bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Seasonal Solution for Offshore Drilling in an Ice Environment
Authors: Keener Chip , Allan Rod 
Published: March 2009

Abstract
The promising potential of prolific hydrocarbon reserves in the difficult Arctic ice environment has spurred accelerating lease activity particularly in the US and Canadian Beaufort Sea, and the Chukchi Sea. The obstacles are formidable: The leases may only be ice clear a few months a year.The fall and early winter months expose severe weather analogous to a North Sea wind and wave environment.Winterization measures must consider potential of severe icing.The vessel hull and exposed machinery must tolerate temperatures of −40° C.The ice management strategy must anticipate operations in one-year ice (sheet ice to a 1.5 meter thickness with rubble fields, occasional multi-year inclusions, and modest ridges).Logistic lines are long and tedious, motivating an unparalleled level of self-sufficiency.Water depths range from 50 meters or less to extreme depth, confounding a station-keeping solution.Heavy ice and formidable ridges compel an exodus mid-winter through mid-summer, and obligate consideration for off-season marketability and high speed open water transit.Consideration must be given for wintering over … in contingency or with ambition to extend the season.Extreme environmental sensitivity will be expected.
Against these challenges, a fit-for-purpose vessel has been conceived. optimized for extended-season operations in the Arctic, and uncompromised ultra-deepwater off-season performance in a more hospitable environment.
Confidence Limits Associated With Values of the Earth's Magnetic Field used for Directional Drilling
Authors: Macmillan Susan , McKay Allan , Grindrod Steve 
Published: March 2009

Abstract
This paper describes updated uncertainties for use with predicted geomagnetic parameters within magnetic Measurement-While-Drilling (MWD) survey tool error models. These models are used to define positional error ellipsoids along the wellbore which assist in hitting geological targets and missing existing wellbores.
The declination, dip angle and total field strength of the Earth's magnetic field are used with magnetic survey tools for surveying the wellbore. These values are often obtained from mathematical models such as the British Geological Survey Global Geomagnetic Model (BGGM). As the Earth's magnetic field is continually varying with time the BGGM is updated annually to maintain accuracy. However a global predictive model cannot capture all sources of the Earth's magnetic field which results in uncertainties of the predicted parameters. The Industry Steering Committee on Wellbore Surveying Accuracy (ISCWSA) published a MWD error model in 2000 (Williamson, 2000). The geomagnetic field uncertainties that are part of this model were derived from work done by the BGS in the early 1990s. Since then more accurate data from magnetic survey satellites have been introduced into the BGGM and the uncertainty of the predicted geomagnetic field parameters has been reduced.
The original approach to deriving the uncertainties involved separating the various error sources in the magnetic field and assessing them individually. This paper uses a simpler approach where clean orientated magnetic down-hole data are simulated using geomagnetic observatory data. Spot absolute measurements of the magnetic field made at observatories around the world are adjusted for the crustal magnetic field to make them more representative of hydrocarbon geology. The adjusted observatory data are then compared with the predicted values from the BGGM to assess the uncertainty. The uncertainties do not fit a ‘normal’ distribution so they are expressed as limits for various confidence levels. They vary with time and with location and, in their derivation, do not assume any underlying empirical error distribution. Options to further reduce the uncertainties using data from local magnetic surveys (In-Field Referencing) and observatories (Interpolation In-Field Referencing) are also described.
The use of the revised geomagnetic uncertainty values in the MWD error model will reduce wellbore position uncertainty to reflect the increased accuracy from recent improvements in geomagnetic modelling.
Precise Management of Downhole Pressure Enhances Safety and Enables Access of Challenging Offshore Reserves
Authors: Grayson Brian 
Published: March 2009

