bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors Affecting Gravel Placement in Long Deviated Intervals
Authors: Gurley D. G. , Hudson T. E. 
Published: December 2007

Abstract
Properly designed and installed gravel pack completions have proven to be the most effective method of controlling sand production. The advent of slurry pack techniques, clean fluids and NODAL* analysis have been responsible for improving gravel packed well productivity. Further improvement in gravel placement is needed in long deviated completions.
Although quantitative evaluations of perforation packing cannot be precisely measured, there is good field and laboratory model evidence that the effectiveness declines rapidly in intervals longer than about 10 ft -- even in vertical wells. Both field treatment reports and laboratory data indicates that bridging may occur in the screen/casing annulus before there is adequate leakoff into the formation to pack the perforations. Premature bridging is not always obvious in vertical wells because the bridge usually collapses after the differential pressure across the bridge dissipates. However, in wells deviated more than about ≈ 55° the gravel does not settle after collapse of the bridge. The result is a void in the annulus pack.
Full-scale model studies of screen/casing annulus and perforation packing by numerous researchers have made important contributions in understanding the packing process1-12.Development of a mathematical model by Wahlmeier provided a method to scientifically apply the knowledge provided by these researchers to real wells.13 Factors studied by these researchers and described mathematically by Wahlmeier are: 1) gravel transport, 2) friction pressure and its influence on slurry flow in the screen/casing annulus, and 3) carrier fluid leakoff and its influence on perforation packing.
This paper discusses rheological properties of particulate slurries and geometrical conditions encountered that affect these factors. Simple, but relevant mathematical relationships are used to demonstrate the importance of particle settling, slurry flow velocity, shear rate in the screen/casing annulus, shear rate entering the formation and downhole placement pressures.
The Effect of Temperature on the Size Stability of Conventional and Ceramic Gravel Packs
Authors: Alcocer C. F. , Toups M. M. , Hayatdavoudi A. , Ghalambor A. , Okoye C. 
Published: December 2007

Abstract
Laboratory research was performed to study materials used in gravel packs. There were conventional quartz sand and ceramic pellets. The main objective of this research was to determine the effects of elevated temperatures on the size and shape of subject materials, specifically as related to the generation of fines within the gravel pack itself. Also, the feasibility of using ceramic pellets versus conventional quartz gravel as pack sand material was investigated. These objectives were achieved by examining 20/40 and 40/60 mesh samples of subject materials for the influence of various temperatures (room temperature -up to 550° F) on particle size distribution, grain surface degradation, mechanical strength, permeability and conductivity stability, and fracture limits. SEM photograhs of 40/60 mesh gravel indicated an increased amount of pits caused by temperature. Also, the formation of striations and/or flaking were present on the 40/60 mesh gravel. The crush test performed at 10,000 psi on the 40/60 mesh gravel produced fines in excess of 25% by weight. The 20/40 and 40/60 mesh ceramics and 20/40 mesh gravel displayed a decrease in permeability with increasing temperature. A linear regression analysis was performed. Based on this study, the ceramics appear to be best suited for gravel pack material at elevated temperature. Even though both gravel and ceramics produced fines, the ceramic grains are able to withstand much higher pressures and stresses coupled with higher temperature.
Investigation of Gravel Pack Damage Due to HF Acidizing
Authors: Yeager V. J. 
Published: December 2007

Abstract
Reaction of hydrofluoric acid on 20/40 Ottawa sand used for gravel packing was simulated in a large-scale model under realistic conditions. Changes in (1) silica content of the effluent, and (2) sieve size distribution of the proppant pack indicate that changes are occurring, but that they are relatively small. Formation sand and fines are also affected, however, overall API specifications for gravel pack proppants were maintained even in the presence of substantial volumes of hydrofluoric acid.
Use of CT Scanning in the Investigation of Damage to Unconsolidated Cores
Authors: Gilliland R. E. , Coles M. E. 
Published: December 2007

