scholarly journals Salt Marsh Elevation Limit Determined after Subsidence from Hydrologic Change and Hydrocarbon Extraction

2020 ◽  
Vol 13 (1) ◽  
pp. 49
Author(s):  
R. Eugene Turner ◽  
Yu Mo
Keyword(s):  
Salt Marshes ◽  
Oil And Gas ◽  
Plant Cover ◽  
Plant Stress ◽  
Open Water ◽  
Marsh Surface ◽  
Production Site ◽  
Hydrologic Change ◽  
Hydrocarbon Removal ◽  
High Production

Levee construction aboveground and hydrocarbon removal from belowground in coastal wetlands can create hydrologic changes that increase plant stress through flooding. But the significance of the subsidence they cause individually or in combination is contested. This study untangled them to demonstrate elevational limits of salt marshes by studying dredged and natural waterways in two salt marshes in Louisiana, USA. The areas had a homogenous plant cover before drilling for oil and gas extraction peaked in the 1960s, and now are a mixed network of natural waterways and dredged canals used to drill wells with an average drill date of 1965.8 ± 2.7 (µ ± 1 SEM; n = 18) and well depth of 4661.0 m ± 56.6 (µ ± 1 SEM; n = 18). Aerial imagery was used to document how canals widened to become 2 to 4 times larger than their original construction width at the high production site and 50% larger at the low production site, whereas increases at the nearby natural channels were much less. Light detection and ranging (LIDAR) measurements at the high production site from 2002 showed that the marsh surface near wells subsided by 34 cm compared to undredged sites. Elevation in marshes at producing and dry wells were equal at the low production site, but high production well locations were even lower than at dry wells. An elevation vs. percent open water curve developed from these data overlapped with an independent analysis of a brackish marsh. A relative subsidence rate between 7.4 to 10.4 mm y−1 transformed these salt marshes to an open water habitat within a few decades. The local creation of accommodation space through hydrocarbon removal and leveed wetlands is a parsimonious explanation for the spatial and temporal land loss rates on this deltaic coast over the last 80 years of oil and gas exploration. Substantial losses from the accelerating rates of sea level rise are indicated to occur before 2050.

scholarly journals Topological and Morphological Controls on Morphodynamics of Salt Marsh Interiors

2021 ◽  
Vol 9 (3) ◽  
pp. 311
Author(s):  
Ben R. Evans ◽  
Iris Möller ◽  
Tom Spencer
Keyword(s):  
Salt Marsh ◽  
Salt Marshes ◽  
East Coast ◽  
Marsh Surface ◽  
Coastal Environments ◽  
Coastal System ◽  
Morphological Segmentation ◽  
The Usa ◽  
The Uk ◽  
Over Time

Salt marshes are important coastal environments and provide multiple benefits to society. They are considered to be declining in extent globally, including on the UK east coast. The dynamics and characteristics of interior parts of salt marsh systems are spatially variable and can fundamentally affect biotic distributions and the way in which the landscape delivers ecosystem services. It is therefore important to understand, and be able to predict, how these landscape configurations may evolve over time and where the greatest dynamism will occur. This study estimates morphodynamic changes in salt marsh areas for a regional domain over a multi-decadal timescale. We demonstrate at a landscape scale that relationships exist between the topology and morphology of a salt marsh and changes in its condition over time. We present an inherently scalable satellite-derived measure of change in marsh platform integrity that allows the monitoring of changes in marsh condition. We then demonstrate that easily derived geospatial and morphometric parameters can be used to determine the probability of marsh degradation. We draw comparisons with previous work conducted on the east coast of the USA, finding differences in marsh responses according to their position within the wider coastal system between the two regions, but relatively consistent in relation to the within-marsh situation. We describe the sub-pixel-scale marsh morphometry using a morphological segmentation algorithm applied to 25 cm-resolution maps of vegetated marsh surface. We also find strong relationships between morphometric indices and change in marsh platform integrity which allow for the inference of past dynamism but also suggest that current morphology may be predictive of future change. We thus provide insight into the factors governing marsh degradation that will assist the anticipation of adverse changes to the attributes and functions of these critical coastal environments and inform ongoing ecogeomorphic modelling developments.

Design of Hydrostatically Supported Sand Islands for Arctic Drilling

1980 ◽  
Vol 102 (1) ◽  
pp. 49-54
Author(s):  
B. E. W. Dowse
Keyword(s):  
Oil And Gas ◽  
Water Pressure ◽  
Open Water ◽  
The Arctic ◽  
Paper Briefly ◽  
Construction Technique ◽  
Vertical Side ◽  
Exploration Drilling ◽  
Water Depths ◽  
Permanent Production

The search for oil and gas has already extended to the Arctic areas of the world. To date conventional sand islands have been used for exploration drilling purposes in water depths of up to 43 ft. In deeper water exploration has only been possible using floating drilling equipment which can only operate during the short summer season of open water. This paper briefly outlines the geotechnical principles and development to date of hydrostatically supported sand islands. This construction technique, which utilizes hydrostatic water pressure to stabilize dredged sand at near vertical underwater slopes, would allow sand islands to be quickly and economically built in water depths of up to 200 ft. The hydrostatically supported sand island is a gravity structure and, therefore, is only suitable for use on competent seabed soils. This paper presents two different designs which are currently proposed for use as drilling structures in such areas as the Beaufort Sea. One design is intended for use as a movable exploration structure and the second for a permanent production island that would remain on location for 30 to 50 yr. The near vertical side slopes of the hydrostatically supported sand islands reduce the amount of sand required to manageable amounts, and allow the construction on location to be safely completed during the short Arctic summers. The sand provides sufficient mass to resist ice pressures.

