bluuebunny/crossref_metadata_2025_split huggingface dataset:
Offshore Mineral Terminals -Artificial Islands And Open-Sea Shiploading Of Dry Bulk Materials
Authors: Soros Paul 
Published: October 2008

ABSTRACT
Undersea m1n1ng is expected to enter an era of economical production of high volumes of low cost minerals from increasing water depths to be competitive in world markets, transport costs between mine and ultimate consumer become critical.
Typical transport systems between mineral source and ocean carriers are considered, with storage and shiploading facilities being usually the major problem.
Open-sea mineral loading is illustrated with Port Latta, in successful operation since 1968. The possibilities in this field are demonstrated by a review of all loading facilities now planned in the world for 250,000 DWT and larger vessels, engineered by Soros Associates.
The logical basis for incorporating artificial islands in transport systems between ocean mining and ocean carrier is explained.
The actual design problems and project economics are illustrated with two cases of widely different scale. One is for a 1.5 million ton per year movement, the other is designed for a throughput of 20 million tons per year.

Introduction
Undersea mining at shallow water depths, say up to 90 feet, or dredging, to use a less glamorous word, is one of the lowest cost methods to produce raw materials in large quantities. At larger water depths, production costs are still high, restricting commercial development to high value, low volume minerals. It is a fair assumption that with improved technology these production costs will decline, and undersea mining will become a source of low cost, high volume minerals also from increased water depths.
Our low cost, high Volume mineral, to be competitive with land based sources will be in the range of 25¢ - $5.00 per ton to mine. After being mined from the ocean at a low cost, it will share a fate with its land-based competition - the final selling price and therefore profitability, will greatly depend on the cost of transportation between mine and ultimate consumer.

Transport System from Undersea Mine to Ocean Carrier
Disregarding the special case of a single consumer close to the source of the mineral, the transportation costs for ocean mined minerals will be made up of ocean freight and the cost of the system to process and move the mined material into the ocean carrier.
The elements of such a system would be shiploading, storage, transportation between mining and storage, and processing, as required. Ideally, the mining operation would be at a short distance from firm, flat land suitable for storage, inside a protected harbor that can accommodate large bulk carriers. Unfortunately, reality may be quite different.
The most critical item is likely to be the port for shiploading. An existing port or natural harbor may be too far from the mining operation, may not have room for mineral loading or will-be able to handle only small or medium size bulk carriers.
A Description of Experiments and Results Obtained in the Correlation of Geophone and Hydrophone Response
Authors: Lechenger Louis 
Published: October 2008

ABSTRACT
Experiments were conducted in enclosed pressure tanks using sources capable of exciting the tank and its contents with a sine wave motion, and measuring the-output of calibrated hydrophones within the tank at a precisely known depth.. Other hydrophonegeophone tests were made in and around a large open water tank sunk in the ground using the Dinoseis* as an energy source. Further testing was done involving larger ground area and a large open body of water.
The object of these tests is to correlate geophone response with hydrophone response and to correlate laboratory test conditions with the environment found in the field.

INTRODUCTION
There are many occasions in seismic prospecting when information correlating the response of an array of geophones on land and a group of hydrophones in shallow water could be more than just informative.

OBJECTIVES OF TESTS
It is the object of this report to reveal and analyze the results of some of our experiments in the correlation of geophone and hydrophone response. Experiments were conducted both in the laboratory and at an outside test environment. The main factors to be checked experimentally were correlation of electrical signal amplitude between geophones and hydrophones and the phase relationship between these output signals.

TEST ON SHAKER TABLE
In the beginning, an approach to the problem was made by mounting a container of fluid on our calibrated shaking table. A known velocity was imparted to the fluid and the elctrica1 output of a calibrated hydrophone was recorded with the hydrophone suspended at various depths in the fluid. Figure 1 shows the physical set up for this test. The voltage output of the shaking table calibration coil is directly proportional to the velocity of the table and is related by the transduction constant, 2.55 inches per second per volt. This transduction constant was obtained by measuring the peak-to-peak table displacement optically and the calibration coil voltage while accurately counting the frequency at which the shaking table is driven.
Tests were run and data was calculated based on the assumption that the excess pressure sensed by the hydrophone is related to the acceleration of the fluid by the relationship P =? h a/g where ? is the density of the fluid, his the depth of the acoustic center of the hydrophone, and a/g is the acceleration of the mass of fluid in g's due to the velocity of the shaker at a given frequency. A simultaneous value of the pressure wave was obtained by measuring the electrical output of the hydrophone and calculating the amplitude of this pressure wave based on the transduction constant of the calibrated hydrophone. The hydrophone used in this experiment was the Geo Space MP-15 streamer phone which has a capacity of 8,000 pfd and a transduction constant of 1.0 volt per psi. The MP-15 is shown in Figure 2. The main characteristic which influenced the choice of this hydrophone was its very flat sensitivity vs. depth response characteristic.
Deep Water Hydropnone
Authors: Heaps Stanley 
Published: October 2008

