bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measuring Strategic Investment Value
Authors: Campbell J. M. , Campbell Robert A. , Brown Stewart 
Published: December 2007

Abstract
The quest for better investment decisions, especially under conditions of low prices, has stimulated interest in new methods for quantifying and managing projects. Journals are full of articles outlining the benefits of options theory, decision-trees, contingent claims analysis, simulations, portfolio theory, etc. Each method corrects a specified, well-documented deficiency in traditional valuation procedures.
This paper summarizes the recent criticisms of traditional methods, especially the gap between individual project valuation methods and the strategic objectives of the organization. After reviewing the limitations of traditional discounted cash flow (DCF) analysis, including NPV, IRR, etc., we seek to outline a more comprehensive understanding of DCF that corrects the inherent contradictions at work in most organizations, especially with the tendency to emphasize short-run objectives at the expense of longer-term, strategic investments.
The Fallacy of the Hockey Stick Projection
Authors: McMichael Claude 
Published: December 2007

Abstract
Uncertainty assessment is gaining industry acceptance as an essential part of reservoir and project evaluations. Major research efforts have been undertaken and significant progress made in techniques to evaluate risks. These new techniques provide better estimates of reservoir volumes and future production performance, as well as, defining the uncertainty associated with these estimates. Unfortunately, most research efforts have focused on technical risks and few have studied the equally important risk due to economic and price uncertainty.
Traditionally within the industry, price uncertainty is assessed using a range of forecasts representing the optimistic, most likely, and pessimistic cases. These forecasts are commonly represented by monotonically increasing future prices and, due to their characteristic shape, often referred to as "hockey stick" projections. While common, such projections demonstrate little resemblance to historical price performance and have proven to be poor projectors of future prices.
This paper proposes a new approach based on crude price history over a fourteen-year period from 1/1/85 through 1/1/99. The method assumes that the observed price changes represent "normal price fluctuations" and that future price performance will be statistically similar to the historical data. The "bootstrap" method is used in conjunction with historical data to estimate a statistically similar set of future price forecasts. Each of these distinct forecasts has the same statistical properties and variability as the historical data. The set of price forecasts is then used to evaluate the impact of "normal price fluctuations" on project economic uncertainty.
Application of the method is demonstrated with examples. The frequency distributions of key economic indicators are evaluated for the example case. These can be used to establish the economic viability and associates risk of the project.
In practice, the method is easily applied and most useful in defining the sensitivity of a project's economic viability to "normal price fluctuations" irrespective of the underlying causes of the fluctuations.
Study of Sweet Corrosion at Low Water Cut in Multiphase Pipelines
Authors: Kang C. , Jepson W. P. , Gopal M. 
Published: December 2007

Abstract
Large diameter, long distance multiphase flow lines are now the predominant trend in oil and gas production. Economics demand the use of carbon steel as the material of construction. However, carbon steel is prone to corrosion from the flowing mixture of oil/water and gas. The prediction of the onset of corrosion with increasing water cuts is very important in the design and operation of the flow lines. A study of corrosion for high pressure, large diameter pipelines under horizontal and 2 degrees oil/water/gas multiphase flow conditions was carried out. The water cuts studied were 10%, 20% and 30% ASTM saltwater. A light oil with viscosity of 2 cP was used as the oil phase. Carbon dioxide gas was used in the gas phase. Temperature was maintained at 40 °C. The superficial gas velocities ranged from 1 m/s to 9 m/s under pressure of 0.27 MPa, 0.45 MPa and 0.79 MPa. The predominant flow was found to be slug flow and all corrosion experiments were carried out in this regime.
The results show that measurable corrosion still occurs even at these low water cuts. For example, at a carbon dioxide partial pressure of 0.79 MPa for 30% water, the corrosion rate increases from 2.2 mm/year to 3.3 mm/year with an increase in Froude number from 6 to 12.
The corrosion rate increases with an increase in slug frequency at the same Froude number. At a pressure of 0.27 MPa, Froude number of 6 for 30% water cut, the corrosion rate increases from 0.8 mm/year to 1.4 mm/year with increase in slug frequency from 6 slugs/minute to 38 slugs/minute. At a Froude number of 12, the corrosion rate increases from 1.2 mm/year to 2.3 mm/year with increase in slug frequency from in slug frequency from 6 slugs/minute to 43 slugs/minute.
At a pressure of 0.27 MPa, Froude number of 6 for 10% water cut, no corrosion was observed in horizontal pipes.
Case History of Complex Fracture Behavior in the Hanoi Trough, Vietnam
Authors: Cipolla Craig L. , Mayerhofer Michael , Wilson Brian L. 
Published: December 2007

