scholarly journals Understanding regional-scale structural uncertainty: The onshore Gulf of Corinth rift as a hydrocarbon exploration analogue

2015 ◽  
Vol 3 (4) ◽  
pp. SAC35-SAC53 ◽  
Author(s):  
Alan Wood ◽  
Douglas Paton ◽  
Richard Collier ◽  
Viki O’Connor

A major challenge when exploring for hydrocarbons in frontier areas is a lack of data coverage. Data may be restricted to regional-scale 2D seismic lines, from which assumptions of the 3D geometric configuration are drawn. Understanding the limitations and uncertainties when extrapolating 2D data into 3D space is crucial when assessing the requirements for acquiring additional data such as 3D seismic or exploration wells and of assigning geologically reasonable uncertainty ranges. The onshore Gulf of Corinth Rift provides an excellent analog for rift-scale structural uncertainty in the context of hydrocarbon exploration. We have used seismic forward modeling to explore this area of uncertainty. Synthetic seismic sections have been generated across the rift based upon fault geometries mapped in the field. Comparisons that we made of these sections with the mapped geometries allowed quantification of uncertainties encountered when extrapolating 2D data into three dimensions. We have determined how potential column heights may be severely over and underestimated due to trap integrity, spill point depth, and fault seal ambiguities directly related to fault geometric uncertainty. In addition, fault geometries and linkages also controlled the location of hanging wall synrift reservoirs. Hence, gross reservoir volumes and sediment facies distributions were also significantly influenced by how fault geometries were extrapolated along-strike from 2D to 3D.

Sensor Review ◽  
2017 ◽  
Vol 37 (3) ◽  
pp. 312-321 ◽  
Author(s):  
Yixiang Bian ◽  
Can He ◽  
Kaixuan Sun ◽  
Longchao Dai ◽  
Hui Shen ◽  
...  

Purpose The purpose of this paper is to design and fabricate a three-dimensional (3D) bionic airflow sensing array made of two multi-electrode piezoelectric metal-core fibers (MPMFs), inspired by the structure of a cricket’s highly sensitive airflow receptor (consisting of two cerci). Design/methodology/approach A metal core was positioned at the center of an MPMF and surrounded by a hollow piezoceramic cylinder. Four thin metal films were spray-coated symmetrically on the surface of the fiber that could be used as two pairs of sensor electrodes. Findings In 3D space, four output signals of the two MPMFs arrays can form three “8”-shaped spheres. Similarly, the sensing signals for the same airflow are located on a spherical surface. Originality/value Two MPMF arrays are sufficient to detect the speed and direction of airflow in all three dimensions.


Author(s):  
Eleanor Joyce Gardiner

The focus of this chapter will be the uses of graph theory in chemoinformatics and in structural bioinformatics. There is a long history of chemical graph theory dating back to the 1860’s and Kekule’s structural theory. It is natural to regard the atoms of a molecule as nodes and the bonds as edges (2D representations) of a labeled graph (a molecular graph). This chapter will concentrate on the algorithms developed to exploit the computer representation of such graphs and their extensions in both two and three dimensions (where an edge represents the distance in 3D space between a pair of atoms), together with the algorithms developed to exploit them. The algorithms will generally be summarized rather than detailed. The methods were later extended to larger macromolecules (such as proteins); these will be covered in less detail.


Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 476
Author(s):  
Joshua Chisambi ◽  
Bjorn von der Heyden ◽  
Muofhe Tshibalanganda ◽  
Stephan Le Roux

