bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laboratory Studies of a Pulsed Neutron-Source Technique in Well Logging
Authors: Tittman J. , Nelligan W.B. 
Published: December 2007

Introduction
Refinements in radiation logging techniques during recent years have involved increasing usage of scintillation detectors. These detectors produce voltage pulses whose heights are related to the energies of the gamma rays which initiate them. Analysis of the gamma-ray spectrum, as indicated by the pulse heights, yields information about the chemical elements composing the formations surveyed. Refined scintillation counter techniques can furnish chemical information concerning earth formations in situ, from a study of the gamma-ray spectra emitted by the formation either naturally or as a result of neutron bombardment.
Accompanying the rising interest in gamma-ray scintillation spectroscopy, there has been increased activity in the development of accelerator-type neutron sources (in contrast to encapsulated chemical-mixture sources). Such neutron generators are attractive for several reasons:they greatly reduce radiation hazards to personnel;there is a great reduction in contamination danger if they are lost in the hole;they can produce larger neutron intensities than can conveniently available encapsulated sources; andthey are capable of being pulsed, thus permitting new techniques in logging.
In the past, both accelerator and encapsulated neutron sources have been used by others in conjunction with scintillation-detector pulse-height analysis. The results have not been too encouraging, due to the interference among different gamma-ray spectral lines and to the fact that the gamma-ray peaks were not too clearly distinguishable above the large and ill-defined background "noise".
This paper is a status report on laboratory studies of a technique using a borehole accelerator as a neutron source, which gives an improved scintillation spectrum, thus permitting more accurate chemical analyses of the formations penetrated. The Schlumberger-accelerator neutron source is presented; the origins of inelastic and of thermal-neutron, capture gamma rays are discussed, and results are given for some laboratory measurements performed in borehole geometry.
Dip-Log Computer Chart
Authors: Swift Gilbert 
Published: December 2007

The Dip-Log
A conventional Dip-Log consists of a set of three formation logging curves which register the depths of formation changes at three points around the face of the borehole, together with records of the orientation of the logging tool and the diameter of the well. The three curves may be electrical (resistivity) or mechanical (caliper) recordings.
The three curves which define the bedding planes are presented in essentially the same manner on all commercial dip-surveys. The orientation data, however, is presented in a variety of ways, one of which is illustrated by the Dip-Log shown in Fig. 1. In this form of presentation the direction of the well deviation with respect to the north-seeking end of the compass and the compass direction with respect to the direction of the No. 1 Arm are each recorded, by a separately identified trace, together with the three resistivity traces, in the right-hand column of the log. The compass trace is identified by being recorded as a series of dots while the deviation direction trace consists of dashes.
The diameter of the borehole and the angle of deviation from vertical are recorded by separate traces operating in the left-hand column of the Dip-Log.
While there are numerous other ways of presenting the orientation data the task of computing the amount and direction of dip is substantially the same regardless of the way in which the basic data is read from the log.

Computing Dip
The problem facing the user of the Dip-Log is that of computing from the observed depth differences and the recorded tool orientation data, the amount of dip relative to a horizontal plane (the true dip) and its direction with respect to north.
A number of different methods have been used in the past to solve this problem. Some of these require complicated computations involving the use of trigonometric tables. Others require several separate graph sheets together with numerical computations; while still others employ costly mechanical devices which model the subsurface situation. In contrast, the present computer chart is an 8 1/2 X 11 in. printed sheet on which a simple sequence of graphical steps enables the user to obtain the solution. This chart is used with a transluscent tracing paper overlay which becomes a permanent and reproducible record of each solution. The simplification is obtained primarily through the use of a grid based on the gnomonic projection instead of the stereographic net employed in the previous graphical methods.
Identification of Crude Oil Components Responsible for Foaming
Authors: Callaghan I. C. , McKechnie A. L. , Ray J. E. , Wainwrigh J. C. 
Published: December 2007

Abstract
The foaming characteristics of a number of crude oils from a variety of sources were determined by Bikerman's pneumatic method. Extraction of these crudes with both alkali and acid indicated that the crude oil components responsible for the foam stability were removed by the alkali extraction. Further examination of the alkali extract revealed that after neutralization it was the chloroform-soluble part of this extract (0.02% wt% of the whole crude) that was responsible for the foaming properties of the crudes investigated. This latter point was confirmed by demonstrating that the surface rheological properties of one of the extracted crudes could be restored by adding back the chloroform-soluble portion of the neutralized alkali extract. Analysis of this extract indicated that the foam-stabilizing materials were short-chain carboxylic acids and phenols of molecular weight ≤400. In principle, such analytical information could be used to identify crude oils likely to present severe foaming problems in the field. Such information could enable the process engineer to take appropriate corrective measures early in the life of a new field, thus avoiding the need for high capital expenditure at a later stage.
A Service-Life Model for Casing Strings
Authors: Klementich Erich F. , Jellison Michael J. 
Published: December 2007

