bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transient Dynamic Analysis of the Drillstring Under Jarring Operations by the FEM
Authors: Kalsi M. S. , Wang J. K. , Chandra U. 
Published: December 2007

Summary
A drilling or a fishing jar is used in the bottomhole assembly (BHA) of a drillstring to free the string should it become stuck during the drilling operation. Because many expensive sensors are now incorporated in downhole tools, it is necessary to predict the damaging effect of jarring on these downhole sensors accurately. In addition, BHA's are becoming increasingly complex and are difficult to analyze by closed-form methods. For such reasons, the finite-element method (FEM) was used in this study to predict the dynamic response of a drillstring to jarring.
Effect of Mud Composition on Wear and Friction of Casing and Tool Joints
Authors: Bol G. M. 
Published: December 2007

Summary
Friction and wear between casing and tool joint have been measured on full-scale equipment. The results show that the most important mud property, with respect to lubricity and protection against wear, is its ability to form a film that separates the two steel surfaces. Results from small-scale tests are shown to be nonrepresentative.
Geologic Parameters of Reservoir Sandstones as Applied to Enhanced Oil Recovery
Authors: Gaida K. H. , Kessel D. G. , Volz H. , Zimmerle W. 
Published: December 2007

Summary
This paper discusses the importance of geological parameters of reservoir sandstones and their fieldwide distribution for proper planning and operation of EOR projects. Such parameters are gross and net pay thickness, permeability, porosity, grain size distribution, composition of detrital minerals, amount and type of mineral cements, and amount and type of clay minerals.
Fieldwide distribution of these parameters is shown for the case history of the Hankensbüttel-Süd oil field in the Federal Republic of Germany. Overlaying the distribution maps made it possible to distinguish areas with excellent to good potential for chemical flooding from areas of fair to poor potential. On the basis of these results, a surfactant/polymer flood pilot has been initiated in this field.
Some Factors That Affect the Sour-Service Performance of Carbon-Steel Oil-Country Tubulars
Authors: Ciaraldi Stephen W. 
Published: December 2007

Summary
Carbon-steel oil-country tubular goods, such as API 5AC Grade L-80, combine high strengths for deep-well applications with restricted hardness for resistance to sulfide stress-cracking in sour wells. Despite these general characteristics, field experience with such tubulars has not been completely trouble-free. Problems have been encountered with hardness control and testing. Metallurgical factors involved with heat treatment and upsetting have affected tubular performance. Problems associated with threaded connections and tool damage have occurred. Special considerations are required for electrical-resistance-welded (ERW) tubulars, field welding, and completion operations.
Assessment of Sulfide Corrosion Risks in Offshore Systems by Biological Monitoring
Authors: Maxwell Stephen 
Published: December 2007

Summary
Probably the most common problem encountered with sulfate-reducing bacteria (SRB) in offshore systems is sulfide corrosion. Although SRB-mediated corrosion is related to the production of sulfides at a metal surface, monitoring of SRB has been almost solely by counting of bacteria in and a chemical analysis of the bulk phase. Furthermore, bacterial counts give little information on the in-situ activity of SRB—i.e., the sulfate- reduction/sulfide-production rate. A novel technique that uses [35S] sulfate has been developed, however, that allows for the determination of SRB activity at metal surfaces.
The results of field trials in two situations where the activity of SRB is thought to carry a potential risk of sulfide corrosion are presented: first on external surfaces, the horizontal members of the Thistle platform, and second on internal structures, the metal surfaces submerged in the entrained seawater in the drill leg of the Brent Bravo platform. The results clearly show that current monitoring methods may give misleading results and that by using radiorespirpmetric methods, a better understanding of the processes taking place within these systems can be obtained. Thus remedial measures can be carried out when necessary with greater assurance than previously.
Geological Aspects of the Codell Sandstone, Weld and Larimer Counties, CO
Authors: Hively Roger E. 
Published: December 2007

