bluuebunny/crossref_metadata_2025_split huggingface dataset:
Practical Considerations of Drillstem Test Interpretation of Damaged Formations
Authors: Longfield D. C. 
Published: December 2007

Abstract
Drill stem tests (DST's) often provide unexpected or incongruous results when compared with data obtained from electric well logs, samples, and/or cores. Commonly, DST recoveries from damaged productive zones consist of a combination of gas at low producing rates, oil or gas cut drilling mud, or mud filtrate water. In many cases, DST's such as these have only investigated the reservoir in the ncar-wcllbore area, in which the relative permeability to the productive in situ reservoir fluid has been altered due to the invasion of drilling fluids. Frequently, the damage has been so extensive that the true formation capability, relative to the productive in situ reservoir fluid at initial conditions, has not been either investigated or evaluated.
Many service company and evaluations engineers interpret DST's as described above to represent either productive wet zones, or zones with at best "average", or more often, "relatively low" permeability. When the DST has only investigated the damaged, or invaded zone, such interpretations are correct, but only with respect to the relative permeability of the altered reservoir to the produced fluid. In most cases, this will understate the relative permeability to the in situ reservoir fluid. Often, the buildup portion of the DST is dominated by wellbore storage effects, and no evaluation of permeability, especially to the in situ productive fluid, can or should be made.
Included in this paper are three case histories from Western Canada which demonstrate the importance of recognizing the impact of invasion on DST results and interpretation.
A Case Study for the Matrix Stimulation of a Horizontal Well
Authors: Frick T. P. , Economides M. J. 
Published: December 2007

Abstract
In previous publications we have introduced methods for the matrix stimulation of horizontal wells, damage characterization and removal, and economic criteria for the evaluation of the job effectiveness. The characteristic shape of damage, which is neither radial nor evenly distributed along a horizontal well, would impact the effectiveness of a matrix stimulation treatment. Full removal of damage is probably never practical because of thief zones and a marked inability to divert the stimulation fluids. Also, the large volume of acid to be injected in horizontal wells will likely create significant corrosion problems. Therefore, partial stimulation and perhaps partial completion, by deliberately leaving segments of the horizontal well unperforated, should be contem-plated. By balancing the expected well performance against the fluid volumetric coverage and the length of the open segments, the optimum stimulation and completion design can be evaluated. The net present value (NPV) is used as the optimization criterion.
In this paper a case study of a 1600-ft horizontal well in a 160-acre drainage area in a sandstone reservoir is presented. Based on expressions for original and posttreatment skin effects, which are presented in explicit form, an economic evaluation of several stimulation and completion design options is carried out. A general recommendation on the proper matrix stimulation in horizontal wells is derived based on the results of this case study.
A New Technique for the Evaluation of Acid Additive Packages
Authors: Houchin L. R. , Foxenburg W. E. , Usie M. J. , Zhao Jun 
Published: December 2007

Abstract
The expanded use of sandstone matrix acidizing techniques may have been the most significant trend of the turbulent 1980's. Gulf Coast operators have found that remedial acid treatments cost a fraction of that required for a comparable offshore completion. Improved design and application techniques now provide economic success rates greater than 80% with most treatments paying out in less than 30 days. However, one area that continues to frustrate designers of acid treatments is the unpredictability of crude oil reservoirs. Current testing procedures are inadequate, failing to accurately replicate the interaction between the treating fluid and acid sensitive crudes. Reliance on these procedures can produce catastrophic facility upsets, downhole emulsion blocks, reduced damage removal efficiency or result in a marginal treatment response.
A new simplified laboratory testing procedure was developed which more accurately simulates treatment effects under reservoir conditions. This laboratory test demonstrates the need for less reliance on surfactant non-emulsifiers and an expanded use of mutual solvents. Field data confirms more accurate prediction of add compatibility. In addition, acid treatments designed utilizing this laboratory procedure showed greater initial production response and maintained the incremental increase for a much longer time. Design guidelines are presented which address concerns of mutual solvent/corrosion inhibitor incompatibility, high temperature applications and treating volume requirements.
Mechanisms of Stress-Induced Wellbore Damage
Authors: Dusseault M. B. , Gray K. E. 
Published: December 2007

