bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Stability Approach to Torsional and Lateral Bit Dynamics
Authors: Abbassian Fereidoun , Dunayevsky V. A. 
Published: December 2007

SummaryThis paper addresses the dynamic stability of polycrystalline diamond compact (PDC) bits under induced torsional and lateral vibrations. Dynamic stability is investigated by considering three simple mechanical systems representing string-torsional vibration, bit-lateral dynamics, and coupled torsional-lateral vibration of the bit-string assembly. For each system, the rotary-speed (rev/min)/ weight-on-bit (WOB) domain within which the system is dynamically stable is determined. The influence of various drillstring and bit parameters on the stability of bit motion is studied through their effect on the size of the stability zone on (rev/min)/WOB plots. These illustrate the power of the stability approach in providing valuable qualitative information on the main parameters influencing bit stability.
Early Evaluation of Uncertainties in the Incremental Condensate Recovery Through a Gas Cycling Process
Authors: Massonnat Gérard , Bachtanik Claire , Tutenuit Emmanuelle , Gouel Patrick , Carles Nicolas 
Published: December 2007

Abstract
The process of evaluating and assessing a reservoir early in its development is rather difficult and uncertain although the results of the evaluation may have far-reaching consequences for the reservoir. This paper proposes and describes a methodology for enhancing this assessment. The method involves several basic steps including: identification of key heterogeneities, their quantification, the development of models representing the full breadth of variations in heterogeneity, the detailed modeling of limited areas of the reservoir to assess the effects of the model and geologic uncertainties, and the use of these results for calibrating up-scaled full-field models. The methodology is applied for a gas condensate reservoir appraised by only two wells in which the choice of recovery process (primary depletion or gas-cycling) has not yet been made.
Given that the key heterogeneity is unknown at this early stage, stochastic modeling is then undertaken on a grid emphasizing vertical discretization.
In order to provide contrasted models clearly showing the uncertainty associated with the geological model, two "end-member hypotheses" are used, based on the uncertainty as to the frequency and range of the heterogeneities.
Simulations carried out on only part of the reservoir show how sensitive the results are to the range of the heterogeneities. This is illustrated particularly clearly in the gas-cycling option in which gas injection is much more effective in the case of low range heterogeneities than for long range heterogeneities.
After optimizing the clustering of fine grid cells into coarse grid cells, it is demonstrated that simulation results obtained on a fine grid model can be reproduced with a significantly smaller number of layers.
The Differentiation Method in Rheology: III. Couette Flow
Authors: Savins J.G. , Wallick G.C. , Foster W.R. 
Published: December 2007

Abstract
The theory of the differentiation method for the Couette flow experiment is reviewed. Particular attention is given to the requirements on data analyses in the case of the class of non-Newtonian materials described as viscoplastics, i. e., materials characterized by a yield point or yield stress. Here, changes in boundary conditions arise when the shearing stress attains a critical value with the result that the form of the basic integral equation for Couette flow is determined by the flow conditions existing during the measurement.

Introduction
In the preceding papers in this series, the salient features of the differentiation method of rheological analysis in Poiseuille-type flow were discussed. It was shown that a dual differentiation- integration method analysis of the Poiseuille flow of idealized generalized Newtonian and visco-plastic models could be used to develop a spectrum of highly sensitive response patterns in terms of certain characteristic derivative functions. These functions were shown to optimize the selection of the most appropriate functional relationship between f(p) and p from the Poiseuille flow experiment. The present paper reviews the theory of the differentiation method as applied to the equally important Couette flow experiment. We will also discuss the range of variables over which the basic integral equation for Couette flow is applicable when the non-Newtonian material is of the viscoplastic type, i.e., characterized by a yield point or yield stress.

THEORY
Having described the application of the differentiation method to Poiseuille-type flow in the preceding papers, we now proceed to the case where the test liquid is confined to the annular space between coaxial cylinders of length L, one of which is in motion, i.e., Couette flow, formulating the basic integral equation after the method of Mooney. The observed kinematical and dynamical quantities are the angular velocityand the torque T. Here, the one nonvanishing component of the shear-rate tensor is
........................(1)
and the corresponding component of the shearing-stress tensor at any point r is given by
..........................(2)
The shearing stresses at the inner surface of radius R(1) and the outer surface of radius R(2) are related by
.................(3)
Combining Eqs. 1, 2 and 3, letting = 0 at p = p1 and = at p = p2 and integrating yield
.........................(4)
Note that the definite integral has a finite lower limit. Differentiating Eq. 4 with respect to p1, following the rule of Leibnitz (i.e., in Eq. 11 of Ref. 1), gives a difference equation in the desired function
..................(5)
This result was initially obtained by Mooney who used it as a starting point for an approximate solution. Several other approximate solutions of the difference equation have been described, the principal results of which are described in the succeeding sections. The interested reader is referred to the original papers for the details.
SPEJ
P. 14^
The Effect of Temperature and Pressure on the Interfacial Tension of Water Against Methane-Normal Decane Mixtures
Authors: Jennings Harley Y. , Newman George H. 
Published: December 2007