Summary
Since 1981, nearly 1,000 wells have been drilled in the Denver basin of northeastern Colorado with the Codell sandstone as their primary target. The majority of this exploration has been in the axial portion of the basin, in Townships 4 to 7 North, Ranges 64 to 68 West, in Weld and Larimer counties. Drilling depths of Codell wells range from 6,800 to 7,400 ft [2073 to 2256 m].
Recently discovered oil and gas production in the Codell sandstone encompasses several hundred square miles. Thickness and lithology of the formation are remarkably similar across this widespread area. Geologic limits of this reservoir are less distinct than in most sandstone exploration targets; therefore, geologic parameters must be considered over a large area.
A Dynamic Computer Model of a Kicking Well
Authors: Nickens H. V. 
Published: December 2007

Summary
The dynamic effects of variable pump flow rate, formation-influx distribution, blowout preventer (BOP) and choke closure, choke adjustments, and well stabilization are accounted for in the analysis of a kicking well by solution of the appropriate mass- and momentum-balance equations. In the gas/liquid regions, the system is modeled as separated flow. The mass-balance equations are solved for the gas and liquid separately, but the momentum equation is solved for the mixture.
The model predicts the detailed flow and pressure response of the well at all times and wellbore locations during the kick. The model is currently capable of simulating a single kick in a vertical hole (surface or subsea) with water-based mud and the bit on bottom. The drillers' method (DM), wait/weight (WW), or dynamic kill-control procedures for either a "perfect controller" [constant bottomhole pressure (BHP)] or for any of several choke-control procedures may be simulated.
Formation of Water-Soluble Silicate Gels by the Hydrolysis of a Diester of Dicarboxylic Acid Solubilized as Microemulsions
Authors: Vinot B. , Schechter R. S. , Lake Larry W. 
Published: December 2007

Summary
Relatively inexpensive sodium silicate gels are attractive candidates for large-scale well conformance treatments. For a successful treatment, gelation must be delayed to permit proper placement of the silicate solution within the reservoir, to minimize rock/fluid interactions during placement, and to ensure long-term gel stability. We investigated each of these process phases, focusing on stable high-pH (≈11) sodium silicate solutions ranging up to 10 wt% SiO2 concentration. The addition of an acid or alcohol will cause these high-pH sodium silicate solutions to gel. To regulate the gelling time, an organic material that reacts with water to produce an alcohol and/or acid is often mixed with the silicate solution. An organic rather than inorganic compound is selected because the slow organic reaction rates yield a controlled gelation. The choice of the organic compound normally is quite limited because it must possess sufficient water solubility to be present in the quantities needed to cause gelling. This study shows that diesters, which hydrolize to produce both acid and alcohol, can be solubilized into silicate solutions as a microemulsion (not a macroemulsion), thus eliminating this limitation. All the rules developed with regard to selection of surfactants for EOR also apply to sodium silicate solutions. Field processes should use caustic preflushes to propagate silicate solutions deep into the formation.
Long-term stability studies showed that, upon standing for several weeks, silicate gels tend to contract, expelling water. This process, called syneresis, clearly will affect the long-term effectiveness of a silicate treatment. We investigated syneresis over a wide range of silicate concentrations and temperatures. Gels formed from the high silicate concentrations exhibited the greatest degree of syneresis; up to an 80% decrease in volume. Increasing the temperature increased the syneresis. Some degree of syneresis may be desirable because all treated zones will retain residual permeability.
Performance of Perforated Completions in the Presence of Anisotropy, Laminations, or Natural Fractures
Authors: Tariq S. M. , Ichara M. J. , Ayestaran L. 
Published: December 2007