Double Acting Tanker: Experiences from Model Tests and Sea Trials

2005 ◽  
Vol 219 (3) ◽  
pp. 109-119 ◽  
Author(s):  
P Trägärdh ◽  
P Lindell ◽  
N Sasaki
Keyword(s):  
Model Test ◽  
Oil And Gas ◽  
Single Point ◽  
Open Water ◽  
Model Tests ◽  
Water Model ◽  
Research Centre ◽  
Sea Trial ◽  
Cavitation Performance ◽  
Ice Conditions

The acronym DAT stands for double acting tanker, a concept where the ship is designed to run astern in heavy ice conditions while remaining hydrodynamically efficient for ahead propulsion in open water conditions. Two large aframax DATs - 106.000 dwt (deadweight tons) each - have been delivered by Sumitomo Heavy Industries to Fortum Oil and Gas OY. They are the first crude carriers built according to the DAT principle and also the first using pod propulsion from the beginning (Fig. 1). They will also be the world's largest crude carriers with ice class 1A super and are primarily intended for year-round transportation of North Sea crude to Fortum's refineries in the Gulf of Finland. The ships were appointed ‘ship of the year’ in Japan in 2003. SSPA was contracted by Sumitomo Heavy Industries to perform model tests. A comprehensive open water model test programme was used to investigate aspects of resistance and propulsion, manoeuvring, and cavitation performance. As the ship is designed to operate both in ahead and astern conditions for prolonged periods of time, most tests were performed both ahead and astern. Also, a simulation study of dynamic positioning at buoy or floating production, storage offshore (FPSO) loading was made by SSPA. Comprehensive tests of the ship's performance in ice were performed in the ice tank at MARC (Masa-Yards Artic Research Centre). The eight-month model testing and development campaign resulted in a ship with excellent propulsion and manoeuvring performance, especially with regard to the high ice class. Sea trials carried out with ship in August 2002 confirmed the results of the model test. Interesting experiences of the model test campaign and comparison between model test and sea trial results are presented, as well as some examples of single-point mooring simulations.

scholarly journals A COMPARISON BETWEEN GERMAN AND NORTH AMERICAN TIDAL INLETS

1988 ◽  
Vol 1 (21) ◽  
pp. 199
Author(s):  
Reinhard Dieckmann ◽  
Manuela Osterthun ◽  
Hans Werner Partenscky
Keyword(s):  
Salt Marshes ◽  
Morphological Structure ◽  
Open Water ◽  
Coastal Structures ◽  
Tidal Inlets ◽  
Cross Sectional ◽  
Short Account ◽  
Shaping Process ◽  
Geomorphological Parameters ◽  
Good Agreement

Initial results are presented relating to an investigation of geomorphological parameters from 26 of a total of 28 tidal inlets and 11 coastal structures similar to inlets along the German Bight. The following parameters were investigated: - tidal prism - inlet area relationship, - cross-sectional form and depth, - location of the channel within the cross-section, - ebb tidal deltas and - the structures of the back barrier regions. The most important parameter governing the shaping process of these coastal structures is considered to be the tidal volume. The results of the investigations were compared with data from American publications. Despite the differences between the regions studied, in overall terms, surprizingly good agreement was obtained between the parameters investigated. Notable differences exist only in relation to the morphological structure of the back barrier regions (tidal flats, salt marshes, open water lagoons). In respect of the latter differences, a short account is given of the biological and climatological influencing factors.

scholarly journals Decoupled recovery of ecological communities after reclamation

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7038 ◽  
Author(s):  
Zachary A. Sylvain ◽  
David H. Branson ◽  
Tatyana A. Rand ◽  
Natalie M. West ◽  
Erin K. Espeland
Keyword(s):  
Plant Species ◽  
Plant Communities ◽  
Oil And Gas ◽  
Plant Cover ◽  
Reference Conditions ◽  
Soil Conditions ◽  
Ecological Communities ◽  
Native Plant ◽  
Ecosystem Recovery ◽  
Nematode Communities

