Innovative Ice Protection for Shallow Water Drilling: Part I — Presentation of the Concept

2006 ◽  
Author(s):  
Arne Gu¨rtner ◽  
Ove Tobias Gudmestad ◽  
Alf To̸rum ◽  
Sveinung Lo̸set
Keyword(s):  
Shallow Water ◽  
Shallow Waters ◽  
Drilling Rig ◽  
Modular Concept ◽  
Drilling Operations ◽  
Drifting Ice ◽  
Ice Impacts ◽  
Jack Up ◽  
Near Future ◽  
Ice Period

Recent discoveries of hydrocarbons in the shallow waters of the Northern Caspian Sea arise the need for intensive drilling activities to be carried out in the near future in order to explore the potentials. Experience with mobile drilling units in the seasonally ice infested waters solely originates from the current drilling campaign of the Sunkar drilling barge at Kashagan and Kalamkas. However, with increased drilling activities upcoming, innovative drilling concepts are desirable due to the objective of maintaining drilling operations during the ice period with conventional non-ice-resistant drilling platforms. Hence, this paper suggests the employment of external Shoulder Ice Barriers (SIBs) to protect a conventional jack-up drilling rig from the hazards of drifting ice in shallow water. The SIB’s design is suggested to increase the ice rubble generation at the ice facing slope and thereby provide sufficient protection from drifting ice impacts. The modular concept of the SIB makes it possible to deploy each module in a floating mode to site, whereupon they are ballasted and connected to each other, forming a sheltered position for the jack-up. Subsequent to the termination of the drilling campaign the SIB modules may be retrieved by de-ballasting and tow out, without having significant impact on the environment. This paper presents, on a technical feasible level, the concept of ice protection in shallow water by means of SIBs.

Instrumented Wellhead Load Relief System for Shallow Water Arctic Conditions: Paper 1 — System Design, Installation and Preliminary Results

2018 ◽  
Author(s):  
Scott Benson ◽  
Massimiliano Russo ◽  
Eivind Rasten ◽  
Ward Avery ◽  
Paul LeGrow ◽  
...  
Keyword(s):  
Shallow Water ◽  
Data Gathering ◽  
Processing System ◽  
Field Extension ◽  
Grand Banks ◽  
Oil Companies ◽  
Drilling Rig ◽  
Load Relief ◽  
Drilling Operations ◽  
High Level

In recent years, lower oil prices have forced many oil companies to reduce capex costs by revitalizing brown fields, rather than developing new green fields. At the same time, the offshore drilling rig market has seen many old rigs, typically used for shallow water operations, being scrapped, leaving new generation, deep and ultra-deep water MODUs as the only viable option for new drilling campaigns. Based on the above, wellhead fatigue on older assets, especially in harsh, shallow water environments, has started to gain a central role during the planning phases of workover and intervention operations. In recent years, Suncor Energy began investigating an extension to its Terra Nova field, which began production in 2002. The field uses subsea wells tied back to an FPSO which is moored in 95m of water off Canada’s eastern Grand Banks, an area frequented by icebergs. Drilling operations for the field extension were planned to commence in summer 2017, and continue with a year-round drilling campaign using a Cat 6 MODU. Since the extension would involve sidetracks and interventions from existing wellheads, a series of wellhead fatigue studies were undertaken using a variety of industry recognized methodologies [1] to understand the levels of fatigue accumulation. Although there has been no evidence of wellhead fatigue damage, Suncor chose to take a very prudent and proactive approach, aimed at minimizing fatigue, and maintaining fatigue life for potential future drilling operations. An Instrumented Wellhead Load Relief (iWLR) system was installed, which is designed to restrain BOP motions, thereby reducing the wellhead loads considerably. The load reduction system virtually eliminates additional fatigue accumulation for the planned operations. Additionally, the instrumentation system enables the precise monitoring and tracking of loads applied at the wellhead for future analysis. This paper describes the engineering challenges needed to develop and install the iWLR system in a harsh, shallow water, arctic environment. This area is characterized by very stiff soils pitted with iceberg scours, where subsea equipment must be protected within 10m deep excavated drill centers to prevent iceberg collisions in the relatively shallow water. Additionally, the paper describes how the instrumentation system was integrated with the BOP MUX cable communication system, for the first time, to enable real time monitoring of BOP motions using high accuracy gyroscopes and load cells which monitor dynamic iWLR tether forces. A topside data gathering and processing system was developed to present wellhead loads based on the indirect method, with new algorithms established to account for the tether forces. Finally, the paper presents some preliminary high-level results, showing the efficiency of the system based on measured data.