Abstract
This paper presents a detailed case history of complex fracture behavior in exploratory wells in the Hanoi Trough, Vietnam. The target formations are stacked fluvial channel deposits that occur at depths of 10,000 to 12,000 ft. The initial three wells were drilled from the same pad, with bottomhole locations about 3,000 to 5,000 ft apart and a probable fault between the No. 1 and No. 3 well. The gas reservoirs encountered were slightly over-pressured and varied significantly in quality, with permeability ranging from 0.01 mD to 1 mD. The first three wells were fracture stimulated in an attempt to improve deliverability. However, only one of the three treatments was successful due to complex fracture behavior. A comprehensive data set consisting of core analysis, rock mechanical tests, pre-and post-fracture logs, geochemical analyses, pre- and post-fracture well tests, and detailed fracture modeling was compiled to understand fracture performance in this complex environment. Without such a complete data set, identifying the cause of the treatment failures would probably not have been possible.
Perforating for Stimulation: An Engineered Solution
Authors: Lestz R. S. , Clarke J. N. , Plattner D. , Byrd A. C. 
Published: December 2007

Abstract
Point source perforating has reduced fracture stimulation expenses in the South Texas Lobo trend. Although the producing intervals frequently exceed 100 ft, the operator typically perforates the bottom 5 ft of the interval. Data collected during perforating is used to design optimized fracture-stimulation treatments. The optimized treatments average 55% less proppant than the previously designed jobs using conventional practices with perforations across the entire pay interval. The new well's initial production and sustained performance has been higher than the conventionally stimulated wells of similar potential. In addition, the point source perforated wells have produced significantly less proppant than similar wells with perforations across the entire pay interval. Point source perforating has reduced the cost of perforating, proppant, fluids, equipment rentals, and cleanup.
This case-history paper presents: historical account of previous completion practices (limited entry, multiple-stage fracturing, full-zone perforating)discussion of the "perforating for stimulation" fracturing technique currently usedcomparison of production resultsformation evaluation methods (logs, bottomhole gauges)perforating methods (phasing, charges, perforating interval selection)
Orienting Live Well Perforating Technique Provides Innovative Sand Control Method in the North Sea
Authors: Eriksen Jan Hilding , Sanfilippo Francesco , Kvamsdal Arne L. , George Flint , Kleppa Erling 
Published: December 2007

Abstract
The Varg field is a development in the North Sea operated by Saga Petroleum. It consists of a not-normally-manned wellhead platform (WHP) with dry wellheads and a floating production storage offloading (FPSO) vessel for processing the crude. The reservoir is heterogeneous sandstone of Upper Jurassic age, with estimated reserves of approximately 35 million stock-tank barrels.
During development planning of the field, it was felt that sand production was likely to occur, and this phenomenon was actually experienced during well testing. Since this development was considered to be a marginal field, an extensive program was initiated to review and select a technical completion solution that would minimize the risk of sand production so that production potentials could be maximized. This paper will discuss how a unique perforating solution was developed to provide the controls needed to manage the potential for sand production.
The first part of this paper will summarize: 1) the drainage strategy and implications of this strategy on selecting the perforation intervals, and 2) results of a rock mechanics study that focused on the conditions critical for the onset of sand production as well as recommendations for minimizing the risk. The primary recommendations were to avoid perforation of the weakest intervals and to shoot perforations that would be oriented parallel to the maximum horizontal stress.
The second part of the paper will describe how successful oriented perforating was achieved in these wells. The primary completion challenges included the following: Development of a slickline system that could perforate the entire zone simultaneously in a given direction in a vertical well.A means to remove the perforating guns from the well without having to kill it after completion of the perforation as there was insufficient rathole to leave the guns in the hole.
An oriented modular perforating system was developed so that the above conditions could be achieved. The requirements were met by installing a gun anchor in the well before the completion was installed. Then, the orientation of an orienting lug was measured with a gyro, and based on the data from the survey, the guns were aligned in the correct orientation. Subsequently, gun sections of length maximized to available lubricator length were run on slickline. The gun section aligned itself automatically to the measured orientation of the orienting lug because of the equipment design. Currently, three wells have been perforated using this system, and the desired results have been obtained.
Simulation of the Immiscible WAG Process Using Cycle-Dependent Three-Phase Relative Permeabilities
Authors: Larsen Johne Alex , Skauge Arne 
Published: December 2007

