bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of Time-Lapse Resistivity Log Responses in a Horizontal Well to Understand the Evolution of Polarization Horns and Anisotropy
Authors: Gomes R. M. R. , Allen D. F. , Hurley N. F. , Peeters M. 
Published: December 2007

Abstract
The purpose of this study is to analyze the evolution of polarization horns and resistivity anisotropy as invasion progresses in a horizontal well drilled through a turbidite sandstone reservoir. Polarization horns are spikes of resistivity tool response that occur in highly deviated and horizontal wells. Resistivity anisotropy occurs when the resistivity measured in one direction in a formation is different from that measured in another direction.
The study area is the Albacora field, Campos basin, offshore Brazil. The reservoir is Upper Albian in age and is characterized by a sequence of massive and laminated sandstones with thin (20-30 cm) zones completed cemented by calcite. The horizontal well was drilled with salt-saturated mud and logged using a logging while drilling (LWD) 2 MHz resistivity tool. Seven time-lapse logs were obtained between 60 and 1120 hours after drilling. The time-lapse measurements show significant changes in both polarization horns and resistivity anisotropy as invasion progressed.
Two anisotropic sandstones with different types of layering were identified from offsetting vertical wells and correlated to the horizontal well. The first contains low-porosity calcite-cemented layers in which resistivity "horns", absent in the initial LWD log, developed over time. The second contains low permeability fine-grained layers which result in resistivity anisotropy on the initial LWD log.
Methodology included reservoir characterization using cores, well logs, mini-permeameter and petrophysical data from offset vertical wells. The Coates free fluid and Archie equations were used to calculate resistivities from mini-permeameter, porosity and rock type data. A geologic and invasion model was created and tested by the iterative use of tool-response modeling.
Results show that the peaks in the 2 MHz resistivity logs are polarization horns, which developed during the invasion process because of growing resistivity contrast between calcite-cemented layers and adjacent invaded sandstones. In the non-cemented parts of the reservoir, where low permeability streaks are controlled by textural variation and pore geometry, anisotropy effects occurred but no polarization horns developed.
The State of the Global E&P Industry: Is the World Running Out of Oil?
Authors: Iledare Omowumi O. , Pulsipher Allan 
Published: December 2007

Abstract1
This paper examines trends in recoverable oil reserves and performance measures in the global upstream petroleum industry for evidence to support or reject the view that the world is running out of oil. The performance measures discussed include the appreciation ratio of recoverable reserves; the replacement rate of produced reserves; reserves to production ratios; and the equitable depletion index. The empirical analysis of these indicators suggests a growing world abundance of crude oil and no strong evidence to support the imminent worldwide petroleum exhaustion theory. The analysis shows that the global oil supply market is well positioned to support even a modest growth in world petroleum demand despite institutional and regulatory barriers on resource development in some of the more intensely explored and developed regions of the world. In fact, the current estimate of worldwide remaining recoverable reserves can sustain the current worldwide production rate for at least the next two to three decades, ceteris paribus, assuming a tolerable reserve-life index of twenty years.
Competitive Strategies and Strategic Positioning of Oil Companies in the International Oil Business: Theory and Practice in Perspective
Authors: dos Santos Edmilson M 
Published: December 2007

Abstract
The purpose of this article is to analyze the concepts of competitive strategy and strategic positioning of firms in the international oil industry. The author adopted the model of competitive strategy and strategic positioning of enterprises established by Michael Porter, from the University of Harvard. Despite being one of the most well known authors on strategic management and competition theory, Michael Porter has not very often been studied and considered by those analyzing the global oil competition game. This study tries to fill this gap, by presenting a general theoretical overview of Porter's model and then by applying it in the study of the evolution of the upstream oil business.
Simulation of Process to Control Severe Slugging: Application to the Dunbar Pipeline
Authors: Henriot V. , Courbot A. , Heintzé E. , Moyeux L. 
Published: December 2007

Abstract
The severe or terrain slugging is a periodic phenomenon due to liquid accumulation at the low points of a pipe, leading to a temporary blockage. Periodically the upstream pressure increases and generates liquid slugs, for which the instantaneous flow-rate increases to several times the nominal flow-rate. To prevent such phenomena in multiphase production pipelines, a proper design and a control strategy of process equipments are required to avoid operational problems.
The TACITE compositional code is able to simulate the behaviour of transient multiphase flow in pipeline with process equipments such as controllers, valves, separators and lateral injectors which could be used to prevent severe slugging phenomena during production.
The 22 km long, 16" diameter Dunbar pipeline is designed to transport the Dunbar multiphase production to the Alwyn platform. Due to its profile, this pipe is typically subject to riser induced severe slugging for some given operating conditions corresponding to low flow-rates.
The TACITE code has been used to simulate the Dunbar pipeline in the low flow-rate region where riser-induced severe slugging occurs. For the same rates, different slug control schemes have been tested and the simulation results demonstrated that some of them can control or even eliminate the severe slugging phenomenon. This illustrates that these slug control schemes can be easily investigated and tested by use of a transient simulator. Also the simulation results demonstrate that the use of a transient simulator is essential in the engineering design phase of a slug control scheme.
Fracturing Bypassed Pay in Tubingless Completions
Authors: Olejniczak S. J. , Swaren J. A. , Gulrajani S. N. , Olmstead C. C. 
Published: December 2007

