bluuebunny/crossref_metadata_2025_split huggingface dataset:
Why Control Cement Slurry Density?
Authors: Allen T. E. , Sands F. L. 
Published: December 2007

Abstract
The well cementation design process includes slurry design, spacer design, hole conditioning program design, casing attachments selection, and placement procedure design. This paper is concerned with slurry design and more particularly, the effects of deviations in mixed slurry density from the design point. Concern over these effects has been increasing in recent years. In 1987 an API Task Group in the Eastern Hemisphere Cementing formed a work group to study "the effect of poor density control on cement slurry properties " This group also investigated measurement and control of density. There were wide differences of opinion as to how well density was being controlled in the field and also what was necessary. Additional data and analysis will be presented which will help clarify some of the density slurry property relationships and therefore provide additional means to make rational decisions relative to density control specifications.
Density as a slurry property is significant to wellbore hydrostatic pressure. However, deviations from design density may cause changes in all other slurry properties which may or may not cause future well problems. The relationships defining slurry property dependence on slurry density are important when establishing meaningful density control limits. However, closer limits generally mean higher mixing system and operation costs. Thus, there is an economic motivation for understanding how deviations effect slurry properties. The knowledge of the cost to obtain a specific density tolerance can be weighed against its benefit. More appropriate specifications can be developed to match job requirements. The end result could be a change in the way slurry properties are specified.
Knowledge of the sensitivity of the designed slurry to density variation will make selection of surface mixing equipment more meaningful. Batch mixing gives the ultimate in control but cost more. Offshore, batch mixers take up valuable rig space and add weight.
Management Systems in Production Operations
Authors: Walters K. B. , Henderson Grahaeme 
Published: December 2007

Abstract
The Cullen Enquiry into the Piper Alpha disaster in the U.K North Sea recommended that an operator should formally present it's Company Management System and demonstrate how safety is achieved throughout the life cycle of a platform, from design through Operation to abandonment.
Brunei Shell Petroleum has prepared a corporate level Safety Management System. As part of Safety Case work, the corporate System is being extended to include the development of specific Management Systems with particular emphasis on offshore production operations involving integrated oil and gas facilities. This paper will describe the development of Management Systems, which includes an intensive Business Process Analysis and will comment upon it's applicability and relationship to ISO 9000.
The paper will further describe the applicability and benefits of Management Systems and offer guidance on required effort. The paper will conclude that development of structured Management Systems for safety critical business processes is worthwhile but prioritisation of effort will be necessary. As such the full adoption of Management Systems will be directional in nature.
Improvements in MWD Telemetry: "The Right Data at the Right Time"
Authors: Montaron B. A. , Hache J- M. D. , Voisin Bernard 
Published: December 2007

Abstract
The 1991 SPE Forum on MWD concluded that current telemetry data rate via mud pulse was inadequate. This paper addresses this issue.
New downhole sensors have been continuously added to MWD Systems and have joined the directional measurements and simple formation evaluation tools commercialized in the seventies. As a result, MWD Systems have been challenged to transmit an increasing amount of data to the surface. Most commercial Systems use the mud column as the transmission channel. MWD telemetry is revisited, analyzing in detail the factors affecting the transmission through the mud. Noise sources and new techniques to minimize interference are described and field examples are presented. The maximum data rate achievable through the mud channel is evaluated, and is compared with current and future needs for real-time use. Data compression techniques are discussed. The impact of data rates on log quality, for a given drilling rate of penetration, is illustrated through field examples at different data rates. New techniques of quality checks on the data which allow quantification of the accuracy of the transmission are described with Statistical test results. Examples of current MWD telemetry Systems covering the range of data rates available today (from 0.5 bits/s to more than 5 bits/s) are presented. The use of microprocessors in the new generation of MWD tools is shown to have impacted dramatically the reliability of the transmission, both in quality and versatility with direct benefits to the end user of the data.
Review of Techniques for the Interpretation and Evaluation of Thin Sand Sequences
Authors: Forsyth David , Nawawi Haji , Ho T. C. 
Published: December 2007

