bluuebunny/crossref_metadata_2025_split huggingface dataset:
Incremental Improvements in 50:50 Poz Cementing Yields Enhanced Properties & Cost-effective Application
Authors: Fasesan O. A. , Heinze L. R. , Walser D. W. 
Published: December 2007

Abstract
For nearly 50 years, admixtures of 50:50 Class H (or Class C): Pozzalon with 2% bentonite have functioned effectively worldwide as lightweight slurries for situations where heavier completion cements posed a risk of exceeding low fracture gradients in a particular wellbore.Pozzolanic materials are lightweight, and effectively combine with calcium hydroxide that is liberated during the hydration of Portland cement.Historically, the 2% bentonite has been utilized to assist in the specification of relatively high water-to cement ratios, and therefore lighter slurry density, without the generation of excessive free water as the cement progresses though the setting process.Though the bentonite has fulfilled the role quite well, it has two disadvantages: first, its presence in typical cement slurries reduces the effectiveness of a given concentration of most commercially available fluid loss additives.Second, while the 2% (by weight of cement) volume may seem of no consequence, the shipping costs associated with moving tons of the material over a long period of time can be significant.
A project was undertaken to determine whether or not there were other commercially available materials that could substitute for bentonite and yield improved slurry qualities at the same or reduced cost.
Extensive testing of 50:50 slurries revealed that small quantities of sodium metasilicate (on the order of 0.5% by weight of cement) could effectively replace bentonite.Free water was controlled to the same degree, and a synergy with a commonly available fluid loss additive was discovered, allowing either a) less total fluid loss additive for a given fluid loss control tolerance, or, b) better fluid loss control for a given concentration of fluid loss additive.
The testing is summarized, and relative economics associated with the systems are discussed
Treating Uncertainties in Reservoir Performance Prediction with Neural Networks
Authors: Lechner J. P. , Zangl G. 
Published: December 2007

Abstract
In development projects reservoir parameters are only known within certain ranges – a fact that allows various realisations of the subsurface. Because of the computational time involved, not all of the possible parameter combinations can be covered by simulation models to obtain a probability distribution of possible outcomes. Creating a response surface that is based on a reduced number of simulation runs becomes necessary. Such a response surface can be utilized to approximate results for numerous different variations of input parameters. In contrast to the widely used methodology of fitting a polynomial model to the results of a limited number of simulation runs, an approach, where reservoir response is captured by an Artificial Neural Network (ANN) has been investigated.
As a first step the most sensitive parameters which affect the performance of the simulation model are determined with a limited number of model runs. These simulation runs cannot cover each of the possible model realisations, but they are intended to span over the whole range of input parameter variations. By training an ANN on the so gained simulation results, a model, which is able to interpolate between the individual simulation scenarios is created. In this way a large variety of realisations can be approximated by a limited number of reservoir simulation models.
The trained ANN model is used in Monte Carlo Simulation to generate the probability distribution of all possible outcomes. Due to the very low CPU consumption of the ANN, a large number of realisations can be calculated in a short amount of time.
Suggested Guidelines for Mangrove Assessment: An Ecosystem Approach
Authors: Lowrance C. , Myers J. E. 
Published: December 2007

Abstract
When operating in sensitive environments, mangroves and other areas with high biodiversity require broad environmental assessments that consider the full range of habitats as well as ecological processes and functions. The objective of this paper is to provide site managers and other environmental management professionals a method for mangrove assessment that follows the international guidelines of the World Bank, the Convention on Biodiversity, and the Energy and Biodiversity Initiative set forth by Conservation International. These guidelines emphasize the need to incorporate an ecosystem approach so that environmental assessment is broad and considers both long-term and cumulative secondary impacts as well as more immediate primary impacts. In order to accomplish this, mangroves should be assessed at three levels: landscape, habitat, and species health.
Landscape level assessment is necessary to identify historical trends in habitat loss or expansion, fragmentation, or degradation of mangrove over time. Various types of optical satellite imaging (Landsat TM, MSS and Spot XC), radar satellite imaging (ERS-1, JERS-1, and Radarsat), and aerial photography are used to characterize the expansion and contraction of mangrove communities over time.
Habitat level assessments take place in the field and should be designed to yield information about ecosystem or species functioning. Indicators that are discussed include species distribution and abundance, percent canopy cover, seedling densities, faunal biodiversity, hydrology, and soil and water quality.
Species level assessments consider impacts that range in magnitude from localized individuals to entire populations. These assessments use indicators aimed at individual mangrove trees and include diameter at breast height, lenticel densities, leaf morphometrics and chlorophyll concentrations, and the presence or absence of adventitious roots, pneumathodes, and other morphological adaptations that can be used to track both the structural and functional responses of mangrove trees.
Establishing Key Waste Disposal and Recycling Performance Indicators
Authors: Carley J. 
Published: December 2007

