bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use Of Fracture Mechanics In Tubular Connexions Fatigue Crack Growth
Authors: Putot Claude J. , Truchon Michel L. , Nguyen Quoc S. 
Published: October 2008

ABSTRACT
The experimental studies carried out by IRSID within the framework of a larger european program, are backed up by a French program of theoretical and numerical studies. The purpose of this program is to relate the results obtained in the test specimen experiments to the behavior observed on large scale tubular joints tested in fatigue fracture mechanics. This paper gives some of the results and trends obtained, with the help of which it should be possible to make better life predictions than those in common use.

INTRODUCTION
Leaving aside the effects of corrosion which are by themselves the subject of numerous studies, the following basic information is required to enable the behavior of a joint working in fatigue to be interpreted:The character of fatigue crack propagation obtained by means of classic experiments performed in the parent material as well as in the heat affected zone (HAZ).Verification that the propagation laws, thus obtained, apply to cracks with curved fronts.The influence of biaxial and bimodal effects, always present during crack propagation in a tubular joint.
The experimental work was carried out on a E36-Z steel (AFNOR standard) which is generally used in the construction of offshore platforms. This material was hot-rolled into plates of 20, 40 and 75 mm thicknesses. Its chemical composition and mechanical properties are given in tables I and 2.

PROPAGATION IN A CLASSICAL TEST SPECIMEN
Figure 1 shows tests carried out on 20 mm and 40 mm thick C.T. specimens machined out in the longitudinal direction. The slope of the regression line is 4.3. Figure 1 also shows the-fatigue crack growth rate measured with CT specimens machined out in the short transverse direction. The slope is 3.1 - All these tests were performed with a stress ratio of 0.1.

In the heat affected zone (HAZ)
In a first set of tests C.T. test pieces were cut out of 40 mm thick welded joints so that the crack propagated in the H.A.Z. in a plane close to that describing the limit of the weld perpendicular to the plate: cut-out L-T (fig. 2a).
As shown in figure 3 the rates of propagation recorded, in as-welded joints, are for a given level of stress intensity factor, much slower than in the parent material. A second series of tests was worked out to approach the effective geometry of tubular joints. This is the L-S cut-out direction, as shown on figure 2b. The propagation characteristics observed on KF and KT test pieces corresponding to this series of tests, are recorded on figure 3. They show striking parallelism with short transverse results, in spite of a shift between the two regression lines.

Restrictions concerning the Paris line
Regression analysis carried out on 153 pairs of variables (C,m Paris law parameters) proved that Paris lines depend on only one parameter [I].
Dynamic Behaviour Of Platform Cranes
Authors: Balfour James A.D. , Owen David G. 
Published: October 2008

ABSTRACT
Mathematical models of varying complexity are developed to predict forces occurring in a typical offshore platform crane while lifting from a supply boat. Computer programs based upon these models are used to assess the usefulness of these simulations. It is shown that a simple two degrees of freedom model can be usefully employed at the feasibility design stage whereas a more sophisticated multi-degree of freedom model is required for detailed crane design. These programs are used to investigate the influence upon the induced loads of various operational parameters including the load lifted, the jib angle, the line speed and the instantaneous deck velocity. It is concluded that high dynamic loads will frequently arise in such cranes and that specifically written computer programs are necessary for effective derating. or design. A statistical approach to the assessment of supply boat motions is used to show that maximum deck velocities can greatly exceed those predicted by the simpler methods previously used.