In this contribution, we highlight a correlative approach in which three-dimensional structural/positional data are combined with two dimensional chemical and mineralogical data to understand a complex orogenic gold mineralization system; we use the Kirk Range (southern Malawi) as a case study. Three dimensional structures and semi-quantitative mineral distributions were evaluated using X-ray Computed Tomography (XCT) and this was augmented with textural, mineralogical and chemical imaging using Scanning Electron Microscopy (SEM) and optical microscopy as well as fire assay. Our results detail the utility of the correlative approach both for quantifying gold concentrations in core samples (which is often nuggety and may thus be misrepresented by quarter- or half-core assays), and for understanding the spatial distribution of gold and associated structures and microstructures in 3D space. This approach overlays complementary datasets from 2D and 3D analytical protocols, thereby allowing a better and more comprehensive understanding on the distribution and structures controlling gold mineralization. Combining 3D XCT analyses with conventional 2D microscopies derive the full value out of a given exploration drilling program and it provides an excellent tool for understanding gold mineralization. Understanding the spatial distribution of gold and associated structures and microstructures in 3D space holds vast potential for exploration practitioners, especially if the correlative approach can be automated and if the resultant spatially-constrained microstructural information can be fed directly into commercially available geological modelling software. The extra layers of information provided by using correlative 2D and 3D microscopies offer an exciting new tool to enhance and optimize mineral exploration workflows, given that modern exploration efforts are targeting increasingly complex and low-grade ore deposits.


Geophysics ◽  
2018 ◽  
Vol 83 (2) ◽  
pp. U9-U22 ◽  
Author(s):  
Jide Nosakare Ogunbo ◽  
Guy Marquis ◽  
Jie Zhang ◽  
Weizhong Wang

Geophysical joint inversion requires the setting of a few parameters for optimum performance of the process. However, there are yet no known detailed procedures for selecting the various parameters for performing the joint inversion. Previous works on the joint inversion of electromagnetic (EM) and seismic data have reported parameter applications for data sets acquired from the same dimensional geometry (either in two dimensions or three dimensions) and few on variant geometry. But none has discussed the parameter selections for the joint inversion of methods from variant geometry (for example, a 2D seismic travel and pseudo-2D frequency-domain EM data). With the advantage of affordable computational cost and the sufficient approximation of a 1D EM model in a horizontally layered sedimentary environment, we are able to set optimum joint inversion parameters to perform structurally constrained joint 2D seismic traveltime and pseudo-2D EM data for hydrocarbon exploration. From the synthetic experiments, even in the presence of noise, we are able to prescribe the rules for optimum parameter setting for the joint inversion, including the choice of initial model and the cross-gradient weighting. We apply these rules on field data to reconstruct a more reliable subsurface velocity model than the one obtained by the traveltime inversions alone. We expect that this approach will be useful for performing joint inversion of the seismic traveltime and frequency-domain EM data for the production of hydrocarbon.


2020 ◽  
Vol 191 ◽  
pp. 11
Author(s):  
Marilou de Vals ◽  
Renaldo Gastineau ◽  
Amélie Perrier ◽  
Romain Rubi ◽  
Isabelle Moretti

The choice of stones by the ancient Greeks to build edifices remains an open question. If the use of local materials seems generalized, allochthonous stones are usually also present but lead to obvious extra costs. The current work aims to have an exhaustive view of the origins of the stones used in the Sanctuary of Delphi. Located on the Parnassus zone, on the hanging wall of a large normal fault related to the Corinth Rift, this Apollo Sanctuary is mainly built of limestones, breccia, marbles, as well as more recent poorly consolidated sediments generally called pôros in the literature. To overpass this global view, the different lithologies employed in the archaeological site have been identified, as well as the local quarries, in order to find their origins. The different limestones are autochthons and come from the Upper Jurassic – Cretaceous carbonate platform of the Tethys Ocean involved in the Hellenides orogen. Those limestones of the Parnassus Massif constitute the majority of the rock volume in the site; a specific facies of Maastrichtian limestone called “Profitis Ilias limestone” has been used for the more prestigious edifices such as the Apollo Temple. The corresponding ancient quarry is located few kilometers west of the sanctuary. Then, slope breccia has been largely used in the sanctuary: it crops out in and around the site and is laying on top of the carbonates. Finally, the pôros appear to be very variable and seven different facies have been documented, including travertine, oolitic grainstone, marine carbonates and coarse-grained sandstones. All these recent facies exist in the south-east shore of the Gulf of Corinth, although – except for the grainstone – the quarries are not yet known.


