Compliant Tower Investigations For Larger Topsides And Shallower Water Depths In The Gulf Of Mexico

1993 ◽  
Author(s):  
Makis Manetas ◽  
Gary Reusswig ◽  
V.V.D. Nair
Keyword(s):  
Gulf Of Mexico ◽  
Compliant Tower ◽  
Water Depths

100 Years of Oil and Gas Development: From the Marshes to Deepwater, Louisiana Has Played a Major Role in Water-Oriented Exploration and Development

2002 ◽  
Author(s):  
Donald W. Davis
Keyword(s):  
Gulf Of Mexico ◽  
Oil And Gas ◽  
100Th Anniversary ◽  
The State ◽  
Hydrocarbon Exploration ◽  
Oil And Gas Development ◽  
Energy Demands ◽  
Entrepreneurial Spirit ◽  
Water Depths ◽  
Exploration And Development

September, 2001 marked the 100th anniversary of the oil and gas business in Louisiana. Consequently, hydrocarbon exploration and development has been a vital part of Louisiana’s economy for over a century. In the latter part of the 1980s, the industry was considered dead or dying. Exploration and development had declined throughout the state. In the 1990s Louisiana’s industry was reborn in the deepwater of the northern Gulf of Mexico—a region that holds enormous potential in water depths that create unique exploration, development and production challenges. As technology changed, or was developed to meet the industry’s needs, new frontiers were explored. There was a pioneering entrepreneurial spirit that pushed the limits. Today, the frontier continues to expand and Louisiana is the beneficiary of this activity. One hundred years after the first discovery well in Louisiana, more than 250,000 oil and/or gas wells have been drilled in the state. In addition, over 4,000 structures are anchored parallel to its coast in water depths approaching two miles (3.2 km). From the uplands, to the swamps and marshes and into the deepwater of the Gulf of Mexico, Louisiana has been a leader in helping meet the Nation’s energy demands.

Quickwave: An Impulse Algorithm to Calculate Preliminary Design Shear and Moment Envelopes for Compliant Towers

1995 ◽  
Vol 117 (2) ◽  
pp. 85-90 ◽  
Author(s):  
D. G. Morrison
Keyword(s):  
Dynamic Response ◽  
Closed Form Solution ◽  
Form Solution ◽  
Steel Grade ◽  
Preliminary Design ◽  
Wave Load ◽  
Simple Method ◽  
Compliant Tower ◽  
Computer Analyses ◽  
Water Depths

A novel, simple method to calculate compliant tower (CT) level shear and moment envelopes for preliminary design has been developed, and verified by comparing with rigorous 3-D tower analyses. The approach relies on a vast experience base to define important features influencing the dynamic response of CTs, and a new closed-form solution for the acceleration (needed to construct design envelopes) of the tower caused by an impulsive-type wave load. The main benefits of the approach are: 1) the designer can iterate and quickly converge on a working preliminary design without resorting to time-consuming computer analyses; 2) the designer can quickly evaluate configurations for different water depths, pile arrangements, payload, steel grade, reserve buoyancy, and well counts.

Dynamic Response of the Baldpate Compliant Tower Platform to Major Hurricanes in Gulf of Mexico

2012 ◽  
Author(s):  
Ben C. Chang ◽  
Bor-Feng Peng ◽  
James Craig Edel ◽  
Joe Kallaby
Keyword(s):  
Dynamic Response ◽  
Gulf Of Mexico ◽  
Compliant Tower

Fine-scale vertical profiles of meiofauna in muddy subtidal sediments

1995 ◽  
Vol 73 (8) ◽  
pp. 1453-1460 ◽  
Author(s):  
J. W. Fleeger ◽  
T. C. Shirley ◽  
J. N. McCall
Keyword(s):  
Gulf Of Mexico ◽  
Vertical Profile ◽  
Water Interface ◽  
Vertical Profiles ◽  
Fine Scale ◽  
Weighted Mean ◽  
Nematode Density ◽  
Harpacticoid Copepods ◽  
Louisiana Continental Shelf ◽  
Water Depths