INTRODUCTION
As oil and gas exploration moves into more exposed waters supply boats are required to operate in increasingly severe conditions. This means that the dynamic stresses induced in offshore platform cranes lifting from these boats are likely to increase for three different reasons. Firstly, there will be a tendency for supply boats to stand further off from the platform with the consequent increased lifting radii resulting in increased stresses. Secondly, higher stresses will be produced should higher line speeds be used to reduce danger to the supply boat, the supply boat personnel, and the load. Thirdly, larger supply boat motions mean that the effect of a misjudged lift will prove more severe. Since exploration has moved into the North Sea there have been numerous crane failures, and recognition of the dynamic aspect of offshore lifting is given in the derating rules used when lifting in conditions other than a flat calm. In spite of this, the accident statistics for offshore crane operations continue to make sad reading, indicating shortcomings in the derating criteria adopted.
It is self-evident that to design or derate an offshore platform crane effectively a study of the crane's behaviour over a wide range of conditions must be made. Unfortunately, due to the complexity of offshore cranes, an explicit solution is possible only if the crane structure is reduced to a very simple model. Such models have been studied previously (1,2,3" but they tend to give unrealistic results and they fail to give any information about the forces in many of the primary crane components.
For a more realistic prediction of response mathematical models of greater sophistication must be employed. Such models normally use step-by-step numerical techniques to integrate the equations of motion of the structure through the time domain starting from initial, known, conditions. Essentially the conditions at time "t" are used to predict the conditions a short interval of time "ilt" later.
Actual Measurement Of External Forces On Marine Hoses For SPM
Authors: Saito Hideaki , Mochizuki Takao , Fukai Toshio , Okui Kenzo 
Published: October 2008

ABSTRACT
In single point mooring (SPM), the role played by the marine hose system for transporting oil is so essential that if the hose system develops any trouble, it will not only stop the functioning of the transporting of oil but also may cause oil pollution.
It is indispensable for engineers in developing and designing hose to know how much external loads act on the hoses and how the hoses break. In the Catenary-Anchor-Leg-Mooring hose system (CALM), much trouble occurred on the first off-the buoy hose, tail hose and under-buoy hose. Therefore field testing and/or simulated testing by model in a tank for measuring loads on these hoses, was conducted. From this testing, the relationship between waves and external loads could be generally known, and hoses could be designed more suitable for each location.

INTRODUCTION
The SPM comprises floating hose strings from a tanker to a buoy, the buoy, under-buoy hose strings from the buoy to the sea bottom, and a submarine pipe to land for conveying oil.
Recently, stocking crude oil has been increased and the mooring hours of a tanker shortened, so hoses transporting oil must have bores as large as 20" or 24". Thus, in any accident occuring on the hose system, losses might be larger and more serious than for ordinary hose. For this reason, the design must be greatly reliable. Furthermore, conventionary, values of external loads acting on hoses were estimated mainly through experience, and even if a hose developed trouble, the cause was not sufficiently examined.
Therefore, the authors measured the external loads of the first off-the-buoy hose in Tokyo Bay and the tail hose of a storage tanker in Java Sea (Indonesia) in field testing in order to find the external loads usually expected on marine hoses. On the other hand, in order to find how hoses break under such rough conditions at sea as typhoons, simulated testing with a model was conducted for the floating hose and the under-buoy hose in our wave tank. The enormous volume of data obtained by this testing was processed by a data recorder, A-D converter and computer, and many results were obtained.
This report describes test methods, maximum load, minimum bending radius acting on the hoses under various conditions of waves.

FIELD TEST METHODS AND ANALYTICAL METHOD
1. Field testing the first off-the-buoy hose in the sinking and floating hose system at the Keihin Kawasaki seaberth in Tokyo Bay. As shown in Fig. 1, a water-proof spool for measuring external loads was fitted between the buoy-inlet and a 20" first off-the-buoy hose. Strain gauges were attached to the spool in order to measure the bending moments, torsional torques and axial forces; the relation between the load and strain had been calibrated before hand.
Design And Installation Of The Main Pass 72 Mud Slide Resistant Platform
Authors: Irick Jack T. , Birdwell J. Rick , Henkhaus E.J. , Hayes Don A. , Mannina Glenn A. 
Published: October 2008

ABSTRACT
Exxon, U.S.A., has installed a mud slide resistant drilling and production platform in 119 ft. of water in the Main Pass area, block 72. Mud slides as deep as 50 ft. are possible in this area where rapid deposition has produced a weak, unstable, under consolidated clay. The major configurationally difference between this platform and conventional Gulf of Mexico platforms is the four 154 in. diameter jacket legs required to resist the lateral forces caused by soil movement and to form a protective housing for the conductors. The foundation consists of four 144 in. diameter piles with 72 in. diameter insert piles driven in two legs and twelve 22 in. diameter conductor piles inside each of the other two legs. The design and installation of this structure are especially noteworthy due to loads imposed by the unstable bottom conditions of the site.

