bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Model Pile Tests to Axial Pile Design
Authors: Bogard J.D. , Matlock H. 
Published: October 2008

ABSTRACT
Experiments conducted with instrumented model pile segment probes at Harvey and Empire, Louisiana are summarized and the observed behavior interpreted. Correlations are developed for the time rate of strength gain and interim recommendations are given for construction of t-z curves (soil resistance versus axial pile displacement) for use in design. The methods are compared with existing pile test results.

INTRODUCTION
A comprehensive program of studies of the behavior of axially loaded piles in normally consolidated clay was performed between 1982 and 1986. The studies included a large number of experiments with instrumented pile segment models which were deployed below the bottoms of boreholes. Some were near the sites of large-diameter pile load tests. Continuously recorded measurements included pore pressure and total lateral pressure plus soil shear resistance as a function of axial displacement, under a variety of static and cyclic loadings.
The results of selected experiments done in Louisiana at Harvey and Empire have been given in two companion papers (Refs 1 and 2). In this paper, the complete sets of results will be used to establish proposed interim design procedures for axially loaded piles in similar clays. The procedures will then be applied to two sites at which axial pile load tests have been performed in normally consolidated clays.

SUMMARY OF OBSERVED SOILPROBE BEHAVIOR
A fairly clear concept of the mechanisms of clay soil behavior in interaction with axially loaded piles has been obtained in part from the Harvey and Empire test results. The principal features are summarized here as a basis for the development of correlations and design procedures. In general, when a pile is pushed or driven into the soil, the soil is displaced outward by an amount which is, in terms of analysis, referred to as cavity expansion. The soil is also remolded by the flow around the point and by shear deformations along the length of the pile.
Excess lateral pressures are created by the cavity expansion, primarily in the pore water and therefore in the total pressure. Because of the rapid reduction of shear stress with radial distance from the pile, the significant lateral and shear stresses are confined to a soil band very close to the pile wall.
With time during and after pile installation, the pore water pressure dissipates by a process of radial consolidation and a part of the lateral pressure is transferred to lateral effective stress. Since the process involves the outward migration of pore water there is a slight movement of the soil skeleton inward toward the pile. This results in a reduction of total pressure during consolidation.
A closed-end or plugged pile forces more soil to move laterally and thereby creates somewhat greater initial lateral pressures than an open-end or thin-wall pile. The band of remolded and heavily stressed soil around the thin-wall pile is much thinner, resulting in more rapid consolidation and set-up, This was clearly demonstrated by the Harvey and Empire tests.
Recycling of Larger Offshore Facilities: Relocation of /W.C. 547 "A" Platform to E.C. 278 "C"
Authors: Disher A. , Maddox J.L. 
Published: October 2008

ABSTRACT
The intent of this paper is to document the major accomplishments in the salvage, transportation and reinstallation of a 120 MMCFD gas drilling and production platform from one location in the Gulf of Mexico to another. The project entailed moving a complete 192' depth facility including jacket, deck, and process equipment. The paper Will discuss several Gulf of Mexico firsts for Texaco, such as:Heaviest jacket relocation in the Gulf of MexicoFirst upright lift and tow of a large jacketApplication of the Jones Act and impact on projectIn situ coating of splash zone area of structure

INTRODUCTION
The oil industry has always looked for more cost and time effective methods for developing deposits of hydrocarbons found beneath the Outer Continental Shelf (OCS). One method which has been used successfully is to drill the required wells from a fixed platform. This involves considerable lead time and cost to design, fabricate and install a structure and process equipment. After the hydrocarbon deposits have been depleted, the platform becomes a liability and must be removed and disposed of, often at greater expense than the original platform installation.
In 1988, Texaco successfully recycled an offshore platform, relocating the platform approximately 35 miles from a location with a water depth of 192 feet in West Cameron Block 547 (WC 547) to a location in 177 feet of water in East Cameron Block 278 (EC 278).
Production had ceased in WC 547 in February, 1987. Minerals Management Services (Ml&S)regulations required that this block be cleared of all obstructions within one year of the end of production or February, 1988. Texaco had a requirement for a platform to develop a separate prospect in EC 278. In May of 1987, preliminary engineering was started to determine if the WC 547 platform could be relocated to EC 278.