ABSTRACT
The global demand for oil and gas is continually growing, while the world's resources are becoming increasing more difficult to obtain as the less problematic and operationally straightforward prospects dwindle. A majority of the industry's efforts are being spent in the identification and development of new methods and technologies to enable access and production from these resources where accessibility is technically challenging and hazardous due to difficult drilling environments or geological hazards, or both. At the same time, health, safety and environmental risks are more of a concern than ever before. Exposure to these difficulties is even more evident and challenging in offshore operations where not only the technical problems exist, but now logistics becomes a bigger issue.
Over the past several years, significant advancements have been made towards methodologies and technologies that allow for better control and management of downhole and surface pressure during the drilling and completions of onshore and offshore wells. The technology advancements and lessons learned through the evolution of Managed Pressure Drilling (MPD) techniques are now being utilized to increase safety and drilling operation's efficiencies, and allowing for access of previously inaccessible reserves. MPD is being used as a mitigating technology to eliminate non-productive time (NPT) problems, such as time spent during kick-loss scenarios and reduction of well costs by minimizing the number of casing strings. For many projects, MPD has become the enabling technology that permits feasibility of drilling and completion of the prospect.
This paper will describe the processes and variations, and the technologies used with MPD. It will further detail how MPD techniques are being applied as an enabling technology to a variety of onshore and offshore operations to increase the safety of rig crew and surrounding environment and overcome the problems associated with today's challenging wells.
Intelligent and Interventionless Zonal Isolation for Well Integrity in Italy
Authors: Moroni Nevio , Zanchi Augusto , Barbieri Enrico , Ravi Kris , Mesmacque Anne , D'Ancona Evasio 
Published: March 2009

Abstract
Cement-sheath integrity is fundamentally important for well integrity and helps to ensure that the asset is operated safely and economically. If the cement sheath is damaged during well operations, it could lead to interzonal communication, annular pressure, and casing damage. Remedial jobs are then necessary to fix the problem and continue well operation. In some cases, it might not be economical to fix the problem, leading to well abandonment.
The challenge to cement-sheath integrity is caused by the stresses resulting from change in pressure and temperature during well operation. Examples of wells that could be subjected to changes in pressure and temperature are deepwater, high-pressure high-temperature (HPHT), gas storage, steam injection, and geothermal. Gas storage wells in Italy are addressed in this work. An integrated, intelligent, and interventionless solution has been applied to solve the zonal-isolation challenges in such wells. The well events during the life cycle were integrated into the analysis and a cement sheath was designed and tested so that it was not damaged. Safety considerations were built into the design procedures based on the teachings of designs of other materials. This design procedure helped the cement sheath withstand cyclic loads, which could be significant in gas storage wells.
During well operations, if the stresses on the cement sheath exceed the design limits, the cement sheath could be damaged. The initial damage could be in the form of small cracks and micro-annuli. If these damages can be fixed immediately and without intervention, then the formation fluid can be prevented from entering the annulus. Intelligent features were built into the cement sheath so that small cracks and micro-annuli could be automatically sealed if formation fluid enters the annulus.
The integrated, intelligent, and interventionless zonal-isolation features of the solution offer a unique opportunity to prevent the annular pressure buildup if the cement sheath inadvertently fails. This solution has been implemented in a number of wells and is described in this work. The job implementation and subsequent results during the life of the wells have been successful. The unique features of the solution discussed and presented in this work is a game-changer and should help the industry solve a pressing problem and operate wells safely and economically.
Case Histories of a New Wireline Logging Tool for Determination of Free Point in Support of Drilling and Pipe Recovery Operations
Authors: Kessler Calvin , Dorffer Daniel , Crawford Don , DeHart Rory , Weiser Jerry 
Published: March 2009

