bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluid Properties and Particle Size Requirements for Effective Acid Fluid-Loss Control
Authors: Gdanski R. D. 
Published: December 2007

ABSTRACT
Control of acid fluid loss during fracture acidizing treatments is recognized as being a dominating limiting factor in the effective use of such treatments. This paper will discuss the importance of adequate acid viscosity, proper acid concentration, and proper particle size distribution for maximizing acid fluid loss control. The recommendations are based on laboratory testing which utilizes a severe acid fluid loss test. The test involves the use of a hollow core reactor under conditions of several hundred psi radial pressure drop across about a 5/8 inch thick wall. The pressure drop was from the inside of the limestone core to the outside. Parameters investigated included acid viscosity, acid concentration, and fluid loss additive particle size distribution. It was discovered that simply viscosifying the acid provided a remarkable improvement in acid fluid loss control. This enhancement was most pronounced in very low permeability limestone cores. The nature of the viscosifying agent was found to be a secondary effect with polymeric materials being more effective than surfactant type viscosifiers. A viscosity of 20 cp at 511/sec at the treating temperature was found to be an optimum value. It was also shown that the higher acid concentrations caused poorer fluid loss control. The effect of particle size distribution of a silica fluid loss additive was studied and indicated the particles with sizes larger than 80 mesh were key to successful acid fluid loss control. Silica flour was found to provide little enhancement of acid fluid loss control. The principles learned from the laboratory tests can be used to design improved fracture acidizing treatments. Indeed, these principles have been used successfully.
Interpretation of Directional Gamma Ray Logging Data for Hydraulic Fracture Orientation
Authors: Simpson G. A. , Gadeken L. L. 
Published: December 2007

Abstract
A new directional gamma ray tool has been developed and is being incorporated into an innovative togging service. The service determines the azimuthal pattern of gamma ray emission from a completion material that has been tagged with a radioactive isotope. This paper discusses the interpretation of directional gamma ray logging data following hydraulic fracturing operations. By measuring the intensity of gamma rays emitted from tagged material placed in the induced fracture, the directional gamma ray measurement can be combined with auxiliary wellbore survey information to assist in the determination of propagation azimuth. Such results have a variety of applications – for example, designing a systematic well placement scheme to optimize reservoir drainage efficiency.
Log examples derived from prototype tool measurements following hydraulic fracturing operations are presented and the analysis of the data is discussed. The interpretation of directional gamma ray data is adversely affected by damage to the near-wellbore region during fracturing operations. Data interpretation was found to be more consistent and reliable following micro-frac or mini-frac stress determination operations. In addition, where perforations were oriented in the direction of the anticipated fracture propagation, directional gamma ray data demonstrated an improvement in fracture efficiency.
Sedimentation and Free Water of Cement Slurries: Mathematical Models and Practical Solutions
Authors: Stiles D. A. , Baret J. F. 
Published: December 2007

ABSTRACT
Because the water/cement ratio is a prime determinant of slurry properties, one objective of any slurry design is to keep the annular column of suspension homogenous until the cement has set. Microscopically, there are two extreme situations possible for a cement slurry; either it is dispersed, i.e., the particles are separated by repulsive forces between negatively charged surfaces, or it is flocculated, i.e., the particles form an interconnected structure held by electrostatic bonds between unlike charges. When the slurry is fully dispersed, it becomes unstable and shows sedimentation, resulting in large vertical density gradients while no supernatant water may be present. Conversely, when it is flocculated, free water may form with the suspension below remaining homogenous. Practically, intermediate situations where only a fraction of the particles are flocculated are sought, leaving the slurry stable but not too viscous.
In this paper, the first part describes and provides mathematical models for the two basic phenomena which may create a density gradient in a cement slurry: (1) the subsidence of a network of flocculated particles; (2) the sedimentation of individually dispersed particles. The second part presents slurries with various physical properties which display actual density gradients, and correlates these gradients with the models. The final part describes a newly developed anti-settling additive, which facilitates the design of stable cement slurries, including field case histories.
Ultrafine Cement for Oilwell Cementing
Authors: Clarke W. J. , McNally A. C. 
Published: December 2007