PRELIMINARY INVESTIGATION
Texaco was organized with the Offshore Division office, which included Engineering, Regulatory Compliance, and Legal Departments, in New Orleans and the Offshore District Office, which would perform all field work, in Morgan City. Texaco decided that the project manager would be in the Division Office and the project coordinator would be in the District office until contracts here signed; then the project manager and project coordinator would switch titles. Both positions were filled at Project conception, and the same personnel stayed with the project for the duration of the project.
The Deepwater Pipeline System on the Jolliet Project
Authors: Tillinghast W.S. 
Published: October 2008

ABSTRACT
This paper describes the design and installation of the deepwater pipeline system which transports the oil and gas production from Conocors Jolliet Field in the Gulf of Mexico. This pipeline system used 12 miles of flexible pipe and 42 miles of conventional rigid steel line pipe. The pipeline system has pipelines in water depths as deep as 1760 ft. and as shallow as 230 ft. The paper describes the installation of flexible pipe risers at the TLWP, the laying of flexible pipe through rough seafloor conditions, the installation of rigid steel pipes in 1400 ft. water depth, and a seafloor connection system to facilitate tie-in of future production.

INTRODUCTION
The deepwater pipeline system for Conocols Jolliet Project required the use of many different aspects of offshore pipelining. The project involved two distinctly different pipeline systems - a flexible pipeline system and a conventional rigidsteel line pipe system. Each system presented its own particular challenges.
The complete pipeline system installed by Conoco for the Jolliet Project required the installation of a total of 54 miles of both steel and flexible pipe. The conventional steel line pipe system crossed 42 miles of varying sea bottom terrain. These pipelines started in 1080 feet of water and traversed through 1400-foot depths as the pipelines climbed up the continental slope to a fixed platform in 616 feet water depth. From there, the oil sales pipeline continued northward into slowly decreasing water depths to terminate with a subsea tie-in into an existing oil transportation system. These pipelines encountered a multiplicity of different situations: an undulating seafloor which created the potential for long pipeline spans, water depths to 1400 feet, rocky seafloor outcropping, pipeline crossings, subsea faults, laying lateral tap valves, deepwaterJ-tube riser pulls, and a subsea pipeline tie-in.
The flexible pipeline system used relatively large 8 inch and 10 inch inside diameter flexible pipes in water depths to 1760 feet. A total length of about 12 miles of flexible pipe was installed. Catenary riser configurations were used by the flexible pipes at the Jolliet Tension Leg Well Platform (TLWP). These risers were installed throughpull tubes on the exterior of a column of the TLWP. The flexible pipe was laid around and, in some cases, over areas of rough local microtopography. The flexible pipes were connected to the steel pipelines and connected to an underwater connection skid using saturation divers working to depths of 1080 feet.

GENERAL DESCRIPTION OF THE JOLLIET PROJECT
The Jolliet Projectl accomplished a full-field development to extract oil and gas reserves from Green Canyon Block 184 in the Gulf of Mexico. The development consisted of a Tension Leg Well Platform (TLWP) in 1760 ft of water in Green Canyon Block 184 with 20 TLWP production wells, a Central Production Platform (CPP) in Green Canyon Block 52, a Drilling Platform (52A) which is part of Conoco?s Marquette Project and is bridge connected to the CPP, andintra-field and export pipelines.
Inhibition of Sulphate Scale Nucleation
Authors: Pritchard A.M. , Buckley L.C. , Smart N.R. , Webb P.J. 
Published: October 2008

ABSTRACT
The nucleation of (Ba, Sr)S04 scale has been studied on different surfaces representative of those likely to be encountered in oil production. The amount of scale formed and the efficiencies ofthree typical scale inhibitors depended on the surface used. Similar results were obtained from mixtures of seawater with either synthetic or real formation water.

