scholarly journals Structural style of the Languedoc Pyrenean thrust belt in relation with the inherited Mesozoic structures and with the rifting of the Gulf of Lion margin, southern France

2021 ◽  
Author(s):  
Romain HEMELSDAEL ◽  
Michel SERANNE ◽  
Eglantine HUSSON ◽  
Gregory BALLAS
Keyword(s):  
Offshore Structures ◽  
Strain Partitioning ◽  
Southern France ◽  
Structural Framework ◽  
Structural Style ◽  
Oblique Convergence ◽  
Gulf Of Lion ◽  
Wilson Cycle ◽  
Transfer Zone

The “Wilson cycle” involves reactivation of rifting structures during convergence-driven inversion, then thrust reactivation during post-orogenic dismantling and extension. Classic documented examples of the Wilson cycle, such as in the pyrenean orogen, are based on sequential sections normal to the orogen. However oblique convergence/divergence that involves strain partitioning, and arcuate segments of the orogen prevent simple tectonic restorations. Languedoc region (southern France) provides a case study of a complex poly-phased deformation involving a range of reactivated structures and cross-cutting relationships, acquired in response to different stress-regimes of varying orientations. We analyse and correlate the onshore-offshore structures of the Languedoc, based on reassessment of existing and newly acquired subsurface data. New results in the previously poorly documented coastal area point to the existence of unrecognized major structures that improves onshore-offshore correlations. Our results show i) the part played by the Mesozoic (early Jurassic, then mid-Cretaceous) extensional phases in the development and the localization of pyrenean-related contractional structures; ii) the control of the later Oligocene rifting of the Gulf of Lion. Restoration of the Pyrenean shortening and Oligocene rifting, constructed along sections of relevant orientation (i.e. close to perpendicular to each other) indicate minimum shortening of 26 km and extension of 14km, respectively, in the Languedoc foreland. Integration of the Pyrenean structural framework of Languedoc reveals a wide, NE-trending transfer zone linking the Iberian Pyrenees to Provence.

Progressive Collapse Approach Compared to the Traditional Temperature Screening on Structural Assessment of Offshore Structures Against Fire

2016 ◽  
Author(s):  
Paula T. Nascimento ◽  
Marco A. P. Rosas ◽  
Leonardo Brandão ◽  
Fernando Castanheira
Keyword(s):  
Traditional Approach ◽  
Progressive Collapse ◽  
Screening Method ◽  
Substantial Reduction ◽  
Cost Savings ◽  
Offshore Structures ◽  
Significant Cost ◽  
Fire Scenarios

The present study compares the progressive collapse approach with the traditional temperature screening method on determination of PFP requirements at topside offshore structures. The advantage to evaluate the consequences of fire scenarios on the global integrity and stability of topside modules can be revealed by a substantial reduction of the required amount of PFP, and consequently significant cost savings for operators, when compared to the traditional approach. In the case study presented in this paper, there is a reduction of 79% in PFP allocation.

scholarly journals Structural Assessment of the Hull Response of an FPSO Unit to Dropped Objects: A Case Study

2019 ◽  
Vol 26 (4) ◽  
pp. 39-46 ◽  
Author(s):  
Ozgur Ozguc
Keyword(s):  
Structural Damage ◽  
Local Buckling ◽  
Structural Response ◽  
Offshore Structures ◽  
Mechanical Equipment ◽  
Structural Members ◽  
Impact Area ◽  
Explicit Dynamic ◽  
The Impact

Abstract Offshore structures are exposed to the risk of damage caused by various types of extreme and accidental events, such as fire, explosion, collision, and dropped objects. These events cause structural damage in the impact area, including yielding of materials, local buckling, and in some cases local failure and penetration. The structural response of an FPSO hull subjected to events involving dropped objects is investigated in this study, and non-linear finite element analyses are carried out using an explicit dynamic code written LS-DYNA software. The scenarios involving dropped objects are based on the impact from the fall of a container and rigid mechanical equipment. Impact analyses of the dropped objects demonstrated that even though some structural members were permanently deformed by drop loads, no failure took place in accordance with the plastic strain criteria, as per NORSOK standards. The findings and insights derived from the present study may be informative in the safe design of floating offshore structures.