Grassland restoration is largely focused on creating plant communities that match reference conditions. However, these communities reflect only a subset of the biodiversity of grassland systems. We conducted a multi-trophic study to assess ecosystem recovery following energy development for oil and gas extraction in northern US Great Plains rangelands. We compared soil factors, plant species composition and cover, and nematode trophic structuring between reclaimed oil and gas well sites (“reclaims”) that comprise a chronosequence of two—33 years since reclamation and adjacent, undeveloped rangeland at distances of 50 m and 150 m from reclaim edges. Soils and plant communities in reclaims did not match those on undeveloped rangeland even after 33 years. Reclaimed soils had higher salt concentrations and pH than undeveloped soils. Reclaims had lower overall plant cover, a greater proportion of exotic and ruderal plant cover and lower native plant species richness than undeveloped rangeland. However, nematode communities appear to have recovered following reclamation. Although total and omni-carnivorous nematode abundances differed between reclaimed well sites and undeveloped rangeland, community composition and structure did not. These findings suggest that current reclamation practices recover the functional composition of nematode communities, but not soil conditions or plant communities. Our results show that plant communities have failed to recover through reclamation: high soil salinity may create a persistent impediment to native plant growth and ecosystem recovery.

scholarly journals Design of Flowline, Separator, and Slug Catcher in X Field

2018 ◽  
Vol 1 (3) ◽  
Author(s):  
I Gede Dian Aryana ◽  
Muhammad Taufiq Fathaddin ◽  
Djoko Sulistyanto
Keyword(s):  
Multiphase Flow ◽  
Oil And Gas ◽  
Slenderness Ratio ◽  
Transport Processes ◽  
Hydrodynamic Conditions ◽  
Production Flow ◽  
Gas Field ◽  
Oil And Gas Field ◽  
High Production ◽  
High Possibility

<p>The use of the pipeline is the safest method in sending oil and gas from one area to another in oil and gas transportation system. The only challenge is to keep the pressure drop in the pipeline as small as possible to avoid high pressure differences. This pressure difference can result in reduced production flow rate and affect the flow pattern in the pipeline. The condition can lead to high possibility of a slug on pipelines that drain multiphase flow. Slug becomes one of the main concerns transport processes multiphase flow in pipelines. The emergence of slug in the pipeline could cause an unstable hydrodynamic conditions will continue to affect the liquid level in the inlet separator and cause flooding in the separator. Some of the conclusions mainly on the diameter of the pipeline, the size of the slug catcher and the size of the separator obtained from the calculation based on the study of literature and simulations with software HYSIS and OLGA. Design slug catcher to accommodate the number of processes that occur in the production transportation of X oil and gas field through a pipeline 10 inches along the 12 km with 20.68 m3 volume of slug using 3 (three) finger with diameter 28 inches and length of 10 meters each. For the separation process of oil and gas in the first five (5) years of X oil and gas field  which has a high production of oil and condensate will require separator with 30 inches diameter, seam to seam height of 8.1 ft or 2.5 meters, with retention time for 2 minutes and the 3.2 slenderness ratio of the vertical separator.</p>

scholarly journals Hitchhiking Halophytes in Wrack and Sediment-Laden Ice Blocks Contribute To Tidal Marsh Development in The Upper Bay of Fundy.

2021 ◽  
Author(s):  
Jeremy Lundholm ◽  
Tasha R.M. Rabinowitz ◽  
Lyndsay Greene ◽  
Alisha D. Glogowski ◽  
Tony Bowron ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Salt Marshes ◽  
Coastal Wetland ◽  
Marsh Surface ◽  
Plant Colonization ◽  
Bay Of Fundy ◽  
Plant Debris ◽  
Salt Marsh Restoration ◽  
Potential Source ◽  
Total Sediment

Abstract Salt marshes are a type of coastal wetland that are affected by dynamic coastal processes. Ice blocks and wrack (mats of plant debris) regularly float onto northern marshes and become stranded, affecting vegetation and soil accretion. There is little research regarding the capacity of ice and wrack to transport viable plant propagules onto marshes where they can colonize, which may be particularly important at barren new salt marsh restoration sites. Contributions of sediment by ice may also be important at restoration sites to raise the marsh platform to elevations appropriate for plant colonization. We collected ice (n = 27) and wrack (n = 18) samples at marshes in the Bay of Fundy, ran germination trials with the contents, and measured the quantity of sediment in the ice. We found viable propagules from halophytic and non-halophytic species in wrack, and viable propagules of Sporobolus pumilus in ice. Additionally, we found sediment densities between 0.01 and 4.75 g·cm−3 in ice blocks that translated to 26.61 – 21,483.59 kg of total sediment per block, representing a large source of sediment. We found that the number of germinating propagules could not be predicted by wrack size, and that pH, sediment density, sediment weight in ice blocks were variable across the marsh surface, while ice salinity was negatively correlated with elevation and distance from creek. Our results indicate that ice and wrack represent a potential source for vegetation colonization at salt marsh sites and highlights their contributions to facilitating vegetation colonization through building marsh soils.

scholarly journals Are Elevation and Open‐Water Conversion of Salt Marshes Connected?

2020 ◽  
Vol 47 (3) ◽  
Author(s):  
Neil K. Ganju ◽  
Zafer Defne ◽  
Sergio Fagherazzi
Keyword(s):  
Salt Marshes ◽  
Open Water
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