bluuebunny/crossref_metadata_2025_split huggingface dataset:
Alliance Drilling in Papua New Guinea: A Case History
Authors: Gibson W. R. , Lawson C. L. , Crowson R. L. 
Published: December 2007

ABSTRACT
In today's oil and gas environment, the working relationship between operators and contractors is based on trust, flexibility and long-term cooperation. This paper presents how Phillips Petroleum Company (PPCO) and its subsidiary Phillips Petroleum Company Niugini (PPCON) analyzed several alternatives for drilling a prospect in Papua New Guinea (PNG). The chosen option was to form an Alliance with Parker Drilling Company (PDC) in PNG and to package all required equipment and services. This led to a successful heli-rig drilling operation which met all the objectives of the Bujon-1 prospect in the PNG rainforest. The traditional supplier-customer relationship can be re-engineered to reduce duplication of efforts by forming a single strategy. An Alliance can be a formidable tool to control costs and strengthen commitment from all participants in a drilling operation.
Reliability Methods Applied to Drilling Operations
Authors: Ligrone Angelo , Botto Giovanni , Calderoni Angelo 
Published: December 2007

Abstract
Managing drilling operations requires a careful and skilled use of all the information available.
In most cases, the information is processed by statistical methods. However, sometimes there is the risk of neglecting some part of the information, thus biasing the decision-making process.
In our opinion, the reliability approach can overcome this problem. This paper aims at showing how it is possible to effectively manage the performance of the drillstring by constantly monitoring the reliability of every single drillstring component.
An Integrated Approach to the Development of a Water-Based Mud With Oil-Based Mud Performance
Authors: Sawdon C. A. , Brady M. E. , Cliffe Steve , James S. G. 
Published: December 2007

ABSTRACT
There are many aspects of water based muds (WBM) which must be improved before they can truly approach the performance of an oil based mud (OBM). OBMs provide increased drilling performance by combining shale hydration inhibition, drill string lubrication, reduced stuck pipe risk, low formation damage, corrosion avoidance and high temperature stability. The importance of these attributes is briefly discussed.
Historically, it has been common practice to focus on a single factor (such as shale inhibition) when developing ecofriendly WBM products. Insufficient attention has been given to the mutual compatibility of mud additives designed for different functions. Examples are provided on incompatibilities and side effects which can result from a blinkered component development process.
This paper describes the development of a new, integrated WBM system designed to provide much of the performance benefit of an OBM in all but high temperature well applications. The separate approach to high temperature WBM development is briefly discussed. Each component of the new system was developed to display not only high performance in its intended function, but also mutual compatibility and, where possible, synergy with the other additives. Other design criteria included the avoidance of detrimental side effects such as formation damage and/or adverse environmental impact.
Taking each criterion in order, results are presented on the performance of individual components, both alone and in combination. Synergism and product multifunctionality are highlighted. Finally, results are given for all the performance indicators of a fully formulated drilling fluid containing all the new components. Field trials have commenced on a partial system and this experience, together with subsequent case histories, is discussed.
Although OBM performance may not yet be replicated, an integrated approach does allow the target to be approached.
Steerable Rotary Drilling With an Experimental System
Authors: Barr J. D. , Clegg J. M. , Russell M. K. 
Published: December 2007

ABSTRACT
Some of the needs in directional drilling of extended reach and horizontal wells are discussed. It is forecast that Steerable Rotary Drilling (SRD) will meet some of these needs, providing economic benefits. Known options for an SRD system are briefly discussed. The system devised uses synchronous polyphase modulation of bias from a mechanism connected to, and rotating with, the drill bit, powered by drilling fluid and controlled by a directional sensor package, the orientation of the latter being independent of BHA rotation, stabilized and controlled. This scheme meets structural requirements while being capable of development for a wide range of hole sizes. The concept was proved by drilling an interval of 638m (2092ft) with an experimental SRD system. Deviation, while rotating, was controlled at rates up to 8.5730m (8.6°/100ft) to change elevation up/down and azimuth left/right. The system was successful with both PDC and roller cone bits and the deviation rate vector was largely independent of bit weight, rotary speed and penetration rate. The drilling trials have provided data for a product aimed particularly at extended reach and horizontal drilling. Economic benefits are expected by saving time and by improving directional control.
Formation Compressive Strength Estimates for Predicting Drillability and PDC Bit Selection
Authors: Spaar J. R. , Ledgerwood L. W. , Goodman Harvey , Graff R. L. , Moo T. J. 
Published: December 2007