Evaluating the impact of climate change on offshore structures design: A practical case study

2020 ◽  
Vol 94 ◽  
pp. 101992
Author(s):  
I.A. Mosquera-Mosquera ◽  
Marina L. Simão ◽  
Paulo M. Videiro ◽  
Luis V.S. Sagrilo
Keyword(s):  
Climate Change ◽  
Offshore Structures ◽  
Practical Case ◽  
Impact Of Climate Change ◽  
The Impact

Three-dimensional strain accumulation and partitioning in an arcuate orogenic wedge: An example from the Himalaya

2020 ◽  
Vol 133 (1-2) ◽  
pp. 3-18 ◽  
Author(s):  
Suoya Fan ◽  
Michael A. Murphy
Keyword(s):  
Cross Sections ◽  
Three Dimensional ◽  
Western Himalaya ◽  
Shear Zones ◽  
High Elevation ◽  
Central Himalaya ◽  
Structural Style ◽  
Orogenic Wedge ◽  
Oblique Convergence ◽  
Thickness Variations

Abstract In this study, we use published geologic maps and cross-sections to construct a three-dimensional geologic model of major shear zones that make up the Himalayan orogenic wedge. The model incorporates microseismicity, megathrust coupling, and various derivatives of the topography to address several questions regarding observed crustal strain patterns and how they are expressed in the landscape. These questions include: (1) How does vertical thickening vary along strike of the orogen? (2) What is the role of oblique convergence in contributing to along-strike thickness variations and the style of deformation? (3) How do variations in the coupling along the megathrust affect the overlying structural style? (4) Do lateral ramps exist along the megathrust? (5) What structural styles underlie and are possibly responsible for the generation of high-elevation, low-relief landscapes? Our model shows that the orogenic core of the western and central Himalaya displays significant along-strike variation in its thickness, from ∼25–26 km in the western Himalaya to ∼34–42 km in the central Himalaya. The thickness of the orogenic core changes abruptly across the western bounding shear zone of the Gurla Mandhata metamorphic core complex, demonstrating a change in the style of strain there. Pressure-temperature-time results indicate that the thickness of the orogenic core at 37 Ma is 17 km. Assuming this is constant along strike from 81°E to 85°E indicates that, the western and central Nepal Himalaya have been thickened by 0.5 and 1–1.5 times, respectively. West of Gurla Mandhata the orogenic core is significantly thinner and underlies a large 11,000 km2 Neogene basin (Zhada). A broad, thick orogenic core associated with thrust duplexing is collocated with an 8500 km2 high-elevation, low-relief surface in the Mugu-Dolpa region of west Nepal. We propose that these results can be explained by oblique convergence along a megathrust with an along-strike and down-dip heterogeneous coupling pattern influenced by frontal and oblique ramps along the megathrust.

Integrity Management System for Fixed Offshore Structures Inspection Strategy

2004 ◽  
Author(s):  
Mohamed A. El-Reedy
Keyword(s):  
Management System ◽  
Offshore Structures ◽  
Assessment Method ◽  
Offshore Platforms ◽  
Offshore Structure ◽  
Structure Comparison ◽  
Actual Structure ◽  
Existing Structures ◽  
Integrity Management

The GUPCO offshore structure management system was developed as a part of an integrated infrastructure management system. This paper presents a case study of providing an integrity management system for inspection, evaluation and repair of the fixed offshore platforms in Gulf of Suez. The management system procedure is presented focusing on the first step for defining the highly risky weight to the lower risky weight structure based on API criteria for assessment of the existing structures. The risk analysis methodology for developing design and assessment criteria for fixed offshore structure based on consequence of failure is illustrated. In our case study the assessment method is applied for a number of fixed offshore structures. The above methodology is performed after theoretical assessment and then verifying by using ROV subsea inspection for the fixed offshore structure. Comparison between the actual structure performance and the predicting risk assessment for the structure from the model will be studied. The overall management system will be illustrated in scope of predictive maintenance philosophy and reliability for all offshore structures.

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