Abstract
Ultrafine cements are particulate, cementitious grouting materials that were initially developed as a replacement for unacceptably toxic chemical grouts for Civil Engineering applications. Several basic types are available: ultrafine slag cement (M1), ultrafine Portland cement (M3) and ultrafine portland/slag (M5). The chemical compositions and physical properties of these materials are shown in Table 1 and 2 and in Figure 1. Their extremely fine grain size enable them to permeate medium sands and fine fractures in rock. These and other properties have led to ultrafine M5 cement slurries being adopted for use in oilwell cementing applications, especially for gas and water control. The results of a series of experiments on ultrafine M5 cement slurry have indicated that it remains in a fluid state at high temperatures for at least as long as slurries formulated with Class G portland cement, demonstrating its applicability for use in hot, deep wells.
Applications for M5 involve squeeze cementing the Wasson South Unit 7514 casing leak at 3222 feet. 30 sacks of M5 were successfully used to seal the casing leak as the ultrafine cement was drilled out and the casing tested to 1000 psi with no bleed-off. In another application, M5 ultrafine cement was used to squeeze repair a casing leak. The previously repaired leak had broken down and was taking lift gas and giving up sour water. M5 was used to seal the leak and restored top allowable, water-free oil production from the well.
Comparison of Cuttings Transport in Directional Drilling Using Low-Toxicity Invert Emulsion Mineral-Oil-Based and Water-Based Muds
Authors: Hareland Geir , Azar J. J. , Rampersad P. R. 
Published: December 2007

Abstract
The vast majority of previous work on cuttings transport concentrated on water-base mud systems. The use of low toxicity oil-base mud continues to rise due to increasing environmental concerns with the use and disposal of conventional diesel oil-base mud systems. This study utilizes a full scale test apparatus to compare the cuttings transport performance of low toxicity oil-base and water-base mud systems with similar rheological properties, using limestone drilled cuttings. Extensive comparisons are now being made of cuttings transport efficiency for different mud types and hole angles from a practical standpoint.
The results indicate that the water-base mud and the low toxicity inverted emulsion oil-base mud systems perform slightly different at all angles of inclination except at the critical range 40° to 50° where the oil-base muds have higher annular cuttings concentration due to severe cuttings bed down-sliding. Limestone cuttings transport using a water-base mud, as well as a low toxic oil-base mud, shows cuttings concentrations increase with increasing mud yield point. The effect of increased yield point and plastic viscosity increases cuttings bed buildup, bed down-sliding and gel film thickness, thus reducing transport performance. In most cases the increase in hole inclination angle results in reduced transport efficiency.
Torque requirements are significantly less for oil-base muds having the same annular cuttings concentration. For both muds the torque requirements increase with increasing yield point and plastic viscosity at higher hole inclinations.
Theory and Application of Polynomial Type Curves
Authors: Jelmert T. A. 
Published: December 2007

ABSTRACT
A generalized methodology for flow period diagnostics and type curve matching is discussed. The method which is based on the concept of a polynomial derivative function, can be used under a variety of flow conditions.
A new methodology to highlight possible constant terms during radial or polynomial flow periods is proposed. The constant term reflects the damage skin factor and the degree of convergence to the well.
A Pseudopressure-Pseudotime Transformation for the Analysis of Gas Well Closed Chamber Tests
Authors: Xiao Jinjiang , Reynolds A. C. 
Published: December 2007

ABSTRACT
This paper presents methods for the analysis of gas-well, closed-chamber tests. It is shown that, in most cases, pseudopressure and pseudotime can be used to correlate gas-well, closed-chamber test results with the analogous liquid, slug-test solutions. This allows data from gas-well, closed-chamber tests to be analyzed using slug-test analysis procedures that assume single-phase flow of a slightly compressible liquid of constant compressibility and viscosity within the reservoir. Multirate analysis techniques were found to be applicable to gas-well, closed-chamber tests in terms of pseudopressure and time, not pseudotime.
Applications of a Continuum Damage Mechanics Model to Hydraulic Fracturing
Authors: Valkó Peter , Economides M. J. 
Published: December 2007

ABSTRACT
A fracture propagation model that is intended to describe the geometry of a hydraulic fracture is also supposed to replicate the pressure level and trends during execution. This is often not the case with "abnormally high fracturing pressures" recorded presently. The problem stems from the intrinsic nature of linear elastic fracture mechanics. A relatively new branch of fracture mechanics, Continuum Damage Mechanics (CDM), has been used by the authors to construct a fracture propagation model describing fracturing pressure behavior consistently. The CDM version of the Perkins-Kern/Nordgren model (CDM-PKN) contains a combined parameter responsible for fracture propagation retardation. The parameter is the CDM substitute for the fracture toughness. The new parameter can be identified from step-rate tests and/or treatment pressure diagnostics. Knowing this parameter the CDM-PKN model can be used to predict the net fracturing pressure, fracture length, width and fluid efficiency. In this work several applications of the model are presented. A laboratory experiment, step-rate tests and a minifrac test are evaluated in terms of the new model. A possible range is established for the combined parameter. The large impact of the combined parameter on fracture design is illustrated by a case study.
Consequences of Fracturing Fluid Lag in Three-Dimensional Hydraulic Fractures
Authors: Advani S. H. , Lee T. S. , Dean R. H. , Pak C. K. , Avasthi J. M. 
Published: December 2007

