bluuebunny/crossref_metadata_2025_split huggingface dataset:
Examples of Cased Reservoir Analysis in the Ventura Basin, California
Authors: Odom Richard C. , March Kathryn S. 
Published: December 2007

Abstract
The oil fields of the Ventura Basin are very mature with many wells drilled before the advent of modern logging tools. Despite the years of development, there remain opportunities for cost-effective production, given the great thickness of the productive intervals and the dynamic-nature of the depositional and tectonic environment that created them.
Cased-reservoir analysis in existing wells is an efficient tool to target productive intervals. The well-logs and analysis examples utilize pulsed-neutron technologies. The cased-hole neutron and density porosities from the pulsed-neutron system provide the porosity information and describe gas-bearing intervals. Water flooding and gas injection has changed many of the original fluid properties. In the log analysis examples, Carbon/Oxygen logging describes the water saturations, and Sigma logging helps in the discrimination of the sands from the mudstones.
Natural Gas: The Revolution Is Coming
Authors: Economides M.J. , Oligney R.E. 
Published: December 2007

Abstract
Natural gas today accounts for about 22% of the world energy demand. This figure is skewed because of the 26% gas market share in the biggest consumer of them all, the United States. In Europe, outside of the former Soviet Union, with a population of 1.5 times that of the United States, gas accounts for 19% of the market. In terms of per capita energy consumption, the average U.S. citizen consumes about 2.2 times more gas than a European. These ratios both for total usage and gas market share in the energy mix became much more lopsided for almost all countries. A move toward increasing gas use is now under way, both from a demand and supply standpoint. For example, Brazil, the world's tenth largest economy with a current gas market share of 5%, has embarked into a very ambitious plan of increasing gas use. Several gas-producing countries have also announced very ambitious plans for markedly increased gas output. These include Qatar, Oman, Venezuela and, potentially the largest of them all, Saudi Arabia. Liquefied Natural Gas (LNG) facilities are currently being built, and LNG tankers are forecast to experience very serious shortages over the next three to four years. The United States has made an emphatic move toward increased gas use. Already less than 5% of electric power generation uses oil. Well over 90% of new power generation built in the United States over the next decade will be fueled by natural gas. Gas-fired turbine manufacturing is experiencing a three-year backlog. Once manufacturing catches up with demand, the transition to natural gas will cause substantial shortages for a considerable stretch of time—covering not just the traditional peaks in winter heating but also new peaks associated with summer electricity demands. More crucial, we believe that environmental concerns, real or imagined, will push the emergence of fuel cells much faster than currently envisioned. Natural gas will be in the center of this transformation, resulting in a greatly expanded market share of gas in the world energy mix, increasing to 40–50% by the year 2020.
We present below a comprehensive analysis of the current state of natural gas supply and demand; we provide the conventional forecasts and rationalize our forecasts, which are heavily influenced by electric deregulation, LNG conversion and fuel cells.

Introduction
At the time of this writing, natural gas consumption in the United States has reached an estimated 23 trillion cubic feet (Tcf) per year. This is very near the highest consumption rate of natural gas, which was experienced in the 1972–1974 period. Figure 1 presents the history of natural gas consumption in the United States and the other G-7 countries (Canada, France, Germany, Italy, Japan and the United Kingdom).1
Experimental and Numerical Study of Drilling Fluid Removal from a Horizontal Wellbore
Authors: Biezen Ewout , van der Werff Niels , Ravi Kris 
Published: December 2007

Abstract
After a well has been drilled, the drilling fluid should be removed and replaced with either cement and/or completion fluids. For effective zonal isolation and optimum hydrocarbon production during the life of the well, the entire drilling fluid should be removed from the annulus. Cement and completion fluids are sensitive to drilling fluid contamination, and even a thin layer of oil-based drilling fluid could prevent the cement from bonding to the formation and the casing. In addition, for optimum hydrocarbon production, the cement sheath must be able to withstand the stresses throughout the life of the well.1
Several factors affect the success of drilling fluid removal from horizontal annuli. Under static conditions, drilling fluid usually forms a gel structure. Under positive differential pressure, the drilling fluid loses filtrate and forms a filter cake on the formation face. Sometimes the filter cake is mushy and difficult to remove, but the formation fluid can easily flow through it. The successful removal of the gel and mushy filter cake depends on the structures that form and how these structures behave under flow conditions. In addition, casing centralization affects the fluid flow profile in the annulus, which affects gel and filter-cake removal.
To investigate the mechanism of drilling fluid removal, we conducted both numerical and experimental studies. In the experimental studies, chemical flushes and spacers were tested for their effectiveness in removing drilling fluid. The experiments showed that annulus cleaning begins around the inner pipe and progresses outward at increasing fluid flow rates. Analytical fluid flow models and full 3D multiphase numerical models allowed us to estimate flow profiles and the success of removing drilling fluid under downhole conditions. The large-scale experiments and analytical/numerical modeling have led to a better understanding of the factors controlling drilling fluid removal from horizontal wellbores.
Underbalanced Drilling at its Limits Brings Life to Old Field
Authors: Labat C. P. , Benoit D. J. , Vining P. R. 
Published: December 2007