Abstract
Oil recovery by immiscible WAG is dependent on the saturation cycles that occur in a core-flood or in the reservoir. For the reservoir case, segregation of gas and water can generate other saturation cycles than in a core-flood. In order to predict WAG behavior in the reservoir from experimental results, numerical models with an effective hysteresis description of the three-phase oil, water and gas relative permeabilities should be considered.
There has earlier been developed a methodology that accounts for both three-phase flow effects and hysteresis effects in numerical simulations of the immiscible WAG process. Simulation studies have shown how three-phase flow description may influence the choice of drive mechanisms and also the design of a WAG process.
Furthermore, a principal component analysis (PCA) is conducted on the simulation model that is consistent with the experimental data. The results from the PCA showed how the hysteresis parameters in the simulation model may be correlated to the physical system. The PCA analysis describe how the three-phase effects in water and gas relative permeabilities are connected to oil recovery.
The results show that the cycle-dependent relative permeabilities increase the potential for WAG. Furthermore, the oil production trends with respect to slug length and water-oil ratio is different for models with cycle-dependent hysteresis and without hysteresis.
A New Three-Phase Relative Permeability Model For Various Wettability Conditions
Authors: Moulu J-C. , Vizika O. , Egermann P. , Kalaydjian F. 
Published: December 2007

Abstract
A mathematical model for three-phase flow has been previously developed and validated in water-wet and spreading conditions. The model was based on a description of the porous medium considered as a set of fractal pores. The fluids are allowed to flow together in a same pore, gas in the center, and, for water-wet conditions, water in the vicinity of the walls and oil as an intermediate phase.
The objective of the present study is to confirm that the above model is able, when properly applied, to describe more general wetting conditions. Three-phase relative permeabilities are obtained by history matching gas injection experiments performed in water-wet and oil-wet porous media. Two fluid systems characterized by spreading and non-spreading of oil on water in presence of gas were used. The model is properly modified to take into account different wetting conditions through a wettability index.
It is shown that the model is able to correctly predict oil recovery and breakthrough time for a series of gas injection tests performed under secondary and tertiary conditions. In water-wet condition, the presence of water next to the solid wall determines the shape of the pore space available for the oil and gas flow. It is observed that the fractal linear dimension decreases, with increasing water saturation, from the dimension of the roughness (DL=1.72) to the one of a cylindrical pore (DL≈1). In oil-wet condition, water looses its ability to model the wall of the medium since oil is preferentially in contact with the solid surface. This leads to a constant DL, the value of which corresponds to the surface roughness. In this last case the presence of water in the center of the pores decreases the gas mobility.
Validation of a Modified Carman-Kozeny Equation To Model Two-Phase Relative Permeabilities
Authors: Alpak Faruk O. , Lake Larry W. , Embid Sonia M. 
Published: December 2007

Abstract
This paper presents a validation of an internally consistent, physically based model for relative permeability based on an extension of the Carman-Kozeny (CK) equation. The modified CK (MCK) expression is a function of surface areas of fluid-fluid and fluid-rock interfaces, as well as fluid saturations and tortuosity. The model uses interfacial and surface areas determined from capillary pressure measurements and, by this means, can incorporate variable wettability and hysteresis as well as assuring consistency of petrophysical properties.
To validate the MCK approach, the model is fit to experiments where both capillary pressure and relative permeability are measured simultaneously during flow. The MCK model is further fit to literature-reported water-oil experimental data. Besides the MCK model, each data set is fit with a modification of the commonly used Brooks-Corey (MBC) model to compare the performances of the two.
The surface areas derived from capillary pressure relationship used in the MCK model provide a good description of the experimental relative permeabilities measured under the same conditions. The investigated MCK model fits experimental data almost as well as the MBC model. Furthermore, the MCK model is physically based and appears to agree with the wetting characteristics of the investigated porous media when these are known.
Wave Structure in WAG Recovery
Authors: Marchesin Dan , Plohr Bradley J. 
Published: December 2007

Abstract
For immiscible three-phase flow, potentially three-quarters of the oil recovered through a WAG process can be caused by a non-Buckley-Leverett "transitional" shock wave. This non-classical kind of wave is common in three-phase flow. In this paper, we show how transitional waves arise in WAG flow and how they can be calculated by semi-analytic methods, which are helpful in the design of effective WAG recovery strategies.
Influence of Connate Water and Condensate Saturation on Inertial Effects in Gas-Condensate Fields
Authors: Lombard J-M. , Longeron D. , Kalaydjian F. 
Published: December 2007