Abstract
Th is paper describes a review conducted on data from seiected wells in a mature field with the objective of establishing techniques for the evaluation oflaminated sand sequences and assessing the impact of including such sequences in the reserves of the field. The field is sėtina deltaic environment and has been ander development for twenty years with some three hundred wells having already been drilled. Recent core data have revealed that quite some potential reserves may be contained in thin sand/ laminated sand sequences. Conventional log data have insufficient vertical resolution to resolve individual sands and consequently the contribution to the reserves of these intervals has been dijjficult to assess. Recent advances in logging technology and in data Processing have improved this Situation. This review concentrates on assessing the ęffectiveness of these new techniques. The Integration of core and produetion data with imaging techniques are presented. The results show that such intervals can be evaluated although ultimately the contribution to STOnP is also influenced by other factors not directly measurable in the borehole.
Results of Trial Using Silicon Activation Gravelpack Evaluation Tool (SGPT) in Bokor
Authors: Yahia Ziadil , Elshahawi H. M. R. 
Published: December 2007

ABSTRACT
Conventional nuclear fluid density gravelpack evaluation tool (GPPT) was found to cause misinterpretation when run in well containing fluid of different densities. As a result an alternative tool called silicon activation gravelpack tool (SGPT) was field tested. The principle of the tool is based on detection of activated gamma ray which is produced when silicon atoms are made unstable by striking with fast neutrons.
The trials were carried out in 3 wells in Bokor. In order to get conclusive results, GPPT and PLT were also run in these wells and the results compared. It was found that in wells with single phase fluid, the SGPT results were in agreement with the GPPT′s. When logging from water to oil, both tools were affected but SGPT was less affected than GPPT.
The effect of water on GPPT was almost the same as the effect due to top of gravel. For SGPT, the effect due to gravel was more pronounced compared to effect due to water. When logging from oil to gas, SGPT didn't show any shift in readings whereas the GPPT was badly affected.
In conclusion, SGPT was found to be more reliable than GPPT for evaluating gravelpacks when there were more than one fluid densities in the wellbore.
The Use of a Log-Derived Formation Strength Index for Gravel Pack Decision Making in the Rasau Field
Authors: Clayton F. M. , Van Haeringen Arie 
Published: December 2007

Abstract
It has been proposed in the literature that formation strength could be predicted using the bulk density and sonic transit time derived from wireline logs. Experimental work was therefore carried out which gave a correlation between the density/sonic readings from logs and the onset of sand production. The density/sonic relation is termed the Formation Strength Index (FSI).
The FSI has been used in the Rasau Field, Brunei, in combination with expected production conditions, to predict the onset of future sand production thus allowing it to be used to assess the requirement for sand control.
To date, twelve gravel packs have been avoided. This has resulted in a cost saving of some US$ 3 mln and the avoidance of the normal gravel pack impairment.
Field Tests of a Slim Carbon/Oxygen Tool for Reservoir Saturation Monitoring
Authors: Stoller Christian , Scott H. D. , Plasek R. E. , Lucas A. J. , Adolph R. A. 
Published: December 2007

ABSTRACT
Oil production from many major producing reservoirs is now maintained by water injection programs. The resulting mixed and often very low-salinity formation water presents a serious problem when monitoring water saturation with traditional pulsed neutron capture (PNC) tools. A slim carbon/oxygen (CAD) pulsed neutron tool tested recently in many regions around the world addresses the problems encountered in low- and mixed-salinity environments. The tool's dual y-ray detectors and flexible neutron burst timing allow it to be used for carbon/oxygen logging and, in a separate pass, for PNC logging. New detector and accelerator technologies as well as advanced data processing allow logging speeds that meet or exceed those of traditional, large, single-detector C/O tools.
Application of Deuterium Tracer in Estimating Native Water Saturation in the Gyda Field
Authors: Fjerstad P. A. , Thoreby Helge , Pallatt Nadia , Stockden Ian 
Published: December 2007

