bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drilling Fluids Approaches for Control of Wellbore Instability in Fractured Formations
Authors: Labenski Franck , Reid Paul , Santos Helio 
Published: December 2007

Abstract
The presence of microfractures is now recognized as a common cause of severe wellbore instability, particularly in ultra-low permeability rocks such as shales and some limestones.
In unstable microfractured formations, it is important to avoid pressurizing the fractures with drilling mud. This paper examines the rock mechanics aspects of wellbore instability in microfractured formations, and identifies drilling fluids and drilling practices that reduce the problem. Improved stability can be achieved by the use of certain drilling fluid additives that seal fractures. Limited success is seen with sized solids, asphalts, gilsonites or conventional lost circulation materials but a recently developed additive for use in oil- or water-based muds appears to prevent much of the instability normally observed.
The mechanism of action of this additive is discussed and a recent field case history presented.
Geosteer with Resistivity Forward Modeling to Prevent Drilling into the Loss Circulation Zone of a Prolific Carbonate Reservoir
Authors: Kok Keng H. , Pruimboom John , David Frank M. , Jit-Chiun Then 
Published: December 2007

Abstract
The field development plan for a Sarawak Shell Berhad operated gas field, located in the South China Sea, offshore Sarawak, Malaysia, specified drilling of horizontal wells into the Tertiary Miocene Carbonate reservoir. The wells were planned as high capacity producers of the Big Bore-Long Casing Flow design.
The traditional well design dictated that, prior to entering the reservoir, a casing had to be installed to stabilise the hole in soft shale. The uncertainty of detecting the formation top resulted in premature casing commitment of at least 30 feet TVD above the top of the reservoir and the need to use an expandable liner to cover 300 feet of exposed shale above the reservoir.
To obviate this problem, the capability of one of the components in the Logging-While-Drilling tool array, namely the Electromagnetic Wave Resistivity forward modeling technique, was used to detect the top of the carbonate formation (top reservoir), immediately prior to drilling into it. A standard Logging-While-Drilling tool is configured to prioritize Electromagnetic Wave Resistivity forward model response as the carbonate formation top is approached. This configuration, together with an appropriately designed bottom-hole-assembly and well trajectory, enabled the successful implementation of the plan to stop drilling approximately one foot true-vertical-depth above the carbonate top.
At this point, a conventional 9 5/8-in. casing string was set at an optimum depth. This eliminated potential well control problems, costly remedial actions associated with lost circulation and inferior cementation of the 9 5/8-in. casing string.
Thereafter, the wells were drilled horizontally in a conventional manner, into the carbonate gas reservoir.
This paper compares pre-drilling Electromagnetic Wave Resistivity forward modeling of the proposed well trajectory with the actual well data, whilst drilling. The pre-drilling and post-drilling modeled data is presented.
The cost savings from employing this technique are variable, ranging from substantial - in the event of a well control situation and attendant high losses - to moderate if the need to set an expandable is eliminated.
Analysis of Hook Load Data to Optimize Ream and Wash Operations
Authors: Freithofnig H. J. , Spoerker H. F. , Thonhauser G. 
Published: December 2007

Abstract
Monitoring the borehole condition during the ongoing drilling process is essential for a successful and safe drilling operation. The drilling industry has developed monitoring systems, which offer the possibility to analyze torque and drag effects in real time and typically calculate a borehole pseudo friction factor.
The paper presents a new approach of analyzing recorded drilling data by directly using hook load measurements. The target of the analysis is to minimize the time spent on ream and wash operations. Furthermore the proposed method can be used as an indicator of developing borehole problems at an early stage before they become critical to the operation.
The method is based on the comparison of the hook load during pick-up and slack-off movement of the drill string while reaming one stand of drill pipe prior to making a connection. A characteristic signature is generated, which is then interpreted automatically.
The result shows whether the well bore conditions allow to resume operations or indicate continued reaming, thus optimizing the number of reaming trips and subsequently reducing the total amount of non-productive time.
Based on the comparison of ream and wash sequences of subsequent drill pipe stands, it is possible to generate an automatic well bore condition log, which shows well bore sections with abnormal behavior.
The paper shows that it is possible to identify non-problematic well bore conditions and to avoid unnecessary ream and wash operations.
A software package offers the possibility to post analyze recorded data as well as the evaluation of real-time data. A case study shows the technical and economic potential of this new approach.
Real-Time, Downhole Hydraulics Modelling Helps Operator Drill the Well and Run Liner Under a Narrow Fracture/Pore Pressure Window Condition
Authors: Peng S. , Hodder M. , Kay M. , Milton A. 
Published: December 2007

