Applying Boundary Element Simulation to Generate Stress-Based Fracture Drivers: A Case Study for the Montney Unconventional Oil/Gas Play in Western Canada Basin

2021 ◽  
Author(s):  
Zhong Cai ◽  
Craig Smith ◽  
John Cole ◽  
Chee Phuat Tan
Keyword(s):  
Boundary Element ◽  
Tectonic Evolution ◽  
Strike Slip ◽  
Natural Fracture ◽  
Western Canada ◽  
Fracture System ◽  
Tectonic Events ◽  
Element Simulation ◽  
Regional Tectonic ◽  
Stress Domains

Abstract Natural fracture distribution is critical to the hydrocarbon production from the Early Triassic Montney unconventional oil and gas play. The formation underwent several tectonic events, creating a unique natural fracture system. Identifying tectonic events and their stress field evolution is an import component in fracture system modeling and prediction. The objective of this paper is to identify the evolution of paleo-stress domains, to establish related tectonic models, and to generate the drivers for fracture network modeling which will aid in reservoir understanding and overall play development. Compared with other geomechanical approaches, the boundary element method (BEM) is better suited for the structural characteristics in the study area. Hence, the corresponding boundary element simulation (BES) was applied for the evolution of the paleo-stress domains. The methodology is a combination of 3D BEM and Monte Carlo simulations. The inputs include seismic interpreted faults and natural fractures from Formation Microimager logs. After applying the methodology, several best fit realizations were calculated, and the admissible paleo-stress domains were characterized by the tectonic models which are consistent with the regional tectonic evolution of the formation. The study area is about 400 km2 located at northeast British Columbia in the Western Canada Basin. The main structural features are the thrust and back-thrust faults, forming different fault blocks without any significant deformation structures. The Montney formation within the study area underwent several tectonic events: (1) regime of terrane collision, indentation and lateral escape during end of Middle Jurassic to Middle Cretaceous; (2) regime of left-lateral transpression dominated by strike-slip during end of Late Cretaceous and Paleocene; and (3) regime of right-lateral transtension dominated by strike-slip during end of Early and Middle Eocene which is maintained till present day. Three major stress domains were identified in the study area by the application of the BES method, one reverse event and two strike-slip events, representing paleo and present-day stress domains. These stress domains are consistent with the regional tectonic evolution history of the foreland basin. The stress field parameters, such as stress ratio and maximum horizontal stress azimuth, are consistent. The derived tectonic models are shown to be reliable drivers for the subsequent fracture modeling and geomechanics study.

scholarly journals Oblique reactivation of lithosphere-scale lineaments controls rift physiography – The upper crustal expression of the Sorgenfrei-Tornquist Zone, offshore southern Norway

2017 ◽  
Author(s):  
Thomas B. Phillips ◽  
Christopher A.-L. Jackson ◽  
Rebecca E. Bell ◽  
Oliver B. Duffy
Keyword(s):  
Strike Slip ◽  
Structural Development ◽  
Stress Regime ◽  
Seismic Reflection Data ◽  
Existing Structures ◽  
Reflection Data ◽  
Tectonic Events ◽  
Kinematic Evolution ◽  
Regional Tectonic ◽  
Southern Norway