Abstract
Various indirect measuring techniques are presently employed for estimating formation strength, which in turn is correlated to drillability and polycrystalline diamond compact (PDC) bit selection. Formation mechanical properties derived from conventional open-hole logs in combination with a rigorous assessment of formation shear wave velocities can be used successfully to determine drillability as it pertains to bit selection. Formation drillability is best determined from unconfined compressive strength and the angle of internal friction assessment. Rock strength is found to correlate well with the overall measures of bit effectiveness.
Further, the angle of internal friction, which is a subsidiary rock strength parameter, correlates with PDC bit wear rates.
Compressive strength and drillability have been linked in the laboratory and observed in the field since the early 1960's. Compressive strengths, however, need to be qualified as a function of confinement stress. The concept that compressive strength increases with confinement stress is well-understood and can be easily explained with Mohr's failure criteria. With the Mohr's failure technique, it is important to understand that inherent rock strength properties (cohesion and angle of internal friction) must be known before compressive strengths can be estimated.
This paper also presents case histories from Gulf of Mexico wells that illustrate how unconfmed compressive strength and angle of internal friction can be employed to indicate drillability as it pertains to optimized bit selection.
Interfacial Sealing Properties of Slag Mix (Mud-to-Cement Conversion Technology): Laboratory and Field Evaluation
Authors: Nahm J. J. , Romero R. N. , Javanmardi Kazem , Wyant R. E. 
Published: December 2007

Abstract
Anti-gas-migration slag mix slurries having 24-hour to 48-hour set-times were used for the cementing of five 11¾-inch casing strings at the deepwater Auger prospect in the Gulf of Mexico with no failures or evidence of annular gas migration. The long set-times were required to permit setting and testing of the subsea seal assembly prior to cement hydration, In addition, a slag mix TA plug in the 11¾-inch casing string effectively isolated known gas from the open hole below and a slag mix open-hole kickoff plug isolated gas in the hole below that plug.
Gas migration during slag mix slurry setting and the interfacial sealing properties of the set slag mix were investigated using a U-tube apparatus, a commercial gel strength tester, and a HTHP shear bond tester. Zero gas leak rates, low volume shrinkage, excellent bonding quality, fracture healing, extremely low permeability, and right-angle setting have been observed. It is postulated that the healing or regeneration of slag mix bonds observed in our shear bond tests may be linked to the theorized densified microstructure of slag cement reported in the literature.
Minimization Of Formation Damage, Filter Cake Deposition, & Stuck Pipe Potential In Horizontal Wells Through The Use of Time-Independent Viscoelastic Yield Stress Fluids & Filtrates
Authors: Powell John W. , Stephens Mike P. , Seheult J. Mac , Sifferman Thomas , Swazey John 
Published: December 2007

Abstract
Over 60 horizontal wells have been drilled and completed with slotted liners in Prudhoe Bay, Alaska using a low solids or solids-free clarified xanthan/brine drill-in fluid. As previously described the drill-in fluid demonstrates a functional true yield stress (TYS) in the circulating fluid.1 The yield stress is also present in the filtrate, limiting depth of filtrate invasion. The fluid has been further described as being viscoelastic (VE) under static conditions and at the low shear rates exisiting in an expanded plug flow region. This plug flow region is persistent over a wide range of flow rates and is a function of polymer concentration and brine salinity. The exhibits both time-indepent and pseudoplastic properties at higher shear rates (TIP). Collectively the viscoelastic, time-independent pseudoplastic fluid rheology is abbreviated as VETIP.1 Fluid performance has correlated to excellent well productivity, lack of formation damage, minimization of stuck pipe and liners, minimization of filter cake deposition and the lack of mud cake clean-up or removal problems, improved cost-effectiveness, and apparent improvements in present and long term well values.
Lack of formation damage, near-zero stuck pipe incidence rates, and minimization of filter cake removal problems are attributed to a functional true yield stress (TYS) in the circulating fluid and filtrate. The yield stress is measurable with oscillatory (Rheometrics), capillary, constant stress, and very low shear rate rotational viscometers. New field and laboratory data correlate well to the yield stress measurements. The yield stress of the filtrate declines with time, thermal degradation, biodegradation, and is quickly broken with hypochlorite breaker, restoring original permeability, without formation damage.
KTB-4 Years Experience at the Limits of Drilling Technology
Authors: Claus Chur , Thomas Bendzko , Bernhard Engeser , Axel Sperber , Trach T. V. , Lothar Wohlgemuth 
Published: December 2007

Abstract
The Continental Deep Drilling Program of the Federal Republic of Germany (KTB) is a non-commercial, geoscientific research project that is part of the international lithosphere research.The goals are to investigate the physical and chemical conditions and processes of the earth's deep continental crust. Two wells, the pilot hole and the ultra deep hole, were drilled in the program. The ultra deep borehole reached a depth of 9101 m on October 10, 1994. Drilling conditions are characterised by crystalline rock, borehole temperature exceeding 250 °C and severe borehole instability. The paper describes drilling strategy, equipment and the experience which was made during the operation.
Special consideration will be put on borehole stability that became the number one problem with increasing depth.
Wellbore Stability, Drilling Fluids Design, and the Drilling Performance of Horizontal Wells in Unconsolidated Oil Sands at Peace River, Alberta
Authors: Warren B. K. , McLellan P. J. , Pratt C. A. 
Published: December 2007