Abstract
The measurement of Annular Pressure-While-Drilling (APWD) is widely used as a vital tool today; however, measurement of pressure while running the casing or liner is not available. This paper presents field data demonstrating the use of a real-time, downhole pressure modelling software to provide vital downhole hydraulics. This software was used recently on two critical North Sea wells to ensure that drilling and running of casing and liner could be done within safe margins under a narrow fracture/pore-pressure condition. The description of the hardware set-up and real-time parameters used and its communication with the central, data-logging computer are also included.
In order to verify the accuracy of the software, the computed pressure data was compared with that measured by APWD while tripping in and out of both wells. The measured data during tripping was recovered from the tool memory after the trip. Results demonstrated the close correlation between the calculated and measured data that was observed prior to running casing/liner. This gave the rig crew confidence to rely on the hydraulics information given by the software when running the liner. The software was then used to guide the casing crew to run the liner successfully.
Completion Architecture: A Methodology for Integrated Well Planning
Authors: Sinha S. , Yan M. , Jalali Y. 
Published: December 2007

Abstract
We examine how well completion design is governed by subsurface characteristics, surface environment, and state of technology. We present a methodology of well design that takes into account geology, drilling, reservoir, and operational characteristics and constraints. The method selects pertinent configurations for well trajectory, formation completion, and wellbore components to segment, route, lift, and monitor the flow stream. We discuss how this methodology is derived from case histories in land, platform, and subsea fields.
UBD Creates A Step-Change In Drilling Performance In Syria – A Case Study
Authors: Zonjee Peter , Farren Niall , Hanouf Mohammed , Davidson Ian , Zuber Patrick 
Published: December 2007

Abstract
The Al Furat Petroleum Company (AFPC) has achieved a step-change in drilling performance since the introduction of Under-Balanced Drilling (UBD) in September 2002 in the Omar field. To date 7 wells have been drilled using the UBD technique resulting in up to 55% reduction in drilling duration per well, 16% reduction in drilling expenditure and 17% reduction in cost per meter drilled.
This step change has been achieved due to the following advantages that UBD technology offers when compared to traditional methods. Using UBD: A contingency casing, or liner, can be omittedA slim casing design can be used whilst well functionality is maintainedWell control events associated with high pressure / low volume kicks, can be quickly, efficiently and safely dealt withThe average rate of penetration in the ‘UBD’ section is increased up to 100% due to the lower mud weight used (up to 2.5-5.0ppg reduction in mud weight)
An additional advantage has been the capability to identify and characterise hitherto undetected hydrocarbon zones.
The integrated team approach adopted has proven key to the successful introduction and uptake of UBD technology in AFPC's operations. The success has established UBD as one of the strategic technologies to improve drilling performance and reduce overall well construction costs.
This paper describes the step-change in drilling performance in AFPC's operated Omar field through introduction of UBD technology. Additionally, Project Management aspects and HSE approach used to successfully and safely introduce this technology are included.
Optimum Selection of Underbalanced Techniques
Authors: Alajmi Saad E. , Schubert Jerome J. 
Published: December 2007

Abstract
The growth pattern of attractive new concepts, such as Underbalanced drilling (UBD), can be expected to follow an "S" shaped growth curve (Fig. 1).1 Much UBD technology is still considered relatively new, and probably just leaving the Early Adopters stage. The key to success in moving underbalanced drilling up the growth curve lies in a good understanding of the technology, careful planning (including full consideration of the risks), disciplined execution, and effective dissemination of technological information. Otherwise, early adopters can pay dearly for taking up the flag of new technology.
Several papers have been published discussing UBD processes as well as the benefits achieved from this technology. However, few papers have examined on the criticality of planning for UBD operations. A new research project has begun with the purpose of providing a detailed study in how to achieve proper planning for UBD operations in order to achieve success in drilling the well. This study emphasizes formation stability, well control, environmental restrictions, minimum formation damage, hydraulic analysis, and guaranteed economic incentives. Finally, we present an easy-to-use computer program has been developed to help in designing underbalanced drilling operations.
This paper reports the results of this project and demonstrates the use of the computer program and how it can be used as an easy and practical reference to determine the proper underbalanced drilling technique to apply to a particular situation.
Using a Novel Fiber Cement System to Control Lost Circulation: Case Histories from the Middle East and the Far East
Authors: El-Hassan Hassan I. , Abbas Raafat , Jarouj Haitham , Munk Trevor 
Published: December 2007

