bluuebunny/crossref_metadata_2025_split huggingface dataset:
Natural Backfilling of Pipeline Trenches
Authors: Fredsoe Jorgen 
Published: December 2007

Fredsoe, Jorgen, Inst. of Hydrodynamics and Hydraulic Engineering, Technical U. of Denmark*
A theory, is developed for predicting the rate of natural backfilling of pipeline trenches through the action of waves and currents. The pipeline trenches through the action of waves and currents. The sedimentation originating from bed and suspended loads is studied separately. Four numerical examples demonstrate how to use the theory, which is verified by experiments.

Introduction
The aim of the studies presented here is to provide mathematical models for calculation of natural backfilling in pipeline trenches under the assumption that the seabed consists of noncohesive sediments and that the depth of the trench is small compared with the water depth (Fig. 1). The transportation of noncohesive sediment normally is separated into the transportation of bed and suspended loads. In many contexts, such a distinction of minor importance, but for our purpose it will be demonstrated that such a distinction is necessary. For example. the especially simple case where the alignment of the dredged trench is parallel to the direction of the current is considered. In this case, no suspended sediment is carried from the undredged regions to the trench by the current, if secondary currents are neglected. As long as the variations in water depth are small, the magnitude of secondary currents is negligible. However, while the suspended load is carried in the current direction, the direction of the transport of bed load deviates from the current direction because of gravity effect on the bed load moving on the slopes of the dredged trench. As a result. sedimentation will occur in the trench because of gravity infill of bed load.If the current crosses the trench under a certain angle, some suspended sediment also may settle because of decreasing current velocity and wave action at the bed in the dredged trench.From these considerations, one can see that the sedimentation caused by the bed and suspended loads must be treated separately because the physical background is quite different for the two sedimentation mechanisms.These two different physical processes are described for the case of current only and for the case of combined currents and waves. Numerical examples are given, and the magnitude of backfilling from the various processes is compared. A model test that supports the theoretical findings is described.

Sedimentation of Bed Load
Fig. 1 defines the velocity and concentration profiles and the bed geometry.
Current
The simplest case, where the current is parallel to the alignment of the trench, was treated in detail by Fredsoe . The continuity equation for the bed-load transport is given by
(1)
where Dt is the local depth of the trench, is the porosity of sediments, x1 is a coordinate in the transverse porosity of sediments, x1 is a coordinate in the transverse direction of the trench, and qx is the bed-load transport in the x1-direction, given by
(2)
JPT
P. 1223
Frac/Pack Modeling for High-Permeability Viscous Oil Reservoirs of the Duri Field, Indonesia
Authors: Fan Y. , White D. E. , Aimar A. , Satyagraha M. T. 
Published: December 2007

SummaryThis paper documents frac/pack completions conducted in the Duri field for the shallow, highly permeable, and unconsolidated formations containing heavy viscous crude. A treatment design model with a pressure-dependent leakoff option is presented to investigate effects of fracturing fluids, reservoir mobility, and Young's modulus on the fluid leakoff, net pressure, and fracture propagation. Field treatment data are analyzed with the provided model, and several factors that have significant influence on treatment results are discussed.
Professional Standards and Employment Conditions
Authors: Council Engineers Joint 
Published: December 2007

This report comprises an analysis of problems of current employmentconditions as they relate to the individual engineer. The Engineers JointCouncil (EJC) is an organization composed of eligible professional engineeringsocieties, with each of these societies having appointed representatives whogovern EJC. The functions of EJC are: to act as an advisory and coordinatingagency to seek and study matters of mutual interest to the constituentsocieties; to represent the constituent societies when joint representationseems desirable; and administer activities authorized by the constituentsocieties.

Foreword
Unlike the members of most learned professions, the engineer usually is anemployee rather than a private practitioner. Surveys indicate that about 80 percent of professional engineers are in the employee classification, and thissituation sometimes creates special problems which are not inherent in theother professions. One such problem is how specifically to create and maintainan employment atmosphere consistent with high professional standards.
Certain conditions of employment have had a profound influence on engineersand, among other factors, have caused a number of professional employee groupsto turn to collective bargaining. There is a need, therefore, for theengineering profession to state clearly the employment conditions thatengineers expect as professional men. Employers should align their policieswith respect to the engagement of professional engineering personnel to meetthese expectations. Mutual understanding between employers of engineers and theengineering profession is essential to the establishment of an environmentwhich will encourage the individual engineer to achieve full professionalstature.
A special committee of Engineers Joint Council was charged with a study ofthis employment problem and the preparation for EJC of "a means ofeducation of and vertical communication to the membership of the constituentsocieties (including students) concerning conditions surrounding unionizationof professional personnel."
Another assignment of the special committee was the preparation ofinformation for employers of engineers concerning employment practices, educational opportunities, and general measures for professional developmentthat influence the attitudes of engineers toward a true professional outlook.This study treats but one of many problems confronting the profession.Engineers Joint Council will continue its study of the problem related to theemployed engineer.
Scale Effects on the Application of Saturation-Height Functions to Reservoir Petrofacies Units
Authors: Worthington Paul F. 
Published: December 2007