GOODWYN ‘A’ DRILLING FACILITIES

1993 ◽  
Vol 33 (1) ◽  
pp. 343
Author(s):  
Derek C. Morrow ◽  
Nick E. Jackson
Keyword(s):  
Modular Design ◽  
High Capacity ◽  
Cost Savings ◽  
High Standard ◽  
Drilling Rig ◽  
Contract Administration ◽  
Modular Concept ◽  
Drilling Operations ◽  
Drilling Rigs ◽  
Safety Systems

The Drilling Facilities Package designed and developed by Atwood Oceanics Australia Pty. Ltd. for operation on Woodside Offshore Petroleum Pty. Ltd.'s Goodwyn 'A' Platform will break new ground in the development and application of offshore modular drilling rig technology when commencement of offshore drilling is achieved. These facilities are among the largest, specifically designed, offshore demountable drilling rigs in the world today.Initially, Woodside performed sufficient engineering to determine a design specification for the Drilling Facilities which detailed the types of equipment necessary and the final performance characteristics required by the finished facility to drill the Goodwyn 'A' production wells.Following award of the Drilling Facilities Contract to Atwood Oceanics in 1989, Woodside's role was essentially related to technical interface and contract administration management. The responsibility for the design, fabrication, commissioning and operation of the Drilling Facilities lay with Atwood Oceanics.The Drilling Facilities consist of fifty-two (52) small modules, each weighing up to 105 tonne. These modules are assembled into three (3) major structural packages, these being the Drilling Support Facilities, weighing some 1300 tonne, the Sub-Base weighing 1100 tonne and the Derrick weighing 260 tonne. Total operating weight of the facilities will exceed 4500 tonne.The modular design of these facilities was developed by Atwood Oceanics from previous modular rig design of relatively simple facilities and technical scope, up to the high capacity, technical complexity and flexibility in design demanded for operation on the Goodwyn 'A' Platform. Following the issue of the Cullen Report on the Piper Alpha Disaster, extensive control and monitoring safety systems were included in the design. These systems have had an adverse impact on the modular concept due to the large increase in electrical interfaces, however the modular concept remains sound and viable.Modular rig design has allowed a Drilling Facility to be developed which has accrued savings in design, fabrication, fit-out, transport and installation and has resulted in reduced overall installed weight. These savings are real and demonstrable when compared with conventional large-module drilling rig packages of similar scope and complexity. Unlike its North Rankin 'A' development, Woodside elected to have the Drilling Facilities for Goodwyn 'A' designed, procured, fabricated and commissioned by an experienced drilling contractor, who will then operate and maintain the rig during the drilling phase (P.Scott et al., 1991). Woodside will realise substantial cost savings at the point when the facilities are installed and ready to drill. Further savings will accrue during drilling operations by allowing the drilling contractor more autonomy and responsibility (eg. maintenance of the complete drilling facilities will be by contractor personnel).The relative ease of removal of the facilities and potential for re-use on other installations will generate additional significant cost benefits in the future.The Drilling Facilities are state-of-the-art in their applied technology and are capable of year-round, self-contained operation for the drilling of highly deviated, long reach wells of up to 72° deviation from the vertical and up to 7000 m along hole depth.This paper provides an overview of the design, fabrication, fit-out, onshore commissioning, transport and installation of the modules which comprise the Goodwyn 'A' Drilling Facilities, for which Atwood Oceanics were awarded a Commendation for a High Standard of Engineering Achievement at the Institution of Engineers, Australia 1992 Engineering Excellence Awards.

Operational Challenges for Drilling Shallow Water Wells With Dynamically Positioned Rigs

2020 ◽  
Author(s):  
Rohit Vaidya ◽  
Mahesh Sonawane
Keyword(s):  
Shallow Water ◽  
Weak Link ◽  
Mitigation Options ◽  
Drilling Rig ◽  
Water Wells ◽  
Fatigue Monitoring ◽  
Drilling Operations ◽  
Drilling Rigs ◽  
New Generation ◽  
Selection Of

Abstract Traditionally, shallow water wells have been drilled from fixed platforms, jack-ups or moored drilling rigs. Recently there has been increased interest in performing operations on these wells using new generation of Dynamically Positioned (DP) rigs, driven by available capacity of these rigs and environmental regulations that restrict laying anchors on the seabed. Shallow water offshore drilling operations present a set of unique challenges and these challenges are further amplified when operations are performed on older wells with legacy conductor hardware with newer DP vessels and larger BOPs. The objective of the paper is to present challenges that occur during drilling in shallow water and discuss mitigation options to make these operations feasible through a series of case studies. Key challenges to optimizing riser operability and rig uptime are discussed. Potential modifications to the upper riser stack-up and rig deck structure for maximizing operational uptime are discussed. Riser system weak point assessment is presented along with solutions for mitigating risks in case the wellhead or conductor structural pipe is identified as the weak link. Selection of the drilling rig can have significant impact on wellhead fatigue response. Some criteria for rig selection based on drilling riser and wellhead system performance is presented with the objective of optimizing the fatigue performance of the wellhead and conductor system. Wellhead fatigue monitoring solutions in combination with physical fatigue mitigation options are presented to enable operations for fatigue critical wells.