Abstract
The performance of a company's waste management program can be efficiently interpreted from waste disposal and recycling metrics for industrial and hazardous waste disposed or recycled from its facilities. This paper presents systematic methods for collecting, interpreting, and illustrating corporate waste disposal and recycling data. The generated performance profile encompasses waste management and minimization, benchmarks with objectives, and cost control issues, and it provides information to predict long-term environmental risks.
We present best practices for waste disposal and recycling parameter identification (e.g., treatment categories vs. cost and volume), efficient data collection (e.g., incorporating metric requirements of preferred vendors), and data presentation and evaluation for both hazardous and nonhazardous waste streams. These practices reduce information collection costs and time-consuming data evaluation.
In this paper we demonstrate how applying this performance data reduces long-term environmental risks and liabilities to the company through careful vendor selection, continuous vendor evaluation and monitoring, and confirming the choice of preferred vendors on a geographic basis. The volumes of waste disposed or recycled are assessed to determine if treatment categories with higher environmental risk are being used and if shifting to lower risk categories is feasible. In addition, the company demonstrates the benefits of including the waste disposal and recycling performance metrics in the environmental risk management and awareness training programs.
Implementing an Environmental Excellence Program: Encouraging Personnel to Go Beyond Compliance and Environmental Performance Metrics
Authors: Edgar J. 
Published: December 2007

Abstract
The majority of companies strongly support and encourage the active commitment of all their employees to protect our environment. This commitment is in the best interests of customers, employees, stockholders, and those in the communities in which we live and work.
How can a company demonstrate going beyond the traditional, but absolutely paramount, routes of compliance programs and metric measurement?
Line management can fulfill its leadership in this area by empowering employees to incorporate environmental initiatives into their normal course of business. The difficulties arise when trying to capture what local environmental initiatives have been conducted, especially if one operates in a global reach.
This paper will demonstrate how one service company implemented and encouraged an employee-driven Environmental Excellence Program. Since the inception of the Environmental Excellence Program in late 2001, more than 20 projects have been recognized. In the following pages we share some of these success stories.
An Integrated 3D-Seismic Exploration Method for Fractured Reservoirs in Tight Gas Sands
Authors: Reeves J. J. 
Published: December 2007

Abstract
In a tight gas exploration and development study conducted for the U. S. Department of Energy by GeoSpectrum, Inc., a 3D seismic interpretation method for fractured sandstone reservoirs is developed. The method is based on a comprehensive reservoir characterization of the Lower Dakota Sandstone in a gas producing Unit, Rio Arriba County, New Mexico.
The following reservoir attributes are used: Lead areas containing brittle reservoir rocks are defined by geologic attributes such as acoustic impedance and a collocated cokriged clay volume map for the Lower Dakota.A gas sensitive AVO seismic attribute, near-trace stacked phase minus far-trace stacked phase, phase gradient, is used to further define drill locations having high gas saturation.Reservoir fractures are predicted using seismic lineament mapping in the reservoir section.A seismic interval velocity anisotropy attribute is used to investigate fractured reservoir potential in tight sands up hole from the main reservoir target.
A four well drilling program was recently completed to test GeoSpectrum's fractured gas reservoir prospects and exploration technology. The nearly 100 percent success ratio of the drilling program indicates GeoSpectrum's fracture detection method is ready to be applied on a commercial basis.
The Application of Transient Pressure Testing to Track Phase Boundaries during Production—A One-Well Case Study from UKCS
Authors: Dahroug A. , Zheng S. , Baily J. 
Published: December 2007

Abstract
In gas fields, the most common way to define the drive mechanism is by using the material balance equation to determine the gas initially in place (GIIP).
Yet, the P/Z plot upon which the material balance equation is based can be extremely insensitive in practice, leading to a misjudgement of the drive mechanism and serious GIIP overestimation. The more sensitive Havlena-Odeh method is recommended as a means of checking the validity of the P/Z plot and as a better application of the material balance method. Aquifer support in dry gas fields will affect the material balance equation greatly and adds complexity to its application. Associating aquifer support with the difficulty of economically monitoring the gas/water contact (GWC) throughout the life of the field creates an ambiguity in efficient reservoir management. In large, long-life gas fields, 4D seismic may be a viable approach to monitoring aquifer movement, but in small developments or marginal satellites, this may prove uneconomic. One method for reducing the uncertainty of the GWC in a dry gas reservoir is being able to monitor it efficiently and economically.
This study seeks to ascertain from reservoir simulation models whether time lapse pressure transient testing during production is reliable for identifying aquifer encroachment toward producing wells in real time and also provide a useful tool for reservoir management.
Risk Analysis Method of Continuous Air Emissions from Wells with Sustained Casinghead Pressure
Authors: Duan S. , Wojtanowicz A. 
Published: December 2007