The fine-scale vertical profile (2-mm intervals to 2 cm) of meiofauna was surveyed at three water depths (20, 50, and 80 m) on the Louisiana continental shelf and at two depths (25 and 55 m) in a subarctic Alaskan bay. Meiofaunal densities at these sites measured through 4 cm were similar to those of other subtidal muddy-sediment sites, nematodes averaging about 1000 and 1500 and harpacticoid copepods averaging 125 and 30 per 10 cm2 in Louisiana and Alaska, respectively. Overall, harpacticoids were numerous at the sediment–water interface and exceptionally shallow in depth profile; densities decreased with increasing depth, with few individuals below 6 mm. Across all sites and water depths, weighted mean depths of harpacticoids averaged 5.4 mm. Nematodes were distributed to much greater depths, and generally increased in density with depth, with highest densities below 6 mm. In the Gulf of Mexico, nematode density peaked in the second centimetre. Across all sites and depths, nematode weighted mean depth averaged 10.5 mm within the upper 2 cm. Harpacticoids were the most abundant meiofaunal taxon in the upper 4 mm in the Gulf of Mexico at the 50- and 80-m sites. Overall, harpacticoids were disproportionately abundant at the sediment–water interface to a depth of 6 mm, and play a more significant role in events that take place at the surface than their down-core abundance would indicate. For example, harpacticoids are potentially more influenced by bottom-feeding fish and erosional events than are nematodes, and may exert an influence over the initial burial of sedimented phytodetritus.

Float Over Installation Method—Comprehensive Comparison Between Numerical and Model Test Results

2006 ◽  
Vol 128 (3) ◽  
pp. 256-262 ◽  
Author(s):  
Arcandra Tahar ◽  
John Halkyard ◽  
Atle Steen ◽  
Lyle Finn
Keyword(s):  
West Africa ◽  
Gulf Of Mexico ◽  
Model Test ◽  
Test Results ◽  
Sea State ◽  
Numerical Predictions ◽  
Single Piece ◽  
Heavy Lift ◽  
Compliant Tower ◽  
Comprehensive Comparison

Installing a large deck onto a platform, such as a spar, using the floatover method is gaining popularity. This is because the operational cost is much lower than other methods of installation, such as modular lifts or a single piece installation by a heavy lift barge. Deck integration can be performed on land, at quay side and will not depend on a heavy lift barge. A new concept for a floatover vessel has been developed for operations in the Gulf of Mexico and West Africa. In this application sea state conditions are essential factors that must be considered in the Gulf of Mexico, especially for transportation. In West Africa, swell conditions will govern floatover deck (FOD) installation. Based on these two different environmental conditions, Technip Offshore, Inc. developed the FOD installation concept using semi-submersible barge type vessels. A significant amount of development work and model testing has been done on this method in recent years on spar floatover. These tests have validated our numerical methods. Another test was conducted to investigate the feasibility of a deck float-over operation onto a compliant tower for a West Africa project. The project consists of a compliant tower supporting a 25,401metricton(28,000s.ton) integrated deck. This paper will describe comparisons between model test data and numerical predictions of the compliant tower floatover operation.

Float Over Installation Method: Numerical and Model Test Data

2004 ◽  
Author(s):  
Arcandra Tahar ◽  
John Halkyard ◽  
Atle Steen ◽  
Lyle Finn
Keyword(s):  
West Africa ◽  
Gulf Of Mexico ◽  
Test Data ◽  
Model Test ◽  
Sea State ◽  
Numerical Predictions ◽  
Offshore Engineering ◽  
Single Piece ◽  
Heavy Lift ◽  
Compliant Tower

Installing a large deck onto a platform, such as a spar, using the floatover method is gaining popularity. This is because the operational cost is much lower than other methods of installation, such as modular lifts or a single piece installation by a heavy lift barge. Deck integration can be performed on land, at quay side and will not depend on a heavy lift barge. A new concept for a floatover vessel has been developed for operations in the Gulf of Mexico and West Africa. In this application sea state conditions are essential factors that must be considered in the Gulf of Mexico, especially for transportation. In West Africa, swell conditions will govern floatover deck (FOD) installation. Based on these two different environmental conditions, Technip Offshore Engineering developed the FOD installation concept using semi-submersible barge type vessels. A significant amount of development work and model testing has been done on this method in recent years on spar floatover. These tests have validated our numerical methods. Another test was conducted to investigate the feasibility of a deck float-over operation onto a compliant tower for the Benguela Belize (BBT) project. The BBT project consists of a compliant tower supporting a 25,401 metric ton (28,000 s. ton) integrated deck. This paper will describe comparisons between model test data and numerical predictions of the compliant tower floatover operation.

scholarly journals Seafloor observations at Campeche Knolls, southern Gulf of Mexico: coexistence of asphalt deposits, oil seepage, and gas venting

