Exploration Insights September 2020 - Page 20

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The authors would like to acknowledge Neftex staff members , past and present , who have contributed to building the underlying content that forms the basis of the assessment described herein .
Treloar , M ., D . Slidel and O . Sutcliffe 2018 . Illuminating the Anatomy of Super Basins . Exploration Insights Magazine . Exploration Insights Magazine no . May , p . 6-12 . ( XURBB _ 639037 ).
Dr . Owen E . Sutcliffe , Head of Global Geology and Geophysical Practices , Halliburton Landmark
Owen started his career as a postdoctoral research assistant with the University of Wales , Aberystwyth and LASMO , researching the petroleum geology of the Late Ordovician glacial clastics of North Africa . In 2000 , he joined Badley Ashton & Associates as a sedimentologist , before his employment began at Neftex Petroleum Consultants in 2003 . Since the acquisition of Neftex by Halliburton in 2014 , Owen has held roles as Head of Stratigraphy and as Manager of the Neftex ® Insights portfolio . He is a member of the Geological Society , London and the Petroleum Exploration Society of Great Britain ( PESGB ).
Mike Treloar , Product Owner — Screening Applications , Halliburton Landmark
Mike is responsible for guiding the development of cloud-based technologies that drive efficiency gains and integration , in screening workflows . He has six years of industry experience , having performed different roles across several areas , including content management , technical marketing , and exploration-focused regional geoscience . Mike has a Master ’ s degree in Geology from Imperial College London , U . K .
Daniel Slidel , Team Lead — Petroleum Systems Analysis , Halliburton Landmark
Daniel started his career as a field assistant , working for CASP in the Canadian Arctic Islands . He joined Neftex Petroleum Consultants in 2011 , where he was involved in building regional exploration projects for the Arctic . In his current position at Neftex ® , Daniel is responsible for operational management of the Petroleum Systems Analysis team . He has eight years of industry experience , and holds an MSci Geology degree from Royal Holloway University , London , U . K .
This article is a synthesis based upon published data and information , and derived knowledge created within Halliburton . Unless explicitly stated otherwise , no proprietary client data has been used in its preparation . If client data has been used , permission will have been obtained and is acknowledged . Reproduction of any copyrighted image is with the permission of the copyright holder and is acknowledged . The opinions found in the articles may not necessarily reflect the views and / or opinions of Halliburton Energy Services , Inc . and its affiliates including but not limited to Landmark Graphics Corporation .
20 | Halliburton Landmark context. When plate tectonic models are created using a dynamic plate boundaries approach, plate boundaries additionally provide geometrical constraints to reduce the degrees of freedom in the models, and enable true plate tectonic reconstructions to be created. Dynamic Plate Boundaries The vast majority of plate tectonic models focus on the reconstruction of present-day continental blocks, while paying little or no attention to plate limits. The results are closer to continental drift than to plate tectonics (Hochard, 2008). While the rotations and paleo-positions of GDUs are important, we must also consider plates in their entirety, rather than solely continents/terranes. Plates can comprise a contiguous association of continental and oceanic lithosphere separated by a passive margin and sharing the same motion for a given period of time. Oceans open and close, plates separate and amalgamate. For this reason, the plate framework evolves through geological time — tectonic ‘plates’ are, therefore, time-dependent. The motions of plates change and with them the plate boundaries evolve. The concepts of ‘dynamic plate boundaries’ (Stampfli and Borel, 2002; Hochard, 2008) or ‘dual control approach’ (Vérard, 2018), provide additional A geometrical T E A constraints P L to global plate tectonic reconstructions. Plate boundaries are dynamic because they PLATE D evolve from one reconstruction to the next one, following a consistent geodynamic evolution. The concept of dynamic plate boundaries emphasizes the importance of plates as entities defined by their limits (i.e. ridges, rifts, subductions, collisions, obductions, and Exploration Insights | 21 transforms), making the assertion that plates are mostly rigid, and the only evolving elements are the plate boundaries (Stampfli and Borel, 2002; Hochard, 2008). At any time within a plate tectonic model, the plate boundary connections, or triple junctions, must be stable. Thus, each boundary configuration must fall into one of the following categories: 1) it is unchanged through time; 2) it moves geographically with its three boundary components unchanged (Fowler, 2005); or 3) it follows a consistent geodynamical evolution (e.g. an active margin can become a collision) (Mckenzie and Morgan, 1969). Constructing Dynamic Plate Boundaries Once plate positions