Abstract
Intervals with marginal production potential are often bypassed during the early stages of reservoir development. As existing reservoirs mature, production from these bypassed intervals offer a more economical alternative for production enhancement over either in-fill or re-drilling operations. Effective fracture stimulation of such payzones using conventional techniques can be limited by a variety of operational and economical considerations.
The integration of coiled tubing operations with hydraulic fracturing procedures overcomes many of the constraints associated with the stimulation of bypassed payzones. Specialized bottomhole assemblies are used to isolate existing perforations. A high pressure coiled tubing workstring transports the fluid and proppant system. The coiled tubing also protects the existing well tubulars from the high pressures experienced during fracture stimulation. A viscoelastic fracturing fluid is preferred over conventional polymeric fluids. This fluid exhibits significantly reduced frictional pressures and hence achieves the desired injection rates under such pressure-constrained conditions.
This paper describes the operational and design aspects of the coiled tubing fracturing procedure. A field case study is finally presented to demonstrate the economical benefits realized by this methodology.
An Empirical Model for Three-Phase Relative Permeability
Authors: Blunt Martin J. 
Published: December 2007

Abstract
We present an empirical model for three-phase relative permeability that overcomes the limitations of current formulations, such as Stone's methods.1,2 We provide a self-consistent treatment of wettability, changes in hydrocarbon composition, different saturation paths, and the trapping of oil, water and gas. The theoretical development is motivated by a review of recent three-phase experiments. The model is based on saturation-weighted interpolation between the two-phase values.3 To account for the effects of wettability we apply saturation-weighting to all three phases. By writing the relative permeabilities as unique functions of a flowing saturation, the model predicts the behavior for any sequence of saturation changes and accounts for trapping. Layer drainage, which allows oil relative permeabilities to be extrapolated to low saturation, is included for water-wet media. The model ensures smooth changes in relative permeability with changes in hydrocarbon composition and tends to the appropriate limits as the gas and oil become miscible. The model is tested against the data of Oak and co-workers.4,5 We show that it is necessary to include layer drainage and oil trapping to predict three-phase oil relative permeability at low oil saturation accurately.
A New Method of Measuring Relative Permeabilities for Calculating Gas-Condensate Well Deliverability
Authors: Mott Robert , Cable Andrew , Spearing Mike 
Published: December 2007

Abstract
Well deliverability in most gas condensate reservoirs is reduced by condensate banking when the pressure falls below the dew point, but the impact of condensate banking may be reduced due to improved mobility at high capillary number in the near-well region.
Fevang and Whitson1 have shown that the key parameter in determining well deliverability is the relationship between krg and the ratio krg/kro. They also suggested an experimental technique for measuring krg as a function of krg/kro using core plugs.
We have applied the experimental pseudo-steady-state technique proposed by Fevang and Whitson to long cores at high pressure and temperature, measuring relative permeabilites under conditions which are similar to the near-well region of a gas condensate reservoir. A gas condensate fluid is introduced into a core whose pressure is below the dew point of the fluid. The condensate saturation in the core builds up until it becomes mobile and a steady state is reached, reproducing the mechanism which occurs in the reservoir. By varying the fluid composition, core pressure and flow rate, it is possible to measure all of the relative permeability data needed to predict well deliverability, including the increase in mobility at high capillary number.
We describe the experimental techniques and present results for a sandstone core from a North Sea gas condensate reservoir, using a 5-component synthetic fluid. The results show a clear increase in mobility with capillary number, at flow rates which are typical of the near-well region.
The pseudo-steady-state technique measures relative permeabilities and does not require saturations to be measured. The dependence of krg on krg/kro can be used directly in pseudopressure methods to calculate well deliverability. We also describe how the data for krg versus krg/kro can be used to define parameters for empirical correlations of relative permeability versus saturation, so that the results can be used in reservoir simulators.
Organisational Design and Systems for Effective Safety and Environment Management
Authors: Chakraborty Ashok B. 
Published: December 2007