Summary
Finite-element method (FEM) was used to evaluate the steady-state flow response of the near-wellbore region in the presence of anisotropy, shale laminations, and natural fractures. The relative importance of various geometric perforation parameters under such conditions was also examined. The study indicated that completion efficiency is strongly influenced by common heterogeneities. The variation in productivity is substantial and emphasizes the importance of including a good description of the formation heterogeneities in the design and evaluation of a perforating program. The best description is derived by use of data from all available sources (cores, well tests, and logs).
The principal findings of this study were (1) that high shot densities are needed in anisotropic and laminated formations, (2) that the performance of perforated completions varies with the type, orientation, and density of the natural fractures, (3) that different geometric parameters assume different significances for different types of fracture networks, and (4) that a sound fracture detection and evaluation program is essential for the proper design and evaluation of the perforated completion in such an environment. The results presented can be used to design and to evaluate perforated completions in naturally fractured environments.
Generation of Earthquake Response Spectra for Production Equipment
Authors: Fisher F. A. 
Published: December 2007

Summary
The importance of seismic design requirements for the facilities and equipment on the deck of an offshore platform is increasing. This paper presents an efficient procedure for the generation of earthquake response spectra for light equipment in a massive structure. It is assumed that the equipment may be modeled as a single-degree-of-freedom linear oscillator attached at a single point to a multi-degree-of-freedom linear system. Modal properties of the combined equipment/structure system may be determined from the known properties of the separate systems. The peak equipment response to a given ground-motion time history is determined from a frequency domain analysis of the combined system and the ground-motion response spectra. This procedure takes into account equipment/structure interaction, correlation between modes, and response transience, some or all of which are typically ignored in current practice. Because most of the theoretical development for this procedure has been done in the nuclear industry, the primary focus of this paper is on the application of the procedure to offshore platforms. Several numerical examples are included to demonstrate the excellent agreement between this procedure and time-history results.
Design Features of Improved Electric-Submersible-Pump Cable To Withstand Installation and Service Conditions
Authors: Neuroth D. H. 
Published: December 2007

Summary
Field studies, with oil industry assistance, identified major failure mechanisms that currently limit the service life of conventional electric-submersible-pump (ESP) cable. A new cable, designed to address each of these failure modes, was developed and tested. Special load-bearing members placed within the cable improve crush resistance from 500 lbf/cable in. [876 N/cable cm] with conventional cable to 3,000 lbf/cable in. [5254 N/cable cm], while enhancing decompression strength. The manner in which the new design increases edge protection, eases installation handling, enhances abrasion resistance, and provides greater chemical protection is also discussed. The mechanisms by which design features achieve these improvements are supported by laboratory results and field experience.
Injection Rates - The Effect of Mobility Ratio, Area Swept, and Pattern
Authors: Deppe John C. 
Published: December 2007

Abstract
A method is presented for calculating approximate injection rates in secondary recovery operations. The method can he applied to cases of unequal fluid mobilities, irregular well patterns and boundary patterns.
The steady-state pressure distributions for the four flood patterns reported by Muskat and for five additional patterns reveal that most of the difference in pressure between the injection and producing wells occurs in regions around the wells which can adequately he described as regions of radial flow. This leads to a method of calculating injectivity by approximating the flood pattern with radial flow elements (or a combination of radial- and linear-flow elements for some patterns such as the direct line drive). Irregular and boundary patterns can also be approximated by radial and linear elements.
Each of these elements can be described by radial- and linear-flow equations and the results combined as series flow resistances to give an approximate equation for the initial injection rate. The mobility ratio does not affect the initial rate; therefore, if the well pattern is one of those regular patterns for which theoretical rate equations have been derived for unity mobility ratio, the approximate initial rate equation can be improved by adjusting it to match the theoretical equation. The available theoretical rate equations are listed, including five new cases.
As the flood progresses, the injectivity changes because in general the flood front will divide the pattern into areas of different fluid mobilities. Simple shapes can be assumed for the flood front so that both areas can be divided into radial- and linear-flow elements. Radial- and linear-flow equations are applied to these elements to account for the change in flow resistance behind the front.
To calculate injection rates after breakthrough, it is necessary to know the sweep efficiency at breakthrough. Areal sweep data are available in the literature for a number of patterns, and sufficiently accurate breakthrough sweep efficiency can be estimated from these data if it is not otherwise available.
The Development of Stability Theory for Miscible Liquid-Liquid Displacement
Authors: Perrine Richard L. 
Published: December 2007