Abstract
Eliminating or controlling lost circulation during drilling or cement operations is a costly and time-consuming process. Traditional treatments include lost circulation materials (LCM), cement, crosslinked polymers, dilatent slurries, reinforcing plugs, and silicate systems. The general practice is to cure the losses before proceeding to the cementing operation. The mixed results of such treatments plus the fact that cementing operations sometimes proceed even with partial or total losses have led to the development of a new advanced-fiber cement system (AFCS). This paper will discuss the properties and the mechanism of the AFCS and its successful applications as a solution to lost circulation in the Middle East and the Far East.
AFCS forms a fibrous network across highly permeable formations, induced and natural fractures, and vugular formations to prevent and stop the losses during remedial or primary cementing operations. Unlike conventional fibers that normally are difficult to disperse in the cement slurries and tend to plug surface and downhole equipment, AFCS does not suffer from such drawbacks.
Laboratory tests have shown the effectiveness of AFCS in plugging different hole sizes. The efficiency of this system was enhanced in the laboratory when combined with high-performance lightweight cement slurry (HPLW), an optimized particle size distribution system. Several jobs in Abu Dhabi showed substantial success rates compared with traditional lost-circulation treatments. This was confirmed by cement returns to surface and cement coverage across the lost-circulation zones.
Other field locations utilized AFCS in cement plugs, top jobs, and primary cementing operations through different float equipment, liner hangers, and even coiled tubing without any plugging problems.
Short Radius TTRD Well with Rig Assisted Snubbing on the Veslefrikk Field
Authors: Grinde Jan , Haugland Torstein 
Published: December 2007

Abstract
During the turn of the year to 2003 the sidetrack A-19 A was drilled from the motherwell A-19 as a Through Tubing Rotary Drilling (TTRD) well, on the Veslefrikk Field in the Norwegian sector of the North Sea.
A whipstock with holes to produce the motherwell through was set in the 5 in. liner. 4 1/8 in. polycrystalline diamond compact (PDC) bit and 2 7/8 in. high torque motor with adjustable kick off (AKO) setting of 3.8° were run on 2 7/8 in. drill pipe through 5 ½ in. tubing.
The sidetrack started with 25° inclination and the wellpath was horizontal after 24 m true vertical depth (TVD) drilled. An average dogleg severity (DLS) of 42° /30 m was achieved in the build up section. An 80 m horizontal section was drilled and geo-steered using gamma ray (GR) and multi propagation resistivity (MPR) measurements. The same bottom hole assembly (BHA) was used for the horizontal section as for the build up section of the sidetrack.
A pre-perforated 2 7/8 in. liner was installed in the 4 1/8 in. open hole.
The operations were performed using a Rig Assist Snubbing (RAS) unit in cooperation with the rig system. The pre and past-drilling operations were performed in underbalance while the drilling operation was in overbalance through the snubbing BOPs.
The motherbore and the sidetrack were set in production immediately after the liner was run.
In the future Statoil are looking at performing a similar drilling operation in underbalance. It should then be possible to make a sidetrack in approximately 10 days.
Optimal Horizontal Drilling of Hard and Abrasive Unayzah Sandstones
Authors: Simpson Michael , Zhou Shaohua , Treece Mark , Rondon Carlos 
Published: December 2007

Abstract
The first ‘Unayzah horizontal well (W-4) with a 5-7/8″ lateral was drilled with considerable difficulty. The 5,732 ft lateral at 14,000 ft TVD traversed the most productive, albeit hardest and most abrasive section of the ‘Unayzah B with average unconfined compressive strength of 22,000 psi, with hard streaks up to 35,000 psi; and internal angles of friction ranging from 39 to 60°.
Drilling horizontally, the TCI bits were subjected to increased bearing stress and gauge wear. Moreover, they had to be run on PDM's for directional control at minimum bit speeds of 130 – 170 rpm, in the sliding and rotational modes respectively, which substantially cut on bottom rotating time. The PDC and Impregnated bit performance diminished drilling horizontally, as did PDM stator and bearing life with static BHT of 278° F. However, since W-4 required a pilot hole, and two sidetracks it offered a unique opportunity to compare drive mechanism, TCI, PDC, TSP and Impregnated bit performance at equivalent TVD's and formations in the same well.
This paper presents a summary of primarily 5-7/8″ lateral drilling experience in the ‘Unayzah B reservoir along with cost and performance comparisons with other ‘Unayzah horizontal wells. Valuable lessons learned are also discussed.
New-Technology Application to Extend the Life of Horizontal Wells by Creating Uniform-Flow-Profiles: Production Completion System: Case Study
Authors: Qudaihy D. S. , Nughaimish F. N. , Sunbul A. H. , Ansari A. A. , Hembling D. E. , Faraj O. A. , Voll B. A. 
Published: December 2007

Abstract
Horizontal wells have dominated the conventional wells due to their increased production rates, improved recovery efficiency, increased reservoir drainage area, and delayed gas and water coning. However, non-uniform flow profiles can result in premature water / gas production, loss of production and reserves, and decrease in profitability, which will shorten the life, and defeat the purpose of a horizontal well.
This paper will describe a new production technology system that will optimize production, delay water / gas coning, eliminate / minimize annular flow, and ensure uniform inflow along the lateral at the cost of a minute pressure drop in long, high-rate horizontal wells. Case history will be presented from Saudi Aramco, where this production technology, combined with sand control technology, has resulted in significant saving for the operator, and improved production in horizontal offshore oil wells.
Automated Drilling Application for Gaining Higher Efficiency on Extended Reach Wells
Authors: Hofschröer Martin 
Published: December 2007