INTRODUCTION
Exxon's Main Pass 72 platform (Figure 1) is in the state-owned portion of the block and is approximately 6 statute miles from the mouth of Pass A Loutre in water depth of 119 ft. The regional seafloor slope is to the east-northeast and averages0.4°. Under consolidation and high pore pressure have decreased the sediment strength sufficiently to make the delta front prone to mass sediment movements, which are categorized as either creep, slide, or oscillation. Creep is a gradual soil deformation with time, typically associated with a slope. A slide is a sudden movement of a mass of soil down a slope. Oscillation is a cyclic movement of the soil, including both horizontal and vertical motion, driven by wave pressures on the soil surface. Consideration of soil motion in conjunction with the wave loading leads to the design concept of encasing the well conductors within the large diameter leg members. Most other platforms (e.g Reference 1) for mud slide areas have this common design characteristic. However, the platforms are quite different, primarily due to the large array of concepts for jacket and piling installation.
The structural design of Main Pass 72 platform was initiated in 1977. The design goal was to maximize the use of proven technology, particularly that required during the offshore installation.

PHYSICAL FEATURES
The Main Pass 72 platform (Figure 2) was designed to accommodate 24 wells and provide 16,900 sq. ft. of deck space on each of two levels for drilling and production. The platform was designed to be installed in 119 ft. of water and to withstand hurricane storm loads and those additional loads caused by moving soil.
The jacket has four plumb 154 in. diameter legs whose centers in plan form an 85 ft. square. The leg members penetrate 50 ft. into the mud to stabilize the jacket during the early stages of pile driving. Each leg is grouted to a 144 in. diameter pile driven to a penetration of 200 ft.
Hydrodynamic Coefficients For Macrd-Roughnesses
Authors: Nath John H. 
Published: October 2008

ABSTRACT
Consideration is given to the drag of cylinders in fluid flow as influenced from the very large and lumpy roughnesses of marine growths. A means of characterizing the effective diameter is based on the Strouhal number of the roughened cylinder. This can be applied even to cylinders covered with thick accumulations of kelp, or heavy encrustations of mussels or barnacles, or any combinations. Thus, the effective diameter can be a function of Reynolds number. The effective roughness can be evaluated from force measurements. This paper presents results from measurements on laboratory models of marine growth roughened cylinders.

INTRODUCTION
A considerable fund of evidence has been developed on the force transfer coefficients for smooth and sand roughened circular cylinders in steady and unsteady ambient flow. In particular, the offshore industry and the U. S. government have sparked a considerable effort on the very complicated problem of determining wave and current forces on platforms at sea. It would be futile in the space alloted here to try to review the large number of reportings of others on this subject. Suffice it to say that the recent works of Borgman, Chakrabarti, Dalrymple, Dean, Garrison, Hudspeth, Keulegan and Carpenter, Morison et al, Sarpkaya and Wiegel (arranged in alphabetical order) and many others, have contributed greatly to the understanding of cylinders in the drag, drag/inertia and inertia regimes. Only the work of others that has direct bearing on a particular subject in question will be referenced in this paper. Even so, much work of others will be omitted and no doubt even overlooked. I apologize if anyone feels slighted and say at the outset that applicable work not mentioned herein and later brought to my attention will be much appreciated.
This paper presents the results of some studies on heavily roughened cylinders in steady flow. A relatively smooth cylinder was tested and a sand roughened cylinder in order to establish a "ground truth." This is part of a larger study presently in progress at Oregon State University of macro-roughened cylinders in waves and in oscillatory flow. However, testing is still in progress at this writing and results are not yet available for publication. (References, etc. at end of paper).
Heideman, et al (2) show a plot of the post-critical steady flow drag coefficient as a function of relative roughness, k/D, where k is the height of the roughness elements and D is the smooth cylinder diameter. It is reproduced here as Fig. 1 to illustrate that the drag coefficient still increases with increasing k/D at the limit of the plot, where k/D has a value of about 0.05 or so. However, it is known that marine growth thickness in the Santa Barbara channel (for at least one place) can be greater than one foot in the near surface levels on structural members greater than, say, two or more feet in diameter. One 3/8" steel wire rope, observed by the author and his diving partner, supported growth that had an approximate circumference of 2.2 feet.
The Variable Bore Ram - Present And Future
Authors: Williams Bolie C. 
Published: October 2008