Abstract
Well cement problems such as small cracks or channels can result in gas migration and lead to sustained pressure at casingheads (SCP). Regulations require removal of significant SCP while tolerating small SCP during production operations. However, SCP of any size must be removed prior to well plugging and abandonment (P&A) as it is believed that even very small leaks might lead to continuous emissions of gas to the atmosphere. In some wells, however, small gas leaks may diminish in time as the gas migration channels are plugged off by the gas condensate. Thus, the objective of this work was to develop a method for computing potential of self-plugging in wells with SCP using priciples of phase behavior and theory of two-phase flow in small channels.
Towards Better Correlations for Water Production Prediction Using Sensitivity Analysis and Numerical Simulation Models
Authors: Zamonsky G. , Lacentre P. E. , Larreteguy A. E. 
Published: December 2007

AbstractMost of the work related to water production in oil wells found in literature deals with the problem of determining the critical flow rate for water coning, but very few has been done to determine the water production above the critical rate. Moreover, the available correlations use to differ considerably.The aim of the present study was to determine the performance of water production in a single well for a range of operational conditions and petrophysical parameters characterizing a petroleum reservoir.A well simulation model in radial geometry was constructed, considering undersaturated oil and including a water contact. The model was simple enough to allow for the simulation of the thousands of cases required to perform the sensitivity analysis at reasonably low computer cost. Variation intervals were taken for selected parameters; for the rest of them reasonable average values were considered. This technique applied to a numerical simulation model constitutes a powerful tool for generating enough statistical data to analyse the behaviour of water production.A database consisting of almost 20,000 cases was built, comprising both cases in which the production is carried out with a flow rate smaller than the critical one, and cases in which the cone instability is reached and the flow rate is higher than the critical one.Existing correlations for breakthrough time and water production were checked for validity against the database. It was found that, although in some cases they provide a reasonable approximation, there are many cases in which this is not true, despite the relative simplicity of the cases analysed.Based on this evidence, it is clear that better, more general correlations are needed. A correlation for breakthrough time was developed, for a wider range of validity than existing ones with respect to the reservoir parameters. As future work we plan to analyse the large amount of useful information generated and stored in our database to seek for functional relationships between water production and operational and petrophysical parameters.
Continuous Improvement in Fracturing Fluid Design in Gas Fields of the Italian Adriatic Sea Region
Authors: Cobianco S. , Pitoni E. , Ripa G. , Perez D. , Patey M. , Jeanpert J. 
Published: December 2007

Abstract
An aggressive design and testing program addressing a wide range of technical and environmental issues has been implemented specifically to optimize frac-pack processes in the Italian Adriatic sea region. Three formulations of viscoelastic surfactants have been developed to improve productivity and reduce environmental issues in these mineralogically immature (dirty), unconsolidated sandstone reservoirs. The first-applied viscoelastic surfactant (VES) carrier fluid used a cationic surfactant; the newly developed fluid systems use anionic and zwitterionic surfactants. Laboratory testing has focused on improving fracture conductivity, reducing formation damage, and complying with Italian environmental regulations. This paper describes the laboratory development and field application of an environmentally friendly VES system that complies with current offshore Italian regulations.
In formations with high clay content, filtrate from cationic VES fluids exhibited low retained permeability owing to surfactant adsorption on the clays. Methanol was added to these fluids to solve this problem; however, environmental constraints require the elimination of methanol. Recent laboratory tests have proven that the newly developed anionic and zwitterionc VES fluids achieve excellent permeability recovery after backflooding, without requiring methanol. The laboratory study was also performed to optimize the VES concentration as a function of the desired rheological and suspension properties. The zwitterionic VES could also be formulated with heavy brines such as calcium chloride (CaCl2) and seawater, thus providing a significant cost savings.
Results of this process confirm that environmentally friendly systems provide dramatically improved, cost effective fluids, while reducing the environmental impact of VES applications that use alcohols.
The paper also presents a field case incorporating details of execution and production results. The treatment process has been continuously reviewed to provide a more technical and environmentally acceptable service.
High-Resolution Environmental Survey around an Exploration Well Drilled with Formate Brine in the Barents Sea, Norway
Authors: Zuvo M. , Bjørnbom E. , Ellingsen B. , Buffagni M. , Kelley A. , Trannum H. C. 
Published: December 2007