Abstract
The interfacial tension of water against mixtures of methane and normal decane bas been measured in the interval 74 to 350 degrees F and 14.7 to 12,000 psia. These measurements show the range of interfacial-tension values obtained with water against an ideal "live-oil" system under reservoir conditions of temperature and pressure. The interfacial-tension data were obtained by the pendent drop method. The density data used for pendent drop method. The density data used for the pendent drop calculations were based on visual cell pressure volume measurements of the mutually saturated phases. Seven systems covering the methane-decane composition range from 100 percent decane to 100 percent methane were studied at three temperatures and 11 pressure intervals in the single-phase, hydrocarbon region.
A minimum in the interfacial-tension vs methane-decane composition curve was observed. The minimum occurred at about the same composition in each isotherm, namely, with a mixture containing nearly equal weights of methane and decane. Both temperature and pressure affected the interfacial tension. For some compositions at constant pressure the interfacial tension increased with increased temperature.

Introduction
Although crude oil usually occurs in the formation saturated to some degree with methane, interfacial-tension data for methane-oil mixtures against water have not been published. These data are fundamental to an understanding of the role of interfacial forces in oil recovery and provide a basis for interpreting the interfacial tensions against water obtained with "live" crude-oil systems.
We obtained interfacial tensions against water for an ideal "live-oil" composed of mixtures of methane and normal decane. Portions of this three-component (water, methane, normal decane) system have been studied and reported and these data serve as limits for our results. Hough et al. presented data for the methane-water system at presented data for the methane-water system at temperatures to 280 degrees F and pressures to 15,000 psia. Stegemeier studied the two-phase methane-decane system to 183 degrees F and 5,100 psia, and Jennings published results for the normal psia, and Jennings published results for the normal decane-water system to 350 degrees F and 12,000 psia.
In this study we have obtained data for water-oil interfacial tension as a function of temperature to 350 degrees F. and pressure to 12,000 psia, using a series of live oils of known composition. The interfacial-tension data were obtained by the pendent drop method.
A Generalized 3D Well Model for Reservoir Simulation
Authors: Ding Y. 
Published: December 2007

Abstract
Well modelling plays an important role in reservoir simulation. Commonly used well models are based on the 2D analytical pressure solution (radial flow) and on an "adequate" numerical productivity index calculation. These models applied to 3D simulations may give erroneous results, especially while modelling undulating wells (slanted wells), multi-lateral wells, finite-length horizontal wells or partially penetrating vertical wells. The main reasons are the lack of 3D pressure solution and the inaccurate flow calculation near the well.
In this paper, the layer potential is introduced for representing the 3D pressure distribution of the steady-state flow in the vicinity of wells. The flow approximation is improved by modifying the near well transmissibilities, taking into account this 3D pressure solution. This new well model is valid for any well configuration and allows to describe accurately 3D well behaviour.
Theory of Multicontact Miscible Displacement with Nitrogen
Authors: Dindoruk Birol , Orr Franklin M. , Johns Russell T. 
Published: December 2007

Abstract
Solutions obtained by the method of characteristics (MOC) for displacement of mixtures of methane, butane and decane by nitrogen or nitrogen/methane mixtures are used to explain conflicting experimental observations concerning the sensitivity of minimum miscibility pressures to changes in the compositions of an initial oil or the injection gas. The solutions presented show why some investigators have reported weak dependence of the minimum miscibility pressure (MMP) on methane concentrations while others have reported significant sensitivity. The analysis of displacement composition routes indicates that either observation can be correct for some ranges of initial and injection fluid compositions, and shows that the sensitivity behavior depends on the relative positions in composition space of three key tie lines (the initial, injection, and crossover tie lines) with respect to the critical locus.
Determining Flow Equations from Stochastic Properties of a Permeability Field: the MHD Model
Authors: Lenormand R. 
Published: December 2007