Abstract
In this article we discuss mechanisms of stress-induced wellbore damage, concentrating on the drilling phase. Damage is usually considered to be negative; we argue that yield and mechanical damage are often positive factors in stabilizing boreholes and in enhancing permeability. Various behavioral models for rock under different situations are discussed, and conceptual models of damage and stresses around boreholes are presented. Finally, we discuss briefly issues of borehole stability in high stress fields during production, with respect to solids production management.
Two Double Azimuth-Double "S"-Shaped Wells Planned and Drilled Using Torque and Drag Modeling
Authors: Wilson T. P. , Yalcin Oguz 
Published: December 2007

ABSTRACT
Two unique double azimuth - double "S" shaped wells were recently planned and drilled in Conoco's Eugene Island Block 208 in the Gulf of Mexico.
El 208 J-4 S/T was drilled with a 25° "S" shaped top hole section which dropped back to vertical at 6,800′, then underwent a 60° azimuth change and built inclination to 32° and 48° then dropped to 12° in an "S" shaped lower hole section to TD at 12,860′.
El 208 J—5 was drilled with a 45° "S" shaped top hole section which dropped back to vertical at 7,670′, then underwent a 92° azimuth change and built to 36° in the lower hole section to TD at 11,286′.
Both wells were drilled with water based mud, steel drill pipe and conventional rotary drive, and completed as gravel packed duals.
This paper discusses how the wells were planned, drilled, and completed.
Torque and drag models were:
used extensively to plan the wellpath; updated during drilling with the actual surveys, then projected to TD to insure the drillability of the well; and used to design the drillstrings, casing, and completion tubular s.
The second well was drilled 45% faster and for 37% less cost than the first well. This was due to the optimization of the second wellplan and drilling practices.
How to Understand a Rig Hydraulic System and Use It Effectively
Authors: Wardlaw H.W.R. 
Published: December 2007

Abstract
No hydraulic system, however large, can be effective unless it ensures delivery of sufficient horsepower at the bit, where it can perform useful work. perform useful work. A numerical relationship is developed and computer plots presented, showing the critical dependence of bit hydraulic horsepower on pump operating pressure for selected combinations of variables.
The need for raising pressures is indicated for deeper wells, where the bit is remote from its source of hydraulic supply. Other factors shown to be of prime importance in determining pressures levels are pipe size, mud density and hole size.
The choice of nozzle diameter combination is less critical than is often supposed. A simple method of choice., due to Goins, is discussed and recommended. With this method, choice virtually depends only upon hole size and pump operating pressure, and the selection remains unchanged until one or another of these criteria is changed. Validity can be readily checked at the rig. A simple tabulation is available to the driller or the tool pusher. Results are proven to be within 96 to 100 percent of absolute optimum. percent of absolute optimum
Introduction
A hydraulic system in a rotary drilling rig is relatively wasteful of power. For example, it would not be unusual for a pump receiving mechanical energy at the rate of 1,000 hp to deliver not more than 750 hp to the hydraulic system, of which only about 400 hp is actually being used in hydraulic jetting action at the bit.
If such a system, normally wasteful of power, is also operated inefficiently and power, is also operated inefficiently and without proper engineering foresight, it would not be surprising to find the bit action starved of hydraulic power, and the drilling capabilities of the rig seriously curtailed.
This paper will examine the important factors controlling efficiency of the rig hydraulic system, and indicate how these factors should be adjusted to provide reasonably high efficiency with a reasonable economy of engineering effort.
Survey of the System
Fig. 1 shows the rig hydraulic system in diagrammatic form.
Trans
Increasing Extended-Reach Capabilities Through Wellbore Profile Optimization
Authors: Banks S. M. , Hogg T. W. , Thorogood J. L. 
Published: December 2007

