The Sea Tower Design of a Deep Water Jack - Up Mobile Drilling/Production Unit

1986 ◽  
Author(s):  
R E Scales ◽  
◽  
J E Steele ◽  
Keyword(s):  
Deep Water ◽  
Production Unit ◽  
Jack Up

Riser Analysis of a New Dry Completion Concept for a Monocolumn Platform

2011 ◽  
Author(s):  
Fernando Jorge Mendes de Sousa ◽  
Marcos Queija de Siqueira ◽  
Claudio Marcio Silva Dantas ◽  
Lui´s Volnei Sudati Sagrilo ◽  
Isai´as Quaresma Masetti
Keyword(s):  
Gulf Of Mexico ◽  
Deep Water ◽  
Environmental Conditions ◽  
Public Institutions ◽  
Oil Fields ◽  
Production Unit ◽  
Floating Body ◽  
Campos Basin ◽  
To Receive

In recent years, PETROBRAS has developed the concept of a monocolumn platform to be used as a floating production unit in deep and ultra-deep water oil fields. This platform, referred as MonoBR, is characterized by low heave and pitch induced motions, even in hurricane conditions, allowing its use as an alternative for locations such as Campos Basin and the Pre-Salt Area in Brazil, and also for the Gulf of Mexico. Despite their low vertical motions, this platform is not generally regarded as a dry completion unit. However, PETROBRAS and two public institutions in Brazil, UFRJ/COPPE and USP/POLI, have studied and designed an innovative mechanism to be installed in MonoBR, called Inverted Cup, which is a sliding floating body installed inside the MonoBR moonpool. In such way, the platform transmits only horizontal motions and rotations to the Inverted Cup; the heave responses of both bodies are decoupled. The Inverted Cup is then designed and dimensioned to receive dry completion X-mas trees and risers. The aim of this paper is to present the results of the riser analysis performed under this new concept — Inverted Cup system — to allow dry completion in the MonoBR. The environmental conditions refer to fields in the Gulf of Mexico and in the Tupi Field (Pre-Salt). The results point to a technically feasible mechanism to allow dry completion, according to adopted criteria.

Evolution of the Design of a Jack-up Type Offshore Structure

1975 ◽  
Vol 12 (01) ◽  
pp. 50-59
Author(s):  
R. P. Giblon ◽  
V. U. Minorsky
Keyword(s):  
North Sea ◽  
Water Depth ◽  
Deep Water ◽  
Basic Concept ◽  
Ocean Engineering ◽  
Offshore Structure ◽  
The Past ◽  
Production Platform ◽  
Jack Up

Naval architects have greatly diversified their work in the past few years and are becoming involved in ocean engineering, among other pursuits. This paper describes a basic concept for a jack-up drill rig in deep water, using a trussed structural platform at mid-water depth to reduce the leg spans to acceptable lengths. Next, it describes how this idea was adapted by steps to the design of a steel, gravity-type, self-erecting production platform for a specific North Sea field, and reasons are given for the advantages of this design.

scholarly journals Investigation of jack-up leg extension for deep water operations

2015 ◽  
Vol 7 (2) ◽  
pp. 288-300
Author(s):  
Yousri M.A. Welaya ◽  
Ahmed Elhewy ◽  
Mohamed Hegazy
Keyword(s):  
Deep Water ◽  
Leg Extension ◽  
Jack Up

scholarly journals SCOUR UNDER A VERTICALLY OSCILLATING LEG

1974 ◽  
Vol 1 (14) ◽  
pp. 95 ◽  
Author(s):  
Richard Silvester
Keyword(s):  
Deep Water ◽  
Research Program ◽  
Reynolds Numbers ◽  
Water Erosion ◽  
Pilot Studies ◽  
Size Scale ◽  
The Subject ◽  
Jack Up ◽  
Comprehensive Research Program ◽  
Period Of Oscillation

Mishaps with jack-up oil rigs could be caused by scour beneath their legs as they oscillate vertically, either on site or when being shifted to or from site. This action was replicated in the laboratory by moving cylindrical feet to and from a sandy bed at frequencies appropriate to the scale of the model. By retaining equal Reynolds numbers for the sand grains, whose size was commensurate with prototype material, the period of oscillation had to vary with the leg diameter. By adopting a suitable size scale, a range of periods was determined from knowledge of resonant motions of rigs in relatively deep water. Erosion was recorded which appeared sufficient to cause mal-distribution of load in the structure. Even when oscillations occurred in a leg penetrating the bed, no support was available due to liquifaction of the soil. The two pilot studies herein described indicate the need for a comprehensive research program on the subject, due to the large investments in jeopardy.

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

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