ABSTRACT
Research investigations on three-dimensional (3-D) rectangular hydraulic fracture configurations with varying degrees of fluid lag are reported. The interpretations deduced from the computed stress intensity factors for a wide spectrum of fracture slenderness ratios and effective minimum in situ stresses are dramatically different from those derived from plane-strain crack simulations. In particular, this paper demonstrates that a 3-D fracture model coupled with fluid lag at the fracture tip can predict very large excess pressure measurements for hydraulic fracture processes. In addition, this paper demonstrates that 3-D predictions of fracture propagation based upon critical stress intensity factors are extremely sensitive to the pressure profile at the tip of a propagation fracture and that plane-strain models of fracture propagation will underestimate the fracture pressures required for propagation. This rationale for the excess pressure mechanism is in marked contrast to the crack tip process damage zone assumptions and attendant high rock fracture toughness value hypotheses advanced in the literature. Selected model result comparisons with experimental data are presented to provide additional validation of the proposed 3-D rectangular geometry and fluid lag-fracture fluid pressure sensitivity phenomenon.
A Lesson in Site Management and Cleanup: The Bishop Tank Farm Remediation
Authors: Chaconas J. D. J. , Hunter R. W. , Huismann S. S. 
Published: December 2007

Abstract
The decommissioning of the Bishop Tank Farm began as a simple equipment dismantling and removal. However, the presence of soil contamination led to a costly and lengthy site remediation. The successful cleanup of the lease provided valuable lessons in minimizing environmental contamination and managing remediation at oil and gas facilities.
Waterflood Management During Production Shut-In of the McArthur River Field, Cook Inlet, Alaska
Authors: Wolodkiewicz D. E. , Walker R. K. , Pospisil Gordon 
Published: December 2007

ABSTRACT
A case history of the Hemlock Reservoir of the McArthur River Field in Cook Inlet, Alaska demonstrates continued water injection during an extended production shut-in resulted in higher oil rates once production was resumed. With volcanic eruptions of Mt. Redoubt, located 30 miles to the south, production was shut-in for over three months during 1990 due to interruption of oil shipping and storage operations. This paper describes the results of effective waterflood management and the benefits of data gathering through pressure mapping and static tracer surveys during the production shut-in.
Maintaining water injection during the 1990 shut-in raised the average reservoir pressure by 230 psig and resulted in higher oil rates upon the resumption of production. Previous extended production shut-ins during 1976 and 1985 were followed by oil rate declines of up to 25%.
Reservoir pressures were monitored during continued water injection while the production was shut-in to define areas of lower pressure and poor reservoir conformance. Pressure mapping and static tracer surveys significatly improved the Hemlock reservoir description. Based on this data, infill drilling and waterflood conformance projects are being designed to increase recovery through improved vertical and areal sweep efficiency.
The waterflood management decisions and reservoir analysis techniques discussed in this paper provide useful insights to increase oil rate and reserves in future waterflood applications.
This case history describes waterflood surveillance and analysis which may be implemented during extended production shut-ins to improve reservoir description and define recovery enhancement projects.
Prudhoe Bay Rig Workovers: Best Practices for Minimizing Productivity Impairment and Formation Damage
Authors: Dyke C. G. , Crockett D. A. 
Published: December 2007

ABSTRACT
A field wide review of rig workovers was carried out for the Prudhoe Bay reservoir to enable a set of ‘best practices’ to be drawn up and implemented. Particular emphasis was placed on well killing, together with the minimisation of formation damage and loss in productivity index associated with rig workover operations. Clear conclusions emerge which have a significant impact on productivity as well as reducing total workover costs.
The results of this case history are of direct relevance to all workover operations, detailing how cost effective well killing can be performed with the minimal productivity loss.
Prudhoe Bay: Development History and Future Potential
Authors: Szabo D. J. , Meyers K. O. 
Published: December 2007

ABSTRACT
Prudhoe Bay Field is the largest producing field in North America. Prudhoe Bay is currently expected to yield at least 25% more reserves than estimated at field start up. This paper briefly describes the history of the field and some of the key developments that have taken place which have contributed to improved recovery efficiency. These incremental developments have resulted from a process of continuous surveillance, interpretation of field performance, management of multiple reservoir mechanisms, efficient utilization of the gas resource, and exploitation of the existing field infrastructure.
There are four dominant recovery processes currently at work in Prudhoe Bay; Gas Cap Expansion/Gravity Drainage, Waterflood, Miscible Flood, and Gas Cycling. Continuous management of these processes and analysis of field performance leads to identification of attractive targets for further development. Major components of the current field development plan are described in this paper.
Prudhoe Bay is seen by many as a mature oil field on an inevitable and irreversible decline. The major Owners in Prudhoe Bay continue to pursue incremental developments to mitigate decline and supplement proved reserves. Unit technical studies are typically done in multi-company, multi-disciplinary work teams. The pooling of resources in this manner has enabled efficiency gains and has promoted the sharing of ideas and best practices. The current view of potential future development targets and some of the opportunities under consideration for development of these targets are discussed.
Electrical Load Shedding Program at the Salt Creek Field Unit
Authors: Collier F. B. , Hardgrave E. N. , Stanley R. J. , Hatfield L. K. 
Published: December 2007