Abstract
A new logging tool that is will identify the free point in drill collars, drill pipe, tubing, or casing has been developed and field tested. The tool is commercially available in the wireline service sector for drilling support and well abandonment operations. Unlike previous free point methods, which used strain measurements of the pipe obtained as a series of stations with and without the application of pipe stretch or torque at each station, this new method is simply overlay of two logging passes. The first logging pass is recorded with the pipe in a neutral weight condition, and the second logging pass is recorded with tension or torque applied to the pipe. The tool utilizes the property of steel called magnetostrictive effect. When a mechanical stress is applied to the steel, the magnetization of the material is modified. Thus when torque or tension is applied to the pipe that is free to move, their magnetization will change. If the pipe is not free to move their magnetization will remain the same. The tool has been successfully tested in steel alloys that have minimal magnetic properties.
This new logging tool has many advantages over legacy free pipe determination methods. First, from a rig safety standpoint, the application of pipe stretch, or torque is applied only once for a few minutes for the logging pass. With legacy free point methods numerous stationary measurements were required, with the pipe being stretched/torqued at each station. Since determination of free point is a comparison of two logging passes, real time operations and 24/7 satellite communications allow remote based operator and service company pipe recovery experts to be involved with the well site decisions. While this new technology uses a comparison of two logging passes, well site operations is not dependent on a pipe recovery expert with extensive hands on experience to be on location, or delays waiting for pipe recovery experts to arrive on location. This benefit is extremely important with the aging of the industries workforce.
The small diameter logging tool is run centralized, and does not require weight bars added to the tool for slip engagement, this shortens the length of the tool string and simplifies e-line rig up procedures.
Drilling a 2-inch in Diameter Hole in Granites Submerged in Water by CO2 Lasers
Authors: Kobayashi Toshio , Nakamura Masahiro , Kubo Satoshi , Ichikawa Makoto 
Published: March 2009

Abstract
As part of a fundamental study of rock drilling by laser irradiation, this paper describes laser drilling of a 2-inch-in-diameter hole in granites submerged in water. In the air, fused rock produced by laser irradiation reflects or absorbs successively irradiated laser beams, thereby refraining laser heat from being transmitted into the rock. This absorption leads both to a temperature rise of the fused rock and a further increase in absorption of laser radiation by the fused rock, causing the rock destruction process to cease completely. From consideration of the lack of success in past laser rock drilling methods, we arrived at the idea that laser-induced mechanical forces could be utilized to generate a hole in rocks by laser irradiation in water. A granite specimen was submerged at 50mm from a water-surface and then 10.6 pm carbon dioxide laser (CO2) beams which have a high absorption coefficient in water were intermittently irradiated. The laser beams induced underwater shock waves, bubble formations, and micro-water jet formations upon bubble collapse.
High-speed video observations revealed the generation of an initial cone-shaped cavity in the water, propagation of the laser beams through the cavity and eventual ablation of the granite surface. The laser beams locally melt the granite surface to form small glassy beads, which are readily removable by mechanical methods. Repetition of this procedure demonstrated that a high-power laser beam propagating in water can be used to generate a hole in rocks. The laser beam irradiation indeed drilled the granite specimen submerged in the water. A 2-inch-in-diameter hole in the underwater granites was successfully generated by two methods that were melting and spalling by the laser. Melting the granite to generate a 2-inch-in-diameter hole requires energy almost 3 times as much as spalling the granite to generate the same size hole.
Coring Unconsolidated Formation—Lower Fars: A Case Study
Authors: Al-Sammak Ibrahim , Ahmed K. , De Santanu , Al-Bous Faisal , Ahmad Fatma , Abbas Faisal 
Published: March 2009

Abstract
Lower Fars is a shallow unconsolidated sandstone reservoir with high inter-granular porosity filled with heavy oil in southern part of Ratqa Field in Kuwait. The shallow depth (500′ to 800′), friable sand laminated with shale and high viscosity heavy oil in pores have made coring this sand quite challenging. Last recovered core with rubber-sleeved core barrel in the eighties was only up to 60%.
This paper describes how thoughtful mix-up of technology, innovative techniques and proper coordination by aligning all concerned has helped in meeting the challenge of coring unconsolidated sand and it's processing.
Using low invasive core fluid, shorter core length, Aluminum inner core barrel, separate core bit to cut major sand / shale, full core catcher system, vertical slabbing at well mouth and on-site freezing have improved core recovery in excess of 85%.
While low-solid content coring fluid with a pH of 9 resulted in low mud invasion, reduced WOB, ROP and SPM ensured fewer washouts during coring. Low abrasive core head with clam shell full closure core catcher produced good recovery. Core barrel length was reduced from standard 30′ to 10′, which was slabbed to 3′ size keeping barrel vertically at well mouth. At well site it was frozen vertically with foam on top to minimise lateral movement and transported in freezer. At Core Lab it was kept frozen with dry ice, slabbed and plugged with liquid N2.
It is expected that the obtained core plugs from similarly cored 6 wells shall lead to meaningful Routine and Special Core Analysis, which was suspected in old cores. This would help in developing the depositional geological model in conjunction with the image logs.
An Innovative Stimulation Approach for Horizontal Power Injectors in Sandstone Reservoir, Saudi Arabia: Field Experience
Authors: Al-Zain Ahmed , Al-Driweesh S. , Al-Jandal A. , Said R. X. , Metwally S. , Abitrabi A. 
Published: March 2009

