bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methods for Determining Residual Oil with Pulsed Neutron Capture Logs
Authors: Richardson J.E. , Wyman R.E. , Jorden J.R. , Mitchell F.R. 
Published: December 2007

The special techniques described here appear to be promising for determining precise quantitative residual oil saturations - under certain reservoir conditions. A field test of one method was encouraging. The PNC logs showed saturations that agreed with other measurements, and the degree of uncertainty in the estimates approached theoretical expectations.

Purpose and Scope
The basic physical principles of pulsed neutron capture (PNC) logging and descriptions of logging instrumentation and operation have been documented in earlier publications.3,4 In addition, several methods of PNC data interpretation for petroleum engineering applications have appeared in the literature.6 These latter reports demonstrate that PNC logging has become a valuable technique for formation evaluation. The most significant use of PNC logging has been to discriminate among gas-bearing, oil-bearing, and salt-water-bearing formations in cased holes. For example, gas-oil, gas-water, and oil-water contacts have been found and followed. Unsuspected hydrocarbon migration between zones also has been detected. In addition, water saturations have been calculated from PNC log data when porosity, rock type, formation hydrocarbon type, and formation water salinity were known or could be estimated.
Interpretations of PNC log data are often precise enough for decisions regarding recompletion or for a qualitative assessment of reservoir mechanism and performance. But how useful are these data when we must decide whether or not to conduct a tertiary recovery project in the flooded-out portion of a reservoir? In comparison with waterflooding, tertiary recovery is more complicated; thus its performance is harder to predict. Also, the process costs are higher, so there is much less margin for error. Therefore, many of the parameters must be measured with great accuracy for designing a tertiary recovery project.
One of the most important parameters is the residual oil saturation - the target for profit. A decision to undertake a tertiary recovery project could depend entirely on the estimate of residual oil saturation and the margin of error associated with the estimate. Minimum expected errors in oil saturation and saturation distribution (among other parameters) are essential for a tertiary recovery project.
The purpose of this paper is to describe in some detail the possibility of using PNC data to estimate more precisely the residual oil saturation remaining at the end of a waterflood (either natural or induced).
Use of Higher Moments for the Description of Upscaled, Process Independent Relative Permeabilities
Authors: Durlofsky Louis J. 
Published: December 2007

SummaryTraditional approaches for the scale up of highly detailed reservoir descriptions to the coarser scales more appropriate for reservoir simulation often rely on the use of pseudo relative permeabilities. Two of the major limitations in the use of pseudo relative permeabilities are the process dependency inherent in the resulting curves and the need for a different set of curves in each coarse scale grid block. In this paper, these limitations are illustrated and quantified through numerical simulations of viscous dominated displacements in fine scale, heterogeneous, two dimensional systems. It is concluded that the functional form of traditional pseudo relative permeability descriptions is too limited to capture a wide variety of flow behavior and that an ‘extended description,’ in which the upscaled relative permeabilities depend on variables in addition to the phase saturations, is required. The additional variables we propose are higher moments of the fine scale variables, specifically the variance of saturation, the variance of pressure and the velocity-saturation covariance. It is then shown that these new variables are capable of accurately correlating upscaled relative permeabilities for a variety of displacements in a process independent manner; i.e., the extended description can account for varying inlet conditions and permeability realizations. The practical use of this methodology in an actual reservoir simulation will, however, require the derivation and solution of coarse scale evolution equations for the moments.
Field Tests Indicate New Perforating Devices Improve Efficiency in Casing Completion Operations
Authors: Wade R.T. , Pohoriles E.M. , Bell W.T. 
Published: December 2007

Abstract
New completion concepts by the petroleum industry have resulted in renewed activity in the design of perforating equipment. This paper coversthe development and use of explosive devices for the "single-point entry" technique used in formation preparation,field results achieved with the reactive-liner shaped-charge ("Crack-Jet") perforators anda discussion of the magnetic positioning of perforating guns.
Through application of magnetic positioning devices, uniform high-performance perforations may be made in large casings with small, through-tubing guns. Field results have indicated an appreciable advantage in the placement of a circular notch or several perforations in the plane of desired fracture initiation. The use of radial-firing, multi jet devices for the "single-point entry" technique is discussed. Reactive-liner shaped charges, initially field-tested in West Texas, have been used in all types of formations, both consolidated and unconsolidated. Field results are presented, and various formation test targets perforated with the reactive-liner charge are shown. Performance in several problem areas indicates improved rates of injection and more-favorable production rates.