2016 ◽  
Author(s):  
Heiko Sahling ◽  
Maxim Rubin Blum ◽  
Christian Borowski ◽  
Elva Escobar-Briones ◽  
Adriana Gaytán-Caballero ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Heavy Oil ◽  
Gas Hydrate ◽  
Gas Bubble ◽  
Remotely Operated Vehicle ◽  
Gas Emissions ◽  
Common Component ◽  
Southern Gulf Of Mexico ◽  
Oil Seepage ◽  
Water Depths

Abstract. We studied asphalt deposits, oil seepage and gas venting during a multidisciplinary cruise in the Bay of Campeche, southern Gulf of Mexico. We conducted multibeam bathymetric mapping with an autonomous underwater vehicle and performed seafloor observations as well as sampling with a remotely operated vehicle. While previous studies concentrated on the asphalt volcano Chapopote Knoll, we confirmed that asphalt deposits at the seafloor occurred across numerous other knolls and ridges in water depths between 1230 and 3150 m; this is evidence that the outflow of heavy oil is a common component of hydrocarbon seepage of Campeche Knolls. The outflow of heavy oil either created whips or sheets floating in the water that subsequently descend and pile-up as meter high stacks at the seafloor over time or spread at the seafloor forming flows ranging from meters to tens of meters in diameter. Unlike seafloor-covering asphalts known from other continental margins, those in our study include relatively fresh material. Seafloor observations documented how chemosynthetic communities develop on the asphalts, with bacterial mats and juvenile vestimentiferan tubeworms colonizing the most recent flows. Gas bubble emissions were an additional widespread component of hydrocarbon seepage at Campeche Knolls. The hydrocarbon gas had thermogenic origins, as indicated by the composition (C1/C2-ratio: 14 to 185) and stable carbon isotopic signature of methane (δ13C-CH4: −45.1 to −49.8 ‰). Gas emissions were detected by multibeam echosounder at water depths as great as 3420 m over Tsanyao Yang Knoll. Gas emissions occurred at sites without large asphalt deposits (Tsanyao Yang Knoll) as well as through old, fragmented asphalts (Mictlan Knoll, Chapopote Knoll). The gas emissions feed gas hydrate deposits at shallow seafloor depth. Gas hydrate formed mounds that were ~ 10 m wide by several meters high in soft sediments and filled the space within fragmented asphalts. The largest gas hydrate mounds supported dense colonies of 1–2 m long tubeworms that covered areas > 100 m2. These tubesworms grow with their posterior tubes implanted in a 5 to 10 cm thick reaction zone composed of authigenic carbonates, detritus, and microbial mats that overlie gas hydrate layers that were at least 2 m thick in places. This association between gas hydrates and vestimentifera has been noted in gas seeps at lesser depths, but was developed to an unequaled extent in the Campeche Knolls. Previous studies have documented oil slicks on the ocean surface across many sites in the region. This study found liquid oil emissions in diverse settings. Sites with oil seepage are characterized by oil-soaked sediments, chemosynthetic fauna with associated heterotrophs, and bacterial coatings. Gas bubble emissions and oil seepage occurred independent of asphalt deposits or through old, fragmented asphalts, indicating that presently active hydrocarbon seepage overprints older asphalt deposits. Campeche Knolls are unique in several aspects including the occurrence of recent flows of heavy oil, deep-water hydrocarbon seepage, with many species that are new to science.

Microbiologically Influenced Corrosion of Gulf of Mexico Mooring Chain at 6,000 Feet Depths

2012 ◽  
Author(s):  
Jonathon D. Miller ◽  
Brett J. Warren ◽  
Luc G. Chabot
Keyword(s):  
Gulf Of Mexico ◽  
Steel Structures ◽  
Microbiologically Influenced Corrosion ◽  
Mooring System ◽  
Ambient Conditions ◽  
Sulfate Reducing ◽  
Hypoxic Environment ◽  
Reducing Bacteria ◽  
Mooring Chain ◽  
Water Depths

During a post-installation inspection of a polyester and chain mooring system in water depths of approximately 6,000 ft, evidence of microbiologically influenced corrosion (MIC) was found in the form of rust tubercles known as rusticles. These porous concretions commonly form on submerged steel shipwrecks and provide evidence that subsea corrosion occurs in a hypoxic environment. Iron and sulfate-reducing bacteria cause corrosion in marine environments. This paper will discuss one form of MIC found on submerged steel structures, analyze the ambient conditions required for MIC to occur, and compare rusticles found during the mooring inspection to those found on other subsea shipwrecks such as the RMS Titanic. An analysis of the type of iron used in mooring chains and the rate of rusticle formation will be presented. Possible remedies to prevent rusticle growth on mooring chains will be summarized.

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