CIDS: A Mobile Concrete Island Drilling System for Arctic Offshore Operations

1984 ◽  
Vol 21 (01) ◽  
pp. 1-11
Author(s):  
Sherman B. Wetmore ◽  
Harold D. Ramsden
Keyword(s):  
The Arctic ◽  
Structural System ◽  
Drilling Rig ◽  
Gravity Load ◽  
Unique System ◽  
Landfast Ice ◽  
Drilling Operations ◽  
Drilling System ◽  
Key Features ◽  
Water Depths

This paper describes a unique system that can provide an alternative to gravel islands as a means of supporting drilling operations in shallow Arctic waters. The Concrete Island Drilling System (CIDS) is composed of modular concrete "bricks" stacked one on top of the other which, in turn, support a barge-mounted drilling rig. Sequentially stacking these modules provides a great deal of flexibility in siting the modules in water depths of 18 to 52 ft. The modules incorporate an efficient concrete "honeycomb" structural system that offers inherent longitudinal, transverse and torsional strength. The superior strength of the CIDS, coupled with its massive ballasted weight, enables it to withstand the ice pressures prevalent in the landfast ice areas of the Arctic. Several key features of the CIDS make it a unique and economically advantageous exploratory drilling platform. Because it is modular, the CIDS reduces construction and transportation problems and allows the use of various configurations that can be modified to suit the water depth requirement. No dredging or gravel-hauling activity is associated with the CIDS since the gravity load is achieved by merely ballasting the modules with seawater. The entire system, with the drilling rig intact, can be relocated by pumping out the saltwater ballast and towing the CIDS to a new site. No rig demobilization or "under-dredging" of caisson fill is required. The use of concrete insures a long-lived structure that can be reused on many wells.

The Influence of Drilling Rig and Riser System Selection on Wellhead Fatigue Loading

2012 ◽  
Author(s):  
John F. Greene ◽  
Dara Williams
Keyword(s):  
Fatigue Life ◽  
Shallow Water ◽  
Deep Water ◽  
Fatigue Loading ◽  
Careful Consideration ◽  
Drilling Rig ◽  
Drilling System ◽  
Drilling Rigs ◽  
Water Depths ◽  
Selection Of

With drilling and exploration activity currently high in both deep and shallow water regions rig availability and selection is an issue for operators to consider in order to achieve the desired exploration schedule. At present the industry focus is on the development of 6th generation drilling rigs with the capacity to operate in increasing deep water. However despite the focus on deepwater exploration and the associated demand for deepwater drilling rigs there still exists demand for drilling rigs that can operate in shallow to moderate water depths (100m–500m). In addition, certain field development scenarios may exist where planned water depths for drilling activities vary significantly and therefore a drilling rig and riser system is required that can operate satisfactorily in both shallow and deep water depths. For a given drill site, rig availability or well location, may be such that an operator may have to select a modern deepwater 6th generation rig for shallow water activities where a 3rd generation rig would appear to provide a better solution. Other considerations such as vessel station keeping requirements may lead to selection of a 6th generation rig over a 3rd generation rig, as the former tend to have improved DP thrusters capacity. However it is also important to note that while the 6th generation rigs may have been proven to be robust systems for operation in deep water, the response of a 6th generation drilling system in shallow water depths can be very different to that of an older 3rd generation rig and drilling riser system. Thus careful consideration must be made by the operator when considering the selection of drilling vessels for shallow to moderate water depths. Fatigue life of the wellhead is shown to be affected when one compares the response of the 6th generation and 3rd generation drilling systems in shallow to moderate depths. This also needs to be accounted for when selecting rigs for workover or intervention operations on older infrastructure. This paper presents a discussion on the various parameters such as BOP stack size, riser, flex joint and vessel design that influence the response of the drilling system in shallow to moderate water depths (100m–500m). A number of case studies and parametric studies have been carried out and the results of these are presented in order to compare the wellhead fatigue damage from the older 3rd generation systems with the 6thgeneration systems and also to identify the critical drivers for this fatigue life reduction.

scholarly journals Microplastic contamination of the drilling bivalve Hiatella arctica in Arctic rhodolith beds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sebastian Teichert ◽  
Martin G. J. Löder ◽  
Ines Pyko ◽  
Marlene Mordek ◽  
Christian Schulbert ◽  
...  
Keyword(s):  
Polyethylene Terephthalate ◽  
Water Depth ◽  
The Arctic ◽  
Polymer Composition ◽  
Bivalve Species ◽  
Filter Feeder ◽  
Hiatella Arctica ◽  
Long Term Consequences ◽  
Water Depths

