bluuebunny/crossref_metadata_2025_split huggingface dataset:
Towards More Compact and Efficient De-Oiling Equipment
Authors: Plat R. , van den Broek W.M.G.T. 
Published: October 2008

ABSTRACT
The development of a compact oil-water separator is pursued through theoretical and experimental investigation of a number of separation techniques. Plate separation is an effective separation method for oil droplets with a diameter of about 50µm or larger, but ineffective for smaller droplets. Use of gasflotation or of oil coalescence in a porous medium as separation techniques leads to the removal of a part of the smaller oil droplets present in oily waters. To increase the separation efficiency each of the last two techniques will be combined withcentrifugal separation. A design of a separator based on such a combination is presented for both gas flotation and oil coalescence.

INTRODUCTION
De-oiling equipment at offshore oil-production platforms must preferably be light and compact, and the oil concentration of the discharged production water must be below the prescribed limit. In many cases these requirements are not met. This paper describes work on the improvementof de-oiling equipment with respect to size and efficiency. Three de-oiling techniques are studied:Plate separation. This is a suitable technique for the removal of oil droplets above a specific diameter. In practice this diameter is of the order of 50µm.Dissolved gas flotation and oil coalescence in a porous medium. With these two techniques also smaller oil droplets can be removed.

PLATE SEPARATION
A plate separator consists of a pack of parallel plates, through which oily water is led. To enhance the removal of the collected oil the separator is usually placed under an angle with the horizontal, and provided with corrugated platesl. The rise velocity of the oil droplets is determined by the density difference between oil and water and the friction force exerted on the rising oil droplet. It can be shown2 that this results in a stationary rise velocity:(Available In Full Paper)
The use of a plate separator leads to complete removal of all oil droplets above a specific diameter, the critical oil-droplet diameter. The numerical value of this parameter depends on the dimensions of the plate separator and on the velocity of the oily water, and can be calculated as2 :(Available In Full Paper)
In case the angle with the horizontal is larger than about 10 degrees, it is necessary to correct for the tilting of the separator by replacing H by H/cos ? in eq. (2).

Experiments and results
Experiments on plate separation were carried out in straight and in corrugated channels. A flow circuit for oily water with a maximum capacity of 5 m3/h was available for the experiments. We limit ourselves to the discussion of two typical experiments: one on the measurement of the velocity profile inside a corrugated channel and one on the experimental determination of a critical oil-droplet diameter.
Fig. 1 gives a sketch of a corrugated separator channel with dimensions: length 1.50 m, width 0.50 m, height 0.020 m. At a wave-peak (A) and at a wave-trough (B) the velocity profile was measured along a vertical line, with a TNO-Delft laser-doppler anemometer.
Extensive Testing of TFL Techniques in Italy
Authors: Chioetto S. , Donati F. 
Published: October 2008

ABSTRACT
Agip S.p.a. is presently conducting a testing campaign on a complete line of 3 in. (76 mm.) TFL equipment, at a dedicated centre in Cortemaggiore (Italy).
The aim of the testing is to study the functionality and the reliability of each tool, and of the system as a whole, generating an extensive data base on the performance of the system.
This paper is a description of the project and of the test plant that has been dedicated to its development; the procedures that are being followed for the testing, and the logic behind them, are also described.
At the end of the paper, a brief summary of the results that the project has yielded so far is reported, together with some general considerations on the most important problems associated with the use of TFL techniques.

INTRODUCTION
A TFL testing campaign is presently being developed by AGIP in a dedicated R&D centre located at Cortemaggiore, in the north of Italy, on a complete line of 3 in. (76 mm.) TFL equipment
The ultimate aim of the project is the acquisition of the expertise and insight in TFL technology that may eventually lead the company to the choice of TFLsolutions for the maintenance and service of future subsea wells.
So far, in fact, TFL technology has never been adopted by the company for any of its wells, in Italy or abroad, and, although this technology is not new and has already been tested and field-proven by several companies, performance data are still not easily available, and the costs and risks associated with the choice of TFL developments are such thata certain degree of in-house understanding of the capabilities and limits of the technique are felt to be needed, before embarking on a development venture.
The main reason that at first prompted the proposal of a testing campaign on TFL equipment was the foreseeable future necessity to develop subsea wells in very deep waters, such as in the Adriatic basin (water depths from 800 to 1000mts. 1.
The size of 3 in. (76 mm) was selected for the equipment line to be tested, since it appeared to be the most likely choice for a future application.
In the years 1985 and 1986 the pilot plant was set up, complete with flow-line loop and surface TFL facilities, and the equipment to be tested was ordered. The specification of the equipment ordered for testing covered most of the component S used in a typical dual string TFL well completion.
Actual testing started in 1988, and is presently (January 1990) ongoing, followed full-time by a small team of technicians, aided part-time by a TFL specialist from the tools manufacturer.
Close communication and cooperation between test personnel, the manufacturer, and personnel from other companies that also have an interest in TFL testing, has from the start been considered essential to the success of the project, and are constantly contributing to the improvement of the TFL product line, as well as to a better general understanding of the technique.
Design Development of a Soft-Yoke Mooring System for the S236-1 Field in Liaodong Bay, China
Authors: D&apos;Souza A.B. , Huang E.B. , Zhiqiang Zhao , Gui Wen Baa 
Published: October 2008