Summary
Conventional casing design is based solely on the achievement of adequate design factors in burst, collapse, and tension from the loads generated by the hanging weight of the pipe, internal and external surface pressures, and fluid densities. The effects of cementing, temperature changes, ballooning, changes in cross-sectional area, bending, and helical buckling are virtually never considered. This paper describes a service-life model for the design analysis of casing strings that includes the significant factors that affect the performance of the string.
Pressure Transient Analysis in an Elongated Linear Flow System
Authors: Ehlig-Economides Christine , Economides Michael J. 
Published: December 2007

Abstract
Prominent examples of linear flow behavior in the well test literature describe flow within or to a fracture penetrated by a producing well. The characteristic pressure transients generally are exhibited in the early portion of a well test and are followed by infinite-acting radial flow behavior and/or boundary effects. In contrast, if a formation is of a predominantly linear shape, linear flow is expected to develop in late time.
In this paper, analyses of interference, drawdown, and buildup tests that are applicable to linear flow systems are described theoretically and illustrated by practical examples. The necessary equations for the analyses are provided for testing oil, gas, and geothermal steam wells.
In elongated linear flow systems, the pressure transient behavior associated with linear flow occurs late in the drawdown or buildup test. The type curves provided in this work show that this pressure behavior is distinguishable from conventional well tests, particularly in interference tests.
Hydraulic Fracturing in Waterflood Operations in Kermit, Cherrykirk and Pecos Valley Fields
Authors: Riley E.A. 
Published: December 2007

Abstract
A limited amount of published data is available which presents results of hydraulic fracturing in waterflood operations. To add to this knowledge, this report presents data resulting from frac programs performed in three different reservoirs. These programs were performed to effect both injectivity and productivity increases. The majority of applications were performed at a time during flood life which affords valid and conclusive interpretation of results.
Conclusions based upon results obtained from the frac jobs may or may nor be indicative of benefits to be gained in every field. Therefore, no panacea for lagging, negligible, or hesitant well performance is offered. However, it is suggested that sub par well performance in water flood operations may be alleviated and improved by proper applications of the popular hydraulic fracturing technique.
A total of 20 producers and four injectors were treated in the three fields. Only two applications can be termed failures; these are believed to have been due to mechanical features (handout or improper frac technique).
Theoretically, the most beneficial fracture system for flooding operations can be obtained by use of either low injection volumes and high injection rates or medium injection volumes and low injection rates. A resultant multiple fracture system of limited radial distance from the wellbore should occur.

Introduction
Requisite levels of well receptivity of productivity in waterflood operations are not necessarily incurred in every operation. Several factors attributable to local wellbore damage are possible causes.
Until quite recently, no method to improve individual well performance, other than formation fracturing with explosives (nitroglycerin) or acidization, was considered safe enough to be used. Even these methods were unsure and often created expensive cleanout work after the shot.
Pressure Maintenance in SACROC Unit Operations January 1, 1959
Authors: Allen H.H. , Thomas Jim B. 
Published: December 2007

Abstract
The SACROC Unit pressure maintenance plan does not depend on water injection alone for improving reservoir conditions, but in conjunction with 66 water injection wells located along the longitudinal axis of the Kelly-Snyder field, some 400 producing wells along the edge of the field have been shut in and their allowables transferred to more efficiently producing wells in the central portion of the field on either side of the line of injection wells.
This supplemental history will generally follow the pattern of the previous paper, bringing reported operations tip to date and also presenting additional data pertinent to the stages of development occurring thus far in the life of SACROC Unit.

Introduction
It is one thing to discover an oil reservoir of 2,800 million STB, but quite another thing to produce it. The comparison between estimated recovery by pressure maintenance and ultimate recovery indicated by primary production resulted in the creation of SACROC Unit. The organizational setup of SACROC is most complex and little understood except by those intimately involved with overall operation, but no space will be taken to discuss that subject in this paper.

