bluuebunny/crossref_metadata_2025_split huggingface dataset:
Creating a Sustainable E&P Business in Brazil
Authors: Haney John , Koot Michiel 
Published: October 2008

Abstract
The exploration and production business has many stakeholders, including government, investors and contractors. There is a shared interest in generating maximum value from the oil and gas resources in the ground, and then findig a fair allocation of this value. The question that will be addressed in this paper is 'how do we create a viable and sustainable upstream industry in Brazil' that will achieve these aims? It is clear that is only possible with full participation and cooperation of all parties involved.

Introduction - What is at stake?
The Brazilian Government took the decision in 1996 to open the upstream sector to foreign investors in order to reduce oil imports, attract essential Direct Foreign Investment, and ensure performance through competiton.
Foreign investors (International Oil COmpanies) have responded by concluding partnership agreements with Petrobras in the initial phase and thereafter acquiring exploration acreage in the four bid rounds to date. Investments to date by these new players exceeds a billion US$ in exploration alone, with further invesments committed. These investments were being made based against the background of perceived high prospectivity of the acreage, and a belief that Government will remain committed to creating a viable business environment.
Local manufacturing and service companies see it as an opportunity to diversity their client base and grow their business. Other stakeholders see the opening up of the industry as an opportunity that will bring employment, development of local infrastructure and tax revenues - wihtout adverse impact on the environment.
The key point here is that many parties share an interest in the development of oil and gas resources in the ground - and must work together to create the right conditions for investment.

Taking Stock
Having completed the first exploration period of the first vintage of exploration blocks since the opening up of industry and nearing the end of two year Round 0 extensions, it is a good time to take stock of developments and achievements. Each investor does this regularly to see how actual performance compares to their expectations at the outset.
There is no doubt that the opening up of the upstream sector was successful. While Petrobras remains by far the largest player we now have more than 35 investor companies active. The Brazillian Petroleum Agency (ANP) has established itself as an effective regulator. Since its inception in 1997 it has made much progress in creating a regulatory framework and has received much credit for the transparent manner in which it has conducted its bid rounds.
Since 1998 some 320,000 km 2D and 120,000 km2 3D seismic has been acquired and evaluated and some 200 offshore exploration wells have been drilled including 45 by companies other than Petrobras.
However, the offshore exploration results since the opening of the sector have had mixed results. Some 110 technical discoveries have been reported but most are believed to be small to modest size accumulations of generally low gravity crude, or gas.
Canyon Express Subsea Multiphase Flow Metering System: Principles and Experience
Authors: Wallace Bryan K. , Gudimetla Ravi , Nelson Stuart G. , Hassold Thomas A. 
Published: October 2008

Abstract
As Canyon Express is a multi-field, multi-operator, deepwater subsea, gas development flowing into a common transport system, relatively accurate and reliable measurement of the produced fluids is essential to allocate hydrocarbon gas volumes per field and to estimate system water production. Thus, the metering principles and limitations must be understood to ensure that volumes are being calculated as accurate as possible. This paper describes the application, calibration testing, deepwater marinization program, and subsequent implementation of the subsea multiphase flowmeters used for the Canyon Express development in the Gulf of Mexico. This includes description of the meter theory, environmental condition development, and calibration. The overall objective of the metering will be discussed along with how the limitations of the meter affect the computation of the flow rates for the different phases of the produced fluid and the interrelationship of the engineering and testing results with the actual operation of the meter including the affect of liquid loading on the meter performance.
Successful demonstration and implementation of the subsea multiphase meter suitable for deepwater application allows for the measurement of hydrocarbon gas at the wellhead thus permitting the measured gas to flow into a common flowline to be commingled with other production streams for transportation to a host platform. This allows multiple marginal subsea fields, each with different owners, to be operated as a single economic development while maintaining acceptable gas measurement for allocation of hydrocarbon gas volumes. The Canyon Express team also utilized its meter development experience in managing the development of API Recommended Practice RP85 on "Subsea Wet Gas Meter Allocation Measurement".

Introduction
Canyon Express is a deepwater Gulf of Mexico (6450' to 7210'), multi-company (TotalFinaElf, BP, Marathon Oil, Pioneer Natural Resources, and Nippon Oil), ten (10) well, subsea completion, 500 MMSCFD natural gas gathering system with dual, common 12" flow lines to surface processing facilities at MP261. The operational and mechanical challenges for all related subsea facilities is significant as the 7210 foot water depth, at Camden Hills, represents a world record for subsea hydrocarbon production.
The initial (maximum) gas flow rates (per well) range from30-65 MMSCFD flowing at about 4200 psi (downstream of the choke) with an estimated condensate production up to 2.0 barrels/MMSCF. Initially, the water production expected is dry to low (less than 1 bbl/MMSCF) but is predicted to increase to 500 bbls for some wells later in field operations. The presence of the liquid phase in the predominantly gas production fluid must be considered when evaluating options for the measurement of the gas and liquid flow rates per well.
Fatigue Life Improvement of Steel Catenary Risers due to Self-Trenching at the Touchdown Point
Authors: Langner Carl G. 
Published: October 2008

