bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Heat Efficiency of Thermal Recovery Processes Resulting from Non-Uniform Vertical Temperature Profiles
Authors: Prats M. 
Published: December 2007

ABSTRACT
Original analytical results provide estimates of the heat remaining in a homogeneous and uniform reservoir during injection of steam or hot water, for the practical cases where the temperature is not vertically uniform within the reservoir.
Temperatures quadratic in the vertical position within the reservoir are used to accommodate the boundary conditions for three cases: steam extends to the boundary of both, only one, or none of the formations above and below the reservoir. The first case corresponds to steam extending over the full thickness of the reservoir, already published. The second case approximates steam flooding with gravity override, and the third case approximates hot water flooding.
Two graphs, sufficient to estimate the time dependence of the heat remaining in the reservoir, are provided. Results depend on the thermal properties of the reservoir and its adjacent formations, which may differ. Results also depend on the square of the reservoir thickness and the rate of heat injection.
Heat efficiency is defined as the fraction of the injected heat remaining in the reservoir. Comparison of our hot water heat efficiency with Rubinshtein's formal analytical results1 (for equal thermal properties) shows excellent agreement.
The heat in the reservoir is not a function of the injectant temperature, a result which had been shown previously only for the case that steam extends over the full reservoir thickness. Nor is the heat efficiency dependent on the rate of heat injection when the latter is constant.
Because of low temperatures at the boundaries with the adjacent formations, the heat efficiencies of hot water floods and steam floods with override are higher than those for steam extending over the full reservoir thickness. For hot water floods, the increase is as much as 16%. For steam floods with override the increase is more modest.
Conformance Improvement by Using High Temperature Foams and Gels
Authors: Isaacs E. E. , Green M. K. , Jossy W. E. , Maunder J. D. 
Published: December 2007

ABSTRACT
The use of foams to divert the steam from the swept zone has been extensively tested both in the laboratory and the field. On the other hand, gels for plugging unproductive zones have mostly been considered for conventional or relatively low temperature applications. The objectives of this study were the development of strategies for improving the long-distance propagation of foam in the reservoir and evaluation of gels for near-well applications in thermal recovery operations.
The major limitations to the growth of the foam zone include the inefficiencies in foam generation and poor bubble transport. Flow experiments were carried out in sand packs at steamflood conditions to develop strategies for improving foam generation by a pre-foam reduction of residual saturation in the swept zone. The results showed that the pre-foam concept could be used with small slugs of low interfacial tension chemical or solvents to substantially improve the rate of foam propagation.
Studies to determine the propagation behavior once foam is generated showed that bubble transport is sensitive to oil saturation but relatively insensitive to injected fluid velocities and liquid volume fraction.
Laboratory experiments were also conducted to test gel performance in porous media over the temperature range 100-300°C. Although the gel strength diminished at high temperatures, significant reductions of steam mobility were still observed at 300°C. Gels in porous media were shown to withstand moderate pressure gradients for extended periods of time at elevated temperatures. The advantage and disadvantage of foam and gel applications at elevated temperatures will be discussed.
Design and Application of Sintered Porous Stainless Steel Well Screens in Sand Control Completions
Authors: Cole R. C. , Arterbury B. A. , Pearce J. L. 
Published: December 2007

Abstract
Wire-wrapped screens, in many different design configurations, have been the industry standard for use in gravel pack completions. Lately, some of the advantages of prepack designs, have generated interest and are being used in both cased and operinole completions. Of specific interest have been prepack designs having a thinner aggregate layer which affords more annulus clearance to help assure adequate gravel placement and retreivability.
One recent development in porous sintered stainless steel technology introduces a thin-walled, sintered stainless steel screen that appears to offer improvements over prepack screens. Some advantages to the porous sintered metal screens (PSMS) over thin-wall designed prepack screens (TWPS) have been confirmed by current testing. These include uniformity of the porous metal screen media and resistance to damage due to handling.
In addition to a discussion of the above findings, the paper presente results of comparative testing of the two type screen designs for the effect of bending stresses, flow capacity, scaling tendencies, and cleanout by backflusbing. A study of the effects of brines, acids, and H2S on the porous metal is also included.
The most gravel pack screen-related failures have been traced to. impact damage and erosion cutting. The introduction of this new porous sintered metal technology to reduce screen failures can save money in reducing the number of workoveis and in prevention of production declines.
Waterflood Stimulation for Fractured Limestone of the Austin Chalk
Authors: Rose R. E. , Austin C. E. , Pike J. R. 
Published: December 2007