Introduction
Rapid changes in completion practices during the past few years have required the development of new perforating tools. The need for small, through-tubing perforators to penetrate large casings has led to the technique of magnetic positioning. The advantages of the "single-point entry" technique for formation fracturing have been realized by the development of radial-firing explosive devices for use on electrical cables. A major breakthrough in shaped-charge design has been achieved with the new reactive liner which develops high lateral pressures within the perforation, resulting in cleaner holes and, in tight formations, intensive fracturing. These recent developments provide increased efficiency and permit successful revision of older completion techniques.

Magnetic Positioning
Through-tubing completions, which continue to gain in popularity, pose additional problems in gun design. Besides improved safety and convenience, they make possible a differential pressure into the wellbore at the time of shooting which results in cleaner perforations. The trend in recent years has been toward even smaller-size tubings to permit multiple completions. Gun design problems, already severe in the small diameters, thus have increased. Excessive ranges of clearance that are encountered create a major problem in the design of through-tubing perforators. Clearance is defined as the distance from the perforator to the casing along the axis of the jet. Fig. 1 illustrates the clearance problem resulting from the use of a 1–11/16-in. gun below 2-in. tubing. In 7-in. casing the individual shot clearances could vary from 0 to 4 1/2-in. Obviously, the performance on the large-clearance shots would be drastically reduced; both penetration and entrance hole sizes are severely affected.
JPT
P. 1069^
Interactive Reservoir Simulation With the World Wide Web
Authors: Chawathé Adwait , Ouenes Ahmed , Schofield Samuel , William Weiss 
Published: December 2007

Summary
Technology transfer through the World Wide Web (WWW) allows efficient use of available computing resources. A centralized highspeed computer can be accessed through the Internet by many users (independents) who otherwise may be handicapped by lack of such resources. The Petroleum Technology Transfer Council (PTTC) has a regional lead office in New Mexico dedicated to this objective. As an example of sharing resources, we have coupled an automatic history-matching algorithm to an analytical polymer/waterflood simulator that may be accessed over the Internet.
The polymer/waterflood predictive model (PFPM) was developed for the U.S. Dept. of Energy (DOE) and is available to the public as a freeware from the Internet site http://www.bpo.gov. The simulator has been tested by various users over a period of time and is considered to be reliable. We attached a user-friendly, Web-based graphical user interface (GUI) to the PFPM model and put it on a fast, dedicated Internet server. This paper describes the development and implementation of this new Internet-based, interactive simulation tool.
Studies of the Mechanism of Paraffin Deposition and Its Control
Authors: Shock D.A. , Sudbury J.D. , Crockett J.J. 
Published: December 2007

Abstract
A review of the background literature on the paraffin deposition problem has shown:it is a major production operational problem,the problem apparently occurs in all crude oil types and areas of production, andinsufficient information is available to clearly delineate its occurrence.
A number of experiments have been performed which show that there are numerous types of paraffin deposition. Several evaluation schemes have been devised, one of the most useful is the determination of viscosity at various temperatures. The viscosity temperature curves of several types of crude oils are discussed with reference to the deposition problem. Solvent evaluation procedures have been proven useful in determining the response of a given paraffin to a proposed solvent treatment.

Introduction
When considering that wax or paraffin problems have been recognized as a major problem from the inception of oil production, it is slightly less than amazing that the literature contains only a handful of references in which the problem is surveyed. The latest thorough examination of the problem by Reistle is now 20 years old. Brown reported on the API survey in 1940, Wright on Southeastern Ohio problems, and Sayre on problems in the Bradford, Pa., field in 1951. These papers have discussed the various developments on the problem from an operational standpoint. There is no evidence in the literature that additional work is being done to define the conditions under which paraffin problems occur and examine critically the various means of alleviation.
During the past two years, the authors have gradually accumulated background on these aspects of the paraffin problem. Thc technology has advanced sufficiently that a new appraisal of the problem by the industry would yield profitable results. This paper is presented not so much as a completed investigation, but as a stimulus to encourage others to re-examine the problem. This presentation will cover our appraisal of the problem and several techniques we have found useful.
Pore-Level Mechanisms for Altering Multiphase Permeability with Gels
Authors: Thompson Karsten E. , Fogler H. Scott 
Published: December 2007