ABSTRACT
A general purpose hydrophone has been developed which £features high sensitivity, wide band operation, and high pressure capability. An internal preamp overcomes the usual problems related to cable noise and cable capacitance. The internal battery is charged through the amplifier output leads. This hydrophone was originally designed for detecting low frequencies at oil well-depths in geophysical applications. These density and high frequency response have been improved to adapt the unit to a number of oceanographic problems.
The pressure sensitive element of the hydrophone is a hollow cylinder of lead zirconate. Its mechanical resonance above 40 KHz determines the maximum usable frequency. Other resonant modes of vibration of the metal housing land amplifier assembly restrict the 3 db band width to 8 KHz.
Figures I thru VII, at end of paper. The transistorized preamplifier has three stages with direct coupling. The feed-back 's factory adjusted to provide a choice of hydrophone sensitivities. Its high input impedance in conjunction with the zirconate cylinder establishes the low frequency cut off below 1/2 Hz. The output impedance is determined by the output coupling capacitor of 500 microfarads. This is near 5 ohms at 60 Hz. The minimum load resistance of 300 ohms permits coupling of this hydrophone to the input of most seismic amp audio amplifiers.
A diode switch permits the preamp battery to be charged through the amplifier output leads. The preamp, having no switches or adjustments, runs continuously.
Rugged construction permits the hydrophone to withstand the high pressure at deep depths and the usual rough handling of the outdoor environment. A plastic cone serves to protect the sensitive element from impact. The two conductor electrical cable serving as mechanical support enters the stainless steel housing through molded fittings with an o-ring seal.

INTRODUCTION
To meet industry's requirements, a hydrophone was developed for use in deep oil well bore holes for acoustic velocity measurements of the geological formations. In this application there was no need for high frequency response above 500 Hz, and the design was tailored to permit rapid assembly by nontechnical people.
The hydrophone is novel because of its internal preamplifier. This serves to isolate the pressure sensitive crystal from the cable capacitance and the recording amplifier input impedance. The self-contained battery is charged occasionally through the amplifier output leads hence only two-conductor cable is needed.
The hydrophone has been pressure tested for 10,000 ft. depths. On the barrel it is identified as "Geo Space Corporation Hydrophone Model MP-I0". (Fig. 1 is a photograph of-the hydrophone.)
Fig. II shows a response graph of the hydrophone. Here we see that it has sensitivity at 40 KHz, but a resonant condition near 2 KHz exceeds the 3 db tolerance for good linearity. This marks the upper end of the flat response band of the hydrophone.
A Probabilistic Approach to the Wave-Structure Interaction Problem
Authors: Gomez Alberto Gomez 
Published: October 2008

ABSTRACT
The analysis of the interaction of wave forces and structural response is a typical case of a random process. In the dynamic analysis of the platform only random excitations are of major concern, while the other parameters of the system can be reasonably considered to be deterministic. In this paper, a mathematical model for the deterministic analysis of wave-structure interaction developed by the author in a previous investigation 1, is modified and presented as a stochastic model. Maximum response of a platform using a random excitation is compared with the results obtained from the deterministic model. The nature of the wave-structure interaction is, such that the maximum response can be obtained with a few passes of the most critical wave.

