bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concrete Repairs With Corrosion Protection: An Economical Alternative To Platform Replacement
Authors: Sgouros G.E. , Webster T.E. , Hennegan N.M. 
Published: October 2008

ABSTRACT
The combination of structural repairs and galvanic (sacrificial) cathodic protection has extended the service life of an offshore reinforced concrete platform by 10 to 15 years. The 18-year-old structure had suffered severe corrosion-related deterioration because of shortcomings of the original design and exposure to both seawater and high-chloride brine leakage from the waterflood injection facilities.
Several innovative repair techniques were used. The underwater sections of the columns were repaired using preplaced aggregate concrete. Embedded zinc anodes were used to protect the above and underwater portions of the reinforcement in the columns. The deck was repaired using cast-in-place concrete or shotcrete, and its underside was sprayed with metallized zinc for cathodic protection of the reinforcement.
Other reinforced concrete platforms in the Gulf of Mexico have been protected with impressed current cathodic protection1. However, we believe this is the first application of galvanic cathodic protection on an offshore reinforced concrete platform in the Gulf of Mexico. This project proved that properly planned and executed concrete repairs can offer a much faster and economical alternative compared to replacement, even for severely deteriorated structures.

DESCRIPTION AND FUNCTION OF THE WATERFLOOD PLATFORM
The waterflood platform at Main Pass 69, about 20 miles east of Venice, Louisiana, is a concrete barge which was installed in 1972 for Shell Oil Company. The purpose of this facility is to support waterflood equipment which filters and reinjects water into underlying oil-bearing formations to maintain reservoir pressure and help sweep residual oil out of the ground.
An overall view of the concrete barge is shown in Figure 1. The barge has a 45 ft. by 37 ft. deck area which is supported by 24 straight and 8 battered 16 in. diameter columns on a hollow concrete base of 45 ft. by 45 ft. by 12 ft. The vertical clearance between the two decks is 19 ft. 8 in., which was designed to provide 2.7 ft. of air gap during hurricanes. The dead weight of the structure excluding buoyancy was estimated to be 710 kips. The operational weight of the equipment on the deck was estimated to be 210 kips.
The barge was constructed onshore using lightweight cast-in-place concrete, floated to the location and set on the bottom in about 2 ft. of water by flooding the base section. Draft of the barge and deck during tow was estimated to be 6.25 ft. A channel to the site as well as a 65 ft. square area (16 ft. below the mudline) at the site were dredged for the installation. (The dredged area at the site was backfilled with clam shells before lowering the barge.) The final elevation of the barge bottom was 8 ft. below mudline. Four 24 in. diameter 50 ft. long corner pin piles were driven to help secure the barge in place.
Diverless Intervention Ball Valve System
Authors: Steele John 
Published: October 2008

ABSTRACT
This paper describes the application, design, research and development and field data for Diverless Intervention Insert Ball Valve design. With the ever increasing demand to develop subsea oil and gas fields in deeper water, it has become necessary to subdivide the insert valve range into a valve design which is "diver maintainable" and valves with inserts which can only be recovered using remotely operated tool systems. These remotely operated systems have been designated as DIVERLESS INTERVENTION systems.
The innovative design of the Diverless Intervention Ball Valve provides a new dimension in ball valve technology. Specifically designed for topside and subsea piping systems, the new insert design allows ball, seats, stem, trunnion and seals to be self contained in an insert. The unique one piece unit inserts into a valve housing which can be welded or flanged in the pipeline, allowing the field repairable insert to be easily removed from the housing should future maintenance be necessary.

INTRODUCTION
World-wide oil and gas production through necessity is moving towards an increase in the exploration of deep water fields (over 300 metres deep). In conjunction with this and for commercial exploitation of small fields, we can see an increase in subsea tie-ins back to existing production platforms. These changes in subsea exploration necessitate the need for new technology in all aspects of diverless intervention systems. This paper describes and details a very important part of this new technology. The TK Diverless Intervention Ball Valve design is state-of-the-art in valve technology and also a world first.

INSERT DESIGN APPLICATION AND IN SERVICE DATA
Main applications for insert ball valve technology are predominately for subsea systems. An example of applications are as follows:ESDV (Emergency Shutdown Valve) Subsea Template Isolation/Diversion Block Valves for Import/Export Lines.
At this time TK insert valves are in operation in both United Kingdom and Norwegian sectors of the North Sea.