Abstract
A process for treating older wells completed in the Austin chalk has produced impressive production increases in wells which had previously been fracture stimulated using water-based, sand-laden fracturing fluid. The process utilizes high volumes of water pumped at high rates (more than 25 bbl/min). Termed ‘waterflood stimulation,’ this technique has helped rejuvenate wells which had experienced major production declines since the original fracturing treatment. Incorporated in the treatment fluid are surfactants, diverting agents, weak acids, and friction reducers. Based on analysis of 3 years of treatment results, ‘waterflood stimulation’ appears to provide a waterdrive production mechanism, as evidenced by well response.
Austin Chalk completions have typically been characterized by high initial production followed by rapid production declines. Reservoir characteristics of the Austin Chalk indicate that production is dependent on the fracture system, both natural and created, rather than on the actual rock matrix. Methods have been developed to help determine feasibility of ‘waterflood stimulation’ on an individual well basis. Factors to consider include cumulative production and gas:oil ratio. Guidelines for treatment rates and volumes have also been developed based on well parameters and field experience. Other, similar-type reservoirs may also be receptive to this form of treatment.
Subject paper will present case histories from approximately 20 wells, descriptions of reservoir characteristics, evaluation criteria for candidate wells, and treatment design and operation with production data before and after treatments.
The Mechanisms of Solids Production in Unconsolidated Heavy-Oil Reservoirs
Authors: Chalatumyk R. J. , Wagg B. T. , Dusseault M. B. 
Published: December 2007

Abstract
A research program into the mechanisms and management of solids production is currently underway. The major objective is to develop a comprehensive understanding of solids production mechanisms which will lead to drilling, completion, and operating strategies that can be used to reduce the costs and risks associated with oil and gas production. The research program is comprised of four major components: (1) a Field Study, to conduct a detailed review of past sanding experience by accessing the large body of information that exists within the well records of several companies; (2) a Laboratory Testing program to characterize the hydraulic and constitutive behavior of reservoir materials; (3) a Field Testing program to obtain data for specific reservoir characteristics and to assess products/processes for controlling and exploiting solids production; and (4) a Numerical Modelling program to develop a predictive capability for solids production. At present, the research program is focussing on sand production from heavy oil deposits in Alberta and Saskatchewan. The technical challenges associated with the field study component of the research program are presented and discussed.
This study of solids production is analyzing the entire history of the well, extending from spudding to abandonment This includes the "formation disturbance" effects that accumulate from drilling, cementing, perforating, production and workovers. Data management procedures developed for handling field information are presented. A Reservoir Disturbance Index (RDI) has been developed to quantify the degree of reservoir disturbance created during drilling, completion, production and workover phases. The procedures for computing RDI values and use of this index in comparative statistical analyses are described. Geophysical logs are incorporated in the field study to develop a capability for assessing solids production potential.
An Experimental Investigation of Formation Damage in Heavy Oil Reservoir During Steam Injection
Authors: Okoye C.U. , Onuba N.L. , Ghalambor A. , Hayatdavoudi A. 
Published: December 2007

SPE Members

Abstract
A laboratory study was conducted to evaluate formation damage due to steam injection. The investigation includes the adsorption and desorption of divalent ions and the transportation of scales through the formation. Several displacement tests were made at different elevated temperatures (200 degrees F to 500 degrees F) and steam salanity or alkalinity to determine the rate and nature of formation damage during steamflooding. Other tests conducted in this study include; roller oven tests, SEM EDEX and petrographic studies.
The results from this study show there is decline in the permeability when temperature permeability when temperature and alkaline concentrations are increased. It was also observed that the alkaline solution PH decreased with increase in temperature. SEM, X-Ray, EDX and petrographic analysis show petrographic analysis show pseudo-hexagonal stacks of pseudo-hexagonal stacks of mineral overgrowth which blocked the pore throats. There was dissolution of minerals and precipitation of aluminosilicate such as zeolite. This study provides screening procedure for estimation of potential formation damage due to steam injection. Also, the results obtained in this study relate to actual formation during steam cyclic steam and direct steam injection.

