bluuebunny/crossref_metadata_2025_split huggingface dataset:
Short-Range Multivariate Process Prediction for Use in Automatized Systems
Authors: Durrer E.J. , Somerton W.H. , Mueller T.D. 
Published: December 2007

Abstract
Automatic process control requires the maximum amount of information about the future behavior of parameters that affect the regulated system. For a particular set of processes, formal mathematical relationships describing this behavior can be established. However, certain processes cannot be described by formal processes cannot be described by formal relationships and their analyses must be based on statistical evaluation of their past histories. In the particular case of multivariate processes, particular case of multivariate processes, regression and time series analyses are the two most powerful tools which can be utilized to describe powerful tools which can be utilized to describe their behavior and to project this behavior into the future.
The above techniques were studied using data from a small natural gas distribution system. The natural gas demand for space heating and the prevailing meteorological conditions were prevailing meteorological conditions were recorded hourly for a group of 14 residential homes in Northern California for over a year's time. Statistical evaluation of the data included study of the correlations of precipitation, wind velocity and direction, radiation, relative humidity, and temperature with demand. Temperature and relative humidity showed the best correlation with demand.
Stepwise regressional analysis applied to the parameters and various combinations of them parameters and various combinations of them revealed that mean values or gradients, predominantly of temperature conditions, are needed in predominantly of temperature conditions, are needed in order to stabilize the system and to obtain reasonable predictions. However, due to the averaging propensity of regressional analyses, peak demands are not well predicted. This peak demands are not well predicted. This difficulty is minimized if one uses methods of time series analysis. Various methods for detrending and elimination of periodicities were checked in order to obtain stationary series to which autoregressive spectral analysis can be applied. Linear filters seem to be simple and yet are as powerful as more complicated ones. Of the three powerful as more complicated ones. Of the three algorithms (matrix defactorization and the autoregressive schemes of Hingorani and of Robinson) tested for spectral analytic predictions, Robinson's proved to be the most efficient. This algorithm also has the advantage that, in addition to better accuracy than the regressional analysis only a relatively short record length is necessary. Therefore, for example, no corrections for population growth in the demand are needed. population growth in the demand are needed. In the present application it was concluded that the greater accuracy of the Robinson algorithm far outweighs the additional costs incurred by the lengthier computations and greater complexity of the method over regression analysis.
Fatigue Failure of API 8-Round Casings in Drilling Service
Authors: Payne M. L. , Leturno R. E. , Harder C. A. 
Published: December 2007

Abstract
This paper presents case studies of casing fatigue failures in API 8-Round STC and LTC connections. This mode of failure is unique and unfamiliar to most industry personnel. The failure mode is important because of the inherent cost of casing failures and because fatigue failures most often occur in drilling casings near the surface, thereby exposing operations to severe well control risks. Key considerations in these fatigue failures include casing and cementing design, landing, drillstring/casing interactions, dimensions and gauging of 8-Round connections, casing ovality, and mill and field make-up control. Conclusions from field and engineering data are provided, along with recommendations to eliminate these failures.
Hole-Cleaning Study of Polymer-Based Drilling Fluids
Authors: Zamora Mario , Jefferson D. T. , Powell J. W. 
Published: December 2007

ABSTRACT
A laboratory study was conducted to substantiate the exceptional hole-cleaning performance of "rheology engineered", biopolymer-based mud systems used in Prudhoe Bay, Alaska, horizontal wells. The study focused on the impact of very-low-shear-rate viscosity and evaluated the combined effects of rheology, flow rate, velocity profile, eccentricity, pipe rotation, and inclination on hole-cleaning efficiency.
The study confirmed that the rheological "fingerprints" of the biopolymer fluids provide optimum hole-cleaning and suspension. These benefits were attributed to the time-independent, yield-pseudoplastic behavior not obtainable with traditional viscosifiers. Engineering of the specially formulated biopolymer fluids represents a clear departure from conventional methods and field rheological concepts.
Rheological properties of the drill-in fluids were simulated by solutions of clarified xanthan gum. The biopolymer fluids consistently outperformed pseudoplastic, hydroxyethyl cellulose fluids tested for comparison. Hole-cleaning studies were run on two flow loops; measurements were taken on several types of rheometers to characterize the fluids. Videotape recordings documented the interaction and interdependence among the hole-cleaning parameters and allowed measurement of velocity profiles in tubes and annuli.
Petroleum Applications of Emerging High-Pressure Waterjet Technology
Authors: Iyoho A. W. , Summers D. A. , Galecki Greg 
Published: December 2007