Experimental Study of a Tanker Ship Squat in Shallow Water

2014 ◽  
Vol 66 (2) ◽  
Author(s):  
Mohammadreza Fathi Kazerooni ◽  
Mohammad Saeed Seif
Keyword(s):  
Experimental Study ◽  
Shallow Water ◽  
Experimental Approach ◽  
Model Tests ◽  
Ship Hull ◽  
Experimental Results ◽  
Shallow Waters ◽  
Towing Tank ◽  
Ship Model

One of the phenomena restricting the tanker navigation in shallow waters is reduction of under keel clearance in the terms of sinkage and dynamic trim that is called squatting. According to the complexity of flow around ship hull, one of the best methods to predict the ship squat is experimental approach based on model tests in the towing tank. In this study model tests for tanker ship model had been held in the towing tank and squat of the model are measured and analyzed. Based on experimental results suitable formulae for prediction of these types of ship squat in fairways are obtained.

MODELING MOVING BOUNDARY IN SHALLOW WATER BY LBM

2013 ◽  
Vol 24 (01) ◽  
pp. 1250094 ◽  
Author(s):  
Y. PENG ◽  
J. G. ZHOU ◽  
J. M. ZHANG ◽  
R. BURROWS
Keyword(s):  
Shallow Water ◽  
Present Model ◽  
Moving Boundary ◽  
Lattice Boltzmann Model ◽  
Shallow Waters ◽  
Shallow Water Flows ◽  
Moving Body ◽  
Body Boundary ◽  
Multiple Relaxation Time ◽  
Boltzmann Model

A lattice Boltzmann model (LBM) for a moving body in shallow waters is developed. Three different schemes, FH's, Guo's and MMP's schemes, for a curved boundary condition at second-order accuracy are used in the study and compared in detail. The multiple-relaxation-time (MRT) is adopted for better stability. In order to deal with the moving body boundary, a certain momentum is added to reflect the interaction between the fluid and the solid; and a refill method for new wetted nodes moving out from solid nodes has been proposed. The described method is applied to simulate static and moving cylinders in shallow waters. The corresponding experiments are further performed for validation of the present model. It is found that all of the three schemes produce similar results that agree well with the experimental data for the static cylinder. However, for the moving boundary, MMP's scheme performs best. Overall, the proposed modeling approach is able to simulate both, static and moving cylinders in shallow water flows at acceptable accuracy.

Quantification of Bioerosion by Sphaerechinus Granularis on ‘Coralugène’ Concretions of the Western Mediterranean

1997 ◽  
Vol 77 (2) ◽  
pp. 565-568 ◽  
Author(s):  
Stephane Sartoretto ◽  
Patrice Francour
Keyword(s):  
Shallow Water ◽  
Small Diameter ◽  
Western Mediterranean ◽  
Biological Agent ◽  
High Abundance ◽  
Shallow Waters ◽  
Mean Diameter ◽  
The Mean ◽  
The Mediterranean

Sphaerechinus granularis (Echinodermata: Echinidea) is involved in the erosion of ‘coralligène’ concretions in the Mediterranean. In shallow water (10 m), a high abundance of this species (>20 ind 25 m−2) is associated with small diameter individuals (56·7 ±7·7 mm). In deep clean waters (>40 m), the abundance is lower (<1 ind 25 m−2) and the mean diameter is higher (86·0±9·3 mm). Daily erosion of Corallinaceae by this species is related to the urchin diameter (r=0.87). Local variations in urchin abundance and diameter influence the amount of CaCO3 eroded annually. In shallow waters, the eroded CaCO3 mass reaches 210 g m−2 y−1 vs 16 g m−2 y−1 in coralligène concretions in deep clean waters. Sphaerechinus granularis is an important biological agent which substantially erodes the Mediterranean coralligène concretions.

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.

Life history of Mysis stenolepis Smith (Crustacea, Mysidacea)

1975 ◽  
Vol 53 (7) ◽  
pp. 942-952 ◽  
Author(s):  
T. Amaratunga ◽  
S. Corey
Keyword(s):  
Young Adults ◽  
Life History ◽  
New Brunswick ◽  
Shallow Water ◽  
Field Study ◽  
Sexual Maturity ◽  
Developmental Stages ◽  
Shallow Waters ◽  
Passamaquoddy Bay ◽  
History Of

A 17-month field study showed that Mysis stenolepis in Passamaquoddy Bay, New Brunswick lives for about 1 year. Young are released in shallow water early in spring and grow rapidly during the summer. In the fall, young adults migrate to deeper water where they reach sexual maturity. Transfer of sperm lakes place during winter in deeper regions of the Bay. soon after which the males die. Females survive and in spring migrate to shallow waters to release young after which they die. Females breed once and carry an average of 157 young per brood. Developmental stages of the postmarsupial young are described and discussed.

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