Introduction
In order to understand the theory of reaction kinetics related to this experimental investigation, it is necessary to look at the physio-chemical aspects of reaction kinetics.
Fracture Reorientation in Model Tests
Authors: Weijers Leen , de Pater C. J. 
Published: December 2007

Abstract
An experimental study has been carried out to investigate the influence of the cementing chronology. That is to say, cementing of a perforated casing in a stress-free borehole or a loaded borehole resulted in a difference in near wellbore fracture geometry.
Starter fractures, propagating into multiple fractures, were observed when the casing was set and cemented in a stress-free borehole. Cementing the casing in a stressed borehole resulted in a continuous fracture along the wellbore, which sometimes ignored the perforations. Therefore, hydraulic fracturing experiments with the aim to represent field situations should be carried out when the casing is cemented in a stressed borehole.
Predictability of Formation Damage by Modeling Chemical and Mechanical Processes
Authors: Chang F. F. , Civan Faruk 
Published: December 2007

Abstract
A phenomenological model for formation damage by chemical and mechanical processes in petroleum reservoirs is presented. Geochemical reactions involving dissolution/precipitation and ion exchange are modeled. The precipitates are considered mobile and mixed with formation particles to contribute to the pore throat plugging. Size distribution of both precipitates and clay fines is represented by a bimodal distribution function. A semi-empirical approach is used to estimate the fraction of the plugged pore throats. The model parameters are determined through an optimization method by matching the model predictions to laboratory core test data.
The capability and validity of the model are demonstrated by comparing the predictions obtained from this model with experimental data for four cases. The predicted and the experimental data are shown to be in good agreement in each case. This model can be used for diagnosis, evaluation, and simulation of damage and alteration of reservoir formation during drilling, production, and chemical flooding processes.
Study of Waterfall Effect on Formation While Underbalance Tubing-Conveyed Perforating
Authors: Sampson T. W. , Dunn H. E. , Walton D. S. , Combo J. C. 
Published: December 2007

Abstract
This paper describes the naturally occurring phenomenon of hydrostatic reduction and oscillation about an underbalance pressure when hydrostatic pressure is decompressed by the opening of a ball valve to the underbalance pressure when tubing conveyed perforating is performed. Downhole memory pressure gauges have recorded this event on wells on three separate zones. Laboratory testing was conducted and was successful in recreating and recording this pressure transient. All the data indicates that the magnitude of the hydrostatic reduction to be a function of the differential pressure being decompressed. The continued decrease of pressure below the underbalance pressure occurs at a rate of approximately 20 psi (.14 MPa) per 100 psi (.69 MPa)of differential pressure. The duration of the oscillating pressure wave (i.e., the time from the opening of the ball valve until the pressure wave is damped out) is a function of the volume of fluid being decompressed. Theduration time increases at a rate of one second per400 U.S.gals (1.514m3).
The data has been plotted on pressure vs. time graphs. The curves are characteristic of damped harmonic motion with a single degree of freedom and therefore, can be solved by using a linear second order differential equation.
Chacterization of Carbonate Precipitation and Scale Formation in Solids-Free Clear Brines
Authors: Swartwout R. T. , Ho Tien 
Published: December 2007

