bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oil in Marine Waters
Authors: Frey M. Gordon 
Published: October 2008

ABSTRACT
Oil has been in marine waters for millions of years, entering from marine seeps as migrating oil reached the sedimentary surface. Most of this oil was biodegraded by marine bacteria. The lighter fractions evaporated and a portion resisted weathering, becoming tar balls or asphalt slabs. More recently, greater volumes of oil have reached the oceans, both as crude and refined products. Nature still cleans up most of what man spills, but special problems occur when large volumes of crude or ' refined products suddenly are dumped into a coastal environment. The industry has maintained a remarkable record in its offshore exploration and production program, contributing less than 1/½percent of the petroleum in marine waters.

MARINE SEEPS
From historical records, we have learned that oil has been found in marine waters for many centuries. Geologically, we recognize oil has found its way into sea waters for millions of years.
The early Greeks skimmed oil from the surface of the Aegean Sea and used it in their ancient lamps. Here in the United States, we learn from the journals of the early explorers, that the Indians on both the Gulf Coast and along the California shores used oil and tar for many purposes: affixing arrowheads to shafts, waterproofing baskets, and mending pottery.
Perhaps the earliest reference8 to oil and tar in the New World is from the records of the Hernando de Soto expedition2, which included an area of exploration from the Savannah River southward and westward to the Mississippi River and East Texas. Before his death in 1542, de Soto appointed Don Luis de Moscoso as his successor. After a discouraging expedition in East Texas, de Moscoso built seven rickety vessels and set sail down the Mississippi on July 2, 1543. After reaching the Gulf of Mexico, the Spaniards decided to sail west along the coast. Upon reaching the mouth of the Sabine, they found a scum called copee, which is like pitch. They beached their vessels and, using dry slabs - tar, caulked their boats. The pitch was formed from a large oil seep that was known to exist off the coast near the Sabine River as late as 1903.
About the same time, the journal11 of the Portugese explorer Juan Rodrigues Cabrillo in 1542 reveals that oil seeps were prevalent in the Santa Barbara area of Coastal California. Later references to land and/or marine petroleum seeps in the area include the records11 of Father Pedro Font, 1776; Captain Cook, 1792; and the records of Benjamin Silliman, 1864.4
Environmental Aspects Of Drilling Muds And Cuttings From Oil And Gas Extraction Operations In Offshore And Coastal Waters
Authors: Monaghan P.H. , McAuliffe C.D. , Weiss F.T. 
Published: October 2008

ABSTRACT
Drilling mud and cuttings discharged from the more than 21,000 wells drilled offshore and in coastal waters of the United States have not caused detectable environmental damage either short-term or long-term. This is the conclusion from a study of reports of underwater observations during actual discharges of mud and cuttings, laboratory bioassay results for materials used in drilling muds, and actual well histories and laboratory results used in estimating the concentrations of mud components.
Discharged cuttings normally fall to the bottom and form a circular or elongate pile up to 150 feet in diameter and less than 3 feet high, thinning rapidly to the edges. Both measurements and calculations indicate that mud discharged during normal drilling quickly mixes with sea water and is diluted at least a thousand fold about 300 yards down-current. Divers have observed fish swimming back and forth through the mud and cuttings discharges, have observed organisms working in the cuttings piles, and have found barnacles growing on and in the exit of the discharge pipe.
The materials added in greatest amounts to drilling muds are barite (barium sulfate) and bentonite clays. Bioassay data indicate that these solid materials are nontoxic. Any acute toxicity for a typical mud should be due mainly to the dissolved lignosulfonate thinner. However, rapid dispersion and dilution quickly lower the concentrations (within a few minutes to an hour) below those found to be toxic in bioassay tests conducted for four days without provision for dispersion and dilution.
Mud and cuttings discharges apparently have not caused long-lasting effects, as a wide variety of mobile and fixed organisms are found on and under oil producing platforms. In the Gulf of Mexico, 10- to l5-yr old cuttings are no longer distinguishable from the normal sediments. Studies in Timbalier Bay (shallow water and a long history of petroleum operations) have documented no adverse effects on marine life or buildup of hydrocarbons metals.