2004 ◽  
Vol 52 (3) ◽  
pp. 215-233 ◽  
Author(s):  
Glen S. Stockmal ◽  
Art Slingsby ◽  
John W.F. Waldron

Abstract Recent hydrocarbon exploration in western Newfoundland has resulted in six new wells in the Port au Port Peninsula area. Port au Port No.1, drilled in 1994/95, penetrated the Cambro-Ordovician platform and underlying Grenville basement in the hanging wall of the southeast-dipping Round Head Thrust, terminated in the platform succession in the footwall of this basement-involved inversion structure, and discovered the Garden Hill petroleum pool. The most recent well, Shoal Point K-39, was drilled in 1999 to test a model in which the Round Head Thrust loses reverse displacement to the northeast, eventually becoming a normal fault. This model hinged on an interpretation of a seismic reflection survey acquired in 1996 in Port au Port Bay. This survey is now in the public domain. In our interpretation of these data, the Round Head Thrust is associated with another basement-involved feature, the northwest-dipping Piccadilly Bay Fault, which is mapped on Port au Port Peninsula. Active as normal faults in the Taconian foreland, both these faults were later inverted during Acadian orogenesis. The present reverse offset on the Piccadilly Bay Fault was previously interpreted as normal offset on the southeast-dipping Round Head Thrust. Our new interpretation is consistent with mapping on Port au Port Peninsula and north of Stephenville, where all basement-involved faults are inverted and display reverse senses of motion. It also explains spatially restricted, enigmatic reflections adjacent to the faults as carbonate conglomerates of the Cape Cormorant Formation or Daniel’s Harbour Member, units associated with inverted thick-skinned faults. The K-39 well, which targeted the footwall of the Round Head Thrust, actually penetrated the hanging wall of the Piccadilly Bay Fault. This distinction is important because the reservoir model invoked for this play involved preferential karstification and subsequent dolomitization in the footwalls of inverted thick-skinned faults. The apparent magnitude of structural inversion across the Piccadilly Bay Fault suggests other possible structural plays to the northeast of K-39.


Author(s):  
Pierre-Philippe Dechant

E 8 is prominent in mathematics and theoretical physics, and is generally viewed as an exceptional symmetry in an eight-dimensional (8D) space very different from the space we inhabit; for instance, the Lie group E 8 features heavily in 10D superstring theory. Contrary to that point of view, here we show that the E 8 root system can in fact be constructed from the icosahedron alone and can thus be viewed purely in terms of 3D geometry. The 240 roots of E 8 arise in the 8D Clifford algebra of 3D space as a double cover of the 120 elements of the icosahedral group, generated by the root system H 3 . As a by-product, by restricting to even products of root vectors (spinors) in the 4D even subalgebra of the Clifford algebra, one can show that each 3D root system induces a root system in 4D, which turn out to also be exactly the exceptional 4D root systems. The spinorial point of view explains their existence as well as their unusual automorphism groups. This spinorial approach thus in fact allows one to construct all exceptional root systems within the geometry of three dimensions, which opens up a novel interpretation of these phenomena in terms of spinorial geometry.


2021 ◽  
Vol 2 ◽  
Author(s):  
Richard Skarbez ◽  
Missie Smith ◽  
Mary C. Whitton

Since its introduction in 1994, Milgram and Kishino's reality-virtuality (RV) continuum has been used to frame virtual and augmented reality research and development. While originally, the RV continuum and the three dimensions of the supporting taxonomy (extent of world knowledge, reproduction fidelity, and extent of presence metaphor) were intended to characterize the capabilities of visual display technology, researchers have embraced the RV continuum while largely ignoring the taxonomy. Considering the leaps in technology made over the last 25 years, revisiting the RV continuum and taxonomy is timely. In reexamining Milgram and Kishino's ideas, we realized, first, that the RV continuum is actually discontinuous; perfect virtual reality cannot be reached. Secondly, mixed reality is broader than previously believed, and, in fact, encompasses conventional virtual reality experiences. Finally, our revised taxonomy adds coherence, accounting for the role of users, which is critical to assessing modern mixed reality experiences. The 3D space created by our taxonomy incorporates familiar constructs such as presence and immersion, and also proposes new constructs that may be important as mixed reality technology matures.