INTRODUCTION
Mineral scales are frequently formed in oil production, usually as the result of changes in the temperature or pressure of produced fluids, or the mixing of incompatible formation and injection waters. The scale may form a precipitate in thebulk fluid, and be carried along with it in suspension, or it may nucleate on the walls of containing vessels and grow to form an adherent scale. This adherent layer can reduce the flow of fluids in tubulars, prevent the proper functioning of chokes and safety valves, and concentrate some radioactive species from produced fluids to an extent sufficient to create a local radiation hazard. Some of the suspended scale may betransported to the walls to form a particulate deposit that is more porous, mechanically weaker, and easier to remove than those formed by direct nucleation on the surfaces.
Despite the widespread occurrence of scale in oil production and other industrial and domestic situations, relatively little attention has been paid to the distinction between adherent and non-adherent scale. This paper describes some of the work being undertaken on scale nucleation on surfaces, and the effects of scale inhibitors on its inhibition and growth, in an on-going research programme at Harwell, supported by a number of oil producing companies. In view of the preponderance of mixed barium and strontium sulphate scaling in North Sea oil production as a result of mixing formation waters and seawater1, work has concentrated on (Ba, Sr)S04 scale formation on a number of surfaces representative of those likely to be encountered both downhole and topside.

THE NUCLEATION PROCESS
Nucleation of solid deposits is likely to be affected by the nature of the surface involved. The free energy change for the formation of a solid particle in a liquid can be written as(Available In Full Paper) where ø the driving force for the phase change, is given by(Available In Full Paper) in which S is the saturation index or saturation ratio, n is the number of molecular units in the particle,? the surface energy of the particle and A its surface area2. The change in G as the part1cle grows is given by(Available In Full Paper) where ? is the molecular volume and r is a measure of the radius of the particle that also allows for its shape. This change in free energy is thus affected by the saturation ratio, which isdetermined by the chemical composition of its surroundings and their temperature and pressure, and the energy required to create the new surface.
Diverless Pull-In, Connection, Service, and Testing of a Subsea Production Flowline
Authors: Webb P.H. 
Published: October 2008

ABSTRACT
This paper reviews the development, for BP Exploration 'DISPS' Project, of two tools to perform the pull in, testing and connection of a subsea production flowline without the aid of diver intervention. Information is provided on the design, manufacture and factory testing of the two tools by Cameron Iron Works Ltd, Leeds.

INTRODUCTION
One of the objectives of BP Exploration's DISPS project was to perform dry testing of diver less tie in techniques, as part of its development of diverless flowline systems of 4 - 12 inch diameter pipes in water depths of 350 - 750 metres. This paper describes the design, manufacture and factory test undertaken by Cameron Iron Works Ltd, Leedsof two remotely operated tools for use in tying in a flowline to a subsea structure by three techniques, namely:Direct pull-inLateral deflectionVertical stab and hinge over.
The first two methods are similar in their requirements in that a cap is required to be fitted to the outboard flowline hub, which allows a cable to be attached to the front of the flowline pullhead. This is then used to pull the flowline into the correct alignmenton the subsea structure. The third method employs a hinged funnel permanently attached to the subsea structure into which the flowline is stabbed.
With this system the flowline is aligned when the funnel swings down during layaway - thus not requiring a pull in operation. All threemethods require the pull-in tool to be able to pressure test, pig and remove (or replace) the cap from the outboard flowline.
To achieve these functions four main pieces of equipment were required:-A piggable termination cap.A pull in tool.A connection tool.A clamp connector.
Ancillary equipment needed were the Inboard and outboard hubs (including handling rings), shipping bases and protection caps for the inboard flowline hub. The general connection system is shown in Fig. 1 and isdesigned for an 8 inch diamater flowline. However it can be adapted to operate on 6" to 12" pipes.