INTRODUCTION
A well drilled for oil and gas is not simply a hole drilled from the surface to total depth. Rather, it is several concentric holes, the smallest being deepest, and each often lined with steel casing. This casing is held in place by placing cement in the annulus between it and the hole wall. The casings prevent collapse of the hole and/or uncontrollable flow of fluids into or out of the wellbore. Typical hole size and casing programs for 10,000- and 20,000-ft wells are shown in Table I. Also shown are the volumes of rock removed to drill each segment of the well. Note that doubling the depth triples the amount of rock removed and that this increase occurs in the shallow part of the hole.
In the rotary drilling process, a steel pipe rotates a bit against the rock face to break off chips of rock. As drilling proceeds, lengths of steel pipe are added to keep the bit in contact with the rock.
Newest Pumpdown (TFL) Completion Capabilities
Authors: Yonker John H. , Arendt Henry P. , Johnston Russell A. 
Published: October 2008

ABSTRACT
The latest pumpdown (TFL) completion methods and capabilities are now being used with consistent reliability worldwide including the North Sea, Gulf of Mexico, Borneo, and on land United States.
These capabilities allow placing the H-member at well bottom, full alternate multiple zone dual completions, surface selective downhole shifter/locator system, and downhole gas lift and safety systems; all of which are adaptable to subsea manifolds and atmospheric chambers, riser systems, floating platforms and standard platform completions.

INTRODUCTION
The search for oil has pushed the oil industry into deeper and less accessible waters. The costs for production platforms and pipelines have increased accordingly. For a well to be profitable under these conditions it must be able to produce large amounts of oil and be easily maintained.
The result has been an increased demand for pumpdown (TFL) completions with large bores specially designed for deep water. These completions, in addition to the basic pumpdown (TFL) requirements, must also incorporate other certain features as discussed below.The capability to perform maintenance and service work on subsea wells with flow lines up to 20 miles long. This distance results from cluster and satellite wells being placed further from fixed or floating platforms.The capability to locate downhole equipment selectively. This is more a demand on the deep or long flow line wells where the pressure response is minimal.The capability to perform limited maintenance work on wells with BHT up to 450½F and BHP's over 20,000 PSI that are in excess of 20,000 feet deep.Maintaining pressure integrity and response and keeping fluid losses to minimum While performing service operations. This is very important in wells having low bottom hole pressures and subsea wells having extremely long flow lines.The compatibility of downhole equipment within the whole system.The incorporation of a circulation path (H-member) of some sort, whether downhole or in the wellhead.Surface controlled subsurface safety systems. This is a necessary safety precaution with the ever present threat of damage to wellheads and flowlines.
As will be discussed in this paper, recent innovations in pump down (TFL) equipment now provide these features and offer solutions to the problems of well maintenance.

DESCRIPTION OF EQUIPMENT
In the past three to four years much development work and testing has taken place to help answer the problems faced by deep water completions. The developments include wellhead plugs, pumpdown retrievable ball valves and tubing retrievable ball valves for pumpdown use, pumpdown kickover tools with side pocket mandrels and side-pocket H-members, 'Select-20' shifter and locator systems, upper H-members with emergency circulating shear discs, sliding sleeve H members for gas lift in tubing less completions, and equipment for servicing deep, high pressure land wells.
An Acoustic Navigation System For Site Survey And Geodetic Positioning
Authors: Sharpe Richard T. , Galyean Paul G. 
Published: October 2008

ABSTRACT
An integrated navigation system which combines data from the Transit satellite system, a network of underwater acoustic transponders and an assortment of secondary sensors is described. Particular emphasis is placed on the techniques developed for relative and geodetic calibration of the acoustic grid. The system is scheduled for deployment in Spring 1977 for survey operations in the North Sea.

INTRODUCTION
Integrated navigation systems have evolved significantly during the recent past to keep pace with the needs of the offshore oil and exploration communities. As production and exploration activities move beyond the range of shore based navigation aids, there has been an increased incentive to produce accurate, portable navigation aids for use at sea. The use of underwater acoustic beacons has been one approach to this problem.
Acoustic navigation systems are typically comprised of the following components: a network of underwater transponders deployed on the ocean floor, a hull mounted or towed transducer connected to the vessel to be navigated and an interrogation or control unit. The transponders are designed to transmit a pulse of acoustic energy in response to an interrogate pulse issued by the interrogation unit. The time delay between transmission of the interrogate pulse and receipt of the reply pulse by the vessel's transducer provides a measure of the slant ranges to each of the underwater transponders. When properly calibrated, these systems can provide precise navigation over a limited area.
The system described in this paper is designed to use this type of acoustic structure in combination with the Transit Satellites and the various navigation aids discussed below.

SYSTEM CONFIGURATION
Fig. 1 is a block diagram of the system configuration. The navigation sensors include a gyrocompass, speed log or sonar, satellite receiver, Decca main-chain or Loran-C receiver, and the acoustic subsystem. The keyboard/printer is the primary operator interface device. The CRT is used for display of real-time navigation parameters. The track plotter is used to provide a graphic record of the vessel's path.
The data logging unit may be a magnetic cassette device or a reel to reel tape drive. In addition to recording survey data it is also used to log satellite data necessary for the geodetic calibration of the acoustic array. At the heart of the system is a Hewlett Packard minicomputer with a 24K word memory.
The acoustic subsystem is interfaced via an eight channel multiplexer to the CPU. Each channel in the multiplexer contains its own range counter unit, which uses a stable 100 KHz output from the satellite receiver as its frequency reference. This arrangement obviates the need for a full BCD interface with the acoustic interrogation unit, since only start and stop pulses are required to obtain range measurements.
An Investigation Into The Stress Distribution And Fatigue Strength Of Awelded Tubular T-Joint
Authors: Martin T. , McGregor J. 
Published: October 2008