Abstract
The emergence of reliable systems for developing high pressure waterjet (HPWJ) technology during the past few years has created a tool capable of concentrating intense cutting energy over very small surface areas. However, the use of jets at very high pressure (&gt;14,500 psi; 100 MPa) requires sophisticated equipment and an expensive delivery system, with considerable maintenance costs. To over come this problem, recent trends by investigators are to develop systems which combine waterjets at lower pressure (about 5,000 psi, 35 MPa) either with conventional mechanical drill bits, or with abrasive-laden cutting fluids.
Over the past several years, the University of Missouri-Rolla (UMR) has been one of several institutions which have made significant theoretical and experimental contributions to these innovative developments. Applications of this technology for use in horizontal drilling, mining and environmental systems are discussed in this paper. Results show that with the increased reliability of equipment and improved technical knowledge and experience, the emerging technologies of high pressure mechanically assisted and abrasive-laden waterjet tools can be increasingly applied in improving performance for both conventional and the more challenging conditions of horizontal drilling.
Coring Technology for Point McIntyre Wells
Authors: Wylie G. S. , Rathmell J. J. , Tibbitts G. A. 
Published: December 2007

Abstract
Nine wells were cored in Alaska’s North Slope Point Mclntyre field to provide engineering and geological data for oil reserve estimates. The goals for this coring operation were: (1) provide high quality permeability, porosity, and water saturation core data using mineral oil base mud, and (2) achieve 100% core recovery. Low invasion coring methods were used. Coring, core handling procedures, a new core bit, a new mineral oil base coring mud, and a new chemical tracer for the mud filtrate were developed for the Point Mclntyre operation. This paper describes the bit development, coring, and handling procedures. The mud and tracer developments are documented in companion paper, SPE 26326.1
Point Mclntyre’s reservoir is lithologically complex, consisting of high permeability consolidated quartzose sandstone, low permeability highly cemented litihic sandstone, occasional lithic conglomerate, and occasional poorly consolidated quartzose sandstone. Existing core bits were not optimal for low invasion coring at Point Mclntyre. The hard rock low invasion bit developed for the Point Mclntyre project has smaller, more numerous cutters to increase bit stability and eliminate the tendency to cut undergage cores. Coring rates using the new bit were increased in the harder racks. This core bit achieved low mud filtrate invasion in the low as well as the better quality sands.
Bits and core barrel lengths were selected to maximize the core recovery and minimize rig time. Cutting of core plugs occurred immediately upon arrival in Anchorage. The goal was to keep elapsed time as short as possible to minimize tracer diffusion in the core. In the first two wells, core plugs were cut and trimmed both at the well site and in Anchorage to evaluate the time dependence of tracer distribution in the core and effectiveness of preservation methods. Time dependent effects of water saturation and mud filtrate distribution were not observed. Core plugging was moved to Anchorage for the remainder of the project. The coring methods used at Point Mclntyre provided 99.6% recovery, for 3,068 feet cored with less than 2% of the cored interval having significant mud filtrate invasion in 10 md to 2,000 md pay zone intervals. Technology development for this project was accomplished rapidly and was successful. The technology applied here produced high quality data. This enabled the coring program to be reduced with substantial cost savings. Other cost savings were obtained from high quality operational planning.
CO2 EOR Economies for Small-to-Medium-Size Fields
Authors: Flanders W. A. , McGinnis R. A. , Shatto A. G. 
Published: December 2007

ABSTRACT
CO2 projects undertaken in the past have generally been large fields that benefited from economy of scale and substantial remaining life. Future CO2 projects will generally not have these advantages. However, since the CO2 source and distribution infrastructure are in place, many smaller oil fields may be candidates for CO2 enhanced oil recovery (EOR). This paper investigates the economic viability of conducting CO2 EOR operations in small to medium-size fields under today’s market conditions. The evaluation uses actual production data from a representative CO2 project, current costs to equip the field for CO2 operations, and operating costs in the actual range of ongoing projects. Sensitivity to these factors plus depth and porosity acre-feet are discussed. The economic impact of EOR tax incentives are also considered. Each potential EOR project must be evaluated for its specific conditions. Rate of return and cost values cannot be directly applied to other EOR projects, but can be used as a guide to relative profitability.
It's Time to Educating the Supervising Engineer
Authors: Schwartz D. H. 
Published: December 2007

Abstract
This paper covers the education required of engineers who directly supervise technical staff. Why is this training important? What skills are required? What is wrong with the way we are currently training our supervisors? What type of program is required? These questions form the foundation of a study which eventually relied on sources outside of the Petroleum Industry as there had been little published by the industry. In 1987, the National Research Council along with four other prominent groups, formed the Task Force on Management of Technology and published "Management of Technology: The Hidden Competitive Advantage." The study listed eight primary needs for the management of technology and was the catalyst for the growth of an industry aimed at training managers of technology. Using the NRC conclusions as a guide and looking outside of the Petroleum Industry, this paper develops the justification for and approach to educating supervisors of technical staff.
A New, Fast Parallel Simulated Annealing Algorithm for Reservoir Characterization
Authors: Ouenes Ahmed , Saad Naji 
Published: December 2007