Abstract
Underbalanced drilling along the Gulf Coast recently brought new life to an old field. Natural gas misted with diesel was used to drill the low permeability Smackover and Norphlet formations at the Hatters Pond field north of Mobile, Alabama. The success of the project along with a four-fold increase in production has generated new interest in an old asset. This case history reviews how detailed safety hazard analysis and proper planning resulted in a safe and successful operation even under the most extreme design and regulatory requirements.
Field Application of Glass Bubbles as a Density-Reducing Agent
Authors: Arco Manuel J. , Blanco José G. , Marquez Rosa L. , Garavito Sandra M. , Tovar José G. , Farias Antonio F. , Capo Jesus A. 
Published: December 2007

Abstract
This communication describes preliminary results and observations of a successful application in a field environment that incorporated hollow glass spheres, also known as glass bubbles, as a density reducing agent in a drilling fluid. In this field application, a proprietary oil-in-water emulsion fluid developed by PDVSA-INTEVEP which contained hollow glass bubbles (3M) was used during the drilling of a producing interval. The oil-in-water emulsion provided a suitable fluid base, whereas the glass bubbles, by virtue of their low density, imparted a lower finished density than that of the corresponding base fluid. The density lowering capacity of the glass bubbles is proportional to the concentration of bubbles incorporated in the fluid.
The field trial substantiated that the fluid-glass bubble pair is stable, homogenous, and compatible through conventional mud motors, bits, surface cleaning equipment, and of such rheological and filtrate properties, as to lend itself to be used in low pressure reservoirs and in producing zones of high permeability.
During this field application, we were able to lower and maintain the density of the base fluid at 7.1 PPG. Additional oil production increase was observed relative to a vicinal well (vs. GF-134D) drilled with oil based fluids at an excessive overbalanced. This observation may suggest that damage to the producing zone has been avoided.
This technology is an alternative to the use of aerated fluids, with potential economic and technical advantages due to the elimination of surface compressing and air injection controller equipment, and to the simplification of operations required to avoid excessive overbalance during pipe trips.
Other potential benefits of using this low density fluid includes torque reduction as a result of higher lubricity, reduction in casing wear, higher penetration rates, decreased formation damage, lost control mitigation, and the use of mud pulse MWD tools. Glass bubbles are also a viable alternative to reduce the density of water based drilling fluids, oil and polymer-based fluids, and brines.
Laboratory tests were also carried out with conventional fluid systems to include water-based, 100% mineral oil and oil-in-water emulsions, with different concentrations of LITEDENTM in order to evaluate the potential field use of such formulations as substitutes for aerated fluids in wells which might require lower density fluids. Several formulations for the systems mentioned above were developed with the purpose of achieving maximum density reduction without affecting filtrate control or rheological properties. Fluid densities as low as 5.5 and 6.0 ppg were obtained for corresponding 100% oil and O/W emulsions based fluids.
Relative Permeability Modification in Gas-Liquid Systems Through Wettability Alteration to Intermediate Gas-Wetting
Authors: Tang Guo-Qing , Firoozabadi Abbas 
Published: December 2007

Abstract
The wettability of Berea and chalk samples for gas-oil and gas-water fluids were altered from strong liquid-wetting to intermediate gas-wetting. Two polymers, FC-722 and FC-759, were used to alter the wettability. FC-759 is soluble in water and some 20 times less expensive than FC-722. Gas and liquid relative permeabilities were measured before and after wettability alteration. The results demonstrated a significant increase in liquid-phase relative permeability. Gas-phase relative permeability for a fixed saturation may increase or decrease. However, because of the very high liquid mobility and reduced liquid saturation, the gas mobility also increased for a fixed pressure drop.
A number of liquid injectivity tests were also carried out. The results revealed that the liquid-phase mobility could increase significantly when the wettability of rocks was altered from strong liquid-wetting to intermediate gas-wetting. All the results show clearly that the application of wettability alteration to intermediate gas-wetting may significantly increase deliverability in gas condensate reservoirs.
Use of Solvents To Improve the Productivity of Gas Condensate Wells
Authors: Du Liangui , Walker Jacob G. , Pope Gary A. , Sharma Mukul M. , Wang Peng 
Published: December 2007