Introduction
Variable bore blowout preventer rams are a relatively new development. Since these rams increase the flexibility of the ram-type BOP substantially, they have become the subject of considerable current interest. This paper contains general background information on the variable bore ram (VBR), as well as discussions of the advantages and limitations which are to be considered when specifying BOP equipment and when designing and implementing well control procedures using VBRs.

DESCRIPTION
A variable bore ram (VBR) enables a ram-type BOP to close and seal on more than one size pipe. This is in contrast to the standard pipe ram which is designed to seal on only one size pipe. In the standard pipe ram, the elastomeric packing material is supported against extrusion by rigid steel plates which are shaped to fit closely around the pipe. In VBRs the elastomer is contained by a series of segmented inserts which cooperate to conform to any of several pipe sizes as well as tool joints, kellies and other parts of the drill string whose size lies within the range of the VBR.
VBR packers are actuated in the same manner as standard pipe ram packers. The packers extend forward of the ram block faces. When the rams are closed, the packers contact each other on the leading surfaces at the sides of the pipe bore. As the rams continue to close, the elastomer in the packers is displaced inward against the pipe. In standard pipe rams, the packers extend forward of the ram block faces only a fraction of an inch since the elastomer is only required to "feed" inward sufficiently to replace material lost through wear. In the case of the VBR however, much more radial displacement is required. There must be enough displacement to cover the pipe size range of the ram, plus enough to replace material lost through wear. In VBRs, the packers may extend forward of the ram faces an inch or more. There are practical limits to the amount that the packers may extend forward of the ram face. The most obvious limiting factor is the requirement that the ram packers may not extend into the wellbore when the rams are fully retracted. This limits the pipe size range of the VBR, especially in the case where they are designed to fit existing BOPs.
Another factor which limits the pipe size range of a VBR is the width of the ram block, or the width of the packer recess in the ram.
The annular area that can be closed off by the packer is proportional to both the packer width and the distance that the packer extends forward of the ram face. As a result, VBRs for large bore BOPs can have a greater pipe size range than VBRs for small bore BOPs. For example, the maximum pipe size range for the Cameron VBR the 11" bore BOP is 5" to 2-7/8", whereas in the 18-3/4" BOP, the VBR can cover 7-5/8" to 3-1/2" pipe.
Availability And Pricing Of Insurance For Offshore Operations
Authors: Petersen Warren T. , Sinnott John T. , Whalen Leo R. , Sammis Russel F. 
Published: October 2008

Section I.

Fixed Structures And Pipelines - Installation Stage

Scope Of Available Insurance
With surprisingly few exceptions, the insurance industry has been able to meet the coverage requirements presented by the rapid change in offshore risks over the past dozen or so years. It has been necessary for the insurance industry to provide:Broad All Risk PerilsCoverage For Accidents Resulting From Error In DesignCoverage For Loss Of Income As A Result Of Delay In Start-upProtection For Loss Due To Certain Political Risks