ABSTRACT
This paper presents a new parallel simulated annealing algorithm for computational intensive problems. The new algorithm enables us to reduce the overall time required to solve reservoir engineering problems by using the simulated annealing method (SAM). A simple geostatistical optimization problem (variogram matching) applied to two fields is used for illustration purposes. The reduction of computation time starts by optimizing the sequential simulated annealing algorithm. This task is achieved by an efficient coding and an appropriate choice of topology. Three different topologies are used and their effects on the overall run time and the quality of the generated image are discussed. After optimizing the sequential algorithm, the problem of high rejection rate at low annealing temperature is solved by using parallelization. The new algorithm uses, in an optimal manner concurrently many sequential algorithms. The number of concurrent algorithms is adjusted throughout the optimization to increase the acceptance rate with the optimal use of a CPU. The new algorithm was implemented on a CRAY Y-MP with 4 processors. A 50,400 (280x180) gridblock field was used to test the parallel optimization method. The overall run (clock) time was reduced by approximately the number of concurrent calls of the sequential algorithm.
Semianalytic Solutions for a Well with a Single Finite-Conductivity Vertical Fracture
Authors: Blasingame T. A. , Poe B. D. 
Published: December 2007

ABSTRACT
In this paper, we develop a simple, closed form approximation for the Laplace transform solution for the case of a well with a finite conductivity vertical fracture in an infinite-acting reservoir. Our hybrid solution is based on a coupling of the solution for a bilinear finite conductivity vertical fracture model (which does not model radial flow) and the solution for a uniform flux/infinite conductivity vertical fracture (which does model pseudoradial flow). These solutions are readily obtained from the literature.
Overall, we consider our solution to be valid for CfD≥0.5 and we show that our solution gives less than 1 percent error in both pD and p D’ for CfD&gt;2. We suggest that our hybrid solution is not valid for CfD&lt;0.5 and do not recommend its use for CfD&lt;0.5 under any circumstances.
We have verified this solution against four different solutions given in the literature. Each comparison was excellent which suggests that our simplified solution is more than adequate for practical applications. In particular, we provide verification for constant rate and constant pressure production for values of CfD between 0.25 and 10,000. We also show that our solution is capable of producing very accurate derivative functions.
In addition, by reproducing the literature solutions so well, we also verified that individual flow regimes (formation/fracture bilinear flow, formation linear flow, and pseudoradial flow) are all modeled accurately by our new solution.
A Lithology-lndependent Porosity Model Using Three Neutron Measurements: Part II—Applications and Error Analysis
Authors: Oraby M. E. , Wolcott D. S. 
Published: December 2007

Abstract
A lithology independent porosity model, N3LIP, using three neutron measurements, thermal and epithermal neutron porosity and thermal absorption cross section, was developed and presented at the 33rd SPWLA annual logging symposium (reference 1). This model considers any formation, regardless of its mineralogical composition, as two major regions. The first region is the pore space which is filled with fluid, while the second, the matrix, is the rest of the formation. N3LIP deals with the second region, the matrix, as a black box. The model calculates matrix diffusion length, which is the most lithology dependent parameter of a formation, without a need to know its lithological composition. This matrix diffusion length is calculated using two different techniques while iterating on porosity. The final solution, porosity, is deterrnined by analyzing the difference of the diffusion lengths.
In Part I (reference 1), the methodology of N3LIP was described in detail and applied to some artificial logs generated using SNUPAR (reference 2) as a forward model. Here, the applications of this model to actual reservoirs are presented, and an error analysis of the calculated porosity is discussed. N3LIP has been used to calculate porosity in two different types of reservoirs, shaly sandstone and carbonates. The shaly sand reservoirs are Kuparuk in the North Slope and Long Beach in California, while the carbonate reservoir is Sycamore in the Permian Basin.
Due to concerns of the environmental effects on the calculated neutron measurements, especially the borehole rugosity on the epithermal tool, the uncertainty in the calculated porosity using N3LIP in those reservoirs has been studied by applying uncertainties to the logs that have been used. The effect of these uncertainties are presented and discussed in detail.
Reservoir Scale Sandbody Architecture of Pliocene Turbidite Sequences, Long Beach Unit, Wilmington Oil Field, California
Authors: Lowry Philip , Jenkins C. D. , Phelps D. J. 
Published: December 2007