AbstractThere is an increasing number of studies reporting microplastic (MP) contamination in the Arctic environment. We analysed MP abundance in samples from a marine Arctic ecosystem that has not been investigated in this context and that features a high biodiversity: hollow rhodoliths gouged by the bivalve Hiatella arctica. This bivalve is a filter feeder that potentially accumulates MPs and may therefore reflect MP contamination of the rhodolith ecosystem at northern Svalbard. Our analyses revealed that 100% of the examined specimens were contaminated with MP, ranging between one and 184 MP particles per bivalve in samples from two water depths. Polymer composition and abundance differed strongly between both water depths: samples from 40 m water depth showed a generally higher concentration of MPs and were clearly dominated by polystyrene, samples from 27 m water depth were more balanced in composition, mainly consisting of polyethylene, polyethylene terephthalate, and polypropylene. Long-term consequences of MP contamination in the investigated bivalve species and for the rhodolith bed ecosystem are yet unclear. However, the uptake of MPs may potentially impact H. arctica and consequently its functioning as ecosystem engineers in Arctic rhodolith beds.

A new Antarctic foraminiferal species for detecting climate change in sub-Recent glacier-proximal sediments

2009 ◽  
Vol 21 (5) ◽  
pp. 439-448 ◽  
Author(s):  
Wojciech Majewski ◽  
Andrzej Tatur
Keyword(s):  
Climate Change ◽  
Climate Warming ◽  
The Arctic ◽  
South Shetland Islands ◽  
King George Island ◽  
Tidewater Glaciers ◽  
Admiralty Bay ◽  
Shetland Islands ◽  
Foraminiferal Species ◽  
Water Depths

AbstractCribroelphidium webbi sp. nov. is the only adequately described sub-Recent elphidiid foraminifer from Antarctica. In Admiralty Bay (King George Island, South Shetland Islands), it is found at several locations within inner fiord setting at water depths between 33 and 165 m, but most commonly shallower than 100 m. In outer basins this foraminifer is absent. In the cores analysed, C. webbi sp. nov. is present in well-constrained sub-Recent horizons that are clearly related to climate warming and deglaciation. These horizons represent a diachronous facies marker rather than a single stratigraphic layer. Cribroelphidium webbi sp. nov. shows clear association with retreating tidewater glaciers, therefore it is an important sensitive glacier-proximal indicator. It appears that it shares similar ecologic affinities with Cribroelphidium excavatum clavatum, which is widely distributed throughout the Arctic.

scholarly journals Autonomous Decision-Making While Drilling

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 969
Author(s):  
Eric Cayeux ◽  
Benoît Daireaux ◽  
Adrian Ambrus ◽  
Rodica Mihai ◽  
Liv Carlsen
Keyword(s):  
Decision Making ◽  
Internal State ◽  
Drilling Process ◽  
Autonomous Decision ◽  
Internal States ◽  
Markov Decision ◽  
Drilling Operations ◽  
Drilling System ◽  
Drilling Conditions ◽  
Erratic Behavior

The drilling process is complex because unexpected situations may occur at any time. Furthermore, the drilling system is extremely long and slender, therefore prone to vibrations and often being dominated by long transient periods. Adding the fact that measurements are not well distributed along the drilling system, with the majority of real-time measurements only available at the top side and having only access to very sparse data from downhole, the drilling process is poorly observed therefore making it difficult to use standard control methods. Therefore, to achieve completely autonomous drilling operations, it is necessary to utilize a method that is capable of estimating the internal state of the drilling system from parsimonious information while being able to make decisions that will keep the operation safe but effective. A solution enabling autonomous decision-making while drilling has been developed. It relies on an optimization of the time to reach the section total depth (TD). The estimated time to reach the section TD is decomposed into the effective time spent in conducting the drilling operation and the likely time lost to solve unexpected drilling events. This optimization problem is solved by using a Markov decision process method. Several example scenarios have been run in a virtual rig environment to test the validity of the concept. It is found that the system is capable to adapt itself to various drilling conditions, as for example being aggressive when the operation runs smoothly and the estimated uncertainty of the internal states is low, but also more cautious when the downhole drilling conditions deteriorate or when observations tend to indicate more erratic behavior, which is often observed prior to a drilling event.