Abstract
The fatigue problem associated with the Touchdown Point (TDP) of a SteelCatenary Riser (SCR) may be less serious than is commonly understood, particularly for "soft" seafloor sediments typical of the Gulf of Mexico. Forsuch soft sediments, a SCR will dig for itself a trench having a curvedvertical profile that minimizes the shear forces in the SCR at the TDP andconsequently reduces the fatigue damage in the vicinity of the TDP. In thispaper this trench is modeled as a rigid curved surface upon which the SCRlands.
Quasi-static analysis predicts that the fatigue life of a SCR with the TDPtouching down on a rigid curved trench is much greater than that of an SCRlanding on a rigid flat seafloor. The maximum fatigue damage either occurswithin the trench past the TDP, where riser motions are small, or occurs up theriser away from the TDP, where shear forces are small. Dynamic analysesutilizing finite element computer models are less clear. One early FE analysisincorporating a rigid curved trench showed a fatigue life improvement factor ofabout 2.3, whereas other analyses were inconclusive. Therefore, it is too earlyto draw general conclusions about potential fatigue life improvements untilfurther research is done.

Introduction
Since 1994 the population of Steel Catenary Risers has grown from zero tomore than 60 worldwide, connecting marine pipelines and flowlines with TLPs, SPARs, Semisubmersible FPSs, Ship-Shaped FPSOs, and other fixed and floatingplatforms. Many more such risers are planned in sizes ranging from 4" to 24", and water depths ranging from about 1000 feet to more than 6000 feet.
The primary design criteria for Steel Catenary Risers are the usual internaland external pressure requirements, and a requirement that the predictedminimum fatigue life of the riser must exceed the field life by a specifieddesign factor. (The usual factor of 10 is thought to realistically cover themany unknowns in material strength and oceanographic loadings.) Fatigue damageis caused by cyclic bending of the riser, induced by the combination ofplatform motions and direct wave and current loadings on the riser, includingvortex-induced vibrations. Fatigue analysis of a SCR involves counting thebending cycles that will be applied to the riser over the full range of theoceanographic loading conditions that will occur during its lifetime.
Fatigue damage is concentrated in the girth welds at both the upper end ofthe SCR where the riser is connected to the platform, and at the TouchdownPoint where the SCR first touches down onto the seafloor. This paper focuses onthe conditions at the TDP.
Productivity, Water Breakthrough And Ultimate Recovery In Horizontal Wells With A Range Of Completion Types
Authors: Jones Colin , Cameron John , MacKay Eric 
Published: October 2008

Abstract
The effect of completion ID in four different sand control completions was studied using inflow modeling and reservoir simulation. An expandable sand screen and three different IDs of external gravel packs were studied, in various lengths of horizontal well and over a range of flow rates.
The ID of a completion affects the performance of a completion through the flow friction pressure generated. The friction pressure is a function of the ID to the inverse 5th power so even small changes in ID can have an effect.
Each completion configuration was assumed to have the same realistic production rate. The friction pressure tends to act as a choke on production from the toe of the well; this concentrates production towards the heel. The expandable sand screen has the lowest inflow at the heel and the smallest ID gravel pack has the highest inflow. The high inflow at the heel draws water up from the underlying aquifer and initiates water breakthrough. The time to breakthrough was calculated using a simple analytical theory. The predicted time agreed well with available production data.
A reservoir model was built to further study the heterogeneous inflow. This showed that the larger ID completions gave the best sweep of the reservoir with the highest recovery. The reservoir model was run for a variety of well lengths and productions rates and showed that for long high rate wells the completion with the largest ID gave the best sweep and the longest water breakthrough time.

Introduction
Long horizontal wells are an increasingly common option for the drainage of certain reservoirs. They have numerous advantages over vertical wells. Larger contact with the formations gives low flow rates and drawdowns. This is especially valuable in wells drilled close to the oil water or gas il contact, such as in oil rim or attic developments. It is crucial in the planning of such developments that the effects of wellbore friction are taken into account. In a horizontal well of infinite hydraulic conductivity the friction is zero and the drawdown and inflow are constant along the entire well length. For a finite hydraulic conductivity the friction pressure causes variations in drawdown and inflow along the well.
The effect of friction in a horizontal well is to concentrate production towards the heel of the well. This is due to flow from the toe experiencing an additional backpressure due to the friction, which inhibits inflow. The high flow at the heel, which can be double the infinite conductivity case, accelerates water or gas coning into the well. There are ways to deal with this effect, both before and after the fact. For long drains, inflow control devices can be placed in the screens to choke back the flow at the heel. This in effect chokes back production and it is still difficult to achieve the correct inflow without downhole flow and pressure measurements. After water breakthrough, options involve downhole flow control and water shut off treatments.
Development of a Non-Toxic Simulated Oil For Marine Testing Programs
Authors: Overfield Jerome L. 
Published: October 2008