Abstract
Numerical reservoir simulations can be improved by using "homogenized" transport equations which account for real flow mechanisms: instability, fingering, channeling, etc. In this paper, the homogenized transport equations and relative permeabilities are derived by using a standard stochastic representation of the permeability field and an original stochastic calculation for the flow equations which uses the concept of streamtubes. An approximate equation, called "MHD", is proposed for displacements in reservoirs for various types of permeability fields. The equation contains a dispersive term (dispersion coefficient D) and a nonlinear convective term with the product H (heterogeneity factor) multiplied by viscosity ratio M. The main advantage of the method is that the D and H parameters that characterize the permeability field are determined from a one-phase numerical simulation, a simulation that is not time consuming.
A Novel Technology To Control Proppant Backproduction
Authors: Card R. J. , Howard P. R. , Féraud J-P. 
Published: December 2007

Summary
Backproduction of proppant from hydraulically fractured wells continues to create operational problems for oil and gas producers. As much as 20% of the proppant placed in the fracture can be returned to the surface, necessitating costly and labor-intensive surface-handling procedures. The development of unmanned platform operations remains impossible in some areas because of proppant backproduction. Flexibility in well turnaround and production strategies also can be very limited. Curable resin-coated proppant (RCP) has provided the most cost-effective and widely used method to control proppant backproduction. While this is a valuable technique that has served the industry well for many years, it is not universally successful.
A new technology has been developed to control proppant back-production and to increase flexibility in well turnaround and production strategies. The technology has been used successfully on several hundred hydraulic fracturing treatments. In this technology, a mixture of fibers and proppant is pumped into the fracture to form a pack that is resistant to proppant backproduction under typical oil/gas production conditions. The proppant/fiber mixture depends on a physical mechanism rather than chemical bonding to increase pack resistance to flowback. There are no minimum closure stress, temperature, or shut-in time requirements associated with the use of this technology, which increases the flexibility available to the operator to optimize well turnaround and production strategy.
This paper reviews the laboratory data relevant to the understanding and application of this technology. Studies include proppant pack resistance to flowback in one- and two-phase flow, the effect of cyclic loading, aging phenomena, permeability/conductivity studies, and fluid/breaker interactions. The benefits of the technology are illustrated with field studies.
Estimating Permeability by Use of Neural Networks in Thinly Bedded Shaly Gas Sands
Authors: Malki H. A. , Baldwin J. L. , Kwari M. A. 
Published: December 2007

Summary
In this paper, we develop methods of estimating permeability that use conventional log and nuclear magnetic relaxation (NMR) log data to estimate both computed permeability (by NUMAR Inc.) and Klinkenberg core-permeability measurements. The permeability estimation methods we use in this work are based on multilayer neural networks. We compare the proposed methods of estimating permeability to traditional methods in a thinly bedded siliciclastic gas reservoir in the U.S. The results of this comparison demonstrate that neural networks can be used successfully to transform conventional or NMR logs into desired permeability. The three different permeabilities predicted by use of appropriate neural networks operate by transforming (1) conventional log data into NUMAR-derived permeability, (2) conventional log data into Klinkenberg permeability, and (3) NMR echoes into Klinkenberg permeability.
Extrapolation of Historical Storm Data for Estimating Design-Wave Heights
Authors: Petrauskas C. , Aagaard P.M. 
Published: December 2007

Abstract
An improved method is presented for selecting offshore structure design waves by extrapolating historical storm data to obtain extreme value statistics. The method permits flexibility in choice of distribution functions through use of computerized procedures, estimates extrapolated wave-height procedures, estimates extrapolated wave-height uncertainty due to small sample size, and includes criteria for judging whether or not given wave-height values can be represented by one or more of the distributions implemented in the method. The relevance of uncertainty to selection of design-wave heights is discussed and illustrated.