PIGGABLE TERMINATION CAP
This is a pressure containing vessel which comprises a flowline collect connector, a pull in cable release latch, access for pressure testing and a two stage valve for flooding and pigging operations of the flowline (see Fig. 2). Connection to the Outboard flowline hub is made by the collet segments which are clamped onto the hub flange and released by movement of an actuator sleeve through a handling ring.
A wedge action between the actuator sleeve and collect segments produced by movement of the sleeve opens or closes the segments. When fitted onto the outboard flowline hub, axial movement of the actuator is prevented by shear pins.
A pressure test can be performed with an Hydraulic Pressure Test Stab on the pull in tool, which opens a pressure balanced piston to uncover radial ports connected to the main body cavity. This can then be pressurised via the pull in tool umbilical line.
Settlement of Mat-Supported Mobile Units in Very Soft Clays
Authors: Cox W.R. , McClure S.C. , Sorensen K.H. 
Published: October 2008

ABSTRACT
The behavior of a mat-supported mobile rig founded on very soft clay has been examined. The settlement of the mat into the clay during preload when setting up on the location is used to arrive at the ultimate bearing capacity of the soil. Analyses are then made of the bearing pressure of the mat on the soil when the mobile unit is subjected to storm loadings and these bearing pressures are compared to the ultimate soil beam pressures generated during settlements that accompanied preloading. This comparison provides guidelines for predictions of additional settlements that may occur under the storm loadings. The method putting bearing pressures under storm loadings is unique is that it considers elastic-plastic response of the soil resistance as contrasted to conventional elastic solutions or equivalent-area solutions.

INTRODUCTION
The first mat-supported submersible mobile unit, as reported by Howe (1966), was the Barnsdall-Hayward Breton Rig 20, later known as Kerr-McGee Rig 40 that was completed in 1949. Many years before the advert of the submersible rig, there were units known as marine drilling rigs that operated in lakes, bayous and dredged canals. These marine rigs were used offshore beginning in the late 1940's, and they were often founded on shell pads to increase their operating water depth. The submersible mobile units and the marine drilling rigs share one common feature: the large area of the mat permits the units to operate with minimum settlement, even on some very soft clay bottoms.
Hirst et al (1976) have reported that the average seafloor contact pressure of mat-supported mobil units is approximately 50 psf when there is no wave loading. They also reported no significant settlement of the rigs as long as clay bottoms had shear strengths of 100 psf or greater. For very soft deltaic clays with shear strengths of 40 to 50 psf, settlements do occur under contact pressures of 500 psf. A handful of clay soil with 40 to 50 psf shear strength can easily be squeezed between the fingers.
To control settlement in very soft clay bottoms a planned preload is applied when setting up the unit on locations, Turner et al (1987). As the mat settles into the seafloor under the preload, additional bearing capacity is developed from three sources: the increasing strength of the soil as the mat goes deeper, the increased buoyancy from the displaced soil, and the increasing friction of the soil on the sides of the mat.
Young et al (1981) have presented an extensive discussion of foundation performance of mat-supported mobile units in soft clays.
An Investigation Into the Effects of Using a Pit To Simulate Deep Water for a TLP Model Test
Authors: Murray J.J. , Mak L.M. , Sullivan M.A. , Winsor F.N. 
Published: October 2008

ABSTRACT
A test program has been carried out on a 1:50 scale model of a 150,000 tonne tension leg platform in a water depth of 350 m. The same model was tested under the same wave and wind loading conditions in two separate facilities. The first was a 200 m by 12 m tow tank having a water depth of 7 m (350 m full scale). The second facility was a 75 m by 32 m basin having water depth of 2 m (100 m full scale) with the additional 5 m (250 m full scale) accommodated using a pit. The paper compares results found in the tow tank and those found in the basin. Presentation is based on comparison of the tether tension and rigid body motion response of the TLP to a number of wave and wind spectra simultaneously applied to the model. These results are also compared to numerical predictions.