Summary
An internally self-consistent reservoir model has been constructed to investigate the effects of scale on the numerical form and application of four saturation-height functions and on the resulting predictions of reservoir fluid saturations. The treatment uses reservoir partitioning into strongly characterized, physically distinct lithounits, or petrofacies, for purposes of petrophysical interpretation, and a separate, correlative reservoir zonation for subsequent parameter mapping and volumetrics. The context is therefore that of a deterministic reservoir model.
The numerical difference between apetrofacies-specific saturation-height function calibrated at the well-log scale (&lt; 1 m) and the same type of function generated at the reservoir zonal scale (&gt;10 m) varies with the function used and the physical character of the particular petrofacies unit. The application of saturation-height functions established separately at these two different scales has allowed the departures introduced through scale transgression to be assessed quantitatively. This has been done by comparing the predicted zonal hydrocarbon saturations generated for reservoir mapping with benchmark values of the same parameter. For this deterministic approach to reservoir description, an extended algorithm that uses bulk volume water as predictand provides the most accurate evaluation of water saturation at the reservoir zonal scale, which must be used in volumetrics applications. In contrast, an exponential form of the saturation-height function shows relatively large errors at both scales.
The significance and variability of scale effects have required the formulation of a structured approach to the optimum application of saturation-height functions in deterministic reservoir description. Through this facility, it is possible to contain the uncertainty associated with the distribution of hydrocarbon saturation at the reservoir mapping and volumetrics stages.
Effects of Discontinuous Shales on Multizone Steamflood Performance in the Kern River Field
Authors: Williams Lee. L. , Fong William. S. , Kumar Mridul 
Published: December 2007

SummarySteamflood performance of the Monte Cristo I lease in the Kern River field was analyzed with a detailed, 18-pattern, heterogeneous model incorporating all reservoir zones. Results were used to improve reservoir management, quantify the impact of discontinuous shales on oil recovery from individual zones, determine interzone gravity drainage, and identify bypassed oil zones for future infill drilling.Results show that detailed modeling provides a more realistic description of actual performance. Furthermore, small pattern-element or single-sand models used in previous steamflood studies are inadequate for such reservoirs. Calculated oil recovery and temperature profiles compare well with field data. Discontinuous shales allow significant oil drainage to occur from the upper to the lower sands. As a result, the upper, unsteamed zones contain less reserve than expected. On the other hand, the lower zones continue to produce long after steam injection into the zone has stopped, giving high apparent recovery. The multipattern, heterogeneous model also may be used to identify bypassed zones for future infill drilling.
Prediction of Oil Recovery by Waterflood - A Simplified Graphical Treatment of the Dykstra-Parsons Method
Authors: Johnson Carl E. 
Published: December 2007

Introduction
A method for predicting waterflood oil recovery was reported by H. Dykstra and R. L. Parsons in 1950. It is now generally known as the Dykstra-Parsons method and is widely used by petroleum engineers.
The method is semiempirical and consists of a correlation of four fundamental variables. These are: V, vertical permeability variation; a, mobility ratio; Sw, initial water saturation; and R, fractional recovery of oil in place at a given producing water-oil ratio. The correlation extends over a wide range in each of these variables, and may be applied to all formations with initial oil saturations of 45 per cent or greater.
The method of calculation originally outlined by Dykstra and Parsons closely follows their derivation. And this is a convenient way of illustrating the development of some rather complicated ideas. However, in actual use it is more cumbersome than necessary. The purpose of this note, therefore, is to provide a simplified method for making Dykstra-Parsons predictions.
A Literature Analysis of the WAG Injectivity Abnormalities in the CO2 Process
Authors: Rogers John D. , Grigg Reid B. 
Published: December 2007

SummaryThis paper summarizes the hypotheses and theories relating to the causes and expectations of injectivity behavior in various CO2 and gasflooded reservoirs. The intent of the paper is to:Provide a concise compendium to the current understanding of the water-alternating-gas (WAG) mechanism and predictability. Provide a comprehensive single-source review of the causes and conditions of injectivity abnormalities in CO2/gasflood EOR projects. Aid in formulating the direction of research. Help operators develop operational and design strategies for current and future projects, as well as to input parameters for simulating current and future projects.
A Model Study of Iceberg Scouring in the North Atlantic
Authors: Chari T.R. 
Published: December 2007

A model has been developed to predict the maximum depth of iceberg scour in the north Atlantic Ocean. A prior knowledge of the environmental parameters: -such as the bathymetry, seabed properties, iceberg dimensions, and Ocean current data would be required to compute safe burial depth for blowout preventer stacks and pipelines.