AbstractExperiments have been done with a retrograde gas condensate fluid to measure the decrease in gas relative permeability due to liquid dropout below the dew point and to evaluate the use of methanol to restore the gas relative permeability. The methanol was found to increase the end-point gas relative permeability by a factor of 1.2 to 2.5 depending on the initial water saturation. A likely reason for the increased gas permeability is the miscible displacement of the condensate and water phases by the methanol. The use of an inexpensive solvent such as methanol to improve the productivity of gas wells that have been damaged by production below the dew point due to condensate and/or water blocking presents an attractive approach deserving further investigation.
Differential Scanning Calorimetry: A New Technique to Characterize Hydrate Formation in Drilling Muds
Authors: Dalmazzone Christine , Dalmazzone Didier , Herzhaft Benjamin 
Published: December 2007

Abstract
With the increasing number of deep offshore drilling operations, operators and service companies are confronted to more and more complex technical challenges. Extreme conditions encountered at these depths require an adaptation of the drilling muds. In particular, range of temperature and pressure (up to −1 °C and 400 Bars) are favorable conditions to the formation of gas hydrates. Hydrates are solid structures formed from water and gas: water contained in drilling muds will form under certain temperature and pressure conditions, a solid cage which entraps the gas molecules. Formation of these solid gas hydrates is liable to plug kill and choke lines as well as the annular, and may cause interruption of the drilling operation and even destruction of rig equipment. Deep offshore drilling operators are aware of this problem and some operational solutions and drilling mud formulations are proposed and utilized, but when extreme water depths are attained, classical inhibitors solutions alone may be ineffective. The usual way to determine the thermodynamic conditions of the formation of hydrates in drilling mud formulations is to use PVT cell. This technique required heavy instrumentation and often does not permit to work with a whole formulation (specially in the presence of solids). Moreover, PVT cells do not give a quantitative evaluation of the kinetic properties of hydrate formation.
In this work, we present experiments using Differential Scanning Calorimetry (DSC) to determine the thermodynamic equilibrium properties and kinetic of hydrate formation in whole mud formulation. With this technique, we measure heat transfer as a function of time, temperature and pressure and thus detect phase transition. The possibility of characterizing hydrate formation with this technique is shown for the first time on a synthetic mud formulation. Validation with PVT cell measurement and investigation of the influence of several additives (salts, solids) are performed. Hydrate formation on a whole mud formulation is underlined. This technique is easy to use and when correctly interpreted permits to determine the dangerous zones for hydrate formation.
Real Options Application: From Successes in Asset Valuation to Challenges for an Enterprise-Wide Approach
Authors: Faiz Soussan 
Published: December 2007

Abstract
Various "business technologies" will distinguish future industry winners. For instance, the Real Options paradigm is emerging as the state-of-the-art methodology for asset valuation. The concept of an "efficient frontier" is also making headway for Portfolio Optimization within the energy sector. The notion of Enterprise Risk Management (ERM) is being viewed as far more effective and efficient than the current "silos" in companies’ risk management practices. In addition, the proponents of Value-Based Management (VBM) are fostering a more integrated and shareholder-focused approach to performance measurement and accountability.
There is, however, a large gap in both the literature and in practice on combining Real Options with Portfolio Optimization and linking these efforts to ERM, VBM, and the broader business perspective. The ability to integrate and align these disjointed initiatives is of critical interest to senior executives. A seamless enterprise-wide approach is needed.
This paper discusses some insights and challenges of a Real Options application, a Portfolio Optimization case study, an ERM method, and a VBM concept. It concludes that while these approaches are visibly superior to their traditional predecessors, they are limited if applied in isolation. Although the paper does not provide the solution, it proposes a framework for the integration effort, which could equip executive management with a cohesive and orchestrated enterprise approach.
Use of Carbon Oxygen Logs Run in Open Hole in Wells Drilled with Oil Base Muds
Authors: Sullivan M. J. , Stewart W. F. , Belanger D. L. 
Published: December 2007

Abstract
The Cabinda concession offshore Angola has several oilfields where waterflood operations are being used to enhance recovery. Because the injected water has a relatively low water salinity (33 kppm NaCl equivalent seawater), detection of zones experiencing injection water breakthrough is difficult using traditional Pulsed Neutron Capture logging tools, which rely on measurement of chlorides in saline formation waters. One technique frequently employed in these circumstances is the use of Carbon Oxygen logging tools. These tools measure the relative abundance of carbon and oxygen, thereby distinguishing oil from water independent of salinity. These tools are usually run in existing wells that have been on production for some time. In some fields however, active infill drilling programs are underway where new wells are drilled through producing horizons that may have already been swept with low salinity injection water. These swept layers can be difficult to distinguish from oil-bearing intervals using conventional resistivity logs. Recently, Carbon Oxygen logging tools have been run in open hole as part of the standard open hole logging program. This has proven to be an effective means of distinguishing oil from low salinity water before casing the well, despite the influence of mud filtrate invasion.
Effect of Trapped Gas on Relative Permeability and Residual Oil Saturation in an Oil-Wet Sandstone
Authors: Kralik J. G. , Manak L. J. , Jerauld G. R. , Spence A. P. 
Published: December 2007