Deep Water Scientific Drilling in Lake Malawi, Africa

2006 ◽  
Vol 40 (1) ◽  
pp. 29-35
Author(s):  
K. Moran ◽  
M. Paulson ◽  
M. Lengkeek ◽  
P. Jeffery ◽  
A. Frazer
Keyword(s):  
Deep Water ◽  
Lake Malawi ◽  
Design Work ◽  
Scientific Drilling ◽  
Drilling Rig ◽  
Core Recovery ◽  
Lake Floor ◽  
Drilling System ◽  
Rift Valley Lakes ◽  
First Time

A new deep water drilling system was developed and applied to recover deeply buried sediments for scientific analyses in one of the deep rift valley lakes of Africa—Malawi. This approach overcame the difficulty of maintaining position over a drill site in a remotely located, large, deep lake. Environmental conditions in Lake Malawi are similar to deep water marine settings and, as such, a marine approach was adopted for the Lake Malawi Drilling Project (LMDP). In February and March 2005, the modified pontoon, Viphya, successfully completed a scientific drilling expedition in Lake Malawi. This expedition recovered core at depths greater than 380 m below lake-floor in water depths as great as 600 m. The major refit of Viphya included installation of a moonpool, bridge, crew accommodations, mess, washroom, power system, dynamic positioning, and a drilling system. These major modifications required early pontoon surveys and naval architectural analyses and design work prior to their commencement. The expedition also used modified scientific coring tools with a marine geotechnical drilling rig for the first time, resulting in excellent core recovery and quality.

Numerical Simulations of Ocean Drilling System Behavior With a Surface or a Subsea BOP in Waves and Current

2008 ◽  
Author(s):  
Celso K. Morooka ◽  
Raphael I. Tsukada ◽  
Dustin M. Brandt
Keyword(s):  
System Behavior ◽  
Traditional System ◽  
Drilling Rig ◽  
Advantages And Disadvantages ◽  
Ocean Drilling ◽  
Sea Bottom ◽  
Drilling System ◽  
Drilling Rigs ◽  
High Level ◽  
Drilling Bit

Subsea equipment such as the drilling riser and the subsea Blow-Out Preventer (BOP) are mandatory in traditional systems used in deep sea drilling for ocean floor research and petroleum wellbore construction. The drilling riser is the vertical steel pipe that transfers and guides the drill column and attached drilling bit into a wellbore at the sea bottom. The BOP is used to protect the wellbore against uncontrolled well pressures during the offshore drilling operation. Presently, there is a high level of drilling activity worldwide and in particular in deeper and ultra-deeper waters. This shift in depth necessitates not only faster drilling systems but drilling rigs upgraded with a capacity to drill in the deep water. In this scenario, two general drilling systems are today considered as alternatives: the traditional system with the subsea BOP and the alternate system with the surface BOP. In the present paper, the two systems are initially described in detail, and a numerical simulation in time domain to estimate the system behavior is presented. Simulations of a floating drilling rig coupled with the subsea and surface BOP in waves and current are carried out for a comparison between the two methods. Results are shown for riser and BOP displacements. Critical riser issues for the systems are discussed, comparing results from both drilling system calculations. Conclusions are addressed showing advantages and disadvantages of each drilling system, and indicating how to correct the problems detected on each system.

ADDITIONAL HEAT FLOW DETERMINATIONS IN THE AREA OF MOULD BAY, ARCTIC CANADA

1966 ◽  
Vol 3 (2) ◽  
pp. 237-246 ◽  
Author(s):  
W. S. B. Paterson ◽  
L. K. Law
Keyword(s):  
Heat Flow ◽  
Canadian Arctic ◽  
The Arctic ◽  
Canadian Arctic Archipelago ◽  
General Area ◽  
Geothermal Heat ◽  
Field Methods ◽  
The Mean ◽  
Water Depths ◽  
Made In

Seven determinations of geothermal heat flow were made in the general area of southern Prince Patrick Island in the Canadian Arctic Archipelago. Measurements were made from sea ice in water depths of between 200 and 600 m. The mean heat flow for the two stations on the continental shelf in the Arctic Ocean was 0.46 ± 0.08 μcal cm−2 s−1. The mean heat flow for the five stations in the channels to the east of Mould Bay was 1.46 ± 0.16 μcal cm−2 s−1. The instrument and field methods are described. Errors due to the instrument and to the environment are discussed.