ABSTRACT
An independent method for estimating initial reservoir water saturation in the Gyda Field has been investigated. Further application of recent tracer technology was used in describing the initial fluid saturations in the reservoir. This was achieved by using a deuterium tracer technique to quantify aqueous mud-filtrate invasion to core and which enabled ‘native’ water saturation determinations to be made. The volume of extracted core-water was translated into native reservoir water saturations after correcting for mud-filtrate invasion, reservoir overburden, pressure and temperature effects.
The technique is an alternative method for obtaining initial water saturation data. The proposed proved method could be replaced by empirical determinations of water saturation from wireline responses where exponents are derived from special core analysis data. The tracer technique proposed has particular application not only to thick bedded sands, carbonates and conglomerates, but also to thin bedded zones where logging resolution is poor. The method has also particular application in low resistivity pay sands in which large volumes of immobile capillary water occur.
Channel Detection Using Pulsed Neutron Logging in a Borax Solution
Authors: Sommer F. S. , Jenkins D. P. 
Published: December 2007

Abstract
The PNL/Borax log was designed as a replacement for temperature and radioactive tracer logs in identifying channels in the cement sheath surrounding the casing in production or injection wells. This isnl the only application of the log. Because of the correction for thermal neutron diffusion, it can be used to differentiate between a channel and other mechanisms of fluid movement, such as a leaking packer, leaking squeezed perforations, and gas migration under an impermeable barrier within the formation. These added capabilities can result in a better diagnosis of the well condition. With the downhole processes pinpointed, the proper kind of remedial wellwork can be recommended to optimize the performance of the well.
The PNL/Borax log has been successfully used to diagnose channels (or lack of channels) in dozens of producers in Alaska's Prudhoe Bay oil field, and has been run with mixed results in injectors. It has also been used to successfully distinguish between leaking packers and channels. In addition, the borax tracer has been found to be safe to wellsite personnel, and can be produced back out of the formation to minimize impacts of future neutron logging operations. This paper presents the basic theory behind PNL/Borax logging and provides field examples of its use in producers and injectors.
Analysis of Pressure and Pressure Derivatives Without Type-Curve Matching: I—Skin and Wellbore Storage
Authors: Tiab Djebbar 
Published: December 2007

ABSTRACT
The current type-curve matching technique is essentially a trial-and-error procedure without any independent and accurate way of checking the validity of the end results.
This paper introduces a new technique for interpreting pressure tests. This technique uses log-log plots of the pressure and pressure derivative versus time to calculate reservoir and well parameters WITHOUT type-curve matching. This paper concentrates on the interpretation of pressure tests in which wellbore storage and skin are present. The technique essentially consists of obtaining characteristic points of intersection of various straight line portions of the pressure and pressure derivative curve, slopes and starting times of these straight lines. These points, slopes and times are then used with appropriate equations to solve directly for permeability, wellbore storage and skin. A step-by-step procedure for calculating these parameters without type-curve matching for five different cases is included in the paper.
The most important aspect of this new technique is undoubtedly its accuracy because it uses exact analytical solutions to calculate permeability, skin, and wellbore storage. The second most important feature of this new technique is that it is verifiable. Any two parameters calculated from two independent equations corresponding to two different portions of the pressure derivative curve are verified by a third equation which corresponds to a known and unique point relating the two parameters. The proposed technique is applicable to the interpretation of pressure buildup and drawdown tests. This technique is illustrated by several numerical examples.
Technique Improves Openhole Gravel Pack
Authors: Wilton B. S. , Swain R. S. , Tuttle J. D. , Harkey Dee 
Published: December 2007