Abstract
The use of Computed Tomography (CT) scanners has proven to be a valuable tool in the evaluation of damage to unconsolidated cores. When examining sleeved cores to determine slabbing angle, undamaged sites for future plug and whole core analysis, sample heterogeneity and depositional features, CT scanning proves invaluable by providing nondestructive internal inspection capability.
The core material recovered from these unconsolidated friable formations typically undergoes, a series of damaging alterations between in situ conditions and the laboratory. Studies have shown that improper handling techniques in the lab can often do as much damage to the core as the coring, wellsite handling and transportation phases. In the process of investigating the fragility of these sands and evaluating which processes are generally responsible for their damage, CT scans aid in greatly reducing such damage in subsequent cores by revealing not only the magnitude of the damage but also the implied cause in many cases. Examples are provided to demonstrate the effect of several types of core damage from both unavoidable sources such as pressure and temperature changes associated with bringing the core to the surface to the more catastrophic events resulting from physical shock. Invasion profiles and other useful drilling information can also be gleaned from this technique,
The Occurrence and Control of Acid-Induced Asphaltene Sludge
Authors: Houchin L. R. , Dunlap D. D. , Arnold B. D. , Domke K. M. 
Published: December 2007

Abstract
Successful acid stimulation programs are achieved when more near well-bore damage is removed than is induced by the acid treating fluid. Acid induced asphaltene sludging is becoming an increasing cause of oil well stimulation treatment failure. Laboratory tests on 231 crude oils from 17 formations in the U.S. and Canada, have been tested for sludge sensitivity.
Numerous chemical processes involved in an acid system contribute to the effect of acid on sludge potential. Surface tension has been used in the past as a guideline for predicting the sludge potential of a chemical system. However, surface tension, in and of itself, is not a factor in acid induced sludge. In addition, this data indicates that as oilfields mature and are placed on secondary and tertiary recovery, sludge sensitivity increases. As a result of this data, a crude oil classification system is presented based on API gravity and asphaltene content. By classifying the crude oil, conclusions can be reached regarding sludging potential.
This study addresses many such chemical options which include acid strength, acid type, solvent preflush, iron control and additive compatibility. The oxidation potential of iron contaminated acid is also clarified.
Shock Wave Boundary Effects on Jet Perforator Penetration in Stressed Berea Targets
Authors: Henderson S. W. , Navarette M. 
Published: December 2007

Abstract
Tests in annular stressed Berea targets demonstrate that shock wave reflections can have either positive or negative influences on shaped charge perforator penetration. These results imply that boundary effects which alter shaped charge performance are inherent in the current API RP 43 Section II target. Data and results begin to identify a target which more realistically models downhole conditions.
Evaluation and Treatment of Organic and Inorganic Damage in an Unconsolidated Asphaltic Crude Reservoir
Authors: Efthim F. P. , Garner J. J. , Bilden D. M. , Kovacevich S. T. , Pence T. C. 
Published: December 2007

Abstract
Formation damage results primarily through three types of mechanisms: particulate plugging, organic deposition and chemical incompatibilities. Each of these damage mechanisms can be very detrimental to production performance. Complex damage caused by a combination of formation fines migration, calcium carbonate scale and asphaltene precipitation can result in severe reduction in productivity. When this type of complex damage exists, a specialized stimulation treatment design is required to effectively remove the damage.
The production history of an unconsolidated, asphaltic crude reservoir indicated that a damage mechanism existed and was responsible for abnormally low production rates. Quantitative and qualitative studies were performed in order to analyze this damage and generate an operationally feasible and cost effective treatment. The conclusions generated from this investigation resulted in the design of a unique treatment and placement technique. This technique was applied using a specialized solvent and acid system in a stimulation program that resulted in significant, stabilized improvement in well productivity.
Treatment descriptions and production results are presented from the 18 wells that were included in this ongoing stimulation program. Candidate selection criteria and corresponding stimulation performance are also discussed.
Petroleum Investments in the Asia-Pacific Region
Authors: Partowidagdo W. , Cockcroft P. J. 
Published: December 2007