DIVER MAINTAINABLE
A 16"class 1500 metal seated insert ball valve was installed spring 1990 and commissioned autumn 1990. The valve application is emergency shutdown on the main platform gas transfer line between platforms B & A in the Beryl field.

DIVERLESS INTERVENTION
9" class 5000 metal seated insert ball valves were installed summer 1992 commissioned (subsea) autumn 1992. Valve application is isolation/diversion for production templates located in the Loke and Sliepner East fields.

DIVERLESS INTERVENTION APPLICATION - STATFJORD SATELLITE FIELD
Insert ball valves 9 class 5000 will be utilized for (production and injection) templates (Fig. 5) isolation on Statfjord North and East fields (Fig. 9 and 10), in over 300 metres depth of water. Production from both fields is pipelined to the Statfjord "C" platform.
Two valves are installed on each template (Fig. 5) one valve on each template has been designed for hydraulic actuation at a later date.
Computation Of Hydrodynamic Damping Coefficients At Low Keulegan Carpenter Numbers
Authors: Dalton Charles , Sun Xiaohua , Zhang Jianfeng , Zhuang Lixian 
Published: October 2008

ABSTRACT
This paper presents the results of a numerical calculation of the drag coefficient on a circular cylinder in planar oscillatory flow at low Keulegan-Carpenter numbers. This calculation represents the classical hydrodynamic damping problem. The two dimensional time-dependent stream-function/vorticity equations for an incompressible fluid are solved by a finite-difference procedure. The drag coefficient values are determined through an integration of the pressure and shear stress around the surface of the cylinder. The results show that the Stokes-Wang result is duplicated at ? =1035 (? = d2/vT, where d is the cylinder diamter, T is the period of the flow oscillation, and v is the kinematic viscosity of the fluid). For values of ? as high as 130,000, the calculated drag coefficients agree closely with experimental values.

INTRODUCTION
The hydrodynamic damping of moving bodies is important in several areas of offshore engineering. Small amplitude, high frequency oscillations can occur in situations involving marine riser vibrations, the oscillations of the tethers on compliant structures, etc. The prediction of fatigue and the analysis of the dynamic behavior of a moving structure require an understanding of hydrodynamic damping. The accurate prediction of damping is then an important factor in describing platform motions and, therefore, in accomplishing platform design. Our analysis considers damping due to viscous effects on small bodies only; radiation damping will not be considered in this study.
Understanding of the fluid motion generated by a body undergoing sinusoidal oscillations is the first step in determining the hydrodynamic damping. The flow field can be characterized by two of the following parameters: KC =Umax T/d =2?a/d, Re =Umax d/v and ? =Re/KC =d2/uT, where Umax is the maximum oscillatory velocity, T is the period of oscillation, d is the diameter, u is the kinematic viscosity, and a is the amplitude of oscillation. In the above definition, KC is the Keulegan-Carpenter number, Re is the maximum velocity Reynolds number and ? is the frequency parameter. For small KC (KC &lt; &lt;l) and large ? (?&gt; &gt; 1), the drag coefficient can be predicted by the Stokes-Wang law, (Mathematic equation)(available in full paper)
The Stokes-Wang drag coefficient is developed from the Navier-Stokes equations in the absence of the convective terms which were taken to be negligible, an assumption which is applicable only for low values of KC. When KC increases, the convective terms increase in magnitude and the Stokes-Wang law no longer adequately represents the solution. The higher KC problem has no analytical solution; therefore, the force description is based on experimentally determined coefficients. The conventional force description is given by the Morison equation which typically represents the force on a fixed cylinder due to an oscillating fluid. The Morison equation decomposes the instantaneous force into a linear sum the drag and inertia forces.
An Experimental Study Of Tendon/Riser Pairs In Waves
Authors: Duggal A.S. , Niedzwecki J.M. 
Published: October 2008

Abstract
Results from a large-scale experimental study to investigate wave interaction with single and paired flexible cylinders are presented. The cylinders were designed to be representative of TLP risers or tendons in 1006 m (3000 ft) of water. The data from the single cylinder tests illustrates the complex, multi-modal nature of the response. Direct comparison of the experimental data with Morison equation based finite element simulations are presented. Analysis of the paired cylinder data shows the importance of modeling the hydrodynamic interference between the cylinders. The importance of accounting for the non-Gaussian nature of the relative displacement between the cylinders in the prediction of collisions between the cylinders is discussed.