Abstract. Pre-existing structures within sub-crustal lithosphere may localise stresses during subsequent tectonic events, resulting in complex fault systems at upper crustal levels. As these sub-crustal structures are difficult to resolve at great depths, the evolution of kinematically and perhaps geometrically linked upper-crustal fault populations can offer insights into their deformation history, including when and how they reactivate and accommodate stresses during later tectonic events. In this study, we use borehole-constrained 2D and 3D seismic reflection data to investigate the structural development of the Farsund Basin, offshore southern Norway; this E-trending basin represents the upper crustal expression of the Sorgenfrei-Tornquist Zone, a major lithosphere-scale lineament extending >1000 km across Central Europe. The southern margin of the Farsund Basin is characterised by N-S and E-W-striking fault populations, the latter extending down through the Moho and potentially linking with the Sorgenfrei-Tornquist Zone as imaged within sub-crustal lithosphere. Due to this geometric linkage, we can analyse the upper crustal fault populations to infer the kinematics of the Sorgenfrei-Tornquist Zone. We use throw-length (T-x) analysis and fault displacement backstripping techniques to determine the geometric and kinematic evolution of upper-crustal fault populations during the multiphase evolution of the Farsund Basin. We document a period of sinistral strike-slip activity along E-W-striking faults during the Early Jurassic, representing a hitherto undocumented phase of activity along the Sorgenfrei-Tornquist Zone. These E-W-striking upper-crustal faults are later obliquely reactivated under a dextral stress regime during the Early Cretaceous, with new faults also propagating away from pre-existing ones, representing a switch to a phase of dextral transtension along the Sorgenfrei-Tornquist Zone. We show that the Sorgenfrei-Tornquist Zone represents a long-lived lithosphere-scale lineament that is periodically reactivated throughout its protracted geological history. The upper crustal component of the lineament is reactivated in a range of tectonic styles, including both sinistral and dextral strike-slip motions, with the geometry and kinematics of these faults often inconsistent with what may otherwise be inferred from regional tectonics alone. Understanding these different styles of reactivation not only allows us to better understand the influence of sub-crustal lithospheric structure on rifting, but also offers insights into the prevailing stress field during regional tectonic events.

scholarly journals Present-Day Deformation of the Gyaring Co Fault Zone, Central Qinghai–Tibet Plateau, Determined Using Synthetic Aperture Radar Interferometry

2019 ◽  
Vol 11 (9) ◽  
pp. 1118
Author(s):  
Yong Zhang ◽  
Chuanjin Liu ◽  
Wenting Zhang ◽  
Fengyun Jiang
Keyword(s):  
Synthetic Aperture Radar ◽  
Fault Zone ◽  
Crustal Deformation ◽  
Tectonic Evolution ◽  
Slip Rate ◽  
Strike Slip ◽  
Synthetic Aperture ◽  
Tibet Plateau ◽  
Regional Tectonic ◽  
Qinghai Tibet Plateau

Because of the constant northward movement of the Indian plate and blockage of the Eurasian continent, the Qinghai–Tibet Plateau has been extruded by north–south compressive stresses since its formation. This has caused the plateau to escape eastward to form a large-scale east–west strike-slip fault and a north–south extensional tectonic system. The Karakorum–Jiali fault, a boundary fault between the Qiangtang and Lhasa terranes, plays an important role in the regional tectonic evolution of the Qinghai–Tibet Plateau. The Gyaring Co fault, in the middle of the Karakoram–Jiali fault zone, is a prominent tectonic component. There have been cases of strong earthquakes of magnitude 7 or greater in this fault, providing a strong earthquake occurrence background. However, current seismic activity is weak. Regional geodetic observation stations are sparsely distributed; thus, the slip rate of the Gyaring Co fault remains unknown. Based on interferometric synthetic aperture radar (InSAR) technology, we acquired current high-spatial resolution crustal deformation characteristics of the Gyaring Co fault zone. The InSAR-derived deformation features were highly consistent with Global Positioning System observational results, and the accuracy of the InSAR deformation fields was within 2 mm/y. According to InSAR results, the Gyaring Co fault controlled the regional crustal deformation pattern, and the difference in far-field deformation on both sides of the fault was 3–5 mm/y (parallel to the fault). The inversion results of the back-slip dislocation model indicated that the slip rate of the Gyaring Co fault was 3–6 mm/y, and the locking depth was ~20 km. A number of v-shaped conjugate strike-slip faults, formed along the Bangong–Nujiang suture zone in the central and southern parts of the -Tibet Plateau, played an important role in regional tectonic evolution. V-shaped conjugate shear fault systems include the Gyaring Co and Doma–Nima faults, and the future seismic risk cannot be ignored.