Drilling Riser Disconnection Challenges in Ultra-Deep Water

2018 ◽  
Author(s):  
Alexandre Diezel ◽  
Germain Venero ◽  
Victor Gomes ◽  
Leandro Muniz ◽  
Rafael Fachini ◽  
...  
Keyword(s):  
Good Representation ◽  
Regular Wave ◽  
Computational Simulations ◽  
Successful Operation ◽  
Dynamic Positioning System ◽  
Drilling Rig ◽  
Wave Approach ◽  
Short Period ◽  
Drilling Operations ◽  
The Time Domain

With the extension of the offshore drilling operations to water depths of 10,000 ft and beyond, the technical challenges involved also increased considerably. In this context, the management of the riser integrity through the application of computational simulations is capital to a safe and successful operation — particularly in harsh environments. One of the main challenges associated with keeping the system under safe limits is the recoil behavior in case of a disconnection from the well. The risk that an emergency disconnect procedure can take place during the campaign is imminent, either due to failure of the dynamic positioning system or due to extreme weather in such environments. Recent work [1] in the field of drilling riser dynamic analysis has shown that the recoil behavior of the riser after a disconnection from the bottom can be one of the main drivers of the level of top tension applied. Tension fluctuations can be very large as the vessel heaves, especially in ultra-deep waters where the average level of top tension is already very high. In order to be successful, a safe disconnection must ensure that the applied top tension is sufficient for the Lower Marine Riser Package (LMRP) to lift over the Blow-Out Preventer (BOP) with no risk of interference between the two. This tension should also not exceed a range in which the riser will not buckle due to its own recoil, that the telescopic joint will not collapse and transfer undesirable loads onto the drilling rig or that the tensioning lines will not compress. A good representation of such behavior in computational simulations is therefore very relevant to planning of the drilling campaign. A case study is presented herein, in which a recoil analysis was performed for a water depth of 11,483ft (3,500m). Numerical simulations using a finite element based methodology are applied for solving the transient problem of the riser disconnection in the time domain using a regular wave approach. A detailed hydro-pneumatic tensioning system model is incorporated to properly capture the effect of the anti-recoil valve closure and tension variations relevant during the disconnection. A reduction of conservativism is applied for the regular wave approach, where the maximum vessel heave likely to happen in every 50 waves is applied instead of the usual maximum in 1000 waves approach. ISO/TR 13624-2 [4] states that using the most probable maximum heave in 1000 waves is considered very conservative, as the event of the disconnection takes place in a very short period of time. The challenges inherent to such an extreme site are presented and conclusions are drawn on the influence of the overall level of top tension in the recoil behavior.

Proposition of Operational Maps As Tools for Evaluating Safety During the Emergency Disconnection of Risers

2018 ◽  
Author(s):  
Marcelo Anunciação Jaculli ◽  
José Ricardo Pelaquim Mendes ◽  
Kazuo Miura ◽  
Márcio Yamamoto
Keyword(s):  
Material Properties ◽  
Drilling Fluid ◽  
Environmental Loads ◽  
Finite Elements Modeling ◽  
Sea Bottom ◽  
Open Sea ◽  
Operational Safety ◽  
Waves And Currents ◽  
Drilling Operations ◽  
Water Depths

The construction of subsea wells under deep water depths brought the necessity to understand the behavior of columns on such conditions. These columns can be risers, drill strings or casing strings, which are either being installed by lowering them until they reach the sea bottom and/or inside the well, or they are already connected and fully operational. Since these columns are exposed to the open sea, environmental loads such as waves and currents will affect them. Depending on how harsh these environmental conditions are, drilling operations may be suspended. Therefore, understanding how such loads interact with such columns are of the utmost importance if one wants to ensure operational safety. In this paper, we discuss about the problem of emergency disconnections of risers. The concern of doing an emergency disconnection is fundamental for ensuring operational safety because the well will lose a safety barrier, as the level of the drilling fluid inside the well can no longer be controlled after the riser is disconnected, and thus the fluid cannot maintain its downhole pressure anymore. This work focuses on a finite elements modeling of riser dynamics, with the appropriate applied loads, to verify under which sea conditions the riser must be disconnected. The result of such analysis is called an “operational map”, which displays the maximum values of stress along the riser as a function of different sea conditions. Using the riser material properties, this map can then be divided in two regions — failure and admissible — and thus one can see for which sea conditions the riser must be disconnected to avoid its failure. The contribution of the present study is proposing a methodology to elaborate an operational map for a given riser scenario, from which both failure and admissible regions can be seen for emergency disconnection operations.

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