Abstract
The following brines, a 11.0 lbm/gal (1.32 g/cm3) NaCl/NaBr, 13.5 lbm/gal (1.62 g/cm3) CaCl2/CaBr2 and 16.0 lbm/gal (1.92 g/cm3) CaCl2/CaBr2/ZnBr2 were studied for carbonate precipitation and scaling tendencies in the presence of CO2 gas. The brines were subjected to CO2 gas pressures ranging from 50 to 500 psi (0.34 to 3.45 MPa) and temperatures between 200 to 400°F (93.3 to 204°C).
The 11.0 lbm/gal (1.32 g/cm3) NaCl/NaBr and 13.5 lbm/gal (1.62 g/cm3) CaCl2/CaBr2 brines formed small amounts of carbonate solids upon exposure to CO2 gas. The 16.0 lbm/gal (1.92 g/cm3) CaCl2/CaBr2/ZnBr2 brine in contact with CO2 gas produced significantly large amounts of carbonate solids. The concentration of precipitated carbonates formed by the 16.0 lbm/gal (1.92 g/cm3) CaCl2/CaBr2/ZnBr2 brine would raise concerns of possible formation damage.
Two commercial scale inhibitors were evaluated and were found to provide very little to no protection towards inhibition of carbonate solids formation.
Wellbore Stimulation Using Microorganisms to Control and Remediate Existing Paraffin Accumulations
Authors: Peiger J. W. 
Published: December 2007

Abstract
This paper will explain and demonstrate a method to increase production in individual wells or fields with skin damage, due to paraffin accumulations, corrosion, emulsion and scale formation, utilizing an individual treatment design from a library of facultative anaerobic microorganisms.
These neutrally charged marine organisms, in a saline solution of nutrients, are naturally occurring, non-pathogenic, non-toxic, non-careinogenic, non-combustible and require no permits from the Environmental Protection Agency for storage, transportation or disposal. Environmentally, these microorganisms are as safe as any product in our industry to control and reduce skin damage.
Paraffin, corrosion, emulsion and scale formation have resulted in significant economic losses, reducing profitability for producers and operators. The resulting skin damage can be controlled and reduced through proper treatment by locating microorganisms in the immediate formation, perforations, and in the case of most problem preventing restrictions in production streams or failures in lifting equipment. Traditional control methods for treatment involve implementing techniques such as hot oiling, paraffin cutting, chemical and condensate treatments. These techniques have been marginally successful, economically prohibitive and temporary at best. Many of these traditional methods are dangerous from a safety standpoint and often have caused serious long term damage to the productive life of the well (especially in the case of hot oiling).
Laboratory Investigations of the Effects of Formation Damage in a High-Permeability Reservoir
Authors: Mehdizadeh A. M. , Hashemi Reza , Caothien Scott 
Published: December 2007

Abstract
A four foot long pipe (ID = 2″) packed with silica sand was used to study the effects of formation damage caused by completion and work-over fluids in a high permeability reservoir. Pressures were recorded at five locations (1 foot apart) across the high permeability sand pack as different fluids at a rate of 5 ft/day were injected into it. Bentonite and salt concentration of the injected fluids were changed and their effects on the single phase permeability of the sand pack at different filtration levels were investigated. Some runs were performed using field water from San Ardo field in California. Finally, effects of formation damage on oil recovery by water-flooding were also studied.
Results show that depending on the composition and the amount of the injected fluids, high permeability sand pack develops irreversible permeability loss which in turn limits the ultimate oil recovery during water-flooding. Results also show that maintaining proper filtration level can minimize the degree of damage to the high permeability sand pack.
Dual-Diameter Drillpipe Offers Advantages in High-Angle Drilling
Authors: McNeely B. M. 
Published: December 2007

ABSTRACT
This paper introduces a unique drill pipe design concept proposed primarily for high angle/horizontal service. The design consists of a pipe joint, the middle two-thirds of which are light-wall and has an outside diameter only slightly smaller than the tool joint. Handling space of nominal diameter is provided at both ends. Tool joints are conventional.
Two principal design effects are tabulated comparing Dual Diameter Pipe with API in four sizes. (1) Mud volume and pressure loss to produce various annular velocities. (2) Load to produce buckling calculated using Dawson Paslay and Euler.
Consideration for Design of Drilling Conductors for the New Generation of Deepwater, Harsh Weather Jackups
Authors: Wetmore S. B. , Halbleib B. L. 
Published: December 2007