ABSTRACT
The prerequisites for fatigue analysis of tubular joints are knowledge of local stresses at critical areas and an appropriate design S/N curve. Cumulative fatigue damage can then be calculated for a given loading spectrum.
This paper describes an experimental investigation of an axially loaded small-scale T-joint to measure the maximum stress concentration and compare it with formulae from the literature, to obtain constant-amplitude fatigue data for comparison with proposed design curves and to investigate the suitability of Miner's rule from the results of variable-amplitude fatigue tests.

INTRODUCTION
With the expansion of offshore oil exploration to hostile waters such as the North Sea there is an urgent need for reliable fatigue analysis procedures to be included in design codes for offshore installations. The tubular welded joint is the most widely used constructional detail in steel jacket type structures, and is an economical method of febrication, which produces a joint with a remarkable reserve static strength1. It has been used extensively without unduly large failure rates in environments, such as the Gulf of Mexico, in which the high risk of damage tends to be confined to short periods of storm conditions when the static strength of the joints is critical. In other locations where the wave spectrum includes appreciable numbers of waves that are higher than approximately 20 per cent of the design wave height, there will be a high risk of fatigue cracking. The complex stress distribution in a tubular joint, which is caused by the interaction of the restraint of the welded joint and the deformation of the tubular members, gives rise to high stress concentrations, adjacent to the weld toe, at critical positions around the joint. These areas of local high stress are potential sites for the initiation of fatigue cracks and progressive failure.

PROPOSED ANALYSIS PROCEDURES
The fatigue analysis procedures proposed by the UK Department of Energy2 and the British Standards Institution have the same basic format as the AWS Fatigue Criterion which has been considered to be applicable to tubular joints1.
A designer using these procedures would have to carry out a suitable experimental or computational study, which takes account of geometrical parameters and modes of loading to establish stress concentration factors for each joint of the structure. He would then use the resultant local stress spectra at the hot spots in a cumulative damage calculation, based on an appropriate design SIN curve, to estimate the fatigue lives of the joints by Miner's rule.
An alternative technique of analysis, which can be used for chord members of some simple T- and K-joints, is based on the punching shear stress range. The nominal axial and bending stresses in the brace are used to calculate the spectrum of punching shear stress, Vp, using the formula 4
(Mathematical equation available in full paper)
A Probabilistic Approach to Structural Operational Safety
Authors: Planeix J.-M. 
Published: October 2008

ABSTRACT
The aim of this paper is to introduce the notion of operational safety, i.e, the influence of the action of man on the safety of a system. Explicitly or not, this action must be taken into account when designing a structure. For a given operation, man has :to decide whether or not to attempt carrying out, as a result of his judgment of the environmental conditions, andif his decision is to go ahead, to perform it.
The decision and the eventual performance of the operation constitute the action of man, modifying the environmental loads. Both the decision and the performance of the operation involve errors, with respect to the conditions taken for design. These errors combine with the error inherent in any design analysis, due to calculation of environmental forces and modelization of the structure, to form the error in demand. Quality of materials, building, and maintenance also deviate from the-design standards, resulting in an error in capability. The design safety factor, giving an excess of design capability over design demand; must be such that safety is achieved, i.e. that, in operation, capability remains larger than demand, in spite of the influence of all the above mentioned errors, to an acceptably high probability. To carry out illustrative calculations, on a number of systems for marine work, Gaussian distributions are taken for the errors in the factors affecting capability and demand. These calculations show the influence of the various safety parameters on the number of safe operations allowed by the design.

INTRODUCTION
The problem of safety of units for work at sea, and more particularly of offshore units, is given more and more attention. Oil companies, operators, governments, and regulatory bodies strive to obtain a high degree of safety of these units, but, at the same time, owners (oil companies or operators) must make sure that this search for safety does not result in an uneconomical over-design of the units. To achieve both goals, an assessment of safety must be made, i.e the probabilistic distributions of capability and demand must be found, for each constitutive element of the structure, the failure of which is considered unacceptable.
At design, both demand and capability are evaluated and the design is based on a safety factor, or a set of safety factors, leaving some margin of design capability over design demand. In operation, demand and capability deviate from their design value. Safety in operations is achieved when the influence of these deviations does not absorb the margin of safety at design. The assessment of safety consists in finding out whether or not the design safety factor is insufficient or more than sufficient to ensure safety for an acceptably large number of operations.
Design demand results from an analysis of the motional and/or structural behaviour of the unit, in a given set of environmental conditions.
Experimental Study On The Behavior Of Concrete Structural Elements In Natural Sea Water
Authors: Peyronnet Jean Paul , Trinh Jacques Paul , Kavyrchine M. Paul , Seguin Michel Paul 
Published: October 2008