Abstract
The results of a program supported by the Environmental Protection Agency to demonstrate a non-toxic, low oxygen demand simulated oil for marine testing is presented herein.
The simulated oil exhibits a broad range of physical characteristics that can be used to replace more toxic crude and fuel oils for testing control and cleanup devices in a marine environment.
The simulated oils circumvent many of the problems associated with using natural oils or simple substitute oils in a testing program:
*The high cost and scheduling problems associated with going far out to sea to test are avoided because of the non-toxic nature of the simulated oil.
*Adverse public relations are avoided.
*Adverse ecology effects, even if out at sea, are avoided.
*The viscosity and density of the oils which an oil cleanup skimmer or containment boom encounter have been shown to have a significant effect on the performance of the device. A simple substitute oil can not match specific crude or fuel oil viscosity and density and can not cover the broad range of viscosity and density of natural oils which are spilled.
*The non-toxic simulated oils can be used to simulate test temperatures other than those encountered at the test site, thus avoiding the expense or scheduling problems associated with relocating to a different temperature test site or waiting until the temperature reaches the desired level.
In the project, three (3) representative natural oils were chosen which constitute a large percentage of the oils transported by water in U. S. trade and which cover a broad range of viscosity and density. Simulated, non-toxic oils were formulated and compared to the viscosity and density of the natural oils. Other fluid properties such as surface tension were also compared.
Physical tests have also been performed to compare the flow properties on water of the simulated oils and the chosen natural oils. The tests performed have been:*Oil Spreading Rate on Water.*Oil Containment Barrier Tests.*Pumping (Emulsion) Tests.*Oil /Water Separation Tests.*Bioassay.
Additional tests have yet to be performed on simulated oil dispersion into water and a final bioassay.

Introduction
After the several oil spills such as the Torry Canyon and Eagle, new devices were developed to clean up or contain spilled oil. However, the new devices need to be tested to determine their efficiency and effectiveness. Also, the testing process normally reveals design changes which will improve the performance of the device. In planning the testing program, several difficulties associated with the oil used in testing become apparent. These are listed below:If real crude oils are used, the test must be performed far out at sea to be legal. Tests performed at sea are very expensive in transporting men and equipment to the test site. The test crew can normally remain on station a relatively short time. Scheduling of at sea tests is dependent on the weather, thus stretching out the development cycle of a very necessary device.
The Cell Spar and Vortex Induced Vibrations
Authors: Finn L.D. , Maher J.V. , Gupta H. 
Published: October 2008

Abstract
Vortex Induced Vibrations (VIV) of Spars under current flow is an important consideration of Spar mooring design. Model tests and Field data show that Spar VIV is a complex issue that can involve a large number of parameters which include Spar hull characteristics, dynamic characteristics of the moored system and current characteristics itself (profile, turbulence, direction). The Cell Spar is a new design that has several physical characteristics that are different than those of the present classic and truss Spars. Some of these characteristics allow the structure to be constructed in a manner that does not degrade the VIV performance in currents. A series of model tests were performed to study the effects of Spar hull and mooring system characteristics on the VIV response of the Cell Spar. This paper presents an overview of the tow tank model tests and the VIV response that was measured. The paper describes in detail the experimental setup and the Spar details that were altered to achieve a VIV response that is superior to all existing Spars.

Introduction
A new configuration of a Spar platform called the Cell Spar is presently being fabricated in Texas. This new hull form is composed of a bundle of cylindrical members called cells that are held together by a number of horizontal and vertical structural elements located in the interstitial space between the cells (see Figure 1).
Since the outer surface of the upper portion of the Cell Spar does not form a regular cylinder, there was a concern that the strakes used on the existing Spars might not work. In addition, it is more difficult to fabricate the conventional Spar strake members to fit on the multisurfaced exterior of the Cell Spar. A number of plausible new strake configurations were proposed as possible solutions, but since VIV-suppression effectiveness has proven to be difficult to predict, a series of model tests were conducted to adequately quantify performance. This paper describes the various strake configurations that were tested and presents the VIV test results that were obtained.
Figure 1 Sketch of the Cell Spar Platform.(AVAILABLE IN FULL PAPER)