ABSTRACT
Shell Canada Limited drilled two pairs of twin horizontal wells in the Peace River oil sands in the summer of 1993. This paper describes the detailed planning for the drilling of these wells, including wellbore stability, hole cleaning, differential sticking, lost circulation and torque-drag concerns. The drilling fluid selection process used to address potential problems will be highlighted. The value of thorough pre-planning led to the successful drilling of these four, one kilometer long horizontal wells in underpressured, uncemented oil sands.
Cost Effective Design Change in the Drilling Programme for the Gullfaks Field
Authors: Skogseth Ottar , Gaasø Rune 
Published: December 2007

Abstract
Low formation strength, rapid pore pressure build-up and shallow gas sands below the platforms dictated the casing programme for the first wells drilled at the Gullfaks field. A original casing programme containing sizes from 32" conductor penetrating the seabed to 7" liner through the reservoir allowed 7" monobore completions with a gravel pack option.
A standard well was drilled and cased with 6 casing strings and cleaned up before skidding the rig to next slot. A gravel pack was installed with a snubbing rig while the drilling rig was engaged with the next well on the opposite drill shaft (the first few gravel packs were completed with the drilling rig).
New casing programmes have been implemented. Continuous improvement, proven procedures for drilling through shallow gas sands, creative engineering in co-operation with contractors and research institutes and new information gained through a range of formation integrity tests below the conductors have made this possible.
26" casing was originally set at 550 m TVD to isolate the upper shallow gas sands and to obtain formation strength for the next section. After new information obtained by a series of mini-fracturing tests below the 32" conductor shoe, the 26" casing was made redundant.
Advances in drilling techniques resulted in drilling longer sections with smaller hole sizes. This resulted in a casing programme without 26" and 20" casing. A range of alternatives was introduced in the casing programme to cater for the requirements for specific wells.
Introduction of a slimmer casing programme with 13 3/8" casing set as the first string after 32" conductor still allows for a 7" monobore completion. The drilling rig skids over to a new slot after having installed the 7" liner. A snubbing rig cleans up the well, installs the completion string, perforates and installs the gravel pack (optional).
Introduction of alternative casing programmes will reduce drilling costs and drilling time per well by up to 30%, compared to the standard drilling and completion programme used up to 1993 (base case).
Drilling, Completion, and Workover Operations With the World's First Subsea Spool Trees
Authors: Stewart A. A. 
Published: December 2007

Abstract
Kerr-McGee's Gryphon Field in the UK sector of the North Sea was the first development in the world to utilise a subsea Spool Tree system, also known as "horizontal" or "valveless" trees.
This paper describes the operation experiences of using the Spool Tree system during drilling, completion and well intervention operations.
Field performance is reviewed against design expectations and where relevant, comparison between Spool Tree operations and more conventional tree systems is presented.
The successful operational aspects of the system are highlighted and the economic impact on the Gryphon project is reviewed.
Significant attention is paid to lessons learned during installation and interventions, and these are presented along with future recommendations for the benefit of other operators throughout the world.
Overall the Spool Tree system application to the Gryphon field has been an outstanding success providing significant flexibility and economic impact to the development of the field.
Step-Rate, Calibration Injection and Treating Pressure Anomalies in Soft Rock High Permeability Formations: An Explanation Based on Bottom Hole Pressure and Production Results
Authors: Stewart B. R. , Mullen M. E. , Brown J. E. , Norman W. D. 
Published: December 2007

1 Abstract
Soft rock fracturing popularity has resulted in its wide spread use for stimulated completions in sand control environments. Varying degrees of completion efficiency and production improvements have been observed. More importantly these variances have been difficult to explain. This paper explores anomalies in pressure behavior observed during step rate, calibration testing, and fracturing treatments. This investigation will focus on why the predicted and actual production rates as a function of completion efficiency and skin do not always match. Scenarios will be proposed which can explain both the pressure anomalies and the production variances. The scenarios are constructed using bottom hole pressure data, pressure transient analysis, and production prediction using system analysis.
Gas-Lift Unloading and Operating Simulation as Applied to Mandrel Spacing and Valve Design
Authors: Hall James W. , Decker Kenneth L. 
Published: December 2007