Abstract
The pore-level mechanisms by which a crosslinked gel changes a porous medium's physical morphology and multiphase permeability are examined using relative permeabilities, pulse tracers, and micromodel visualization. Coreflood experiments indicate that to retain oil permeability while reducing water-permeability, the maintenance of oil-phase pathways after a gel treatment is crucial. However, because the gel changes the medium's morphology, the original pathways for oil are disrupted if the posttreatment fractional flow of water is nonzero. This redistribution of phases generally causes a loss of oil-phase permeability that cannot be regained under normal flow conditions.
Relative permeabilities during drainage are not affected significantly by the gel, but during secondary imbibition, the hysteresis in relative permeability is much more pronounced. Tracer experiments indicate the reason for this behavior is that the gel reduces the connectivity of the medium and the fluids distribute themselves more inefficiently, causing a large fraction of dead-end or isolated nonwetting-phase fluid to exist. These conclusions are particularly important for water-control applications where water saturation increases with time. The mechanism suggests that even if a gel exhibits preferential permeability reduction, the loss of absolute permeability and the shift in saturation can be highly damaging to the oil-phase permeability of a treated zone.
Mechanistic Foam Flow Simulation in Heterogeneous and Multidimensional Porous Media
Authors: Kovscek Anthony R. , Patzek Tadeusz W. , Radke Clayton J. 
Published: December 2007

AbstractGases typically display large flow mobilities in porous media relative to oil or water, thereby impairing their effectiveness as displacing fluids. Foamed gas, though, is a promising agent for achieving mobility control in porous media. Because reservoir-scale simulation is a vital component of the engineering and economic evaluation of any enhanced oil recovery (EOR) or aquifer remediation project, efficient application of foam as a displacement fluid requires a predictive numerical model. Unfortunately, no such model is currently available for foam injection in the field where flow is multidimensional and the porous medium is heterogeneous.We have incorporated a conservation equation for the number density of foam bubbles into a fully implicit, three-dimensional, compositional, and thermal reservoir simulator and created a fully functional, mechanistic foam simulator. Because foam mobility is a strong function of bubble texture, the bubble population balance is necessary to make accurate predictions of foam-flow behavior. Foam generation and destruction are included through rate expressions that depend on saturations and surfactant concentration. Gas relative permeability and effective viscosity are modified according to the texture of foam bubbles. In this paper, we explore foam flow in radial, layered, and heterogeneous porous media. Simulations in radial geometries indicate that foam can be formed deep within rock formations, but that the rate of propagation is slow. Foam proves effective in controlling gas mobility in layered porous media. Significant flow diversion and sweep improvement by foam are predicted, regardless of whether the layers are communicating or isolated.
Theoretical and Practical Aspects of Free Piston Operation
Authors: Lebeaux J.M. , Sudduth L.F. 
Published: December 2007

Abstract
Theory of operation of the free piston as well as practical limits of the device in prolonged flowing life of wells producing from volumetric type reservoirs are discussed. Reservoir behavior and the gas expansion work formulae are used to exhibit utility of free piston in prolonging natural flowing life. Examples are exhibited to show actual performance of the tool in West Texas. Investment and operating costs of the free piston are compared with those required for other artificial lift methods. A nomograph which may be used in determining adaptability of the tool is exhibited. Use of the free piston in intermittent gas lift operations is briefly mentioned.

Introduction
The basic idea of interposing in the tubing of a producing well of a solid interface, between gas and liquid phases of the produced fluid, to increase the efficiency of the lift is not new. In the original plunger lift the interface used was a solid critical diameter piston. The increase of efficiency of lift was obtained by better utilization of the energy of the compressed gas, either of the formation gas or of compressed gas supplied to the well from an outside source. Reduction to a minimum of the channeling of gas through the liquid phase and the filling back of the oil and water to be produced resulted in better utilization of the energy. This type of installation required a perfectly cylindrical and uniform diameter tubing to permit the travel of the tool.
Several years ago a free piston was developed which incorporated an expanding rubber element for sealing against the tubing wall and was therefore applicable in any conventional tubing string. Fig. 1 shows the piston.
The piston is manufactured in two types: Type 1, which is designed for installations using an outside source of gas; and Type 2, which is designed for those installations which use the well's own energy as a driving mechanism. This paper will consider only the latter type of free piston which has had considerable success in operations in West Texas, with the performance of the Type 1 only very briefly mentioned later in the text.
A Rotational High Pressure Viscosimeter
Authors: Hawkins Murray F. , Kimmel Marion L. 
Published: December 2007