ABSTRACT
The Suizhong 36-1 (SZ 36-1) Oil Field in northern Bohai Bay in about 30m. water depth is a giant offshore oil fie1d with estimated reserves of 1.2 billion barrels of oil. The development plan requires a Floating Production Storage Unit (FPSU) and a Single Point Mooring (SPM). The SPM is designed for the 10 a-year return non-ice storm and the 25-year storm with 0.24m. first year ice sheet with the FPSU connected. It is also designed for the 50-year ice event with 0.55m. rafted first year ice with the FPSU disconnected. The engineering design of the fixed tower soft-yoke SPM developed for these conditions is presented. Information on system performance analysis, design, procedures for predicting ice loads on SPM and FPSU and on model test results is included.

INTRODUCTION

Field Location
The SZ 36-1 oil field is located in Liaodong Bay in the eastern part of the Bohai Gulf (Fig. 1). The field is about 50 kilometers (km) from shore. It is characterized by heavy, high Viscosity oil, low oil/gas ratio and a loose reservoir which makes the development of the field a technical challenge. It is being explored and developed by Bohai Oil Corporation (BOC) of the China National Offshore Oil Corporation (CNOOC). The discovery and development of the SZ 36-1 oil field was reported in Reference 1. BOC has prepared a field development plan, shown in Fig. 2.
Conceptual design of the engineering facilities conducted by BOC in conjunction with foreign consulting companies has been completed and contracts for fabrication and insta11ation of the facilities are being awarded. The field is expected to be on stream by 1992.
This paper focuses on the preliminary design of the SPM system. Topics specifically addressed are the system design basis, evaluation of alternate SPM systems and selection of a preferred system, system description, mooring analysis and design and model test. The preliminary design may differ from the final design, which will be engineered by an SPM Contractor.

DESIGN BASIS

SPM Location
The coordinate location of the SPM is shown in Figure 2. The mean sea level at the location is 32.80 m. above the seabed with an extreme tidal variation of +2.16, -2.73 m.

Environmental Conditions
SPM environmental design criteria are summarized in Table 1. Of particular concern is the presence of sea ice in the winter.
Ice conditions are categorized into light, ordinary and heavy ice years. In 1ight ice years there will be no ice in the field. In ordinary ice years about half the fie1d will be covered with drift ice with level ice thickness ranging from 5 to 15 cm. and speeds from 0.3 to 0.5 m/s and a maximum of 1.0 m/s. This condition lasts for about 30 days in January and February. The FPSU must remain connected in ordinary ice years.
Heavy ice years have taken place three times since 1936 (1936, 1947 and 1949) when the entire field was covered with land fast ice, with level ice thickness ranging from 20-30 cm.
The Application of Ultrasonic Creeping Waves for NDE o Welds in the Offshore and Related Industries
Authors: Sandy P.A. , Swain N.A. 
Published: October 2008

ABSTRACAT
This paper outlines the theoretical principles of the ultrasonic technique of creeping waves and discusses their advantages over existing methodology for testing weldments.
In this technique, ultrasound is transmitted by compression waves at a very low angle into the weldment and thereby compliments existing ultrasonic testing by working with in 3-4 mm of the entry surface. Creeping waves can therefore be used to supplement and sometimes replace Magnetic Particle Inspection (MPI) and/or Dye Penetrant Inspection (DPI) for examiningwelds in offshore structures and other structures or vessels requiring defect evaluation at or near the surface.

1.INTRODUCTION
Creeping waves have been around for a number of years, being used in the powergeneration sector for detecting crackingunder cladding of vessels used in reactors. Initial usage of creeping waves in the offshore fabrication industry was to resolve production problems stemming from spurious M.P.I. indications along the toes of submerged arc welds. Details of this and the further practical developments of this are detailed further on in the text. This report covers the practical application of creeping waves, but first it is necessary to give a brief outline of the theory.