INTRODUCTION
The tension leg platform (TLP) is one of the most popular concepts in compliant offshore structures employed in water depths ranging form approximately 100 to 1500 meters. The TLP, similar in appearance to a semisubmersible, is characterized by its vertical tethers (or legs) kept taut by excess buoyancy in the floating structure. The objective is to eliminate heave, roll and pitch motions of the platform by taking the associated loads axially in these vertical legs. The platform does however experience motions of surge, sway and yaw.
Among other considerations, hydrodynamic analysis of a TLP is concerned with response of the platform in terms of its motions, and response of the tethers. Normally, in the shallower range of water depths the tether dynamics are assumed to be very small and have negligible effect on the platforms motion, whereas the platform motion is the primary source of excitation to the tethers. In deeper water, tether dynamics can be significant. In this case there are two main methods of analysis; one analyzes the tethers independent of the platform, while another considers the coupled response of the structure-tether system. Similar consideration is given to the riser system attached to the platform.
Scaled prototype modelling is normally used to investigate the behaviour of such structures. The primary objective is to subject a model to an accurate representation of the environment which the full scale version will encounter. Usually, the largest physical model possible is sought and choice of scale is governed by available water depth at a particular facility. Consequently, a problem associated with test facilities for model test programs is the water depth. Most facilities intended for deep water model testing are equipped with a pit extending below the main floor of the tank. This assumes that the floor is sufficiently deep to avoid interference with kinematics of water particles in the water column. These effects are significant when considering the model tether (or riser) responses.
Full-Scale Fatigue Testing of TLP Tendons
Authors: Fowler J.R. , Long J.R. , Albert J.W. 
Published: October 2008

ABSTRACT
The design of TLP tendons and tendon connectors to resist fatigue failures requires consideration of many factors, such as mean and alternating stresses, cycles, welding, residual stresses, base metal fatigue, and weld profile control. Many assumptions are necessary to do this. This paper describes the development of a machine which can validate these assumptions by testing full scale sections of tendons to fatigue loadings similar to those seen in service.

INTRODUCTION
One of the significant design considerations of Tension Leg Platforms is potential fatigue failures of the tendons. [1]* Tendons have a high mean tension and experience a large number of primarily axial tension variations (bending is also present) throughout the design life. In addition, all tendons have welds which have a lower fatigue strength than the base metal. Many tendon designs also incorporate connectors which may result in additional stress concentrations.
Unfortunately, there is a relatively large amount of uncertainty in fatigue design. To account for this, API RP 2T [1] recommends that tendon components be designed for a life of 10 times the tendon design service life and this recommendation was followed in the Conoco Jolliet TLWP. [7] There has been a considerable amount of work done in developing and fatigue testing connectors for TLP tendons [3,4,5,6], but this work has been primarily analysis and testing at scales of 1/3 and less.
Aside from mean stress, alternating stress, and number of cycles (the effects of these variables are customarily accounted for in the fatigue curves), there are a number of factors which influence fatigue life. These are:Metallurgy of base metalWelds and post weld stress relief of residual stressesProfile control of weldsStress concentrations at connectors and weldsSize of structure and amount of material actually stressedCorrosion/stress corrosion; speed of cycles
With the exception of item 6, which is accounted for by cathodic protection, these factors are considered in design by accurate calculation of peak stresses and selection of a fatigue curve which accounts for items 13. Item 5, the size of the structure, is accounted for by the fact that the fatigue curve is a lower bound to actual test data taken from a large number of small test coupons.
However, this process has a number of assumptions and approximations which it may be prudent to verify based on the large amount of welds and connectors in tendons which are subject to fatigue and the relatively small amount of actual test data. For example, a TLP in 3000' of water with twelve tendons and a connector every 80' will have approximately 450 connectors and 900 circumferential butt welds to connect the connector to the base pipe. If a tendon has 100 square inches of cross sectional area and 1" long welds, there are about 90,000 cubic inches of weld metal in all the tendons. Most fatigue data is taken with specimens which are on the order of 0.25" diameter and with a cross sectional area of about 0.05 square inches.