Installation Risks
The installation of offshore fixed platforms confronted insurers with new technology. Hondo, Cognac and North Sea Condeep Platforms are examples. While the designers, builders and installers of these units demonstrated the soundness of their advanced technology, it must be remembered that the insurers did not have the ability to assess the design criteria and installation techniques. They did enlist the services of outside Marine surveyors, but, in agreeing to underwrite these new risks, had to accept as an article of faith that the "experts knew what they were doing". Having done so, they then had to weigh the risk of unexpected fortuitous incidents, acts of God and other happenings beyond the control of these "experts".
The need for underwl'iters willingness eo insure new technological risks will not diminish in the future. Tension Leg Guyed towers and Artie platforms will challenge insurers.
The insurance arrangements for large fixed platform installation risks often entail an owner controlled program. This would cover physical damage and third party liability risks. Protection is provided for the operator, non-operating partners and all contractors and subcontractors. The program would envisage coverage during all phases - fabrication, load-out, transit, installation and hook up.
Insurance on offshore pipeline installation risks involve broad All Ri~k perils coverage similar in scope to platform risks. However, insured amount requirements per risk are substantially less than with platforms. Furthermore, there is rarely a combined program for fabrication and installation. As such, our comments herein relate purely to the installation risk.

Deductible Patterns
The deductible approach on installation risks is fairly straightforward. While approaches can vary, minimum deductibles of $50,000 and $100,000 arerequired for platform and pipeline risks respectively. Larger deductibles can be negotiated but the scale of credits diminishes sharply. Very large deductibles rarely prove economic.

Pricing
The pricing of offshore installation risks is notas mysterious as is sometimes alleged. In the case of fixed platform rate workups, the value and period of each phase (fabrication, tow out, installation, hook up, etc.) is determined, and specific rates assigned to each phase. These rates can vary from say one-tenth of one percent of value for the fabrication stage to 3% for the tow out stage.
The Development of Corrosion-Resistant Tubing
Authors: Yoshida Toshio , Mann Tarlochan , Matsuda Shozo , Matsui Shigetomo , Atsuta Toshio , Toma Shouji , Itoga Koyu 
Published: October 2008

Abstract
Corrosion problems of deep well tubings and their control measures are discussed. As one of the economical solutions, metal-lined tubings are proposed. It is shown that the metal liner can be tightly fitted by the newly developed thermo-hydraulic fit method. The selection of corrosion-resistant material for the liner is discussed. Some designs of the tubing joint and their manufacturing methods pre proposed.

Introduction
With the seriousness of an energy shortage, the drillings of oil and gas wells have become more active. In the last few years, the number of drilled wells has increased rapidly as shown in Fig. 1. It should be noted that eighty percent of these wells were drilled in the United States. Fig. 2 shows the depth distribution of oil and gas wells drilled in the United States in 1977. It can be seen that the numbers of oil and gas wells are about the same, but, in general, there are more gas wells at deeper depths than oil wells. As shown in Fig. 3, well depth increases each year, and recently an exploratory well deeper than 10,000 m has been drilled.
As the well depth increases, the down hole pressure and temperature rise. For instance, in some severe wells at a depth of 6,000 m, the pressure and temperature are more than 1,000 bar and 200°C respec. tively. Therefore, the strength of the tubings used in such severe conditions is a very important factor for deep wells because they have to sustain their ownweight also. Figure 4 diagrammatically illustrates the transitions of design conditions with the increaseof well depth. Figure 5 shows the relationship between well depth and axial and hoop stresses of API standard tubings with various pipe 'dimensions. It isknown roughly that the strength of class P-I05 is required for the tubing of a 6,000 m well.
Another substantial problem in deep oil and gas wells is corrosion. This is mainly due to H2S and C02 which are contained in crude oil and natural gas The density of these contaminants is increased with well depth, and, together with high pressure and high temperature, the corrosion reaction is accelerated.
To solve all the above problems in deep wells, a new type of economical, high strength tUbing which has high corrosion resistance is expected. At present a super Ni alloy tubing, which is extremely expensive, tends to be used. As a solution, the authors propose the Tight Fit Tubing (hereinafter referred to as TFT) which is lined inside with corrosion-resistant alloy to meet the above three requirements for the tubing of deep wells. The thermo-hydraulic fit method used here for TFT has been developed to produce the corrosionresistant pipe, TFP, for corrosive flow lines as reported in Ref. 1.