Abstract
The present paper gives an overview of the environmental impact of cuttings discharges on the bentic sediments, three years after drilling an exploration well (7122/7-1) with formate brine (mixture of potassium and sodium formate) in Production Licence 229 in the southwestern part of the Barents Sea.
Eni conducted a high resolution environmental survey on the physical, chemical and biological conditions of the benthic sediments, in the vicinity of well 7122/7-1 drilled in 2000 in PL229. The cuttings and mud from the well were released to the environment as the drilling operation was conducted before the political decision to restrict the discharge of cuttings and mud from operations using water based mud (WBM) in the Barents Sea1.
The aim of the study was to verify findings in a life cycle assessment (LCA) that had been conducted for formate brine, which concluded with:
"The findings of the study indicate that the discharge of moderate amounts of Formate Brines is not likely to lead to potentially significant negative impacts on the marine environment." 2
Samples were collected from 27 stations surrounding well 7122/7-1. Apart from the reference station, all stations were within 500 meters of the well head (reference station about 3 km to the south of the well head). Samples from 22 stations were analysed physically/chemically and 19 stations were analysed biologically, in addition to the reference station. As stations were very close to each other, very high sampling accuracy was of crucial importance.
The findings in this study are in line with the conclusion in the LCA as only minor environmental impact in the vicinity of the drilling location was detected.
A New Inhibitive Water-Based Fluid: A Completely Cationic System
Authors: Rosa R. C. R. S. , Rosa A. L. A. , Farias S. B. , Garcia M. H. , Coelho A. S. 
Published: December 2007

Abstract
The development process of new technologies in drilling fluids has established that the fluid should have viscosity control and clays inhibition.Some other aspects as fluid loss control and grout thickness had become almost that decurrent of the action of the main products.The search of a highly inhibitive water-based drilling fluid (WBDF) system has been a continuous purpose in the drilling fluid industry.
We have designed and developed new materials that will improve the inhibition capacity of water-based fluid, besides favoring a complete rheology and fluid loss control of the system.Parameter viscosity reached great evolution in the last decades with the implantation of high performance polymer, capable of substituting the bentonite.Through this, the fluid with low solid became the key of the success in perforation fluids.
The developed system consists of an environment-friendly cationic polymer as shale inhibitor, a fluid-loss control, and a polymer that provides viscosity and gel structure. Components were designed for high performance water-based drilling fluids, and present the versatility to be used as much with industrial water, as seawater or saltwater, maintaining the fluid performance. This work will discuss some properties of this system, comparing with the traditional system used by Petrobras - Brazil.
Naturally Fractured Reservoirs: How To Estimate Secondary Porosity
Authors: Pérez-Rosales C. , Luna E. 
Published: December 2007

AbstractNaturally fractured rocks are very complex systems. Due to their morphological complexity, numerical simulation of naturally fractured reservoirs is lacking wholly reliable procedures for determining secondary porosity. The use of incorrect values for this variable may lead to significant deviations when simulating secondary or enhanced oil recovery processes. In this work, a procedure is presented for estimating secondary porosity. The proposed procedure is based on new ways of analyzing well log data of total porosity and formation resistivity factor. It takes into account the fact that fractures behave as flow channels whose conductivity is much greater than that of the matrix. Fundamental to the procedure is a precise physical interpretation of the parameters appearing in the generalized Archie equation, and an adequate use of the concept of rock tortuosity. This concept is used as a classifying tool to identify: (1) useful data for estimating secondary porosity, (2) zones containing conductive material, and (3) very low conductivity compact zones. Two application examples are presented to illustrate the operational aspects of the procedure.
Developments in the Visualisation of Well Tubular Condition
Authors: Oliver D. 
Published: December 2007

Abstract
Modern logging tools for the investigation of the condition of downhole tubulars provide multiple outputs derived from an array of sensors. These sensors provide simultaneous readings and are arranged so a single set of measured data is derived from a cross-section of the casing or production tubing. Data sets are rapidly updated as the tools are run in the well providing a detailed series of depth related cross-sections.
In addition to producing conventional logs in real-time, this data can be used to generate 3D images. Until recently the images produced from array tools were limited to internal dimensions. New thickness measuring tools, together with improved software, provide thickness data which can be displayed either as an image based solely on thickness or combined with internal measurements to provide 3D pictures that are analogues of the actual metal remaining within the well. These images can be used to assess both internal and external corrosion and/ or damage.
This paper describes in outline the tools used to produce the data. It employs examples from both the testing phase and initial operational deployment of the new tools to illustrate the benefits of the image approach to displaying data.