INTRODUCTION
The reliable prediction of the response of offshore platform to random wave action requires knowledge about the interaction of the wave and the structure during motion. With the structural system defined in a deterministic way for its topological and mechanical properties, and with the wave known or estimated as a random excitation, random response follows from application of the proper theory.
The forces exerted by waves on circular piles, plates, ships, and walls have been predicted by analytical methods and measured in the laboratory. Investigators agree in considering that water particle velocity and acceleration are the governing parameters of the hydrodynamic forces exerted by waves on structures. The velocities and accelerations should be relative values with respect to the body in motion and not the values with respect to ground. This fact is often overlooked because most structures designed in the past were fairly rigid; but for some flexible offshore platforms having velocities and accelerations in the same order of magnitude as the water velocities and accelerations computation of forces using velocities and accelerations, with respect to ground, yields completely unrealistic results. 1

DETERMINISTIC MODEL
The author developed a mathematical model for the deterministic study of wave-structure interaction with basis on the following principles1:The force exerted by the wave on a body can be computed by the formula proposed by Morison, O?Brien, Johnson, and Schaaf2(available in full paper)where V and A are the ater particle velocity and acceleration, respectively; Cl and C2 are constants defined by the geometry of the body.For a structural system composed of lumped masses, the equation of motion for each one of the masses can be written as:(available in full paper)where YI (tn) is the acceleration of Mass I and time tn; FI (tn) is the hydrodynamic force of Mass I and is a function of time; M I is the lumped mass at point I; and R I (Yn) is a function of the configuration of the structure at that instant.
The value of RI (Yn) can be computed from the expression available in full paper)
Marine Navigation System
Authors: Mitchell Donald K. 
Published: October 2008

ABSTRACT
In certain types of offshore operations, particularly minerals exploration, there is a need for a small fully automatic navigation system which presents position data in such a form that it can be used to steer the vessel without need for further computation or reference to specially prepared charts. Such a system with an effective range in excess of 20 miles and an accuracy of 50 feet was built and tested. It gathered position data by digitally counting the travel time of a microwave pulse from the vessel to two beacons at known locations. This time information is transferred to a small computer which uses this time information to compute the position of the vessel with respect to a predetermined rectangular coordinate system. By appropriate choice of the coordinate system, the coordinates can be used directly to provide steering information necessary to keep the vessel on the desired course.

INTRODUCTION
When extending subsurface survey techniques from land to water, the greatest changes in techniques and equipment occur not in the actual gathering of information but in the methods of determining where that information was actually gathered. The transits and chains of land surveys can be used under some conditions, but an electronic navigation system is generally required. These systems have ranged from the complex through the extremely complex and sometimes require more equipment and technical manpower than the rest of the instruments needed for the survey. I have seen a gravity survey where one man with a gravity meter conducted the survey and three men with the navigation system told him where he was.
The navigation system had more than adequate accuracy under good conditions, but it had a number of serious drawbacks in operation. The boat had to be in a known position to start up the system and had to return to a known position to recalibrate if the signal was ever lost for any reason. Atmospheric disturbances from thunderstorms to skywave propagation around sunrise and sunset upset the system and occasionally rendered it totally useless. Data came out in the form of distances to two remote stations at fixed points and the rough position could be determined by looking at specially prepared charts, but the accurate position was computed at a remote location and had a turnaround time as long as a month.
In addition to the technical problems, there were the human factor s in trying to find competent men willing to sit in a trailer house at each of the remote locations day after day so that they could perform those few tasks which were necessary to the operation of the navigation system.

REQUIREMENTS ON THE NAVIGATION SYSTEM
When Geophysical Research Corporation became involved in offshore exploration for minerals, it became apparent that there was a need for a navigation system designed for that type of work. A range of 20 miles and an accuracy of 50 feet would be adequate for most mineral surveys, but the system must not slow down the surveyor complicate it any more than absolutely necessary.
Vertical current structures in the Deep Gulf using EOF analysis
Authors: DiMarco S.F. , Reid R.O. , Nowlin W.D. 
Published: October 2008

Abstract
Empirical orthogonal function (EOF) analysis was performed on current meter records and model outputs in the deep regions of the Gulf of Mexico. The results of the EOF analysis were similar for model and observation stations located on the continental slope and rise. The vertical structure of modes, generally, shows a surface-intensified mode containing a high percentage of total variance and a bottom-intensified nearbarotropic mode beginning at roughly 800 m and extending to the bottom.