Introduction
The seasonal presence of icebergs on the Canadian east coast is a potential threat to any possible production of offshore oil or gas. With the recent discovery of oil on the Grand Banks1 and promising results on the Labrador Shelf,2 solutions to the iceberg problem have to be found speedily before production can commence. Existing technology must be improved or new techniques devised for operations in these iceberg-infested waters. Atlantic icebergs appear in different shapes and usually weigh millions of tons. Underwater depths (drafts) as much as 500 ft (150 m) are common for such bergs. Conventional gravity or jacket-type production platforms are not likely to withstand a direct hit from a drifting iceberg unless protected by auxiliary structures3 or artificial islands.
An iceberg drifting freely will tend to ground in the course of its travel when the bathymetry changes either gradually or abruptly, causing the water depth to be shallower than the draft of the berg. Bottom scours as deep as 21 ft (6.4 m) and as long as 9,850 ft (3 km) have been measured4 off the Newfoundland coast. Thus, buried offshore installations such as foundations and pipelines are susceptible to damage and are likely to be torn out by bottom-dragging and scouring icebergs unless buried sufficiently deep. Alternative production systems such as a floating rig in combination with various forms of subsea installations currently are being examined1 by the oil industry. A drillship likely to be in the path of a drifting iceberg can be moved off location by disconnecting the riser pipe. If the iceberg is large, the blowout preventer (BOP) stack itself could be knocked off or scoured out by the berg. Duval5 has reported that an iceberg forced the drillship Pelican to disconnect below the BOP stack during the 1973 drilling season. Even if safe methods are available to avoid a direct hit from an iceberg by moving the rig away from the collision course, gouging icebergs still would be a problem unless ocean-bottom structures are buried sufficiently deep. This paper describes a mathematical model and the associated laboratory tests for estimating iceberg scour depths.

Methods of Estimating Scour Size
It is believed that as many as 40,000 icebergs are produced6 yearly from the Greenland glaciers. They drift along the west Greenland and Baffin Island coasts (Fig. 1) and finally are caught in the Labrador current. In this process a large number of bergs are trapped in the bays and coastal indentations en route and grounded permanently. About 2,500 bergs are believed7 to cross the 60th parallel each year. A detailed description of the iceberg production, drift, and decay is given by Smith8 and reviewed by Chari.9
Development of a Generalized Darcy Equation
Authors: Tek M.R. 
Published: December 2007

Abstract
General equations relating the pressure drop necessary to sustain the flow of a fluid through a porous matrix at a given rate have been developed. The results indicate that at high values of flow rate the pressure-flow behavior may not necessarily satisfy the usual Darcy equation.
The mathematical analysis, carried through the micro-pore geometry and extended through the macro-reservoir scale, indicate that Darcy's law, of limited applicability to certain ranges of Reynolds numbers, can be generalized through the inclusion of some additional parameters.
The "generalized Darcy equation" has also been formulated in dimensionless form permitting the evaluation of its predictive accuracy with regard to literature data.
A comparison between predicted and experimental values indicates that the generalized Darcy equation predicts the pressure drops with good agreement over all possible ranges of Reynolds numbers.

Introduction
The limits and the nature of validity of Darcy's law has been a subject of every-day interest to the industry for many years.
It is well known that as the Reynolds number, characteristic of the fluid flow through porous media, becomes large, Darcy's law gradually loses its predictive accuracy and ultimately becomes completely void. For the last 20 years much has been said and written on this subject. Unfortunately little has been accomplished to bring about a satisfactory agreement, at least on the nature of the threshold of validity of Darcy's law. Fluid dynamists, geo-physicists, and engineers all had their individual views, explanations, interpretations and concepts on the subject. To some, a mechanistic analogy with pipe-flow proved a satisfactory explanation. To others, turbulence, in its random character, was incompatible with the geometric structure of consolidated porous systems. To some, turbulence merely represented a factor influencing the permeability measurements and again to others, empirical or semi-empirical correlations proved satisfactory from an engineering viewpoint.
Deviations from Darcy's law at high flow rates have been studied by systematic experiments by Fancher, Lewis, and Barnes. In an article on the flow of gases through porous metals, Green and Duwez conclude that the onset of turbulence within the pores appears unsatisfactory to explain deviations from Darcy's law. This view is held by many others.
High-Temperature Blowdown Experiments in a Vuggy Carbonate Core
Authors: Dehghani Kaveh , Kamath Jairam 
Published: December 2007