2.THEORY
Creeping wave probes consist of twin transducers which generate compression waves at angles between 70° and 90°. The waves from the part of the beam which travel parallel to the surface are called creeping waves (see Fig. 1). The ultrasonic probe also generates shear waves by mode conversion from the compression wave and these have anangle of incidence of 33-38°. Since the creeping wave is derived from the compression wave and travels first beneath the surface, it is unaffected by weld splatter, surface condition or change of geometry such as seen at a weld toe. Because of this tolerance the creeping wave probe can be used in many applications where surface wave probes are totally unsuitable.
It has been found that the type of creeping wave probe used in this work gave the best practical results when usable beam path was kept to a maximum of 60 mm.

3.EQUIPMENT
The equipment used apart from the probe is conventional A-scan portable ultrasonic equipment. The probe found to give the best results is a twin crystal 4 MHZ with crystal sizes of 6x13 mm, with a focus of 10 mm and a squint angle of 20°.
The test block (see Fig. 2) was a piece of BS4360 50D plate material which was similar to the material under test. The dimension of the block was 20 mm thick and approximately 50 mm wide and 300 mm long. The block had 3 notches spark eroded in the surface of 0.25 mm, 0.5 mm, and 0.75 mm depth. The width of these slots was 0.2 mm. Spark erosion was chosen as the method of producing the slots as this technique gave the smallest width with the most consistency and accuracy. The only other ultrasonic equipment required is a twin crystal 0° compression probe of the same frequency as the creeping wave probe.
South Marsh Island 205-A: Lifted Jacket in a Water Depth of 437 ft
Authors: Palmer R.W. , Oksuzler Y. , Campo J.J. , Kessler K.J. , Sanzgiri S.M. 
Published: October 2008

ABSTRACT
The South Marsh Island 205-A platform is located in the Gulf of Mexico off the coast of Louisiana in a water depth of 437 ft. Instead of launching the jacket from the transportation barge, the jacket was lifted from the barge with two derrick barges. The jacket consists of four main legs which frame directly into four skirt sleeves. This is the first such jacket to be designed for the Gulf of Mexico. It is the largest jacket by weight and water depth to be lifted in the Gulf of Mexico and is the deepest four pile jacket installed in the Gulf of Mexico to date.
The design and configuration of the jacket, the development and analysis of the skirt sleeve to leg connection and the installation of the platform are presented in this paper.

INTRODUCTION
South Marsh Island block 205 is operated by Mobil Exploration & Producing U. S., Inc. The contract for the design of the South Marsh Island 205-A platform was awarded to McDermott, Inc. in March, 1988. In an effort to reduce fabrication and installation costs and to enhance the financial return of the field, the feasibility of a lifted jacket with four skirt piles and no main piles was investigated. Gulf of Mexico fabrication and installation contractors were contacted for input concerning fabrication capabilities, limitations, marine equipment capacity and availability. At the same time, Mobil Research and Development Corporation (MRDC) was contacted for information on a skirt sleeve to leg connection that had been developed for the North Sea. Through preliminary analysis along with contractor and MRDC input, it was concluded that the concept was feasible and that cost savings could be realized.
In another effort to reduce costs, an existing deck was salvaged and refurbished for reuse. The deck was a two level, eight leg drilling/production deck that was originally designed for simultaneous operations. For the removal of the deck, it was cut off 2 ft. below the cellar deck and placed on 2 in. circular plates to be later installed on top of the South Marsh Island 205-A jacket.
Elevation views of the platform are shown in Figure 1. The eight leg deck is supported by the four corner legs of the jacket and four false legs which are braced into the corner legs below the waterline. The legs are tapered from 36 in. diameter at the top to match the deck legs to 80 in. diameter at the bottom. The spacing of the legs at the top of the jacket is 45 ft. × 125 ft. The legs are battered 1:6 in the transverse direction and 1:12 in the longitudinal direction which results in an essentially square base that is 210 ft. × 208 ft.
The jacket weighs 3810 s. tons in air as weighed with electronic load cells prior to loadout. In order to lower the weight of the jacket for lifting purposes as well as on-bottom weight, approximately 45% of the jacket steel is 50 ksi material.
Two-Phase Flows as a Result of a Subsea Blowout and Their Effect on the Stability of Structures
Authors: Moros T. , Dand I. 
Published: October 2008