Introduction
We examined current meter records and model outputs of the University of Colorado Princeton Ocean Model (CUPOM) to construct empirical orthogonal functions (EOFs) which describe the vertical current structure in the deep Gulf of Mexico. EOF analysis, also known as principal component analysis, has become an accepted tool to quantify patterns of variability present in large sets of time-series data1. To facilitate analysis of the EOF modal time series, all EOFs done in this paper used singular value decomposition (SVD) to provide both the modal amplitudes and principal component time series. Further, both east-west (U) and north-south (V) current velocity EOFs were done simultaneously. Therefore, percentages of variance reported are based on the variance contained in both the U and V time series.

Data
Current meter observations. Analyzed were datasets that consisted of simultaneous point measurements of current velocity of 5 or more distinct depths and which lasted at least 4 months2. Initial EOF analysis concentrated on observations in water depths greater than 700 m during the period 1980-1988. The analysis was done on raw unfiltered data from the eastern, central, and western Gulf of Mexico. The analysis was performed using those data that were available at all depth levels, i.e., irrespective of any temporal gaps.
CUPOM data. Model data were generated from a version of the Princeton Ocean Model adapted for the Gulf of Mexico. The model has 1/12° horizontal resolution and 24 vertical sigma levels. The model hindcast covered the years 1993-1998. EOF analysis of model output was performed using data from cross-and along-isobaths as well as from single locations. The across-isobath lines went from 200-3000 m total depth across the continental slope at longitudes 88°, 90°, 92°, 94°, and 96°W and across the slope meridionally in the eastern and western Gulf at 26°N. Along-isobath lines were in the central Gulf along the 500, 1000, and 2000-m isobaths between 89°W and 94°W. In this paper we concentrate on the along-isobath line at 2000 m and the cross-slope line at 90°W (Fig. 1).

Results
Fig. 2 illustrates the typical modal structure seen from slope locations around the northern Gulf of Mexico. The data used to construct the modes of Fig. 2 were from CUPOM model year 1993 and taken near 27.2°N and 89.9°W and at the edge of the Sigsbee Escarpment. Unfiltered hourly current velocity time series at all 24 sigma levels were used to construct the EOF modes.
Reliability Through Data Reconciliation
Authors: van der Geest Robert , Broman William H. , Johnson Tina L. , Fleming Ray  H. , Allen John O. 
Published: October 2008

Abstract
We propose a flexible simulator of an oil well that may be used for several forms of online, real-time reconciliation of data from existing measurement equipment. It turns out that data reconciliation used as part of the instrumentation philosophy on an oilfield constitutes a dissimilar, redundant level of instrumentation. This additional level of instrumentation may be used to make the existing measurement hardware more reliable by verifying the validity of measurement data. In addition, the technology may be used to replace permanently installed hardware in times of failure. Greater reliability is expected to contribute to greater system uptime by reducing the need for workovers.

Introduction
Data reconciliation is a technique that has traditionally been used in process control to verify measured data by reference to a process model. In this paper we consider a more active form of data reconciliation in which we use a model of the process to estimate a number of unknown variables on the basis of other, known variables in the process. Such estimated variables may be seen as virtual measurements of the process; therefore estimators based on data reconciliation are sometimes referred to as virtual sensors. They are also known as software sensors or soft sensors, which distinguishes them from their hardware counterparts. It turns out that soft sensors may be used with great success in the operation of chemical processes for supplementing, and in many cases even replacing, permanently installed hardware.
There is a big potential for soft sensors in offshore oil production. First of all, even though the added value of permanently installed sensors is undisputed, downhole equipment is particularly expensive to install because of the nature of offshore operations. Therefore it is appealing to limit the number of downhole sensors to what is minimally required in order to get sufficient insight into the production process, and to use inferential techniques to make the picture complete. Secondly, it is widely recognized that downhole measurement equipment and the corresponding communication systems are prone to failure during installation in the well, during special events in the life of the well, or after a few years in operation due to harsh living conditions. Furthermore, it is prohibitively costly to repair or replace downhole equipment in offshore wells. Software sensors, as opposed to hardware sensors, typically do not break down. In fact, even though a soft sensor depends on the availability of hardware measurements that may be subject to errors, it does not necessarily depend on the availibility of aparticular piece of hardware. A soft sensor will work as long as the total set of available data contains enough information for the system to make up its mind.
In this paper we propose a flexible simulator of an oil well that may be used for several forms of online, real-time data reconciliation..