Introduction
With the design and construction of Tension Leg Platforms (TLP) in water depths of 914"3048 m (3000" 10,000 ft), the response of the flexible, tubular members like the tendons and risers become an increasing concern. The tendons and risers are subjected to loading due to waves and currents, as well as the motions of the hull of the platform. These structural members have diameters ranging from about 0.25"1 m (0.83"3.28 ft) and are supported by the tension applied at the top. Structurally, due to their low bending stiffness these members can be thought of as strings. The dynamic behavior of a string is characterized by an infinite number of modes with a modal separation equal to the fist natural frequency. This becomes important as an increase in water depth typically implies a larger number of natural frequencies in the range of excitation. This cam lead to a complicated multi-modal response and is further complicated by the arrangement of these flexible members in groups in close proximity with one another. Due to the presence of the other members, the flow kinematics can be modified leading to modifications of the loading in magnitude, frequency and phase, which then influences the response. For members in close proximity, this complicated response phenomenon can lead to extreme excursions resulting in collisions between the cylinders. This leads to design considerations like how to determine the response of these risers and tendons, and how closely spaced can they be placed before the threat of collisions becomes important. To investigate this phenomenon, a research study into the fundamental and applied aspects of wave interaction with flexible cylinders was undertaken at the Offshore Technology Research Center, Texas A&M University. The study involved a complementary experimental and analytical investigation of regular and random surface wave interaction with a pair of flexible cylinders representative of TLP risers or tendonsin 1006 m(3300 ft) of water (Duggal 1992). The research study was divided into three phases.
Deepwater Subsea Completion: State Of The Art And Future Trends
Authors: Ribeiro O.J.S. , Costa L.A.G. 
Published: October 2008

ABSTRACT
This paper describes the state of the art of deep water subsea completion techniques and equipment, showing the milestones that were reached through the completion of wells placed in water depths beyond 700 m, namely MARLIM 03, 06, 07, 08, and 09 (the latter being the current subsea completion record, in 781 m). It also shows the expertise developed through the design and manufacturing of equipment to operate in water depths up to 1,800 m, as well as the future trends in subsea completion. The First End Vertical Connection, Tubing Packer Hanger, Shear able Riser Joint, Integrated Drilling and Completion Base (BINT), and the future use of centrifugal submersible pumps in subsea wells are some examples of the technical innovations that are currently being introduced.

INTRODUCTION
Since 1984, PETROBRAS' most significant oil finds are located in deep waters, beyond 300m. The Albacora and Marlim fields were followed by the Salema, Bijupira, Barracuda and the 382 Area fields, among others. Motivated by these discoveries, the company has been employing efforts to obtain the technological capability to produce economically and safely the immense reserves already discovered in water depths of up to 2,000 m.
In this search for technological capability stand out the PROC.AP program, the Petrobras Technological Development Program on Deepwater Production Systems. The 6 years program that ended in 1991, allowed a coordinated and integrated action between all the different company's departments, suppliers and R&D Centers at low cost and within the time frame the company demanded.
Deepwater production is a vital issue for Petrobras, because although presently only 8% of the average crude production (650,000 bpd) comes from wells that are located deeper than 400 m of water depth, this figure is expected to reach 61% by 2001 (barring any onshore or shallow water discovery). Furthermore, the deepwater fields account for 66% of total proved and potential hydrocarbons reserves in Brazil.
This paper shows the state of the art of the Deepwater Completion Technology, achieved through the PROCAP or via products jointly developed by the Petrobras' Production Department and its suppliers, as well as the innovations that are that are being currently introduced and the future trends in the area.

STATE OF THE ART

COMPLETION OF THE MARLIM FIELD WELLS
In March, 1991 the 3-MRL-3-RJS well was completed in 721 m water depth with a subsea Christmas tree specially designed for operations with a dynamically positioned (DP) drilling unit without guidelines. The success of the operation, the first in the world at that time, confirmed the technical feasibility of the lay-away operation with DP units and the following items summarize the main achievements:Subsea completion water depth record 721 m (2,365 ft)World's first purpose built guidelineless (GLL) lay-away subsea tree installedFirst well drilled with a DP rig completed in the world
Production Subsea Installations Control And Supervision Electronic Systems Development
Authors: Pinho F. O.J. , Sampaio D.S. 
Published: October 2008