Abstract
This paper presents the results of a characterization of flow-unit geometry in a series of basin-floor turbidite reservoirs. These reservoirs occur in the Long Beach Unit, a mature, densely drilled field in the Los Angeles basin, California. The efficiency and quality of the zonation effort was enhanced by the application of proprietary well log correlation software. This software enables rapid correlation of a large number of wells as well as quantification and visualization of the resultant stratal geometries. At the field-wide scale, sandbody geometry is characterized as laterally offset, en-echelon, lobate units. Dimensions of these sandbodies range from 2-3 miles along depositional strike, to 1-2 miles along depositional dip. Numerous deterministic shales occur within these sandbodies, dividing them into smaller units that are 40-60 ft thick and separated by shales that are up to 5 ft. thick. These smaller sandbodies are lobate in form, but several have a pronounced elongate morphology. Their lateral dimensions range from 0.5-1 mile along depositional strike and 0.5-1 mile along depositional dip. Although the focus of this study was to provide a description of a densely drilled mature reservoir, results from the study reveal qualitative and quantitative insight into the architecture of this commonly encountered clastic reservoir type. Data from these types of field studies may be used to complement outcrop data for use in deterministic correlation or probabilistic modeling of similar reservoirs where the density of well data is much lower.
Pressure-Transient Behavior and Inflow Performance of Horizontal Wells Intersecting Discrete Fractures
Authors: Guo Genliang , Evans R. D. 
Published: December 2007

ABSTRACT
New analytical pressure-transient solutions and dynamic inflow performance equations for horizontal wells intersecting discrete fractures in an infinite reservoir are presented. The horizontal well is assumed orthogonally penetrating multiple identical and parallel fractures. The reservoir containing the horizontal well is bounded by non-flow parallel planes at the top and the bottom. The pressure-transient solutions are derived using the source and Green's functions developed by Gringarten and Ramey, as well as the superposition principle. The dynamic inflow performance equations are derived by applying the derived transient solutions.
The derived analytical pressure-transient solutions may provide a theoretical basis for the analysis of the transient pressure behavior of horizontal wells intersecting discrete fractures. New evaluation techniques may be developed for determining reservoir properties and fracture characteristics from horizontal well testing. The dynamic inflow performance models presents a theoretical tool for evaluating the effects of fractures on horizontal well performance. They are particularly useful in the production modelling of horizontal wells in tight reservoirs with natural or induced fractures.
Core Porosity Measurements Using Gamma Rays
Authors: Bodwadkar S. V. , Reis J. C. 
Published: December 2007

Abstract
This paper discusses a method for measuring the porosities of core or outcrop samples using the attenuation of gamma rays. The method has been experimentally validated against porosities measured with Archimedes’ method on a variety of lithologies and over a range of porosities. The method is fast, non-destructive, and can characterize small scale heterogeneities in porosity. The lithology and fluid saturations must be known, however.
Nuclear Magnetic Resonance of Rocks: T1 vs. T2
Authors: Kfeinberg R. L. , Straley Christian , Kenyon W. E. , Akkurt Ridvan , Farooqui S. A. 
Published: December 2007

Abstract
It has recently become possible to make pulsed nuclear magnetic resonance (NMR) measurements of subsurface geological formations in situ. The longitudinal relaxation time, T1, has long been the parameter of greatest interest to petrophysicists. However modeling shows that T1 measurements are not repeatable when NMR logging tools move past bed boundaries. Therefore measurements of the transverse relaxation time, T2, must be relied upon. Unfortunately, reservoir rocks have properties that make T2 measurements difficult to interpret. We discuss the relationship between T1 and T2, and the measurement conditions for which T2 gives meaningful petrophysical information.
The Importance of the Geological Model for Reservoir Characterization Using Geostatistical Techniques and the Impact on Subsequent Fluid Flow
Authors: Bashore W. M. , Araktingi U. G. , Levy Marjorie , Schweller W. J. 
Published: December 2007

ABSTRACT
Fluid-flow simulation results are used extensively as reservoir performance predictions upon which to base economics for reservoir management decisions. The generation of numerical models for simulation purposes may be easily facilitated by computer-aided algorithms, regardless of the quality of data or input parameters. This study focuses on potentially erroneous conclusions deduced from simulator predictions if the simulation models are built without a sound geologic framework and the incorporation of seismic-based information. Models derived from two different correlation strategies, lithostratigraphic and chronostratigraphic, using well logs only are compared. Seismic inversions are included within the chronostratigraphic framework as a third model type. Histograms of breakthrough times indicate little difference between the well only models of either correlation strategy, whereas water displacement patterns are significantly different. Selection of the appropriate simulation results is closely tied to the reservoir management objective in question. Models which have been conditioned by the seismic pseudo-logs show substantially different results for both breakthrough and displacement distributions, and the spread or uncertainty in breakthrough estimates is greatly reduced compared to the log-only model results.
A cloud transform method with correlated probability fields is introduced for stochastically estimating one model parameter (porosity) from another (impedance). This method allows incorporation of the scatter in the relationship between the two parameters (crossplot).