ABSTRACT
Gas-lift has been practiced for many years using principles developed in the 1940's and 1950's. For the most part, these principles have been developed based on experience and "rules of thumb" with little or no regard for actual valve performance. This paper describes the use of a software program that simulates the unloading and lifting of a gas lift well using scientific principles and valid valve performance data.
A brief explanation of the function of the program is provided and then investigated in more detail as it is applied to a planned gas lifted completion in the North Sea. A conventional design methodology is presented and its validity examined with the simulation software. The paper highlights areas of current design methodology which may lead to problems such as multi-point injection, unstable gas injection rate, and excessive lift gas use.
Explanations are given for the occurrence of the problems and suggested modifications are presented to avoid the problems.
Collapse and Post Collapse Behaviour of Tubulars: A Simple Approach
Authors: Abbassian F. , Parfitt S. H. L 
Published: December 2007

ABSTRACT
This paper describes a simple method of evaluating the collapse strength and post collapse behaviour of oil field tubulars subjected to external pressure. The method is based on elastic ovalisation and subsequent plastic collapse by formation of a four-hinge mechanism. The resulting predictions of collapse strength are compared with available collapse test data, and other existing collapse equations. For post collapse behaviour, model predictions are compared with available experimental and numerical data. Applications of the method to collapse of perforated and slotted liners, prepacked screens and collapse under non-uniform loading are described.
An Analysis of Helical Buckling of Tubulars Subjected to Axial and Torsional Loading in Inclined Wellbores
Authors: Miska Stefan , Cunha J. C. 
Published: December 2007

ABSTRACT
This paper describes new theoretical results for prediction of buckling behavior of tubulars in inclined wellbores. Using conservation of energy and the principle of virtual work improved equations for buckling and post-buckling conditions are derived. The effect of torque on the buckling process is considered. Practical examples are provided showing the influence of torque on the critical buckling force. The equations for critical buckling force reduce to those previously derived when torque is set to zero and weightless strings are considered.
Development of a New Theoretical Model for Three-Layered Reservoirs With Unequal Initial Pressures
Authors: Aly Ahmed , Lee W. John 
Published: December 2007

Abstract
In this paper we present a new theoretical model for three-layer reservoirs with unequal initial pressures. We developed a semi-analytical simulator based on the developed model. The computational model proved to be much faster than a three-dimensional, finite-difference commercial simulator used to validate the analytical model. Also, the amount of information (spatial gridding) needed to run the model is much reduced. The analytical model allows each layer to have different layer properties, different boundary conditions, and different initial pressures.
We used the semi-analytical simulator to perform a detailed study of the behavior of three-layered reservoirs during the "pre-production period." The pre-production period occurs early in the life of the reservoir, after perforation but before any surface production and is caused by crossflow in the wellbore. The layer information obtained is very important for scheduling production and making economic decisions concerning the future of the wells. The pre-production well test requires no production on the surface during the test; thus the impact on the environment is negligible.
The main objective of this work is to develop a qualitative approach to extract more information about the reservoir from pre-production wellbore pressure, dimensionless pressure and dimensionless pressure derivative curves. More specifically, we studied the pre-production behavior of three-layered reservoirs. Effects of the ratio of flow capacity and storage in different layers were investigated. We found that the layers with highest and lowest permeabilities can be characterized with the logarithmic time derivative of pre-production pressures. A positive derivative indicates high permeability in the layer with the highest initial pressure, and a negative derivative indicates high permeability in the layer with low initial pressure. Also, the layer with the highest initial pressure will always flow into the wellbore whereas flow will always be from the wellbore into the layer with minimum initial pressure. As the sandface rates reach steady state, the three-layer system behaves like an equivalent single layer system. Thus, we can apply a single-layer model to analyze the late transient in high permeability reservoirs.
Determining Permeability, Skin Effect and Drainage Area from the Inverted Decline Curve (IDC)
Authors: Rietman Noel D. 
Published: December 2007

ABSTRACT
The inverted decline curve, or IDC, is the plot of the inverse of a well's producing rate (1/q) against the log of its producing time. If the well's producing pressure history is known, this curve can be used to determine reservoir permeability, the skin effect, and the area being drained by the well. For a hydraulically fractured well, the length of an infinite conductivity fracture which is equivalent to the actual finite conductivity fracture can also be determined.
This technique uses equations which fit the constant pressure transient radial flow solution. Also, polynomials have been developed which match pre-pseudoradial flow production from hydraulically fractured wells with dimensionless fracture conductivities of 0.01, 0.1, 1, 5 and 500. For pseudosteady state flow periods, a depletion or a pseudosteady-state equation can be used to match the performance of the well. By this technique, the well's entire production history becomes the equivalent of a very long drawdown test. This method is especially useful for low permeability reservoirs.
Advantages of this method over type curves include: greater resolution because the scale of the y-axis is linear rather than logarithmic, the capability of using superposition to account for pressure changes, the ability to include the derivative in the analysis, and better determination of permeability and skin effect because, as in a Homer plot, the fonner is dependent on the slope and the latter on the intercept. The entire production history, including pre-radial, radial, and pseudosteady state flow, can be used in the analysis.