SummaryWe conducted a series of tests on a vuggy carbonate core sample to quantify recovery mechanisms during a high-temperature blow-down process. We heated the core to 300°F, keeping the pressure above the bubblepoint, and then reduced the pore pressure at a constant rate from one end of the sample. Tests were conducted with the core at initial oil saturation, Soi, and at residual oil saturation, Sor, to water, with pressure reduction from top or bottom of the sample. The blowdown experiments show that 50 to 68% of the oil is recovered, with 8 to 20% owing to thermal expansion, 20 to 24% owing to thermally enhanced solution gas drive, 12 to 16% owing to distillation, and 8 to 10% owing to in-situ steamdrive.
Wall-Effect/Gel-Droplet Model of Disproportionate Permeability Reduction
Authors: Liang J. , Seright R. S. 
Published: December 2007

Summary
Many polymers and gels can reduce the permeability to water more than they can the permeability to oil or gas. However, the mechanism of this disproportionate permeability reduction is not clear. This paper considers a promising potential explanation that is based on a combined "wall-effect" and "gel-droplet" model. Many aspects of the disproportionate permeability reduction can be explained by a wall-effect model if the gelant is prepared from or matches the wetting phase, and by a gel-droplet model if the gelant is prepared from or matches the nonwetting phase. The combined model predicts that disproportionate permeability reduction should increase with increasing residual nonwetting-phase saturation. New experimental results support this prediction.
Regional Upscaling: A New Method To Upscale Waterflooding in Heterogeneous Reservoirs for a Range of Capillary and Gravity Effects
Authors: Coll C. , Muggeridge A. H. , Jing X. D. 
Published: December 2007

Summary
This paper presents a new, two-phase upscaling methodology hereafter referred to as "regional" upscaling. A fine-grid flow simulation is performed on a representative section of the reservoir. Dimensionless numbers are then calculated for each fine-grid cell to determine the dominant flow regime in that cell. The coarse grid is selected based upon the spatial locations of the different force regimes observed in the fine-grid simulation model. Two-phase upscaling is then performed from the fine to the coarse grid using the most appropriate pseudoization technique [Kyte and Berry or vertical equilibrium (VE)] for the dominant flow regime in each region. The method is compared with different global pseudoiza-tion methods and its accuracy examined for a range of different heterogeneity models, including one for a reservoir in Lake Maracaibo in western Venezuela.
Advances in Coupled Geomechanical and Reservoir Modeling With Applications to Reservoir Compaction
Authors: Settari A. , Walters Dale A. 
Published: December 2007

SummaryCoupled geomechanical and reservoir modeling is becoming feasible on a full-field scale. This paper describes the advances of the coupled model described previously,1 its extensions for modeling compaction, and the application of the model in full-field studies.The advances of the theory and numerical implementation since the original work1 make it practical to perform full-field coupled studies with complex, realistic descriptions of the geomechanical behavior of the reservoir and shales, which allows prediction of stress changes, reservoir compaction, and surface subsidence. These capabilities are demonstrated in field examples that analyze and predict classical pressure-induced compaction in a gas field and thermally induced compaction in a heavy-oil field. In both cases, the methodology of interpreting the geomechanical laboratory and field data and their integration in the coupled modeling process was the key to obtaining a realistic predictive tool. The examples demonstrate that the technology is maturing to the point that conventional studies can be converted to coupled modeling on a fairly routine basis.
A Centrifuge Core Cleaner
Authors: Conley Francis R. , Burrows David B. 
Published: December 2007

Introduction
A prerequisite to the evaluation and management of oil properties is accurate information derived from the analysis of core samples; but reliable data, such as porosity and permeability, can result only if all oil and water have been removed from the core samples analyzed. The most common method of core cleaning used to date has been Soxhlet extraction - a somewhat static technique, which depends upon the slow diffusion of hot solvent through the core sample. Soxhlet extraction performs satisfactorily only with highly permeable samples and at best requires long cleaning periods.
The centrifuge method was developed in 1951 by Continental Oil Co. to overcome the inefficiencies inherent in the Soxhlet method. The new method is basically an operation in which hot solvents are caused to flow through the samples under the influence of centrifugal force.
The centrifuge unit has proved so successful that samples which formerly required days for partial extraction can now be completely cleaned in approximately one hour.
The original idea was conceived in 1950 by Elmer S. Messer, whose early experiments consisted of flowing solvent over sandstone samples suspended in a revolving basket and driven by a vertically mounted vacuum cleaner motor. Results were so outstanding that more permanent units were constructed.
A modified model using this basic design was recently built by Core Laboratories, Inc., and is now used regularly in their operations.

Design
Fig. 1 shows a photograph of the two extractors routinely used to clean small core plugs in the Production Research Div. of Continental Oil Co.'s Ponca City laboratories. For illustrative purposes, the basket from one of the units has been removed, and because both extractors are of identical design only one is described in the following discussion. Each extractor unit consists of a centrifuge and a solvent still.