Abstract
The relatively conservative behaviour in the drilling industry with respect to implementation of new technology will not survive any longer. More and more difficult formations, extended reach drilling, extreme environmental conditions on the rig locations and increasingly smaller reservoirs need to be explored and are just calling for combined efforts of all parties involved in the drilling process. Experience and application of state of the art technology is the correct answer.
Whereas on Offshore installations, usually gaining higher day-rates, sophisticated technology has been widely accepted already, on movable land rigs it is very often just the opposite. Drilling contractors might not care as they are paid by dayrate. However, if the bore-hole quality is bad, down time has to be faced which is paid on lower rates if at all. Operators will just win since well quality and drilling performance improves. Offshore technology and safety standards will step by step find their way onto land drilling rigs.
The drill bit, pushed downwards by heavy weight drill pipes, is rotated either via Top Drive or via Rotary Table, high pressure mud powers the downhole motors, carries the cuttings upwards and cools the bit down. Simple!
New Performance Motors Set New Benchmarks in Drilling Performance
Authors: Reich Matthias , Oesterberg Marcus , Regener Thorsten , Kent David , Nawfal Nick , Al Khames Shaker 
Published: December 2007

Abstract
The elastomer and its bonding system has always been the one of the most critical areas in downhole motor design. The elastomer's physical properties change due to temperature or from reactions with certain chemicals commonly used in drilling applications. This limits both the motor's operational temperature range and the chemicals that can be used in the mud system. While drilling with a conventional motor, heat is concentrated in a regular elastomer power section's lobes forming hot spots which contribute to a premature heat aging of the elastomer. Today, however, a new manufacturing process for stator tubes permits the forging of a pre-contoured lobe configuration — significantly reducing the elastomer content in the power section. This new design broadens motor capabilities by allowing heat to radiate faster from the thin elastomer and significantly improving the motor's mechanical and volumetric efficiency.
The power output of all sizes of positive displacement downhole motors has more than tripled during the past fifteen years. For example, today's 4–3/4″ motors are significantly stronger than the 9–1/2″ motors built in the 1980's. The latest step change in motor power was achieved in the manufacturing processes that eliminated 60%-80% of the elastomer used in the power section's stator.
These latest generation downhole motors are used as performance motors — delivering over 50% more power output compared to the previous generation motors of the same length and diameter and permitting the operator to select more aggressive bit designs. As a result, operators have experienced Rates of Penetration (ROP) improvements of 100%-300%. In addition, high speed configurations with bit speeds up to 1200 RPM are used in hard and abrasive formations with temperatures up to 160°C (320°F). These configurations outperform previously used turbines where the motors have greater torque capabilities while maintaining full steerability throughout the entire run. Typical performance drilling applications cover re-entry, deepwater and extended reach wells in all parts of the world.
This paper describes the technical features of the latest generation downhole motors in detail and documents their capabilities with case histories from various worldwide applications.
Rotary-Steerable Technology Proves to be Economically Successful in Offshore Arabian Gulf Fields
Authors: Porter Dean S. , Al-Faraj Hasan 
Published: December 2007

Abstract
In the Arabian Gulf, a rotary-steerable system utilizing "point-the-bit" technology decreased the well-construction cost in two Saudi Arabian offshore oil fields. Drilling offshore, in many (if not all) parts of the world, is an expensive adventure. "Point-the-bit" technology has successfully and consistently controlled capital expenditures for wells in these offshore fields and, in head to head comparisons, has cost less money when compared to the conventional drilling systems that had previously been used.
When it comes to offshore operational costs, time is a nemesis. The application of "point-the-bit" technology as a way to help solve this problem by permitting the economical completion of a quality borehole will be discussed in this paper. A major concern has been that the phenomenon known as "hole-spiraling" which has created hole-quality issues. These issues range from tortuous paths, torque-and-drag frictional forces, key-seating or sump effects, and poor log responses to name just a few of the problems. Thus, when the quality of a borehole and the time it takes to drill it are considered less than desirable, the drilling process and its resultant effects increase well costs and reduce operational efficiencies.
Several case histories within two offshore fields will be presented in this paper. These case histories will show that having the capability to make adjustments to downhole drilling tools "on-the-fly" makes for better steering control and creates better hole geometries. Correctly applying "point-the-bit" rotary-steerable systems on these wells demonstrates the value-added potential of this technology.