Abstract
A new technique for open hole circulation gravel packs was implemented on three wells in the Tejon Field, Kern County, California that improved pack placement procedures and resulted in reduced completed well costs. The following contributed to overall well performance: (1) fluid selection to match reservoir characteristics, (2) polymer selection to stabilize the wellbore and place the pack effectively, (3) compatibility and displacement of underreaming and gravel pack fluids, (4) shearing and filtering techniques to minimize microgel effects and (5) breaker selection to eliminate polymer effects in a timely manner. Two smectite rich production zones having a combined length in excess of 500 feet were packed as a single stage circulation pack using an inhibitive carrier fluid viscosified with a clarified xanthan gum biopolymer. The clarified xanthan gum fluid also proved to be superior in maintaining a stable wellbore in which to run the slotted liner. The gravel pack fluid was continuously filtered through diatomaceous earth and 10 micron absolute cartridge filters throughout the circulation pack procedure. Photomicrographs and gravimetric analysis of the fluid illustrate the effectiveness of the shearing and filtering procedure before and during pack placement.
Improved initial production rates were realized by implementing this cost effective procedure.
Reverse Circulation of Cement on Primary Jobs Increases Cement Column Height Across Weak Formations
Authors: Griffith J. E. , Nix D. Q. , Boe G. A. 
Published: December 2007

Abstract
This paper outlines advantages of reverse circulation of cement to reduce the equivalent circulating density (ECD) such that weak formations may not fracture during the primary cementing procedure. A typical operation is outlined for utilizing the method in the Appendix. Tests with large-scale geometries showing no detrimental effect on displacement efficiency are discussed.
Field Study of Efficiencies Between Progressing Cavity, Reciprocating, and Electric Submersible Pumps
Authors: Saveth K. J. 
Published: December 2007

Abstract
With operating costs playing a larger and larger role in the economics of producing a well, optimizing equipment selection by means of an efficient artificial lift system is critical in reducing operating costs for a given field.
Six wells in Carter County, Oklahoma utilizing three different methods of artificial lift were looked at to compare overall system efficiencies between each method. Progressing cavity, reciprocating, and electric submersible pumps were compared on a per barrel of fluid produced basis and the electrical power usage converted to kw-hr/hr.
Fishing With Coiled Tubing
Authors: Hilts R. L. , Fowler S. H. , Pleasants C. W. 
Published: December 2007

ABSTRACT
Improved coiled tubing (CT) technology, development of specially-designed hydraulically-actuated service tools, and increased emphasis on cost efficiency have made coiled tubing a viable option for many fishing jobs. Before the emergence of coiled tubing fishing technology, traditional service procedures included use of wireline to retrieve fish from oil and gas wells. If wireline was unsuccessful, a rig or hydraulic workover (snubbing) unit had to work over the well and remove the fish.
This paper addresses the successful use of CT in fishing operations. The capability of CT to circulate fluids at the fish and generate high downhole forces enables the retrieval of fish in situations that would not be possible or cost effective by other service options. CT fishing can be performed under pressure on live, highly-deviated or horizontal wells; the job can be completed and the well returned to production within 1 to 3 days for only a fraction of the cost of a workover.
The paper will describe the tools, their capabilities, and service techniques currently in use for CT fishing operations as well as new equipment being developed. Data from several case histories will be used to provide considerations, surface rig-up, and job limitations.
Low-Density Acid-Removable Cement as a Solution for Lost Circulation Across Producing Formations
Authors: Bour D. L. , Vinson E. F. , Totten P. L. , Waheed Arshad 
Published: December 2007