Abstract
A comprehensive set of experimental data from preserved reservoir sandstone is used to demonstrate features important to oil-wet systems not usually included in water-wet three-phase relative permeability models. The data are described by a generalized version of the relative permeability model developed by Jerauld (1997). The impact of these features on immiscible and miscible water-alternating-gas performance is estimated with type pattern simulations.
The sandstone reservoir studied shows large amounts of spontaneous imbibition of oil and traps water during secondary drainage. Oil relative permeability is almost a function of oil saturation alone while water relative permeability is significantly lower in the presence of trapped gas. Unlike most systems, the trapped gas saturation depends on the relative amounts of oil and water. While two-phase trapped gas values are consistent with values in the literature for similar sandstones, three-phase trapped gas levels are approximately a factor of two lower. The residual oil saturations for waterflooding and gasflooding followed by waterflooding are the same. Furthermore, the incremental oil production during the waterflood following gasflooding was minimal.
Two different lithologies show the same general behavior. Experiments run with different pressure drops demonstrate that the low trapped gas saturations are not due to capillary desaturation. CT scans show that little redistribution of gas occurs during trapping.
History, Trends and Evolution of Float-Over Deck Installation in Open Waters
Authors: O’Neill L. A. , Fakas E. , Ronalds B. F. , Christiansen P. E. 
Published: December 2007

Abstract
Float-over deck (FOD) installation is no longer a novel approach for heavy integrated decks. It is estimated that over 20 FOD installations have been carried out in open (unsheltered) waters over the past 20 years, which have proven the reliability and cost-effectiveness of this method.
FOD installation is an alternative to lift-installing integrated decks using heavy-lift crane vessels. Although the former may not be the most cost-effective solution in areas where such vessels are readily available, it is increasingly becoming an important solution for deck installations in remote parts of the world. This is due to the considerable cost associated with crane mobilisation in such areas. FOD installation also accommodates integrated deck weights in excess of the lift capacity of crane vessels.
This paper provides a database of all documented FOD installations in open waters to date and addresses the technical issues and challenges, with particular emphasis on the complexity, reliability and effectiveness of the technology used. Trends in deck weight and installation sea-states are also illustrated, confirming the growing confidence of the industry towards FOD installation. Indicative cost comparisons with alternative installation methods such as a single heavy lift or a multi-lift modular installation are also presented for some cases. The paper also elaborates on the limitations of installation methods used to date. Finally, a brief introduction is made to several recent innovations, which focus on the improvement of conventional FOD installation systems as well as the development of novel systems suitable for developments in Australia and worldwide.
An Improved Model for Predicting Separation Efficiency of a Rotary Gas Separator in ESP Systems
Authors: Harun A. F. , Prado M. G. , Shirazi S. A. , Doty D. R. 
Published: December 2007

Abstract
An improved model is presented capable of predicting the separation efficiency of a rotary gas separator in ESP systems. The model incorporates a new two-phase flow inducer model capable of calculating the inducer head. The inducer head generated by a rotary gas separator has been identified as a key parameter that distinguishes between a separator’s high and low efficiency regions. This information was previously determined empirically, but now can be calculated. The new model predicts more accurately the liquid rate at which a rotary gas separator should be installed. A comparison of the model’s predictions with water-air and hydrocarbon-air experimental data indicates that the improved model performs better than earlier models.
Estimation of Bottomhole Pressure in Pumping Oil Wells: Effect of High-Viscosity Fluids and Casinghead Pressure
Authors: An H. , Scott S. L. , Langlinais J. P. 
Published: December 2007

Abstract
The ability to monitoring bottomhole flowing pressure in pumping oil wells provides important information regarding both reservoir and artificial lift performance. Converting surface pressure measurements to bottomhole is currently accomplished by locating the fluid level in the annulus using a sonic device and then applying a correlation to estimate the density of the gas-cut liquid column above the perforations. This gascut liquid column exhibits Zero Net Liquid Flow (ZNLF) conditions where the casing head gas flows through a nearly stagnant liquid. A review of literature reveals that the correlations currently in use by the industry are based on low pressure and low viscosity data. Increasingly, operators are encountering high viscosity fluids and in some instances, casinghead gas flows into gathering systems which are not the typical low pressure systems. This paper presents recent experimental measurements for ZNLF under high viscosity and pressure conditions. The results indicate that viscosity and pressure have a significant effect on the calculated bottomhole pressures and that these effects are not accounted for in the currently applied methods. New methods are presented to calculate multiphase density, i.e. gradient correction factor, under high viscosity and high pressure conditions.