Abstract
While some extended reach wells appear to be drilled with comparative ease, others to deeper targets and lower departures can present all sorts of difficulties. A simple two dimensional model is presented specifically to illustrate the interaction between the key variables associated with an extended reach well: kick-off point, locked-in inclination, build-up rate and tortuousity.
The analysis indicates that the maximum achievable drillable depth depends upon inclination and has a minimum in the region of 45-55 degrees. Maximum reach may be obtained by, wherever possible, adjusting the kick-off depth to achieve a locked-in inclination of 70-75 degrees. Drillable depth is not very sensitive to initial build-up rate. Excessive tortuousity can severely limit drillable depth and should therefore be used as an objective measure of directional drilling contractor performance.
Drilling Contractor Selection: A New Approach Evaluates the Quality of the Contractor
Authors: Boyle J. E. , Turnbull J. B. 
Published: December 2007

Abstract
The paper describes a new approach to Drilling Contractor selection. The objective of this approach is to take into account the human element that significantly influences operational performance. Cost savings can be realised if loss of performance through minimising the learning curve can be achieved.
The evaluation focusses on the intangible factors of the contractor. Primarily reviewing the calibre and experience of his personnel, as quality people are considered key to good performance. Once the cost for the intangible factors has been estimated it is added to the tangible cost to give an overall effective cost. The contract is then awarded on the basis of the lowest overall effective cost.
Optimization of the Drilling Performance in the 17½-in. Section of an Exploration Well in the Overthrust of Southern Italy
Authors: Besson Alain , Toutain Patrick , Scott D. E. , Meany N. C. 
Published: December 2007

ABSTRACT
The overthrust area of southern Italy presents a difficult drilling environment. The terrain is mountainous, the formations are tilted, abrasive, and lost circulation can be anticipated. The formations encountered in the 17-1/2″ section of an exploration well in the area were composed of hard and abrasive quartzitic sandstone containing traces of pyrite and chert with interbedded hydratable shales. Penetration rates were on the order of 1 m/hr with gage wear being a major dulling condition. Roller cone bits were pulled with gage wear of up to 18 mm. Bit life was generally less than 20 meters, resulting in an extreme amount of reaming undergage hole.
An analysis of the drilling performance in this first well was performed. Several areas were identified where significant improvements in performance could be achieved on subsequent wells. The key area for overall improvement was the gage holding ability on the roller cone drill bits. Three different enhanced gage features were selected for evaluation.
Enhanced tungsten carbide gage Diamond coated heels (active diamond) Diamond coated gage (passive diamond)
This paper will examine the benefits of the revision to the drilling program including revised drilling parameters, bottomhole assemblies, and specialized roller cone bits. The impact on drilling performance and cost reduction are quantified for the 17-1 /2″ hole section in the second exploration well in this area.
Case Histories Regarding the Application of Microfine Cements
Authors: Heathman J. F. , East L. E. 
Published: December 2007

Abstract
Microfine cements, which are a relatively new technology to the energy-related industry, have a variety of applications for both primary and remedial cementing operations. These products have been found to penetrate passageways such as channels, gravel packs, and casing leaks that were previously unrepairable with conventional cement slurries and to have various other conventional and nonconventional cementing applications where the special properties exhibited by the fine particle sizes of these materials are desirable.
Conventional cements, when used to attempt to repair a casing leak or channel behind pipe, will typically bridge-off at the point of entry. Microfine cements, on the other hand, will penetrate a passageway in sufficient volumes to provide a boundary usually sufficient to withstand differential pressures normally encountered in drilling and production operations. Microfine cements have also been applied in squeezing off unwanted gas coning in producing zones gravel packed with 40\60 mesh gravel. In summary, high gas\oil ratio and water producing wells and wells with previously economically unrepairable pasings once considered marginally productive now have the potential to become highly profitable wells.
The subject paper presents a comprehensive review of field case histories documenting the use of microfine cements for remedial and drilling applications.
History and Development of a Rotating Blowout Preventer
Authors: Cress L. A. , Stone Rick , Tangedahl Mike 
Published: December 2007