Abstract
Lost return problems have been typically solved with lost circulation pills containing plugging materials like mica, cellophane, and walnut hulls. However, should lost returns occur across potential producing formations, use of such materials may result in permanent damage to these zones. Dislodgment of the plugging material can result in resumption of lost returns. This paper describes the laboratory development of a foamed fluid system that can function to solve the problem of lost circulation. Foaming offers the operator an option to prepare a fluid with densities below that obtainable even with water. Additionally, this system possesses acid solubility, thereby minimizing damage to potential producing formations. Laboratory slurry property data such as thickening time, compressive strength, and acid reaction rates are provided.
In addition to lost circulation, the foamed acid soluble cement system has application in both oil and gas wells as a temporary plugging material. Potential field applications of acid soluble cement in these areas are discussed.
Practical Horizontal Cementing Today
Authors: Kettl F. C. , Edwards M. G. , Covington R. L. 
Published: December 2007

ABSTRACT
Horizontal wells present an effective method to maximize production potential and reduce development costs of some oil and gas fields. The ability to predict induced fracture direction with reasonable accuracy can allow the operator to drill in the direction considered most profitable.1 Ideally the well would have extended reach in the proper direction through a stable, fractured formation, would not require stimulation, and would not be subject to the production problems usually encountered in the life of a field. Since horizontal wells are drilled in a variety of formations, operators are experiencing the normal well problems and are finding stimulation and control methods useful for production improvement. This paper will examine problems associated with cementing of horizontal sections and the recent technology advancements that may be applied to help assure a competent annular hydraulic seal.
Conventional cemented completions have not been used extensively in horizontal wells since some operators lack confidence in the technology that is available. Problems have been perceived in managing cuttings transport, pipe centralization, effective mud displacement, cement free-water control, and effective placement of a cement seal around the casing. These problems do exist and corrective techniques are complicated by highly deviated wellbores, but technology advances have been made to address horizontal conditions. Proper cementing may continue to provide an economical hydraulic seal for zonal or wellbore segment isolation so necessary to effective stimulation and work-over operations.
The use of advanced technology often requires extensive pre-planning and includes the necessity to properly communicate the benefits to field operations personnel to assure the proper implementation of new or different techniques or materials. Little good will come from the best ideas without proper follow-through during application.
Stage Cementer With Integral Inflatable Packer Collar
Authors: Borges J. F. , Turki W. H. , Giroux R. L. , Stepp L. W. 
Published: December 2007

Abstract
Lost circulation during primary cementing is a common problem in the Middle East area. To overcome this problem, operators have commonly used a stage tool with an integral packer element. Often, these elements are inflatable, since most mechanical packer elements have limited differential pressure capabilities.
To improve and simplify the operation of stage cementing integral inflatable packer collars (SCIIPCs), designers have developed an opening system that has no moving parts. This system, featuring replaceable rapture disks, has been successfully tested in the US and Middle East
This paper describes the SCIIPC itself, the lab tests required before it could be ran, and presents test results. The paper also presents actual case histories featuring the new system during initial field testing.
Performance Prediction of Horizontal Wells Utilized To Alleviate Water Slumping
Authors: Kader M. S. Abdel , Hafez H. H. , Badaam H. S. 
Published: December 2007

ABSTRACT
Within ADCO, horizontal drilling has been used to reduce the effects of water slumping between pseudo reservoirs resulting in reduced water cut and increased productivity. This paper discusses the use of finite element models to predict the performance of two such horizontal wells and compares predictions with actual performance.
The reservoir discussed is comprised of two pseudoreservoirs, both pressure supported by peripheral water injection. Water advance in the upper pseudo-reservoir has been faster as its permeability is greater than that of the lower pseudo-reservoir. Local pressure drawdown effects, have resulted in water slumping from the wet upper pseudo-reservoir to the dry lower pseudo- reservoir.
To alleviate water slumping and increase well productivity, two wells were recompleted with short radius horizontal holes of 240 and 850 feet lengths. This resulted in reduction of water cuts from 20 % to less than 1% in one well and 4% in the other and significant increases in well productivity.
A previous paper discussed the element model construction, history matching and performance prediction for the first well. This paper compares the performance predictions with actual well performance and discusses the extended application of the model to the second well.