Abstract
Reliable predictions of productivity decline of gas-condensate wells require a proper description of complex flow behavior occurring in the near wellbore region. In that region, high pressure gradient induces both large condensate saturation and high gas velocities which may lead to significant deviations from Darcy's law for gas permeability. At the present time, no physically relevant model does exist which takes into account these non-Darcian two phase flow phenomena. This paper presents a contribution to the improvement of the description of gas-condensate flowing properties in the near-wellbore region. A laboratory study has been performed with the aims (i) to estimate the influence of the pore structure on the gas inertial coefficient β and (ii) to integrate the effect of the condensate dropout in the Forchheimer flow equation. Specific laboratory equipment has been built in order to perform gas-condensate displacements under conditions as representative as possible of near wellbore conditions i.e. pressure, temperature and velocities up to 1.5cm/s. Experiments were conducted to measure β on sandpacks and sandstone core samples, with and without connate water saturation (Swi), using dry gas (N2) and analog gas-condensate systems (C1-C3 mixtures). For dry gas floods, the measured β-values were found in good agreement with previous published data. β was found to increase with water (immobile) saturation. In addition a new correlation between β and a mean pore radius, r*, is proposed. Gas-condensate steady state experiments performed at different values of condensate saturation showed that β-values increased with the total liquid saturation. Finally a comprehensive methodology is presented to determine, for each specific application, the relevant parameters which must be taken into account to correctly predict the productivity decline.
Multiphase Non-Darcy Flow in Gas-Condensate Reservoirs
Authors: Wang X. , Mohanty K. K. 
Published: December 2007

Abstract
The understanding of multiphase non-Darcy flow is important to the modeling of production from gas-condensate reservoirs. A pore-scale network model is presented here for gas-condensate flow. Porous media are modeled by networks of pore bodies interconnected by pore throats. Pore bodies and throats are characterized by their connectivity, shape, and radii distributions. Pore-level laws are identified from previously published micromodel and multiphase pipe flow experiments. The condensate can flow due to three mechanisms: pressure gradient within the sample-spanning condensate phase, movement of condensate slugs, and condensate droplets carried by the gas flow. The second mechanism appears at high capillary numbers and the third mechanism at high Reynolds numbers. Inertial terms are important for high rate gas flows. This model has been used to identify several flow regimes important to gas-condensate flow. The effect of pore structure is calculated on gas and condensate relative permeabilities in the low capillary number regime. The relative permeabilities and non-Darcy coefficients have been computed for the low condensate saturation-high pressure gradient flow regime.
Isolation and Characterization of Thermophilic Microorganisms from Malaysian Oil Fields
Authors: Illias R. M. , Ooi S. W. , Idris A. K. 
Published: December 2007

Abstract
Oil and water samples were colected from selected Malaysian oil wells and all the experimental works were carried out in laboratory. The samples have been grown in enrichment medium containing hydrocarbon and incubated at temperatures from 40°C to 60°C. Sixteen thermophilic microorganisms have been isolated. All the isolates are able to grow at aerobic and anaerobic condition. Preliminary characterization indicated about 4 groups of gram-positive rod-shaped microorganisms. Growth temperature studies have been done for these isolates, and found that most of the isolates grown better at temperature ranged from 45°C to 50°C. The purpose of this study is to demonstrate the presence of large number of thermophilic microorganisms in Malaysian oil reservoir. This is still a new information for Malaysian oil industry. The isolated microorganisms are capable of producing biopolymer, biosurfactant, and acids, which have vast application in Microbial Enhanced Oil Recovery (MEOR) and environmental biotechnology.
Pore-Size Distributions in Vuggy Carbonates From Core Images, NMR, and Capillary Pressure
Authors: Ausbrooks Robin , Hurley Neil F. , May Andrew , Neese Douglas G. 
Published: December 2007

Abstract
Vugs, which are defined as pores larger than adjacent grains, are common in many carbonate reservoirs. Such pores are not always recognized by conventional wireline logs. The purpose of this study is to compare pore-size distributions in Oligocene carbonates from China using core, borehole images, nuclear magnetic resonance, and capillary pressure.
The Kerr-McGee CFD2-1-2 well was drilled in the Bohai Basin in China. The reservoir consists of dolomitic limestones and fractured dolomite. The core (25 meters) was polished and inked with fluorescent paint, then photographed under black light to generate high-resolution, 2-D black and white photos. Image analysis produced detailed information about vug size and depth. Core images were then used to calibrate a Formation MicroImager (FMI) log, so that pixel counts of vugs from the FMI would match core observations.
Nuclear magnetic resonance (NMR) logs measure the T2 relaxation time, a parameter that is a function of pore size and reservoir fluid composition. Laboratory NMR measurements for six core plugs have been compared to pore-size distributions from core images. These distributions are comparable for high T2s (above 92 milliseconds).
Mercury intrusion capillary pressure (MICP) measurements are used to determine pore-throat size distributions. These distributions, which can be directly compared to NMR and image analysis pore-size distributions, have very similar shapes.
The net result of this study is that a technique has been developed to relate core-calibrated borehole images to NMR and MICP data. This is an important step in the difficult process of understanding NMR log behavior in vuggy carbonate rocks.