Abstract
A stability theory is developed for miscible liquid-liquid displacement within a porous medium. In the usual case considered, a high-density high-viscosity "oil" is displaced downdip by a low-density low-viscosity "solvent". Perturbation methods are used to find the conditions under which the spreading mechanism changes from the stable dispersion process to unstable viscous fingering. We find that instability is conditional, that there is a dependence on the shape of a disturbance leading to a "diameter" effect and that very difficult experimental scaling problems may result. A useful consequence is the definition of a minimum "slug size" for stable miscible displacement. This should make possible optimum use of the solvent process for oil recovery. The results may apply to many situations in which one fluid displaces another of somewhat different fluid properties within a porous medium.

Introduction
The process of miscible liquid-liquid displacement looked very favorable when it first received serious consideration as a means to increase petroleum recovery. Some early laboratory results were interpreted to mean that only a small "slug" of solvent was needed, perhaps 2 to 3 per cent of a hydrocarbon pore volume. This "slug" could recover the oil in an entire reservoir provided the fluids remained miscible. Only a slow growth of the "mixing zone", or gradual transition from oil to solvent, should occur. This would follow naturally from mixing by a dispersion mechanism such as that described by Scheidegger. And, indeed, laboratory cores have shown this kind of behavior provided solvent viscosity was at least as great as that of the oil. The same kind of behavior has also been observed with solvent viscosity lower than that of the oil after the distance traversed became large. Not all laboratory results have been this favorable, however. Mixing zone growth may become proportional to the distance traveled rather than the square root of this quantity. Such behavior accompanies high rates in short systems of large diameter, provided the viscosity ratio is adverse. If this more rapid spreading were to persist in a reservoir, the solvent requirement for miscible "slug" displacement could exceed 30 per cent of a pore volume. There is considerable economic importance in the difference between 3 and 30 per cent solvent.
Effects of Noncondensible Gases on Fluid Recovery in Fractured Geothermal Reservoirs
Authors: Bodvarsson Gudmundur S. , Gaulke Scott 
Published: December 2007

Summary
Numerical simulations are performed to investigate the effects of noncondensible gases (CO2) on fluid recovery and matrix depletion in fractured geothermal reservoirs. The model is of a well producing at a constant bottomhole pressure (BHP) from a two-phase fractured reservoir. The recoverable fluid reserves are shown to depend strongly on the amount of CO2 present in the reservoir system. The results obtained revealed a complex fracture/matrix interaction caused by the thermodynamics of H2O/CO2 mixtures. Although the matrix initially contributes fluids (liquid and gas) to the fractures, the flow directions later reverse and the fractures backflow fluids into the matrix. The amount of backflow depends primarily on the flowing gas saturation in the fractures; the lower the flowing gas saturation in the fractures, the more backflow. An analytic expression has been derived that allows for the determination of mass backflow on the basis of wellhead measurements of noncondensible gases and flowing enthalpy.
Obtaining Low Bottomhole Pressures in Deep Wells With Hydraulic Jet Pumps
Authors: Christ F. C. , Petrie H. L. 
Published: December 2007

Summary
Maximizing production in a well requires reducing the bottomhole pressure (BHP) to the lowest practical minimum by artificial lift. This task is particularly difficult in deep wells because of the need to transmit power a long distance to the bottom of the well and because of the high temperatures encountered at depth. Reciprocating hydraulic pumps have historically been used for this purpose in deep wells, especially those deeper than 10,000 ft [3048 m]. For more than a decade, the hydraulic jet pump has successfully produced deep wells. In a number of cases, jet pumps have produced deep wells to less than 10% submergence. This paper identifies the hydraulic jet pump as a reasonable method to produce deep wells to low BHP's with predictable performance. A number of examples and well tests illustrate the performance of jet-pump production systems.
Saturation Distributions During Displacements Generated by the Simultaneous Injection of Oil and Water
Authors: O’Steen B. L. , Holm L. W. 
Published: December 2007