ABSTRACT
The earnings from oil and gas sales are a very important source of income, both directly and indirectly, for many countries in the Asia-Pacific region. During the past few years, exploration and development has been low, and the future activity level is not expected to be significantly higher. Thus new incentives are needed to entice investors to allot funds for petroleum activities in this region.
A comparison of different fiscal regimes in the Asia-Pacific region is presented, including exploration and development risk and potential, political risk and fiscal risk.
PDC-Bit Evaluation by Cutter Instrumentation and Computer Simulation
Authors: Homstvedt G. , Rødland A. 
Published: December 2007

ABSTRACT
A new tool for monitoring cutter performance is developed for selecting best PDC drilling conditions.
The drilling efficiency of different PDC-bits can show great variations due to different drilling conditions and formations being drilled. Field tests are often unreliable for evaluation purpose because of limited data quality. Theoretical calculations and laboratory experiments have also limited significance often due to unrealistic conditions.
An instrumentation and evaluation system is developed for PDC-bit evaluation purposes. Temperature sensors, mounted in different cutters 1 mm behind the cutting edge, give an 80 % response in 2 seconds. A data monitoring unit is also part of the instrumentation setup situated in a hollow version of a drill collar behind the bit. Cutter-temperatures together with other drilling parameters are monitored for later readout and analysis. Analysis and simulation programs are developed to predict the PDC-wearflat temperatures of each cutter at the bit. The influence of drilling through different formations has thus been evaluated. The influence of actual drilling conditions like pumping rate, weight on bit, rotation speed has also accurately been monitored and analyzed.
By this tool it is possible to make innovative evaluations of bit design and recommended drilling strategies for different formations.
A Petrophysical Model for Shaly Sands
Authors: Stenson J. D. , Sharma M. M. 
Published: December 2007

ABSTRACT
Equations for the electrical conductivity, the electrochemical potential, and the streaming potential of a clay-lined, brine-filled capillary tube have been developed from fundamental principles of irreversible thermodynamics and electrochemistry following the work of Gross and Osterle. Use of the equations gives insight into the role of clay in determining the electrical conductivity as well as the electrochemical and streaming potentials in shaly sand reservoir rocks. The variation in these electrical properties with the magnitude of the electrical potential of the pore lining clay, the radius of the capillary, and the concentration and composition of the saturating brine is investigated. A constant value of surface potential is shown to yield plots which exhibit good qualitative agreement with the experimental shaly sand data of Waxman and Smits and Hill and Milburn. By contrast, a constant value of surface charge density is shown to yield plots of brine saturated capillary conductivity versus brine conductivity which exhibit good qualitative correlation to the experimental shaly sand data of Schon and Borner. The electrochemical potential is shown to vary smoothly form the diffusion potential to the theoretical limit of the Nernst potential as either the surface charge or the capillary radius is changed. The streaming potential of a clay-lined capillary tube is directly proportional to the surface potential of the tube at sufficiently large values of tube radius and brine concentration. This is consistent with Smoluchowski's equation.
Incorporation of the clay-lined capillary tube model into a 3-dimensional network model allows for study of the variation of resistivity index with water saturation in water-wet shaly sand formations. The effects of brine concentration, ion radii, and clay distribution on the magnitude of the Archie saturation exponent, n, are investigated. Relative changes in n are shown to be consistent with experimental results of Waxman and Thomas. The distribution of clays in the rock is shown to significantly alter the resistivity index-saturation plots.
Thin-Bed Reservoir Analysis from Borehole Electrical Images
Authors: Trouiller J-C. , Delhomme J-P. , Carlin S. , Anxionnaz H. 
Published: December 2007