ABSTRACT
This report describes an experimental study on the behaviour of concrete structures in marine environment conducted by C.E.B.T.P. and C.N.E.X.O. Two concrete structures, each composed of two U' form elements, one reinforced, the other prestressed, had been tested under dynamic loadings in two different environments : on land and in natural sea-water (splash zone).
The aim of the study is to investigate the behaviour of offshore structures in its service conditions, so the six months loading program the same in the two cases has been chosen for the simulation of wave induced forces in sea. The dimensions have been also adjusted for a good representation of the phenomena involved.
These tests give an opportunity to develop new means of control which could be applied in such constructions.
In the test conditions, natural sea-water did not induce much unexpected mechanical behaviour compared with that on land. However in sea water, cracks were the site of alterations (destruction and deposit) causing a higher level of residual deformation. Within the test duration, the steel of the reinforced concrete structure showed a beginning of corrosion, which did not reduce over all strength.
The state of corrosion of the reinforcements is evaluated by the electric potential method associated with measurements of the water content inside the concrete using capacity-resistance gauges. Strains in concrete are determined by vibrating wire gauges, and crack widths by an optical micrometer.

INTRODUCTION
For the extraction of marine resources, steel was at first mainly used, in relatively shallow waters. But for deeper sea-beds, concrete is now more employed and offers solutions which are attractive from the technical and economical point of view, especially for durability. Concrete protects embedded steel reinforcement from environmental attack. However this advantage is effective only if the concrete covering has a sufficient thickness and compacity and if cracking can be reasonably limited. But we need actually more tests in sea conditions to determine the limitations of these requirements.
Among the different problems concerning a concrete structure placed in the open sea (I), we, have chosen to study at first its behaviour in its service life, under dynamical loads and corrosive action at sea, and to compare it with its behaviour on land.

EXPERIMENTAL STUDY
This first stage of experimental research on concrete at sea, concerns essentially the comparison of the behaviour of bent elements placed either on land or at sea. These first tests also allow us to control that certain measuring devices will behave well in the marine environment.

TESTING PROCEDURE
To facilite the application of loads, U shaped structures have been adopted (fig. I). Four test elements of identical dimensions have been fabricated in the C.E.B.T.P. Laboratories at Saint-Remyles-Chevreuse near Paris.
Cathodic Protection Criteria for the North Sea
Authors: Eliassen Svein , Steensland Odd 
Published: October 2008

ABSTRACT
Experiences from "the first generation" of offshore structures in the North Sea have shown that cathodic protection criteria that are sufficient in other offshore areas like the Gulf of Mexico cannot necessarily be applied to steel structures in the North Sea. This paper describes some of these experiences. It also gives some background information about the special environmental conditions in the North Sea and their influence on cathodic protection systems.
The main part of the paper is. devoted to the installation of a field testing equipment for measuring current output of anodes and the polarization level of a steel structure in service. Some preliminary results are given. The results show that the necessary practical current density for the North Sea when using sacrificial anodes may be in the order of 100 to 130 mA/m2. Special attention should be paid to calculation of the correct current output and distribute the anodes well to get an even current distribution.
At the end of the paper we have outlined some further developments that are necessary to establish the correct design of cathodic protection. A special item is the combination of a coating system and cathodic protection. Finally, a brief introduction to the DnV rules for cathodic protection systems is given.

INTRODUCTION
Corrosion and corrosion protection are the most important factors to be considered in the design, construction, and inspection of offshore structures and pipelines. If basic corrosion protection technology is neglected, this will result in expensive and serious mistakes, not only in terms of money, but in safety as well. Corrosion, in fact, has turned out to be a major problem for the operation of offshore platforms and production facilities.
For DnV, being a certifying authority in the North Sea area, special interest has been paid to pipelines, risers, and structural members, which are important to the over-all integrity of the structure. Of special concern are members that are difficult to inspect or repair and members that are exposed to very aggressive environments, for instance, the splash zone.
The submerged zone of the structures and pipelines is a part that may be defined as difficult to inspect or repair. This is especially true for the North Sea with its deep waters and rough sea conditions, which are making diving operations more complicated. The predominant way of protecting the submerged zone is by cathodic protection systems, which sometimes may be combined with a suitable coating. Thus, the performance of a cathodic protection system is a very important factor in obtaining reasonable life and safety of the structures.
Cathodic protection can be achieved either by sacrificial anodes, by impressed current systems, or by a combination of both methods. For North Sea applications, most of the systems so far have been sacrificial anode systems. This paper deals mainly with sacrificial anode systems.