ABSTRACT
A number of floating structures have sunk in subsea well blowouts. The cause of rig sinkage has previously been explained by a loss of buoyancy attributed to a density reduction of the surrounding sea by the gas phase. It has been recently shown that this is of secondary importance and the main cause of rig instability are the secondary flows in the water, which are generated as the gas rises to the free surface. In this paper numerical simulations of the two phase flows following a release of gas at the bottom of the sea, for one flow rate and two water depths. are presented. The main findings can be summarised as follows. The dynamic pressure arising from the recirculation of the water is greater than the hydrostatic pressure due to the density defect. A strong jet is formed near the water free surface which in turn affects the dynamics of a floating structure located in the vicinity of the plume. High turbulence levels occur, with frequencies which could coincide with the natural frequency of the structures. Results of the dynamic behavior of a drill ship in such flows, are also discussed.

INTRODUCTION
When a subsea well blows out or an underwater gas pipe line breaks a large amount of gas is released into the water. The gas breaks up into bubbles which rise upwards into a turbulent plume above the release point. As the bubbles rise they carry a considerable amount of water along with them both in their immediate vicinities and in their wakes. These bubbles exert a drag force on the surrounding liquid. A typical value of the Reynolds number for the escaping gas, based on a pipe hole diameter, is of the order of 107. Hence the rising plume is turbulent.
As the plume approaches the free surface most of the gas escapes to the atmosphere while the liquid flow direction changes from predominantly vertical to radial, away from the plume axis. The plume axis however, does not remain at a fixed location. Bubbly plumes are in general laterally unstable. Although the detailed hydrodynamics of the lateral instabilities are rather complicated to analyse and not clearly understood at present, it has been observed that the plume meandering, from its vertical position, is of the order of the plume diameter. This corresponds to a time scale of 1.4 s for a plume rising in 700 m deep water. The flow is rotational and causes massive recirculation of the water.
In most cases, offshore structures or ships are present in the neighborhood of a blowout. The interaction of the two-phase plume with the structure or ships will cause an instability of the floating structure and there are many cases where the structures have been badly damaged. The gas escaping through the free surface is flammable (eg 80% methane) and it is therefore important to predict its dispersion under different weather conditions.
Fire Testing of Valve and Wellhead Equipment to API Specifications
Authors: Guice W.L. , Shinn T.L. 
Published: October 2008

Abstract
Math modeling and test data have been used to predict the temperatures of equipment in API fire testing. The thermal response of these systems is used to select critical parts for fire resistant equipment. Conditions of internal components were found to be calculable based upon the defined test criteria.

Introduction
Interest in fire protection for valve and wellhead components has increased significantly over the past two decades. In most cases, fire protection requires completion costs marginally higher than equipment not so protected, yet the net cost of the completion equipment is very minor when compared to the potential cost of a fire.
This was first dramatically illustrated in the Bay Marchand fire in the Gulf of Mexico, which took months to control, and cost millions. Since this incident, increased awareness of and associated costs of environmental protection have underscored such needs and interest. In addition to rebuilding costs, the price of a well fire must be considered in terms of the future value of the production from a given field or well, rather than the current value. Petroleum price increases and environmental concerns are likely to cause the future demand for fire resistance to grow much faster than the demand for wellhead equipment in general.
Current industry requirements as interpreted by API address two different levels of fire resistance. These levels depend upon the relative proximity of wells. A single isolated (onshore) well which catches on fire and poses no danger to nearby equipment or personnel needs only a system adequate to protect itself. It also has a different fire exposure potential as compared to a well on an offshore platform or a similar situation.
The isolated well, if leaking and burning, will feed its own fire only. If the equipment above the lower master valve is resistant to the expected worst conditions that might occur before the fuel supply is shut off, and the lower master is equipped to completely seal off as a response to this condition, fire safety may be considered adequate. If a worst case scenario is assumed, in which the entire Christmas tree is somehow blown off the well, the well is still a danger only to itself. Fire test criteria for a single isolated well therefore include the assumption that a potential worst case is a fire totally surrounding the well and fed by free convection air and well fluids.
The well in close proximity to other wells (normally offshore) has a far different environment. Such a well, when burning, presents a danger both to itself and to surrounding wells. Burning fuels from one well might impinge directly against an adjacent one, causing it to be endangered. This potential domino effect suggests that all equipment in the region of exposure should be fire resistant. As a minimum requirement a heat activated master valve shutoff coupled with a fire resistant tubing hanger would serve to shut the well down and minimize the fire.