through time have been established on key assemblies, one can calculate the relative stage rotation poles for each pair of plates, and determine the plate boundary types using the Eulerian pole of rotation and associated circles. Small circles determine the orientation of transform faults, while plate boundaries following great circles are mid-ocean ridges or convergent boundaries, depending on the relative Polar Axis plate motion (Figure 6). B P L A T E Only this rigorous approach enables dynamic plate boundaries (i.e. dual control) to create the necessary additional geometrical control on the PLATE C Isochrones Small Circles Great Circles Oceanic Crust Continental Crust E Active Margin Transform Fault Mid-ocean Ridge Relative Plate Motion Figure 6> Construction of plate boundaries between plates A and B, using a calculated Euler relative stage pole (E). Mid-ocean ridge segments follow great circles passing through E. Transform faults follow small circles centered on E (modified after Hochard, 2008). reconstructions that adhere to the core of the plate tectonic theory. Unfortunately, the process remains largely manual and, thus, calls for more automation in order to increase efficiency and modeling accuracy. Developments in the Craft of Plate Tectonic Boundaries There has been consistent improvement over the past few decades in the level of complexity of plate tectonic models and their extension back in time (Figure 2). Many of these improvements were led by early developments in more recent geological time, such as Cenozoic plate models, where oceanic data provide additional constraints, followed by extrapolation into deeper time. Earlier models are invariably based on fewer, less-well-defined GDUs. Later models are increasingly complex and integrate additional information, culminating in the integration of plate boundaries, and possibly reaching the level of dynamic plate boundaries (in the sense of Stampfli and Borel, 2002). Plate tectonic models with dynamic plate boundaries bring together data intrinsic to individual GDUs, as well as information related to their interactions along plate boundaries, in the context of a roughly spherical globe, which in itself provides additional constraints. Paleozoic and Precambrian reconstructions bring additional challenges, requiring the integration of more data types to facilitate model development. Structured, big data compilations are critical to addressing these challenges. Their availability will remain one of the limiting factors for continued development of deep-time models, as will our geoscience understanding of how processes in early Earth history may have differed from more recent processes. Many models are constrained by geoscience concepts; for example, if there was no concept of supercontinent cyclicity, Precambrian models could look very different! The availability of open source software, such as GPlates, has facilitated the implementation of rapidly developed and changeable models. It is now possible to develop and visualize model changes interactively within seconds, allowing model developers to make rapid improvements. Previously, models were, of necessity, developed as a series of snapshots, often at 50 to 100 Ma intervals in the Precambrian, and 10 to 50 Ma intervals in the Phanerozoic. It is now easy to check plate motions at 1 Ma intervals, ensuring that all motions before and after key time frames are internally consistent. Future developments will enhance our ability to integrate even more information with increasing levels of complexity. Some of this information will include data in spatial 3D, from varying depths in the mantle, placing further demands on technology and visualization. All models are inherently uncertain. Available technology and procedures for developing plate tectonic models do not provide mechanisms to illustrate spatial and temporal variations in uncertainty, by themselves. A number of researchers in the academic community and at Halliburton are investigating ways to address this, including machine learning techniques to better integrate numerous sources of information and their uncertainties. Rigorous delineation of plate boundaries is often a time-consuming, manual process at present. Semi-automated to fully-automated definition of boundaries and their integration into models is already being developed, providing yet another way to assess and constrain their geological validity more rapidly. Scientific assessment and Earth processes, including those near-surface and deep into the mantle, will be achievable with these future models, thereby, driving improved resource targeting for users. ACKNOWLEDGEMENTS Earlier personal communication with C. Scotese formed the initial seeds for this article, which the authors would gratefully like to acknowledge. We also acknowledge the contribution of all the many authors cited in this article and the many more we were not able to cite due to the article scope, who have contributed to the field of plate tectonics and associated software development over the years. We salute your continued contribution to pushing the boundaries of geodynamic comprehension. Authors finally acknowledge the editors for their useful suggestions on this manuscript.