ABSTRACT
This paper discusses a recently implemented electrical load shedding program at the Salt Creek Field Unit (SCFU) in Kent County, Texas. The project involves the interruption of SCFU electrical load during the wholesale utility's monthly peak load. By interrupting SCFU load during the utility's monthly peak, the SCFU electrical demand charge is reduced by $7.16 or $6.03 per interrupted kilowatt, depending on the time of year.
A dual demand electrical rate schedule makes the load shedding concept possible. With this rate schedule, the demand charge is divided into two components. One demand charge is based on the highest SCFU electrical load during the billing period while the other is based on the SCFU load during the wholesale utility's monthly peak. The goal of the load shedding program is to interrupt SCFU electrical load at the time of the utility's peak load thereby reducing one component of the demand charge.
A critical element to the load shedding program is the ability to predict when the wholesale utility's monthly peak load will occur. The utility's system load is highly dependent on the temperature in the utility's main load center which is located in and around Stephenville, Texas. By closely monitoring the utility's load and temperature/weather data in Stephenville, the time of the utility's peak load can be forecasted. Historical load and temperature/weather information are also utilized in peak load forecasting.
Another key element is the selection of SCFU electrical load to be interrupted during the utility's monthly peak. Currently, high pressure injection pumps and artificial lift installations are interrupted for load shedding purposes. Since the interruption of artificial lift installations results in deferred production, wells must be carefully prioritized for interruption so that lost revenue is minimized. Also, limiting total interruption time and frequency during each billing period is very important in minimizing lost revenue and cycling of lift equipment. Net profit of load shedding each artificial lift installation is determined by subtracting potential lost revenue from potential electrical savings.
This paper addresses the electrical rate schedule design, wholesale utility load forecasting, load shedding methodology, and results of the program to date.
Comprehensive Description and Evaluation of Polymers as Drilling Fluids
Authors: Talabani Soran , Hatzignatiou D. G. , Chukwu G. A. 
Published: December 2007

ABSTRACT
Unlike conventional oil field drilling fluids, polymers are non-toxic, degradable and cause no serious environmental problems. This paper provides information regarding the microstructural behavior of polymers and presents a detailed description of their physical and chemical properties. It also investigates the performance of polymers with respect to drilling and cementing problems such as hole enlargement, shale stabilization, drilling through difficult formations which may cause ion contamination, drilling at high temperatures and cement bond with the formation.
Through experimental and field studies, this work shows which polymers provide optimum carrying capacity, acceptable fluid loss to the formation, smaller filtration cake and thus, the polymers which can be used to obtain a successful liner or casing cementing with less chance of gas leakage.
Emerging Coiled-Tubing Applications at Prudhoe Bay, Alaska
Authors: Blount C. G. , Ward S. L. , Hightower C. M. , Walker E. J. 
Published: December 2007

Abstract
Coiled tubing (CT) has been used at Prudhoe Bay since the early 1980’s, saving hundreds of millions of dollars in well servicing costs for such operations as cement squeezing, well cleanouts, stimulation, inflatable packers and plug placements, fishing, and temporary artificial lift applications previously performed by drilling/workover rigs. The majority of these CT jobs are currently conducted with 1-3/4″ OD CT which has proven to have excellent strength, capacity, and durability for typical field operations. With the recent availability of 2.0″, 2-3/8″, 2-7/8″ and 3-1/2″ OD CT, additional drilling and production applications once thought improbable to impossible have been achieved.
Cement Slurry Qualification, Field Mixing, and Quality Assurance Procedures for Coiled-Tubing Squeeze Operations in Prudhoe Bay, Alaska
Authors: Vorkinn P. B. , Sanders G. S. 
Published: December 2007

Abstract
This paper is presenting an overview of a refined methodology to secure optimal control of slurry properties for coiled tubing squeeze cementing. The basis is accurate specifications of critical slurry properties, specialized test procedures and slurry mixing procedures.
Special emphasis is placed on properties of filter cake generated during a squeeze. It was verified that slurries with copolymer type fluid loss additives as well as latex based fluid loss control additives produced firm, predictable filter cakes, while retaining other critical properties.
Shear energy imparted to the cement slurry proved to influence several slurry properties. Laboratory and field data verified that filter cake height, fluid loss, slurry consistency and thickening time stabilized when a certain level of shear energy was reached. Reproducibility of test data between laboratory and the field was within acceptable limits.
Specialized methods for preparation of cement slurries, in the laboratory as well as in the field, are described along with the supporting theory.
Quality assurance procedures throughout the process are described in detail.