Abstract
This paper addresses vital issues pertaining to effective functioning of the safety and environment management (SEM) set-up in an organization. The findings of the paper are based on a project study undertaken, covering functioning of the discipline, "its organisational design, development, performance and supporting administration" in selected organizations both upstream and downstream in petroleum sector. The study entailed analysis of systems in vogue i.e. organisational set-up, objectives, functions, performance parameters, monitoring systems etc. and suggests an optimal systematic approach necessary to ensure implementation and monitoring of SEM in the organisation.
The findings of the study highlights non-existence of either uniform or standardised systems in the industry as a whole emphasis everywhere, being more on compliance with statutory requirements than in the evolving and development of SEM as a holistic and integral core of all functional activities in the organisation.
Effectiveness of safety and environment management in an organisation requires, defining of policies, objectives, activities, key performance areas, as well as development of core competencies among others.
An effective SEM facilitates implementation of total loss control, environment protection, compliance with statutory requirements, codes and standards, company's safety and environment policies and achievement of international levels of recognized safety and environment management. The requirement of safety case demonstrates, that the risk to persons in installation's be properly controlled and each safety case should be subject to formal acceptance by the regulator before operations commence and calls for an effective SEM to be in place, in professionally managed organisations.
Implementation of SEM policies and programs lead to reduction of accidental losses, improves overall productivity maintain environment protection and boosts organizational image.
Expandable Tubular Solutions
Authors: Filippov Andrei , Mack Robert , Cook Lance , York Patrick , Ring Lev , McCoy Terry 
Published: December 2007

Abstract
Two challenges facing operators as the energy industry moves into the next century are accessing of new reservoirs that currently cannot be reached economically and maintaining profitable production from older fields. Recent advances in one of the oldest and most fundamental areas of exploration and production, namely tubular technology, will play a key role in meeting these challenges.
A method has been developed whereby the diameter of solid tubulars can be expanded downhole. This paper will describe the process and how this significant technological breakthrough provides cost-effective solutions to several tubular problems that have loomed as obstacles to comprehensive reservoir exploitation. In deepwater and subsalt environments such as the Gulf of Mexico, the ability to expand casing and tubing in-situ enables hole-size maintenance and conservation of internal tubular diameter for increased efficiency. Hence, operators are less likely to run out of hole diameter before evaluating all pay zones. Operators can now use smaller holes to drill deeper vertical wells or to extend the reach of deviated wells to access untapped reservoirs. In older fields, existing wellbores can be retrofitted with expanded tubulars for repair purposes or to increase strength and integrity. In the latter case, deeper high-pressure objectives can be supported, and thus, new in-fill wells can possibly be reduced in number or even eliminated.
In addition to a description of the process employed to expand solid tubulars, the paper will present applications of expandable tubular technology and results of large-scale testing that has been conducted in support of the applications. Potential commercial applications are also presented.
Multiphase Pressure Pulses for Quick-Acting Valves: Offshore Testing
Authors: Falk Kristin , Gudmundsson Jon Steinar 
Published: December 2007

Abstract
Offshore tests were performed by quickly closing a valve by the wellhead. The rapid pressure signals, created by this valve closure, were registered at three different locations upstream of the valve. The effective actuation time of the valve was about. 0.5 second. The tests concluded that the velocity of sound in the multiphase mixture could be predicted using a homogeneous assumption. The pressure waves were attenuated because of friction, but also chokes and bends were important attenuation mechanisms for the rapid pressure waves in multiphase flow.
Case Studies of Expanding Cement To Prevent Microannular Formation
Authors: Baumgarte C. , Thiercelin M. , Klaus D. 
Published: December 2007

Abstract
To improve our understanding of cement debonding linked to microannulus formation and, in particular, to develop better non-shrinking cements to ensure zonal isolation, a well simulating annulus experiment has been developed and tests with expanding cements have been performed. The expansion experiments demonstrate that expanding cements can prevent the formation of a microannulus if the cement properties are designed with respect to the rock properties. A good application for expanding cements is the isolation of gas storage reservoirs. Two examples are shown to demonstrate the efficiency of expanding cements.
Stochastic Reservoir Modeling Constrained to Dynamic Data: Local Calibration and Inference of the Structural Parameters
Authors: Ravalec Mickaële Le , Hu Lin Y. , Noetinger Benoît 
Published: December 2007