ABSTRACT
In very thinly bedded sand-shale sequences, sand counts and sand/total ratios can be determined from high resolution electrical images of the borehole wall. This technique is illustrated here by a case study in turbidites with sand laminae down to 1 cm in thickness. The numerical modeling of the tool response and a comparison with fullbore core data help assess the accuracy of bed thicknesses derived from electrical images for this type of formations.
Correction for Oil-Based Mud Effects on Neutron and Density Tools
Authors: Lau M. N. , Luquette M. B. , Bassiouni Z. 
Published: December 2007

Abstract
Oil-base drilling fluid density changes considerably with temperature and pressure. Significant density changes prevailing in oil-base drilling fluids can seriously affect the neutron and density sonde readings. The effects of oil-base muds on these logs are discussed, and a technique to account for such effects is proposed. A new approach for true porosity determination in gas-bearing formations is also presented for cases where the gas is miscible with the invading fluid. Two well examples representing different lithologies, fluid types, and miscibility conditions are presented. These examples confirm the need for the proposed corrections and their drastic impact on the qualitative and quantitative interpretation of neutron and density logs.
International Variations in Professionalism
Authors: Ikoku C. U. 
Published: December 2007

Abstract
The engineering profession in the West African sub-region is not much different from what it is in developed countries all over the world. The relatively under-developed environment has hampered the maximum utilization of the indigenous engineers, The engineering profession in this region has developed from the free-for-all era of the 1960s to a stage in which it is now regally regulated.
There is now an accepted code of conduct for all professional engineers. The professional engineering societies ensure that high standards of professional practice and ethics are maintained, and that the engineering profession meets the needs of the West African region. The era when non-registered engineers held posts which discharge and purport to discharge functions which are properly those of registered engineers is rapidly being phased out.
Gas Economics and Regulation in the 1990’s
Authors: Carson M. M. 
Published: December 2007

ABSTRACT
The dynamics of the natural gas industry are changing dramatically due to major federal regulatory policy shifts, and growth of the gas transport and spot gas markets. Gas industry sales and transport activities had traditionally been regulated from wellhead to burnertip, but competition is growing due to: ∘growth in 3rd party transport volumes∘growth in non-regulated gas marketing∘pipeline gas supply portfolios being reformed∘negotiation of new gas supply contract terms∘take-or-pay problems being worked down∘deregulation of the traditional pipeline's roles to allow marketing of new services∘swings in spot market gas prices vs. volumes moved∘number of new pipeline projects proposed∘storage trends
The above 9 trends will be analyzed in the paper for their impacts on the future of the gas industry.
The seven years of the American Revolution era characterized the struggle by which the colonies that were to become the United States won independence from British regulation of colonial commerce.
We could say that the 7 years from 1985 to 1992 is the American pipeline revolution era, characterized by the struggle to free interstate pipelines from their overly restrictive regulation of the past.
Let's turn back the pages of history and look first at some recent history:
Measurements and Correlations of Three-Phase Relative Permeability at Elevated Temperatures and Pressures
Authors: Maini B. B. , Kokal S. , Jha K. 
Published: December 2007

AbstractThree-phase relative permeabilities have an important role in numerical simulation of oil recovery processes. Thermal methods for heavy oil recovery, such as steam injection and in situ combustion, involve simultaneous flow of oil, water and gas at high temperatures. A knowledge of three-phase relative permeabilities at elevated temperatures is required to predict performance of these processes by reservoir simulation studies. Measurements of three-phase relative permeabilities for heavy oil systems at elevated temperatures have been unavailable due to experimental difficulties.The objectives of this work were to develop an experimental apparatus for measuring three-phase relative permeabilities at elevated temperatures and pressures and to carry out such measurements in a model system. The rock-fluid system used in these measurements comprised Ottawa sand - refined mineral oil - distilled water - nitrogen gas. A high viscosity mineral oil (405 mPa.s at 23°C) was selected to simulate heavy oil behaviour. The measurements were carried out at 100°C temperature and 3.5 MPa pressure. Two-and three-phase relative permeability measurements were obtained using the steady-state technique. A large number of steady-state tests were carried out to completely define the three-phase relative permeability characteristics in two types of saturation histories; (1) water and gas saturations increasing and oil saturation decreasing, (2) water and gas saturation decreasing, oil saturation increasing.The three-phase water relative permeability was found to be a function of water saturation only and did not change with the direction of saturation change. The gas relative permeability was also a function of its own saturation only. It was lower in the direction of decreasing gas saturation. The oil relative permeability was found to vary with saturations of the other fluids. Oil isoperms were concave towards the oil apex.
Two-Phase Flow in Heterogeneous Porous Media: The Method of Large-Scale Averaging Applied to Laboratory Experiments in a Stratified System
Authors: Quintard M. , Bertin H. , Whitaker S. 
Published: December 2007