ABSTRACT
This paper intends to present not only a supervision and control subsea electronic system development history in the PETROBRAS Production Department, but also their architecture, basic characteristics and offshore operational results.
The aimed projects are:
MUXCOM: The MUXCOM project, conducted by PETROBRÁS and BRASNOR, a PETROBRÁs affiliate company in Norway, has developed an electro-hydraulic multiplexed control system, which has been installed at Bonito-n production wel1 in Campos Basin, Brazi1, and is under uninterrupted operation since November/1990.
SESCO: As a MUXCOM evolution, it was developed by PETROBRAS a second Supervision and Control Electronic System (SESCO " Sistema EletrÔnico de Supervisao e Controle) for application at "OCTOS-1OOO, a subsea production template-manifold, composed by seven "X-mas trees" and also developed by PETROBRÁS. The communication between the surface unit and the seven subsea units is done trough a two-wire network. The subsea units power supply is done by the communication signal, itself. The system is also able to be integrated to the P1atform Central Supervision and Control Station (ECOS), what permits the OCTOS-1OOOoperation from the rig main control console.

MUXCOM PROJECT
The MUXCOM (Multiplexed Control and Monitoring) projects was part of PETROBRÁS "Deep Water Capability Program"(PROCAP) and its main objective was the identification of critical points and cost allocation of a subsea control system designed to operate at 1000 m water depth. The program should also provide the basis for a control system more suitable for the Brazilian scenario.
Reliability is the most important requirement when dealing with subsea production control systems, but some other points 1ike versatility and cost efficacy are important as well.
The project development was based on wel1 tested standard components with good field records in order to reduce cost and failures risk and, therefore, extensive testing at component 1evel was not required. However, a 1ot of tests were carried out to ensure that al1 of them could work together in the proposed configuration and submitted to 100 bar external pressure.
Special attention was paid to some critical components 1ike hydraulic and electrical connectors and solenoids valves.

MUXCOM'S ELECTRONICS
During the MUXCOM project conceptual development phase, a market survey was carried out to verify the feasibility of introducing a market available electronics into the system and so reducing the cost and time of developing it by ourselves.
It was concluded, after sane inquiries, that there was no electronic package available in the market able to fulfill our requirements and to fit the project budget. It was also considered that the effort that should be spent in order to modify and to adapt the market available electronic system to our application would be almost so high as developing a brand new and dedicated one.
Therefore, it was decided to go into a dedicated electronic system development from scratch.
A Fully Compensated High-Pressure Riser Telescope
Authors: Nergaard Arnfinn , Freyer Jan 
Published: October 2008

Abstract:
Riser technology is a key element in the ever increasing number of mobile floating production and subsea well inlervention vessels. When there is a requirement for vertical access though pressurised conduits, the relative motion needs to be catered for by tensioning compensation systems. This paper describes u new approach in which relative motion problems are solved in the riser itself This is achieved through application of a new design telescope that strokes without changing volume or internal pressure. When applying this principle in a production or intervention riser, topside mounted equipment can be fixed on the deck of the floater.

Background
The Petroleum Industry presently faces the challenge of developing smaller fields in deeper waters. In addition we see smaller fields being made commercial by increasing the production over shorter field life. These factors favour developments bused on mobile and/or reusable systems, of which ships and semisubmersibles will represent a major part. The main difference between a fixed and a floating platform is the relative motion between the seabed and the floater.
A point on the floater translates and accelerates along all three axes of freedom relative 10 a point on the seabed. In addition the floater rotates around the same three axes. All connections between the vessel and the seabed need to h designed with this in mind. A floating production system may be based on WC1lSbeing remote or located under the floater. In the latter ease the system is in function comparable to a fully integrated fixed PDQ (Production, Drilling, Quarters) platform. The platform also drills and works over the wells. The basic configuration for this case (when disregarding the Tension Leg Platform (lZP) system) is subsea x-mas trees located on the seabed under the floater. The connections between the vessel and seabed arc generally three main kinds; mooring lines, well extension conduits (production and annulus) and WCI1control lines (electric and hydraulic). See figure I - Basic Floating Production System.
There are two basically different ways to configure risers or connecting lines; a vertical "straight" line or a free-hanging catenary based system. A vertical system needs some sort of compensation to cater for relative motion. For the catenary based systems a number of different configurations have been developed. Examples arc; straight catenarics (anchor lines, flexible risers, control lines), and sleep and lazy S-curve configurations.
The vertical line can be a pure mechanical connection like a guideline that is compensated for motion by a constant tension winch. The basically important and absolutely necessary vertical system is the tieback of the well-bore for well establishment, intervention and maintenance. In that case it is a stiff and rigid connection and it needs to be compensated for motion and tensioned for the weight of the system itself. This applies mainly to drilling risers, workover risers or production risers.