ABSTRACT
As the next generation of harsh weather jackups for the North Sea push the operating water depth limits from 300 feet (91m) upwards to 500 feet (150m), the environmental criteria also increase. At these more severe depth and environmental conditions the increased dynamics of both platform and drilling conductor will increasingly affect drilling operations. When drilling in water depths greater than several hundred feet the conductor must be tensioned to resist buckling and increase its stiffness, the amount of tension being proportional to water depth and environmental conditions. The tensioning device is usually placed at the top of the conductor and just below wellhead/BOP stack, thus creating a point of lateral fixity. As currents and waves act on the tensioned but unstayed conductor, the wellhead/BOP stack rotates about the point of support to suit the structural deflection of the conductor below. At some limiting sea state, the top of the BOP stack no longer lines up with the rotary table and drilling must be suspended. If the top of the BOP stack is also laterally fixed (or hydraulically snubbed), a bending momement is induced in the BOP stack, which under severe storm conditions, can exceed the structural limit of the BOP stack connections.
A frequency domain computer program was used to parametrically analyze the dynamics of the system and to calculate the maximum stress levels in the various components. The paper examines over 75 combinations of physical configuration, water depth, environmental criteria, drag coefficient, conductor diameter, vertical tension and joint stiffness. Appropriate graphical representation of the results are presented. Based on the analysis, the authors conclude that the design of the drilling conductor for winter storm conditions in the North Sea and for water depths greater than 300 feet will be significantly more complex than present shallow water designs. An ongoing analytical program is postulated to study composite configurations, fatigue effects, and drilling downtime.
A Critical Examination of Rotary Drilling Hydraulics
Authors: Bourgoyne Ted , Kimbler O.K. 
Published: December 2007

Abstract
A new computer technique has been developed for providing information on rotary drilling hydraulics. The computer program determines the proper bit nozzle size and pump operating conditions for all combinations of depth and mud density for a given hole size. By performing the calculations for all hole sizes used, the program completely defines optimum hydraulics for a given rig, making repetitive calculations for each well unnecessary.
The computer program presented was used to compare various published optimization procedures over a typical range of field conditions. The optimization procedures studied were
establishment of maximum jet impact force, establishment of maximum bit horsepower, establishment of maximum nozzle velocity, establishment of known cleaning needs with the least pump horsepower expenditure, and pump horsepower expenditure, and establishment of optimum bit horsepower using the Economy Method.
The comparison includes differences among the procedures in pump cost as well as the differences in the hydraulic horsepower, jet impact, and nozzle velocity of the bit.
Introduction
The development of the jet bit has been one of the most significant improvements in drilling technology. The main advantage of the jet bit is its higher efficiency in removing rock cuttings from the hole. Cuttings remaining on the bottom of the borehole will impede further penetration by the bit until they are removed. Wasteful regrinding is prevented if the fluid circulating past the bit removes cuttings as rapidly as they are formed.
In order to utilize the full potential of the jet bit, the proper potential of the jet bit, the proper nozzle size and pump pressure must be used. Figure 1, after Kendall and Goins, illustrates the large increase in bit hydraulic horsepower that can be achieved by the selection of a proper hydraulics program of bit nozzle proper hydraulics program of bit nozzle size and pump operating conditions.
Drilling Contractors Long Overdue Focus on Drill Floor and Its Equipment
Authors: Pedersen P. Carsten , Kudsk G. , Lund T. 
Published: December 2007

Abstract
The paper introduces some suggestions as to why development of new equipment/approaches has been slow in the drilling contracting industry and why this situation now appears to have changed. It goes on to describe a systematic development method utilized by Maersk Drilling in improving the drilling process by focusing on safety and efficiency in the layout and in the equipment chosen.
Some of the results such as driller's control, FOXHOLE etc. are explained from the arrangements on board the contractor's two new harsh environment jack-ups presently under construction in Singapore.