Original Reservoir Conditions
The Canyon Reef reservoir of the Kelly-Snyder field encompasses some 50,000 productive acres. The field was developed by approximately 82 operators with the wells drilled on 40-acre spacing. The Canyon Reef reservoir is encountered at an approximate depth of 6,700 ft, and varies from 0- to 795-ft thick. It is a low mound shape with gently dipping flanks. Average porosity of net reef is 10.03 per cent, and average porosity of gross is 7.11 per cent. Net pay is defined as reef having 3 per cent or greater porosity. The average permeability is 30.6 md to air. Initial oil saturation was 100 per cent of hydrocarbon pore space. Average interstitial water saturation was 28.2 per cent and the average reservoir temperature 130°F. The characteristics of the reservoir fluids are shown in Table 1.
Effect of Dynamic Bit Forces on Bit Bearing Life
Authors: Dareing D.W. , Radzimovsky E.I. 
Published: December 2007

Abstract
This paper presents theory which is used to predict rock-bit bearing life reduction due to simple harmonic variations in bit forces. The theory is based on the premise that it a constant load acts for a certain fraction of the life which the bearing would have if that constant load were applied for its entire life, then the same fraction of the life of the bearing is consumed. Total bearing life is related to simple harmonic variations in bearing life associated with instantaneous bearing loads. The results show that rock bit bearing life is not affected appreciably by forces commonly impressed upon a bit, but it is affected appreciably by relatively large dynamic bit forces occasionally encountered during drilling. In addition, the results show that the life of sealed bearings is more sensitive to bit force variations than is the life of unsealed bearings.
Introduction
Roller bearings are important components in roller cone rock bits because they transmit a large portion of the drill collar weight to the formation being drilled. Unfortunately, they have a relatively short life under down-hole drilling conditions. Roller bearings are usually the first bit components to fail, and their failure leads immediately to failure of the entire bit. Short roller bearing life, and thus short bit life, is due mainly to high unit loads transmitted by the bit and to the adverse environment in which the bearings operate. The results of the study discussed in this report show how dynamic bit forces also affect roller bearing life. The purpose of this paper is to discuss theory developed to predict the effect of different magnitudes of periodic bit forces on roller bearing life. Theoretical results are used to compare the life of rock bit roller bearings subjected to steady forces to the life of rock bit roller bearings subjected m unsteady forces similar to the type of unsteady forces measured at the bit with a special downhole recording instrument.
Background
Manufacturers of bearings have conducted laboratory tests which show how bearing life is affected by steady bearing load. The well-known empirical equation which defines bearing life follows from bearing test data. It is:
L = ...................(1)
where L = bearing life, hrP = bearing load, lbC = constantq = exponent (constant).
The effect of environment on bearing performance is manifested through the exponent q and the constant, C. King, in similar tests conducted on roller bearings used in rock bits, showed that, in addition to the load, the environment (abrasive materials, chemical components, etc.) greatly affects bearing life. His data, which show how the life of roller bearings in a 7–7/8-in. W7R bit rotating at 60 rpm is affected by bit weight and fluid environment, are displayed on a log-log plot by broken lines made up of straight line segments. Each broken line corresponds to a given environment.
SPEJ
P. 272ˆ
Transient Pressure Distributions in Fluid Displacement Programs
Authors: Landrum Bobby L. , Crawford Paul B. 
Published: December 2007

Abstract
The use of a new laboratory model for studying transient fluid flow problems, is described. The theory of the model is based on the analogy between the equations which describe the flow of compressible fluids in porous media and the conduction of heat in solids.
The "thermal model" is used to study the transient pressure distributions during fluid displacement in five standard well patterns. The studies indicate quantitatively how the pressures change with time at any point in the reservoir. It was found that, in general, the equipressure contours are more radial about the wells early in the program than after steady-state conditions are established. In addition two studies of fractured five-spot patterns are presented to illustrate the applicability of the model for a wide range of reservoir conditions.

Introduction
In reviewing the oil recovery techniques involving fluid displacement it was found that a very considerable quantity, if not all of the fluid within the pattern, may be displaced during a time-dependent or transient period rather than the usually applied steady-state conditions. Since the oil is displaced during a transient period, it was believed desirable to study the nature of the transients for several of the commonly used fluid displacement patterns.
A literature review indicated fairly complete studies of the streamlines and isopotentials for steady-state, yet few data were available on the transient displacement process. Several simulated steady-state multiwell displacement programs were carefully mapped by Foster and Lodge on an electrical conducting sheet as early as 1875, but the more recent work of Muskat provides the best source for steady-state phenomena having direct petroleum production applications.
In order to study the transient phenomena a new laboratory model was developed which is based on the similarity of the equations that describe the flow of fluids and the conduction of heat. The equations describing heat flow were developed early in the nineteenth century. Rigorous solutions for most transient problems are in general complex and usually limited to fairly restricted boundary conditions. The thermal model may be used to obtain approximate solutions for many transient problems without some of the restrictions required for analytical solution.
Linear-Stability Analysis of Immiscible Displacement: Part 1—Simple Basic Flow Profiles
Authors: Yortsos Y. C. , Huang A. B. 
Published: December 2007

