Nonlinear Wave Surface Elevation Characteristics Analysis Around a Multi-Body Offshore Platforms System

2019 ◽  
Author(s):  
Xiudi Ren ◽  
Yibo Liang ◽  
Longbin Tao
Keyword(s):  
Free Surface ◽  
Nonlinear Wave ◽  
Incident Wave ◽  
Oil And Gas ◽  
Scattered Wave ◽  
Surface Elevation ◽  
Offshore Platforms ◽  
Wave Surface ◽  
Gas Field ◽  
Multi Body

Abstract Along with the development in offshore technology, the offshore platforms are gradually becoming larger and more complex. Recent development of oil and gas field in the deepwater region often involves multiple floating platforms adjacent to each other. Wave free surface associated with the air-gap design is one of the most important issues as the interaction between the platforms can complicate the hydrodynamics further. In this paper, the nonlinearity of incident wave and scattered wave are considered in diffraction analysis based on the potential theory. In addition, the nonlinear incident wave is considered to capture the nonlinear features of free surface due to wave diffraction and radiation. The wave surface amplitude around a multi-body platforms system is numerically analyzed in the frequency domain and compared with the numerical results of a single platform. The distribution of wave surface amplitude with different scatter parameter at different wave steepness is investigated to examine the relationship between the two parameters critical to the nonlinear wave surface elevation.

scholarly journals Methane emissions in the Netherlands: The Groningen field

Elem Sci Anth ◽  
2018 ◽  
Vol 6 ◽  
Author(s):  
Tara I. Yacovitch ◽  
Bruno Neininger ◽  
Scott C. Herndon ◽  
Hugo Denier van der Gon ◽  
Sander Jonkers ◽  
...  
Keyword(s):  
Natural Gas ◽  
The Netherlands ◽  
Oil And Gas ◽  
Methane Emissions ◽  
Production Volume ◽  
Offshore Platforms ◽  
Source Characterization ◽  
Gas Field ◽  
Study Region ◽  
Individual Site

The Groningen natural gas field in the Netherlands – one of Europe’s major gas fields – deploys a “production cluster” infrastructure with extraction, some processing and storage in a single facility. This region is also the site of intensive agriculture and cattle operations. We present results from a multi-scale measurement campaign of methane emissions, including ground and airborne-based estimates. Results are compared with inventory at both the facility and regional level. Investigation of production cluster emissions in the Groningen gas field shows that production volume alone is not a good indicator of whether, and how much, a site is emitting methane. Sites that are nominally shut down may still be emitting, and vice-versa. As a result, the inventory emission factors applied to these sites (i.e. weighted by production) do a poor job of reproducing individual site emissions. Additional facility-level case studies are presented, including a plume at 150 ± 50 kg CH4 hr–1 with an unidentified off-shore emission source, a natural gas storage facility and landfills. Methane emissions in a study region covering 6000 km2 and including the majority of the Groningen field are dominated by biogenic sources (e.g. agriculture, wetlands, cattle). Total methane emissions (8 ± 2 Mg hr–1) are lower than inventory predictions (14 Mg hr–1) but the proportion of fossil fuel sources is higher than indicated by the inventory. Apportionment of methane emissions between thermogenic and biogenic source types used ethane/methane ratios in aircraft flasks and ground-based source characterization. We find that emissions from the oil and gas sector account for 20% of regional methane, with 95% confidence limits of (0%, 51%). The experimental uncertainties bound the inventory apportionment of 1.9%, though the central estimate of 20% exceeds this result by nearly 10 times. This study’s uncertainties demonstrate the need for additional research focusing on emissions apportionment, inventory refinement and offshore platforms.

Nonlinear wave surface elevation around a multi-column offshore structure

2021 ◽  
Vol 238 ◽  
pp. 109757
Author(s):  
Xiudi Ren ◽  
Longbin Tao ◽  
Yibo Liang ◽  
Duanfeng Han
Keyword(s):  
Nonlinear Wave ◽  
Surface Elevation ◽  
Wave Surface ◽  
Offshore Structure

3D Stereo Imaging of Abnormal Waves in a Wave Basin

2015 ◽  
Author(s):  
Kento Mozumi ◽  
Takuji Waseda ◽  
Amin Chabchoub
Keyword(s):  
Free Surface ◽  
3D Reconstruction ◽  
Linear Transformation ◽  
Analytical Solutions ◽  
New Method ◽  
Surface Elevation ◽  
Regular Wave ◽  
Wave Surface ◽  
Wave Basin ◽  
Net Method

This paper proposes a new method to measure the wave surface elevation in a wave basin. The Direct Linear Transformation (DLT) method is employed in the 3D reconstruction of the free surface marked by an array of floats attached to a flexible net. The method is coined the Marker-Net method (MNM). Experiments were conducted in a large basin to validate the proposed method. Regular wave records are compared against wave wire measurements to quantify the accuracy of the estimation based on the MNM. To demonstrate the advantage of the MNM over conventional techniques used in the tank, a set of experiments based on analytical solutions of the 2D+T nonlinear Schrodinger equations were conducted. The MNM reconstruction of the free surface revealed propagation of an oblique structure, which is difficult to visualize otherwise.

A method of technical diagnostics for offshore structures

1994 ◽  
Vol 16 (2) ◽  
pp. 43-48
Author(s):  
Do Son
Keyword(s):  
Diagnostic Method ◽  
Joint Venture ◽  
Oil And Gas ◽  
Residual Life ◽  
Life Time ◽  
Offshore Structures ◽  
Technical Diagnostics ◽  
Offshore Platforms ◽  
South Vietnam ◽  
Local Destruction

This paper describes the results of measurements and analysis of the parameters, characterizing technical state of offshore platforms in Vietnam Sea. Based on decreasing in time material characteristics because of corrosion and local destruction assessment on residual life time of platforms is given and variants for its repair are recommended. The results allowed to confirm advantage of proposed technical diagnostic method in comparison with others and have been used for oil and gas platform of Joint Venture "Vietsovpetro" in South Vietnam.

Prediction of Ship Motions Via a Three-Dimensional Time-Domain Method Following a Quad-Tree Adaptive Mesh Technique

2020 ◽  
Vol 27 (1) ◽  
pp. 29-38
Author(s):  
Teng Zhang ◽  
Junsheng Ren ◽  
Lu Liu
Keyword(s):  
Free Surface ◽  
Incident Wave ◽  
Time Domain ◽  
Three Dimensional ◽  
Adaptive Mesh ◽  
Wave Profile ◽  
Time Domain Method ◽  
Ship Motions ◽  
Quad Tree ◽  
Mesh Technique

AbstractA three-dimensional (3D) time-domain method is developed to predict ship motions in waves. To evaluate the Froude-Krylov (F-K) forces and hydrostatic forces under the instantaneous incident wave profile, an adaptive mesh technique based on a quad-tree subdivision is adopted to generate instantaneous wet meshes for ship. For quadrilateral panels under both mean free surface and instantaneous incident wave profiles, Froude-Krylov forces and hydrostatic forces are computed by analytical exact pressure integration expressions, allowing for considerably coarse meshes without loss of accuracy. And for quadrilateral panels interacting with the wave profile, F-K and hydrostatic forces are evaluated following a quad-tree subdivision. The transient free surface Green function (TFSGF) is essential to evaluate radiation and diffraction forces based on linear theory. To reduce the numerical error due to unclear partition, a precise integration method is applied to solve the TFSGF in the partition computation time domain. Computations are carried out for a Wigley hull form and S175 container ship, and the results show good agreement with both experimental results and published results.

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