Abstract
The theoretical study of the flow of two fluids in a porous medium begins at the pore level with the Stokes equations. The method of local volume averaging is used to derive the well known extension of Darcy's law. For a heterogeneous porous medium, the method of large-scale averaging is used to average the Darcy-scale equations over a region that is large compared to the length scale of the heterogeneities. The closure problem developed with this method is used to compute the large-scale coefficients, such as the permeability, associated with the heterogeneous porous medium. The closure problem is simplified for the quasi-static (capillary dominant) case, and results are presented for two-dimensional, periodic, heterogeneous media, and stratified media.
The experimental study consisted of the waterflooding of a stratified porous medium made up of Berea sandstone and Aerolith-10, a sintered artificial porous medium. During the waterflooding experiments the saturation field was measured by gamma-ray absorption. The large-scale capillary pressure and permeabilities were computed from the independent characterization of the two layers by solving the large-scale closure problem assuming that the quasi-static condition was valid. The numerical results consisting of averaged volume fractions over a section of the stratified medium, and these are compared satisfactorily with the experimental data.
Evaluation of Two-Phase Steam Flow Through an Orifice
Authors: Griston S. , Cire F. L. 
Published: December 2007

ABSTRACT
Proper management of steamflood projects requires accurate information about heat input to the petroleum reservoir. The first logical step toward obtaining this information is to meter the steam flow rate and quality directly at the injection wellhead. However, this is not an easy task. The need for reliable, cost effective wellhead steam metering methods has existed for many years.
Recently, methods using an orifice or nozzle in series with a second device, such as a critical flow choke or densitometer, have been introduced for metering wellhead steam quality and flow rate. Although orifices are commonly used to monitor superheated or high quality saturated steam exiting an oil or gas-fired boiler, little is known about the reliability and accuracy of using orifice meters over the wide range of pressures, flow rates, and qualities that exist at injection wells. Of primary concern is whether or not there is a strong correlation between the pressure drop across the orifice and changes in steam quality and/or mass flow rate. The effects of two-phase flow regime on pressure drop are also important and must be considered.
This paper presents results of field testing and evaluation of two-phase steam flow through an orifice over an extended range of flow rates, qualities, and pressures. Overall accuracy and reliability of orifice meter data are discussed and compared to published studies. An overview of the fundamental aspects of steam flow through an orifice is given and reasons for the variation in existing empirical correlations are discussed. Finally, the problems encountered when using an orifice or nozzle in conjunction with other metering devices to determine wellhead steam quality and flow rate are examined.
On Fracture Design of Deviated Wells
Authors: Yew C. H. , Schmidt J. H. , Li Yi 
Published: December 2007

Abstract
This paper presents technical concepts and procedures for the design of hydraulic fracture treatments for deviated wells. These Include: the width and location of well surface tensile zones,the length and angle of deviation of initial fracture intersections with the well surface,the orientation of fracture plane propagation relative to the wellbore,the maximum distance between perforations permitted for multiple fracture linkup in open holes,and the effect of casing on perforation orientation and density for cased wells.
Previously derived equations were modified and expanded for use in this analysis. Results of plastic model experimental studies are presented which verify these calculations and agree qualitatively with theoretical predictions. Finally, an example is presented which demonstrates the use of the above procedures.