Introduction
The problem of selecting design-wave heights for offshore platforms has many facets, ranging from the development of oceanographic data to the selection of the prudent level of engineering risk for a particular installation. This paper deals only with part of the problem; it describes an improved method for using the small available amount of wave-height information to estimate the extreme value statistics and associated uncertainties for the large storm waves that have a very low probability of occurrence. probability of occurrence. Hindcast wave-height information for design-wave studies usually covers a period of historical record that is shorter than the return period selected for acceptable engineering risk. Return periods commonly used for selection design waves are 100 years or more, but good meteorological data, on Which the calculated wave heights are based, can rarely be obtained for periods covering more than 50 to 60 years. As a consequence, extrapolations to longer return periods are necessary.
Present methods for making the extrapolation employ probablistic models through the use of special probability graph papers on which a family of distribution functions plot as straight lines. The wave heights are plotted vs their "plotting-position" return period, and a straight line fitted to the plotted data is extended beyond the data to estimate extreme wave heights for return periods of interest. The methods are described in periods of interest. The methods are described in numerous technical papers and books; Refs. 1 through 5 are examples.
The Case for More-Restrictive Oil Imports
Authors: Jameson Minor S. 
Published: December 2007

Introduction
From the titles of this paper bind the paper by Lichtblau dealing with oil imports policy, it is apparent that the two discussions involve questions of degree, in contrast to the "pro" and "con" arguments usually presented on controversial subjects. This, in itself. is a matter of considerable significance when it is appreciated that as recently as five years ago discussions, with few exceptions, revolved around the issue of whether or not national policy as to oil imports should be restrictive or nonrestrictive.
The point of reference as to what constitutes "more" and "less" restrictive is the existing program of Government import controls under the Presidential Proclamation of March 10, 1959, as amended. A brief description of the degree of restriction under the present Government import program, therefore, will place in perspective the discussions to follow.
Standards for restrictions imposed under existing import policy may be summarized as follows:Imports (excluding residual fuel-oil) into Districts I, II, III and IV, the area east of the Rocky Mountains, are limited to 9 per cent of total petroleum demand in these districts.
JPT
P. 703^
The Effect of Surface and Interfacial Tensions on the Recovery of Oil by Water Flooding
Authors: Kennedy Harvey T. , Guerrero Erasmo T. 
Published: December 2007

Abstract
In this investigation, the effects of the surface tension of brine and the interfacial. tension between oil and brine on the recovery of oil by water flooding of Woodbine sand were studied. Variation of the surface forces was. obtained by the addition of small amounts of commercially available chemicals, which did not appreciably change the surface tension of the oil.
Fourteen surface-active agents, which were found to be effective in lowering the surface and interfacial tensions, were further investigated to determine the extent of their adsorption by the Woodbine Sand cores. It was found that adsorption was sufficient in all cases to prevent any substantial concentration of chemical at the flood front. The flow system was, therefore, brought to equilibrium with definite concentrations in the flood water by circulation before each test. The data thus have no relation to the results obtainable by using the chemicals in full-scale water floods, but should be helpful in predicting the performance of surface-active chemicals which are not lost by adsorption, if such can be found.
Flow tests were made on various concentrations of six chemicals selected from the 14 investigated for surface activity and adsorption, with and without the presence of gas in the core. It was found that lowering the interfacial tension had a tendency toward reducing the recovery of oil and that the reduction of the surface tension of the brine had little or no effect. A substantial beneficial effect, however, resulted from the presence of gas in the cores.

Introduction
The movement and distribution of crude oil in a porous medium are governed by such factors as surface and interfacial tensions, viscosity of the oil, pore size configuration, and wetting characteristics of the medium. The knowledge of the part played by each of these factors is limited.
Oil Recovery by a Water-Driven Steam Slug
Authors: El-Saleh M.M. , Ali S.M. Farouq 
Published: December 2007

Abstract
Results of an experimental study of oil recovery by a steam slug driven by a cold waterflood in a linear porous medium are described. The model included simulation of heat losses to the adjacent formations. Steam displacements were conducted, using a number of hydrocarbons and various steam-slug sizes, with the core initially containing a residual oil or irreducible water saturation.
It was found that the steam-slug displacement is more efficient in the case of light oils than for the heavier ones. The injection of cold water following steam resulted in almost total condensation of the steam present in the porous medium, with the process degenerating into a hot waterflood. The oil process degenerating into a hot waterflood. The oil recovery efficiency of the process depends on whether an oil bank is formed during the steam-injection phase and whether the oil responds favorably to a hot phase and whether the oil responds favorably to a hot waterflood.

Introduction
Steam injection has been shown to be an effective oil recovery method both by field and laboratory tests. However, the method has the inherent disadvantages of a high cost of operation and excessive heat losses. The modification discussed here consists in the injection of cold water after a slug of steam, which helps to offset the above disadvantages partly at the expense of oil recovery. The injected water serves to propel the oil bank formed ahead of the steam-invaded zone and transports the heat contained in the steam-swept zone farther downstream, thus leading to more complete utilization of the heat injected.