulation strategies.

UNCONVENTIONAL BOREHOLE BREAKOUT ROTATION ANALYSIS PROVIDES A QC TOOL FOR STRESS MODELS

2006 ◽  
Vol 46 (1) ◽  
pp. 307
Author(s):  
B.A. Camac ◽  
S.P. Hunt ◽  
P.J. Boult ◽  
M. Dillon
Keyword(s):  
Principal Stress ◽  
Input Data ◽  
Distinct Element ◽  
Maximum Principal Stress ◽  
Principal Stresses ◽  
Stress Regime ◽  
Seal Integrity ◽  
Borehole Breakout ◽  
Stress Models ◽  
Kupe Field

In distinct element (DEM) numerical stress modelling, the principal stress magnitudes and orientations are applied to the boundary of the 3D model. Due to data restrictions and typical depths of investigation, it is possible to have much uncertainty in the conventional methodologies used to constrain the regional principal stress magnitudes and orientations.A case study from the Kupe field in the Taranaki Basin, New Zealand is presented where the uncertainty in the input data made it difficult to determine which stress regime—a transitional normal/strike-slip or reverse/thrust—is active at reservoir depth (approximately 3,000 m). The magnitudes and orientation of the principal stresses were constrained using published techniques. A sensitivity analysis was applied to account for the uncertainty in the input data. A model of the Kupe field incorporating 18 major faults was subsequently loaded under both derived stressed regimes, using the calculated magnitudes.Borehole breakout analysis was used to acquire interpreted orientations of the maximum principal stress (Shmax). The work presented herein describes a different or unconventional approach to the general petroleum geomechanics methodology. Typically, the breakout data is averaged to get one data point per well location. Here, all breakout data is retained and displayed vertically. The data is actively used and the variations with depth can be seen to show how faults can generate local perturbations of the regional stress trajectory. These data are then used to compare the observed or field indications of the breakouts along the borehole with the modelled Shmax predicted by both end point DEM stress models. This comparison has provided additional confidence in the derived stress regime and the derived stress models for the Kupe field. The stress models are used to predict areas of enhanced hydrocarbon pooling and low seal integrity.

Hydraulic fracturing operations within an extremely complex stress regime: The case of Fort St. John, British Columbia, Canada

2020 ◽  
Author(s):  
Rebecca O. Salvage ◽  
David W. Eaton
Keyword(s):  
British Columbia ◽  
Hydraulic Fracturing ◽  
Large Scale ◽  
Vertical Plane ◽  
Local Stress ◽  
Complex Stress ◽  
Tectonic Structures ◽  
Principal Stresses ◽  
Stress Regime ◽  
North West

<p>On 30 November 2018, three felt earthquakes occurred in quick succession close to the city of Fort St. John, British Columbia, likely as a direct response to a hydraulic fracturing operation in the area. Events appear tightly clustered spatially within the upper 10 km of the crust. Hypocenters locate at the confluence between a large scale reverse faulting regime (in the north-west, probably due to the influence of the Rocky Mountain fold and thrust belt) and an oblique strike slip faulting regime (in the south-east, probably due to the influence of the Fort St. John Graben), resulting in a variety of focal mechanisms and a very complex local stress regime. Further analysis of the principal stresses suggests that σ<sub>1</sub> is well constrained and close to horizontal, whereas σ<sub>2</sub> and σ<sub>3</sub> are poorly constrained, and can alternate between the horizontal and the vertical plane. Here, we present an overview of the temporal and spatial evolution of this seismic sequence and its relationship to hydraulic fracturing operations in the area, and examine the influence of large-scale regional tectonic structures on the generation of seismicity on this occasion.</p><p> </p>

scholarly journals Regional tectonic stress near the San Andreas fault in central and southern California

2021 ◽  
Author(s):  
John Townend ◽  
M Zoback
Keyword(s):  
Compressive Stress ◽  
San Francisco ◽  
Southern California ◽  
San Andreas Fault ◽  
Horizontal Stress ◽  
Tectonic Stress ◽  
Bay Area ◽  
San Andreas ◽  
Regional Tectonic ◽  
Horizontal Compressive Stress

Throughout central and southern California, a uniform NNE-SSW direction of maximum horizontal compressive stress is observed that is remarkably consistent with the superposition of stresses arising from lateral variations in lithospheric buoyancy in the western United States, and farfield Pacific-North America plate interaction. In central California, the axis of maximum horizontal compressive stress lies at a high angle to the San Andreas fault (SAF). Despite relatively few observations near (±10 km) the fault, observations in the greater San Francisco Bay area indicate an angle of as much as 85°, implying extremely low fault strength. In southern California, observations of stress orientations near the SAF are rotated slightly counter-clockwise with respect to the regional field. Nevertheless, we observe an approximately constant angle between the SAF and the maximum horizontal stress direction of 68 ± 7° along ∼400 km of the fault, indicating that the SAF has moderately low frictional strength in southern California. Copyright 2004 by the American Geophysical Union.

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.

The Criteria Predicting Wrinkling of Thin, Flat, Rectangular Webs

1995 ◽  
Author(s):  
Chen-Chi Lin ◽  
Clayton D. Mote
Keyword(s):  
Aspect Ratio ◽  
Compressive Stress ◽  
Infinite Number ◽  
Simple Shear ◽  
The Other ◽  
Flexural Stiffness ◽  
Membrane Theory ◽  
Principal Stresses

Abstract A web is termed wrinkled when one of the in-plane principal stresses is tensile and the other is sufficiently compressive. A criterion is derived that predicts wrinkling of isotropic, compressible rectangular webs under uniform in-plane principal stresses. The compressive stress at impending wrinkling depends on the flexural stiffness, and it equals zero in the case of a membrane. A criterion of wrinkling is also derived using isotropic, incompressible membrane theory. This criterion predicts an infinite number of wrinkle waves in a wrinkled region. With small flexural stiffness, the number of wrinkle waves becomes finite at wrinkling and it is predictable along with the shape and the size of the wrinkled region. The number of the wrinkle waves increases as the aspect ratio of the rectangular web increases, as the in-plane principal tension increases, and as the flexural stiffness decreases. Analyses of wrinkling of a rectangular web under simple shear and uniform longitudinal stretching illustrate the above predictions.

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