1969 ◽  
Vol 20 ◽  
pp. 99-102
Author(s):  
Stig A. Schack Pedersen ◽  
Lars Ole Boldreel ◽  
Emil Bach Madsen ◽  
Mette Bjerkvig Filtenborg ◽  
Lars Henrik Nielsen

In the c. 40 000 km2 large Phu Quoc basin south-west of Vietnam reflection seismic data suggest a thin-skinned thrust-fault complex concealed by Neogene marine sediments (Fig. 1; Fyhn et al. 2010). The deformed sedimentary succession in the complex is of Early Cretaceous age, which is documented by biostratigraphical studies of outcrops and a 500 m deep well on the Phu Quoc island. A model for the thrust-fault deformation suggests that piggy-back basins were formed during displacement along the thrust faults. The translation was 3–8 km from east to west. The model is based on detailed structural analyses of 36 seismic sections that cover the Phu Quoc basin (Fig. 1). The main structural elements in the complex are flats and ramps with hanging-wall anticlines developed above the ramps. The crests of the hanging-wall anticlines occur as remnants of partially eroded structural highs. This paper describes the thin-skinned thrust-fault structures that form the basis for the interpretation of the concealed fold-belt complex in the Phu Quoc basin.


2015 ◽  
Vol 33 (3) ◽  
pp. 375
Author(s):  
Camila Schweig ◽  
João Carlos Dourado ◽  
Anderson De Souza

ABSTRACT. The São Vicente earthquake, which had occurred in the Santos Basin, approximately 200 km from São Vicente city, São Paulo state in 2008, was well detected in the global network, allowing a good determination of their focal mechanisms and associated nodal planes, sub-horizontal (strike 82◦) and subvertical (strike 341◦). Understanding seismic, geological and geophysical data have been necessary to determine which nodal plane is the earthquake generating fault. Gravity anomaly maps and structural contour maps allowed defining structures on regional scale. It has been observed that the epicenter is located in the high portion of the slope next to a canyon feature and the aligned graben occurrence, the Merluza Graben, coincident with Capricorn Lineament occurrence. The seismic sections have shown that in the direction of the sub-horizontal plane, less significant faults have occurred when compared to the direction of subvertical plane where there have been faults that intersect from the basement layer to the Cenozoic layers, indicating that they were activated or reactivated on neotectonic events. The mapping of a normal antithetic fault to the NS direction quite significant along the data, has suggested that a horizontal trend of this fault plane might bind to the earthquake hypocenter.Keywords: intraplate seismicity, seismic, passive margin. RESUMO. O sismo São Vicente, que ocorreu na Bacia de Santos, a aproximadamente 200 km da cidade de São Vicente (SP) em 2008, foi bem detectado na rede mundial sismográfica, o que possibilitou uma boa determinação de seus mecanismos focais e planos nodais associados, sub-horizontal (strike 82◦) e subvertical (strike 341◦). Para determinar qual plano nodal representa a falha geradora do sismo é necess´ario o entendimento de dados sismológicos, geológicos e geofísicos. Mapas de anomalia gravimétrica e mapas de contorno estrutural permitiram definir estruturas em escala regional. Observa-se que o epicentro está localizado em um alto topográfico na porção do talude próximo a uma feição de cânion e à ocorrência de grabens alinhados, o Graben Merluza, coincidente com a ocorrência do Lineamento Capricórnio. As seções sísmicas mostram que na direção do plano sub-horizontal ocorrem falhas menos expressivas se comparadas à direção do plano subvertical onde ocorrem falhas que interceptam desde o horizonte do embasamento até os horizontes cenozoicos, o que indica que as mesmas foram ativadas ou reativadas em eventos neotectônicos. O mapeamento de uma falha normal antitética de direção NS, bastante expressiva ao longo dos dados, permite supor que uma tendência horizontal desse plano de falha poderia se vincular ao hipocentro do sismo.Palavras-chave: sismicidade intraplaca, sísmica, margem passiva.


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