ABSTRACT
The introduction of horizontal drilling in conjunction with the "advent" (novel approach) of Flow Drilling has created a revitalized need for a Rotating Blowout Preventor "RBOP". In the 60's the original idea of an "RBOP" progressed all the way to a prototype model and then died due to other challenges facing the industry. Revitalized interest in providing a means to contain at least 1500 psi at the surface while drilling has instituted the need to produce an improved rotating blowout preventor. Both laboratory and field tests confirm. the successful manufacture of an RBOP that can assist in well control and possibly help prevent a catastrophic failure.
The IADC Roller Bit Dull Grading System
Authors: McGehee D. Y. , Dahlem J. S. , Gieck J. C. , Kost Bill , Lafuze Dave , Reinsvold C. H. , Steinke S. C. 
Published: December 2007

ABSTRACT
In 1987, the LADC adopted an improved Rock Bit Dull Grading System.1 Although it was modeled after the previously used T-B-G System, it was expanded to provide a much clearer "mental picture" of a dull bit. This paper documents the changes from the 1987 version to the 1992 LADC Dull Grading System. Since the changes are minor, they are listed at the beginning of the paper. Additionally, for those needing more detail, the entire 1992 IADC Dull Grading System is presented.
First Revision to the IADC Fixed Cutter Dull Grading System
Authors: Brandon B. D. , Cerkovnik Jerry , Koskie Earl , Bayoud B. B. , Colston Fred , Clayton R. I. , Anderson M. E. , Hollister K. T. , Senger Jim , Niemi Ralph 
Published: December 2007

ABSTRACT
This paper is one of two describing changes to the IADC Classification and Dull Grading Systems for fixed cutter bits. Dull grading system revisions, described herein, were implemented to improve utilization and effectiveness of the dull grading system.
Classification system changes were required as a result of improvements in bit technology and applications, and are detailed in the companion paper SPE 23940.
Development of a New IADC Fixed Cutter Drill Bit Classification System
Authors: Brandon B. D. , Cerkovnik Jerry , Koskie Earl , Bayoud B. B. , Colston Fred , Clayton R. I. , Anderson M. E. , Hollister K. T. , Senger Jim , Niemi Ralph 
Published: December 2007

ABSTRACT
Following extensive review of the existing system, development of a new IADC Fixed-Cutter Drill Bit Classification System was initiated in late 1990, based on input gathered from the industry concerning the change. It was determined that existing fixed-cutter bit classifications, which attempted to describe each bit style individually, were not being used.
In contrast, the success of the roller cone bit classification system was believed to lie in its grouping of similar bit styles into categories, thus allowing users to relate familiar bit styles with unfamiliar ones.
Specifically, the IADC Fixed-Cutter Work Group committee undertaking the task developed a fixed-cutter bit reference chart patterned after the existing roller cone classification table, which would allow bit styles to be grouped by similar type. IADC classification codes for each bit are then generated by placing the bit style on the chart in the category which best describes it, thus grouping similar bit types under a single category.
The new classification system is composed of four characters, designating body material, cutter density, cutter size or type, and profile, respectively. It is presented as an attempt to improve the ability to classify and thus employ fixed-cutter PDC and diamond drill bits more effectively in the drilling industry.
Gas-Lift-Valve Test Rack Opening Design Methodology for Extreme Kickoff Temperature Conditions
Authors: Lagerlef D. L. , Smalstig W. H. , Erwin M. D. 
Published: December 2007

ABSTRACT
The objective of unloading valves in a gas lift string is to transfer gas to the lift point. Normally, the valve test rack opening (TRO) for nitrogen charged dome pressure valves is based upon the estimated flowing temperature profile. This is appropriate for most situations. However, the valve settings may not unload consistently when a significant difference exists between the shut in, unloading, and producing temperature gradients. Such temperature differences are very pronounced in either high rate wells or in wells with a large upper well bore heat sink, such as when penetrating the Arctic permafrost, and in deep sea completions.
A procedure has been developed to determine an appropriate TRO for each valve to accommodate the range of temperature conditions expected during kick-off operations. It reduces the likelihood of unloading valves operating out of sequence and improves efficient transfer of lift gas to the design lift valve under a variety of well bore temperature gradients.
An Interface Model To Predict Vertical Sweep During Steamdrive
Authors: Palmgren C. T. S. , Bruining Johannes 
Published: December 2007