SummaryThe linear stability of immiscible, two-phase-flow displacement processes in porous media is examined. Multiphase-flow characteristics are included in the stability description through relative-permeability and capillary-pressure functions.A linear-stability analysis of the steady-state saturation and pressure distributions is carried out in terms of normal modes. The resulting linearized eigenvalue problems describing the early evolution of unstable modes show a certain similarity in the respective cases of negligible and non-negligible capillary effects to the Rayleigh and Orr-Sommerfeld equations governing the stability of unbounded shear flows.The stability of noncapillary displacement is first examined. Growth rates of the unstable modes as a function of the wavelength of instability are explicitly obtained for specific classes of initial total-mobility profiles. The Saffman-Taylor1 instability and layer instability2 follow directly as limiting cases of the initial-mobility profiles.The effect of capillarity on flow stability is examined next. Stability curves are obtained for step-saturation initial profiles. Both capillary pressure and a smooth initial-mobility profile exert a stabilizing influence on the flow displacement. The linear-stability-analysis predictions are compared to the results of Chuoke et al.,3 and an estimate for the effective interfacial tension (IFT) is derived. The results find application in prediction of the onset of instability and description of the early stages of unstable growth in immiscible displacement.
Oxygen Fireflooding: Combustion Tube Tests With Light, Medium, and Heavy Crude Oils
Authors: Shahani Goutam H. , Hansel James G. 
Published: December 2007

Summary
Five light, medium, and heavy crude oils were evaluated in a combustion tube, primarily at 750 and 2,000 psig [5.2 and 13.8 MPa] and with O2 concentrations between 21 (air) and 95%. The overall characteristics of combustion with O2 appear to be superior to those with air. For light and medium crude oils, when the combustion conditions are marginal (e.g., at low temperatures at which the kinetics appears to control coke combustion), the apparent kinetics and the quality of the combustion were substantially improved when O2 enrichment was used.
Three of the crude oils in this study did not burn in air; however, with the same flux of contained O2, high levels of O2 enrichment could sustain combustion. For two of the crude oils, as the O2 concentration was increased, the peak front temperatures actually decreased slightly while the O2 use efficiency increased significantly with no change in the coke loading. Further, for a heavy oil at 2,000 psig [13.8 MPa], it was found that O2 enrichment, which provided a higher partial pressure of combustion-derived CO2 and (perhaps) steam because of O2 removal, may have served to reduce the coke loading in comparison with air.
An attempt was made to correlate the relative combustion performance of four of the crude oils. It was found that a high coke loading alone was not adequate to ensure satisfactory in-situ combustion. The relative reactivity of the coke with O2 also appeared to be critical.
Effect of Fractional Wettability on Multiphase Flow Through Porous Media
Authors: Fatt Irving , Klikoff Waldemar A. 
Published: December 2007

Abstract
The concept of fractional wettability is examined. Fractional water wettability of a reservoir rock is defined as the fraction of the internal surface area that is in contact with water. Capillary pressure and relative permeability of unconsolidated sand are shown to be functions of fractional wettability.

Introduction
The petroleum industry has long recognized that wettability of reservoir rock has an important effect on multiphase flow of oil, water and gas through reservoirs. As early as 1928 the American Petroleum Institute sponsored a study of wettability as part of API Project 27 at the U. of Michigan. Despite 30 years of research, there is still little exact knowledge of the wettability of reservoir rocks.
There are two parts to the wettability problem. After agreeing to a uniform nomenclature in regard to wettability, the first question to be answered is, "What is the in situ wettability of a given reservoir rock?" If this can be answered the next question is, "What part does wettability play in determining the characteristics of multiphase fluid flow through the rock?" This paper represents an oblique attack on the problem of wettability. No attempt is made here to answer the basic question of wettability in situ. Instead the consequences of the concept of fractional wettability are examined. Multiphase flow in sandpacks is shown to be highly influenced by fractional wettability.
Jennings has given a definition of wettability and the other terms used in discussing wettability. These terms must be applied to the physical situation existing in reservoir rock. A survey of the pertinent literature from 1928 to 1956 indicates that the concept of a contact angle was applied to reservoir rock in the same way it would be applied to a flat, homogeneous surface. Attempts were made to state quantitatively the wettability of a reservoir rock in terms of a contact angle which was presumably constant at all points on the very rough and heterogeneous interior surface of a porous rock. Calhoun, et al, prepared synthetic consolidated and unconsolidated porous media in which they claimed there was a known uniform contact angle. They then showed the effects on the capillary pressure and relative permeability characteristics of varying this angle.