Description of Cell Spar
The upper portion of the Cell Spar under construction is composed of six outer cells surrounding a central cell. These upper cells provide the buoyancy required to float the vessel. The lower portion of the Spar is formed by extending three of the outer cells down to the keel. Fixed ballast is contained within the bottom portion of these legs to ensure that the structure has adequate stability. Like the existing Spars the structure is unconditionally stable since the center of buoyancy is above the center of gravity.
A Contraflow Tetherless Mechanical Pipeline Crawler
Authors: D&apos;Arcy Susan , Newman Bill , Broze George 
Published: October 2008

Abstract

1. Introduction
There are several situations where it would be desirable to enter and leave a flowline from one end only. Using conventional pigs, this can only be achieved by reversing the flow, which is often difficult due to the storage problems for the line's contents. In some cases, injecting back into the well has been undertaken, but this can lead to later production problems.
The current approach for using conventional pigs is to design in a second line to create a loop or to subsea pig entry facilities. Both of these are costly in CAPEX and OPEX. Therefore the project aim was to produce a tool that would travel against the wellstream flow and return with the flow back to the platform or vessel.
Market research produced a number of drive mechanisms proposed by various contractors capable of meeting the project requirements. The mechanism developed by Astec Developments Ltd. was deemed by Shell to be the most robust as it was a derivative of Astec's down-hole coiled tubing tractor.
All components of the patented tool have progressed through several stages in the last three years to arrive at the current near-optimum configuration. This paper outlines the principal functions of the base carrier tool, its potential accessory modules and a commercial basis for its adoption by other operators.
Fig. 1: Crawler Assembly Configured for Pipeline Cleaning(AVAILABLE IN FULL PAPER)

2. Base-Unit Drive Principle
The stages listed describe the operation of the contra flow crawler.A turbine extracts power from the produced fluid.The turbine internal sleeve has a magnetic coupling to the harmonic drive gearbox.The gearbox output rotates a shaft, via an articulated joint, upon which are a series of offset facings or bearing surfaces.Mounted on each bearing is a five-spoked rimless wheel or rotor (leg set). The spokes constitute the legs of the crawler and bridge the gap from the hub to the inner surface of the pipe.Since the bearings are offset and skewed, the leg sets oscillate (forwards, backwards, inward and outward) as the shaft rotates. Thus the legs forward of the centreline, of the axis of skew, contact the pipe wall at their most forward point and remain in compression contact until past the centre line. At this point their oscillation puts them closer to the pipe centre and thus free of the wall. Legs on the other side of the wheel are following the same cycle (at a different phase) on a different section of the pipe wall. Thus the leg set progresses up the pipe in a walking action.A number of leg sets are set on the shaft at progressively different angles to balance the shaft and provide more traction.The action provides only forward drive and little or no wall contact or drag on the remainder of its cycle.
Spatial Variability of the Marine Soil in the Gulf of Mexico
Authors: Valdez-Llamas Y.P. , Auvinet G. , Núñez J. 
Published: October 2008

Abstract
Using ordinary and simple kriging was carried on an estimated and simulated mapping and cross-section of the thickness of the soft cohesive soil layer found below the sea floor, and the soil water content until 100m depth, respectively. The goals of this geostatistical research is to have a better characterization of the marine soil in the Gulf of Mexico.

Introduction
New techniques are constantly incorporated in site and ground investigation procedures in order to achieve a better characterization of marine soils Simultaneously, reliability methods are increasingly used in offshore engineering. In both regards, geostatistical methods can be extremely useful. They can be used for modeling spatial variations of soil properties as well as to assess the ensuing uncertainty in the design of offshore structures.
When information based on good quality and systematic geotechnical exploration is available, geostatistical modeling of the spatial variability of geotechnical parameters makes it possible to obtain reliable estimates of the soil properties in locations where no sampling or field testing was performed and to assess the remaining uncertainty regarding the soil conditions.
This paper illustrates the usefulness of geostatistics as an auxiliary quantitative method for obtaining a better description of the marine soils of the Sonda de Campeche in the Gulf of Mexico. Spatial variability of two parameters is assessed: the thickness of the soft cohesive soil layer found below the sea floor, and the soil water content until a depth of 100 m.
The maps and cross-sections obtained through geostatistical estimation will be used for the analysis of the foundation of future offshore structures.

Random Field Theory
Soil parameters show random spatial variations that constitute an important source of uncertainty in geotechnical design. These variations and the ensuing uncertainty can be modeled using the theory of spatial random fields (Auvinet, 2002)
Let V(X) be a geotechnical variable either physical (i.e. water content), mechanical (i.e. undrained shear strength), or geometric type (i.e. thickness of a certain stratum), defined at points X of the domain of interest RP (p = 1,2 or 3). If at each point of the domain this variable is regarded as random, the set of these random variables constitutes a random field.