Geochronological and petrogenetic constraints on the regional tectonic evolution of the Guanghua Group in northeastern Jiao-Liao-Ji Belt, China

2018 ◽  
Vol 305 ◽  
pp. 427-443 ◽  
Author(s):  
Chao-Yang Wang ◽  
En Meng ◽  
Hong Yang ◽  
Chao-Hui Liu ◽  
Jia Cai ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Regional Tectonic

Precambrian tectonic evolution of Earth: an outline

2021 ◽  
Vol 124 (1) ◽  
pp. 141-162 ◽  
Author(s):  
J.F. Dewey ◽  
E.S. Kiseeva ◽  
J.A. Pearce ◽  
L.J. Robb
Keyword(s):  
Tectonic Evolution ◽  
Plate Tectonics ◽  
Global Scale ◽  
Sensu Stricto ◽  
Strike Slip ◽  
Small Scale ◽  
Data Sets ◽  
Crustal Material ◽  
Plate Tectonic ◽  
Single Plate

Abstract Space probes in our solar system have examined all bodies larger than about 400 km in diameter and shown that Earth is the only silicate planet with extant plate tectonics sensu stricto. Venus and Earth are about the same size at 12 000 km diameter, and close in density at 5 200 and 5 500 kg.m-3 respectively. Venus and Mars are stagnant lid planets; Mars may have had plate tectonics and Venus may have had alternating ca. 0.5 Ga periods of stagnant lid punctuated by short periods of plate turnover. In this paper, we contend that Earth has seen five, distinct, tectonic periods characterized by mainly different rock associations and patterns with rapid transitions between them; the Hadean to ca. 4.0 Ga, the Eo- and Palaeoarchaean to ca. 3.1 Ga, the Neoarchaean to ca. 2.5 Ga, the Proterozoic to ca. 0.8 Ga, and the Neoproterozoic and Phanerozoic. Plate tectonics sensu stricto, as we know it for present-day Earth, was operating during the Neoproterozoic and Phanerozoic, as witnessed by features such as obducted supra-subduction zone ophiolites, blueschists, jadeite, ruby, continental thin sediment sheets, continental shelf, edge, and rise assemblages, collisional sutures, and long strike-slip faults with large displacements. From rock associations and structures, nothing resembling plate tectonics operated prior to ca. 2.5 Ga. Archaean geology is almost wholly dissimilar from Proterozoic-Phanerozoic geology. Most of the Proterozoic operated in a plate tectonic milieu but, during the Archaean, Earth behaved in a non-plate tectonic way and was probably characterised by a stagnant lid with heat-loss by pluming and volcanism, together with diapiric inversion of tonalite-trondjemite-granodiorite (TTG) basement diapirs through sinking keels of greenstone supracrustals, and very minor mobilism. The Palaeoarchaean differed from the Neoarchaean in having a more blobby appearance whereas a crude linearity is typical of the Neoarchaean. The Hadean was probably a dry stagnant lid Earth with the bulk of its water delivered during the late heavy bombardment, when that thin mafic lithosphere was fragmented to sink into the asthenosphere and generate the copious TTG Ancient Grey Gneisses (AGG). During the Archaean, a stagnant unsegmented, lithospheric lid characterised Earth, although a case can be made for some form of mobilism with “block jostling”, rifting, compression and strike-slip faulting on a small scale. We conclude, following Burke and Dewey (1973), that there is no evidence for subduction on a global scale before about 2.5 Ga, although there is geochemical evidence for some form of local recycling of crustal material into the mantle during that period. After 2.5 Ga, linear/curvilinear deformation belts were developed, which “weld” cratons together and palaeomagnetism indicates that large, lateral, relative motions among continents had begun by at least 1.88 Ga. The “boring billion”, from about 1.8 to 0.8 Ga, was a period of two super-continents (Nuna, also known as Columbia, and Rodinia) characterised by substantial magmatism of intraplate type leading to the hypothesis that Earth had reverted to a single plate planet over this period; however, orogens with marginal accretionary tectonics and related magmatism and ore genesis indicate that plate tectonics was still taking place at and beyond the bounds of these supercontinents. The break-up of Rodinia heralded modern plate tectonics from about 0.8 Ga. Our conclusions are based, almost wholly, upon geological data sets, including petrology, ore geology and geochemistry, with minor input from modelling and theory.

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