Summary
Linear oil/water displacement behavior in a water-wet Berea sandstone is examined experimentally with a scanning microwave absorption system. It is observed that simultaneous injection of oil and water into a core initially at residual oil saturation (ROS) produces a region of anomalously high oil saturation and fractional flow, or an oil hump, at the leading edge of the displacement. This region grows in both saturation and breadth as the flood progresses. Studies at different injection rates and WOR’s indicate that the saturation, fractional flow, and propagation behavior of the oil hump are strongly influenced by rate and ratio. The displacements from ROS confirm the secondary imbibition and drainage results for fractional flow obtained by a sequence of small displacements. A strong hysteresis effect is indicated by these results. The displacements from ROS also reveal the existence of a complex network of inner scanning loops in the steady-state fractional flow behavior. These studies indicate that for sufficiently high injection rate, all displacements above a minimum injected WOR will eventually produce a displacement front approaching that of an oilflood. The frontal saturation and fractional flow for the oilflood case are found to be significantly greater than that predicted by the graphic tangent-point construction of Buckley-Leverett (B-L) theory. This result, along with the observed rate dependence of the hump, suggests that traditional B-L theory, even with fractional flow hysteresis included, might not adequately describe oil/water displacement. It is suggested that transient flow response near a wave front is responsible for the observed displacement behavior.
Nonequilibrium Gas Displacement Calculations
Authors: Attra H.D. 
Published: December 2007

Abstract
The effects of phase behavior on reservoir economics is a function of both fluid composition and flow properties of the reservoir rock. In some operations such as gas injection into volatile crude-oil reservoirs, the stock-tank recovery derived from vaporization of the reservoir oil by the displacing gas can approach the recovery derived from the displacement mechanism. In other cases of gas-cycling reservoirs, the dry injected gas can effectively vaporize a retrograde liquid phase, allowing a substantial reduction in cycling pressure with no appreciable loss in recoverable liquids. Because of these effects, it is essential that phase behavior be considered in developing the economics of any secondary recovery program in which gas is the injected fluid.
The inclusion of phase behavior in conventional calculation procedures has been retarded because of the complexity of the calculation and the large volume of laboratory data required. However, by applying high-speed computers and new laboratory techniques, the phase-behavior displacement calculation has been developed to economically include this basic fundamental of gas displacement.
The calculation is performed by reducing the reservoir to a series of one-dimensional segments. Phase changes, saturation distributions and changing fluid properties are evaluated for each segment as a function of time. The relative volumes of equilibrium liquid and gas displaced from each segment are determined by a trial-and-error procedure to meet the requirements of phase equilibrium and two-phase flow. The produced fluids are flashed through conditions of surface separation approximating those in the field to obtain actual values for stock-tank liquid recovery and producing gas oil ratios.
Based on the results of successful field studies, the technique appears to have application to reservoirs producing under a nonmiscible gas-displacement mechanism and should substantially increase the reliability of this type of analysis when phase behavior is an important factor.
The Unsteady-State Nature of Sorption and Diffusion Phenomena in the Micropore Structure of Coal: Part 1—Theory and Mathematical Formulation
Authors: Kolesar J. E. , Ertekln Turgay , Obut S. T. 
Published: December 2007

Summary
A single-phase, ID mathematical formulation is developed in radial/cylindrical coordinates to examine unsteady-state micropore sorption in a composite micropore/fracture, coalbed-methane transport problem. In the formulation, the micropore transport equation accounts for unsteady-state sorption and diffusion in the primary porosity. Gas entering the fracture network is considered a source term in the fracture-transport equation. The micropore and fracture systems are coupled by equating the gas pressure at the surface of the micropore elements to the pressure in the fracture network.