Abstract
This paper presents a new geostatistical approach, called general inversion method, to incorporate dynamic data (pressure transient, well production, water cut…) into a reservoir model. It essentially involves two basic tools: the Fast Fourier Transform-Moving Average (FFT-MA) generator and the gradual deformation method. The FFT-MA generator produces unconditional Gaussian-related fields that can be perturbed on the basis of the gradual deformation principles. Thus, the initial structure of the realizations is preserved. Integrating these two primary algorithms within an optimization process yields the general inversion procedure. This method is outstanding for at least three points. (1) Unlike the traditional inverse approaches, the general inversion method easily accounts for the constraint relative to the prior geostatistical information; (2) the permeability/porosity distribution can be perturbed globally or locally; (3) the general inversion method makes it possible to condition the permeability/porosity distribution and the structural (or geostatistical) parameters (mean, variance, correlation length…) at once. Because of these distinct facilities, it makes sense to qualify the suggested inversion scheme as a general one.
The suggested approach was applied to a few synthetic examples. These ones were designed to address key issues such as the characterization of the permeability distribution, the updating of a reservoir model to integrate newly obtained data, and the estimation of the correlation length from well data.
Geological and Production Problems Solved by Recognizing the Strike Slip Component on Reverse Faults, Block I, Lake Maracaibo
Authors: Chatellier J- Y. , Sifontes R. de , Mijares O. , Muñoz P. 
Published: December 2007

Abstract
Despite years of oil production and numerous geological and geophysical studies, no structural and sedimentological model succeeded to adequately describe the reservoir architecture or match the production behaviour in Block VLA-31. Around a newly acquired 3-D seismic a multidisciplinary team has integrated all of the available information and came up with a radically different geological model that is coherent with the production history. The newly interpreted faults are reverse but no repetition of section is ever observed. We identified and visualized these faults through various means and discovered the strike slip component responsible for the previous mis-interpretation of the faut system.
Multiphase Flow Conditioning Using Drag-Reducing Agents
Authors: Kang C. , Jepson W. P. 
Published: December 2007

Abstract
Experimental study has been performed in a 10-cm diameter, 36-m long, multiphase inclinable Plexiglass flow loop. Superficial liquid velocities between 0.5 and 3 m/s andsuperficial gas velocities between 2 and 10 m/s in 2 degree inclined pipes were examined. A 2.5 cP oil at 25 °C was used and water cut was 50%. The experiments were undertaken at a pressure of 0.13 MPa and a temperature of 25 °C with carbon dioxide as the gas. Influence of DRA on the flow characteristics such as pressure gradient, slug translational velocity, the height of the liquid film, slug frequency and Froude number using Drag Reducing Agents (DRA) has been studied. The DRA concentrations of 10 ppm and 50 ppm were used in this study.
The DRA was effective in reducing the pressure gradient at all liquid and gas velocities. At a superficial liquid velocity of 1 m/s and gas velocities of 2 and 6 m/s, the pressure gradient decreased from 544 Pa/m to 377 Pa/m and from 793 Pa/m to 477 Pa/m in 2 degree upward inclination at a concentration of 50-ppm DRA. The corresponding DRA effectiveness was 31% and 40% respectively.
Slug translational velocity did not change much with addition of DRA. But the slug frequency and the height of the liquid film decreased with addition of DRA, which led to a decrease in pressure gradient. At a superficial liquid velocity of 0.5 m/s and gas velocities of 2 and 8 m/s, slug frequency was reduced from 21 to 16 slugs/minute and from 18 to 14 slugs/minute in 2-degree upward flow at a DRA concentration of 50 ppm. Froude number increased with addition of DRA. At a superficial liquid velocity of 0.5 m/s and superficial gas velocity of 2 m/s, the Froude number increases from 4.7 to 6.3 when 50 ppm DRA was added.
Improving Asset Performance Through Application of A Structured Decision Process
Authors: McGee M. D. , DeFoe P. R. , Robertson D. I. , McConnell J. D. 
Published: December 2007

Abstract
Company experience, external benchmarking and the application of best practices all contribute to improved capital efficiency and reduced cycle time. Combining these practices with a value-driven decision structure yields a powerful methodology for advancing a business opportunity from inception through completion. Many upstream petroleum companies currently use, or are developing, this type of methodology to improve reservoir characterization and development practices.
Through direct experience in a variety of operational situations within the Gulf of Mexico, a five-step generic decision model evolved that is straightforward, intuitive and scaleable. Core to the process is the initial definition of the opportunity, assessment of value, decision-makers, deliverables and the assignment of accountability to advance the opportunity to the next decision point. The result is a customized roadmap from opportunity identification to the post-implementation evaluation of results.
Any business process change within an active production operation is likely to meet organizational resistance. Unlike previous initiatives, this process has been well received, primarily by establishing a useable plan that is developed by the individuals directly responsible for advancing the business opportunity. Returning immediate value to the participants in the form of alignment of business value with technical detail and uncertainty has also aided acceptance and use. The authors have been directly involved in a variety of applications including complicated infrastructure retrofit projects, pipeline riser repairs, owner operated and non-operated development projects, well planning and operation support activities. The majority of applications are tangible, real-world situations that all operators routinely face.
Each application contributed to the evolution of the model. Lessons learned by the authors and their peers will be presented including cases that illustrate and reinforce essential principles of the process. Conclusions, in the form of quantified financial and technical results, will also be presented.