Introduction
Sage appears to have been the first (1933) to design a rolling ball viscosimeter for the express purpose of measuring the viscosity of oils with natural gas in solution, i.e., under reservoir conditions. In 1940 Hocott and Buckley further refined the rolling ball instrument in both design and method of operation, and their instrument, known as the Humble type, was the forerunner of present day viscosimeters used in petroleum production and research laboratories. They also initiated the technique of charging the viscosimeter with a sample directly from a bottom hole sampler.
In 1948 the committee on engineering research of the Petroleum Division of the AIME in Part 3 (1) of the Physical-Chemical Topics of Table 1 suggested the "development of improved and simpler methods of measuring viscosity of reservoir fluids." This note will describe a rotational, high pressure viscosimeter which has been developed in response to this suggestion but whose relative merits are yet to be determined fully.

The Instrument
Fig. 1 is a photograph and Fig. 2 is a cross sectional drawing of the instrument. It consists of a non-magnetic, stainless steel rotor about 4 in. in length and 1 in. in diameter centered axially within a non-magnetic, stainless steel, pressure vessel of cylindrical bore. The rotor is mounted on miniature, precision ball bearings and has a radial clearance of about 1/64 in. Alnico magnets are inserted perpendicular to the axis of rotation on either end of the rotor, those at the top to serve as indicator magnets, those at the bottom, as the driven magnets which turn the rotor. A constant (but variable) speed motor outside the pressure vessel turns the rotor by means of a driving magnet attached to the motor shaft. The motor speed is checked using an aircraft type, precision, spring-wound interval timer and an electric impulse counter to record revolutions by means of an electric contactor on the motor shaft.
Platforms in the Southern North Sea
Authors: Campbell Patrick J.D. 
Published: December 2007

Introduction
While so much attention is being centered on developments and expectations in the Northern North Sea it is useful to look back at what has been done to date in the South. Such is the tempo in this industry that we rarely realize it was only 6 years ago that we were first faced with placing platforms off the east of England. We then described the environment there with all the superlatives now used for the Western Approaches. However, with familiarization and careful planning, operations in the gas fields are now routine. We should therefore review our experiences in the South and see whether what we have learned there can be used to help us in the North. In this review the platforms considered are those installed by Shell U. K. Exploration and Production Ltd. (Shell Expro) as operators of concessions owned jointly by Shell U. K, Ltd. and Esso Petroleum Co. Ltd.

Leman Gas Field Platforms
In 1967 Shell Expro installed its first platform in the North Sea in the Leman gas field about 30 miles off the cost of Norfolk. This was a drilling platform with decks measuring 150 x 114 ft. It stands on two similar jackets that provide, in all, 16 piles in a 4 x 4 configuration. In 1968 this Complex A development was extended with a production platform having decks 140 ft long and 70 ft wide. The platform is a 12-piled structure, the piles being in a 4 x 3 configuration. The reason for going to a two-platform plan was that it was necessary to install a platform as soon as possible to start development drilling, and install a complex that could safely produce gas to shore without disrupting that drilling. A further important advantage gained by this approach was that more reservoir data could be obtained before the design of the production facilities was completed. The second complex - Complex B - was started in 1969 when Platform BD (B - Drilling) was completed. Before detailed designing on this platform was started, several possible configurations were studied in order to arrive at the most economical platform design to suit the packaged rig that had already been contracted for. As a result, a 12-pile (4 x 3) single-jacket platform was selected with decks 150 ft long and 114 ft wide. A similar optimization study on the production platform resulted in an eight-pile (4 x 2) production platform resulted in an eight-pile (4 x 2) jacket designed to support production decks 150 ft long and 55 ft wide. For the third complex - Complex C - a twin-platform design was again chosen, A third drilling contractor had been selected, so the drilling platform was redesigned to accommodate a different rig configuration. This platform has one jacket of 12 piles, but in two rows of six each.
JPT
P. 1046