Abstract
Steamdrive is a commercially successful recovery technique for heavy oils [1]. It is also recognized as a "valid technology" for light and medium viscosity oils [2].
For slightly unstable situations steam tends to override the oil. The model proposed by van Lookeren has been extended to describe this override behaviour, by using a semi-steady state approximation for the heat transfer at the steam condensation front (SCF). In the absence of heat losses the ensuing equations are completely analogous to the equations for oil-water flow. We have also incorporated heat losses and thus developed the first simple steamdrive model which combines fluid flow and heat losses without empirical assumptions. The interface model comprises Marx-Langen heim and complete override models as limiting cases. The ensuing equations are solved with the method of characteristics.
In order to validate the theoretical model we used a scaled laboratory model. The model is transparent and experiments are performed at subatmospheric pressures. An advanced infrared scanner technique was used, together with thermocouples, to measure temperature distributions in the model. Fluid distributions and interface positions are observed visually.
The interface model describes both the convex (short term) and concave (long term) shape of the SCF and shows excellent agreement with the experimental results.
Steam Distribution Surveillance and Analysis
Authors: Peake W. T. 
Published: December 2007

Summary
Mass and energy balances are presented for a typical steamdrive steam distribution system. Independent measurements of steam mass and enthalpy rates, at the generators and injection wells, are compared using these balances. This comparison and accompanying error analysis of measurements is shown to provide a check on the reliability of steam distribution data. This procedure is demonstrated on a 21-pattern steamdrive. Steam allocation factors are presented for mass and enthalpy rates.
Acquiring Production Logging Data With Pulsed Neutron Logs from Highly Deviated or Non-Conventional Production Wells With Multiphase Flow in Prudhoe Bay, Alaska
Authors: Barnette J. C. , Copoulos A. E. , Biswas P. B. 
Published: December 2007

ABSTRACT
Pulsed neutron logs (PNL) are being used similar to production logging instruments to qualitatively identify gas, oil, and water entry into the wellbore. Gas, oil, and water entry are identified with the pulsed neutron log by measuring flowing and static early-time gamma ray and background gamma ray data in combination with conventionally recorded saturation data.
The PNL's best application for production logging is in difficult logging conditions—multiphase flow in highly deviated or non-conventional wells where quantitative measurements are difficult to interpret using conventional production log data. In multiphase flow conditions, the PNL can usually characterize non-uniform flow profiles, which yields similar results to those of conventional production log measurements. In non-conventional wells where flow conditions are further complicated, the PNL data are an excellent supplement to a suite of conventional production logs.
Use of the PNL for production logging offers a useful addition to conventional wellbore surveillance logging. Gas-, oil-, and water-entry data can be simultaneously acquired with conventional PNL saturation data and channel detection logging data. ‘ Simultaneous data acquisition leads to better remedial work decisions, accomplished by ensuring that all major parameters (e.g., gas-oil contact, oil-water contact, potential for cement channeling, and production entry points) are considered before making a remedial work decision.
Reserves Reporting for Decision-Making Planning and Control
Authors: Higgins J. G. 
Published: December 2007

EXECUTIVE SUMMARY
This paper shows how the established Monte Carlo simulation approach to estimating hydrocarbon reserves can be expanded to provide the basis of a comprehensive valuation, planning and control system meeting all the reserve reporting requirements of an oil exploration and production company. The approach presented is also appropriate for other mining and extractive industries.
The paper demonstrates how individual expectation curves can be modified to reflect both technically and commercially recoverable reserves and how these are in turn combined into the economic valuation, planning and control processes of an enterprise. Estimates across the full range of risk and reserves can be aggregated to provide a powerful planning tool that can be used to set corporate, divisional and individual objectives. The way in which reserve estimates can be used as a sensitive control system to monitor an organisation's ongoing ability to meet its objectives is also demonstrated.