Abstract
Acid stimulation systems to remove formation damage are very well established for vertical injectors, drilled during the early development of a sandstone reservoir in central Saudi Arabia. With the advent of horizontal technology, new injectors are drilled with thousands of feet of horizontal section to expose large reservoir area for injection. The conventional acid stimulation programs, applied on vertical wells, would be impractical and very expensive for horizontal wells due to the expected large quantities of acid and other associated chemicals.
An innovative acid stimulation approach has been introduced for stimulating sandstone horizontal injectors in central Saudi Arabia. The new approach, which has been applied on horizontal injectors, consists of a foam cleanout to condition the horizontal section followed by main acid stimulation using optimized acid volume and overdisplacement of spent acid into the formation.
This innovative stimulation program provides an efficient and cost-effective method to condition the horizontal section by removing as much as possible of drilling mud cake, filtrates, and possible biomass. It also allows acid treatment to be optimized for stimulating the formation rather than only for removal of mud cake. This paper discusses in detail the successful application of the innovative approach and presents the post-job injectivity tests and results.
Investigations of Stress-Dependent Petrophysical Properties of Coalbed Methane (CBM)
Authors: Shedid Shedid A. , Rahman Khalil 
Published: March 2009

Abstract
The increase of successful exploration and economical importance of coalbed methane makes the understanding of petrophysical properties-stress-dependent more essential.
The influences of net stress on porosity, permeability, and reservoir quality index of Australian coalbed methane (CBM) formation are experimentally investigated. Two groups of low permeability from 0.01 to 1.5 md and medium permeability from 5.21 to 13.22 md actual CBM samples were used to perform this study. The variation of porosity, permeability, permeability-porosity ratio (K/φ) and reservoir quality index (RQI) under different stress conditions is studied. Current permeability-porosity models under stress are tested using the newly-attained experimental results from this study.
New correlations were developed capable to be used as simple tools for predicting changes of petrophysical properties with stress. Attained results also indicated that the reduction rate of porosity of low and medium permeability CBM samples can be represented by a straight-line equation form while the permeability reduction of low and medium permeability CBM formations is confidently followed an exponentially reduction mode. The increase of net stress causes a reduction in both ( K/φ) and RQI values. The results also revealed that the effect of stress is more dominant for low permeability samples than that ones for medium permeability CBM.
Well Placement by Boundary Detection / Optimization of Horizontal Well Performance: A Case Study From U.A.E.
Authors: El-Hamawi M. , Al-Amari Khalid , Al Shehhi Noora , Saleh M. , Mirto E. , Madjidi A. 
Published: March 2009

Abstract
Placing a horizontal well successfully within the target reservoir layers of uneven surfaces with uncertainties in dip and thickness is not a simple task, particularly in areas structurally disturbed. The level of difficulty increase when the well intersects a sub-seismic fault of unknown attributes. In such cases it becomes very difficult to decide which way to steer the well, so that it could re-enter the zone of interest, or which part of the reservoir is drilled after intersecting the fault.
A limitation to geological steering is the relatively small volume of investigation of the traditional logging while-drilling (LWD) sensors, which can typically probe no farther than few inches into the formation.
A new LWD directional, deep electromagnetic propagation service was recently developed with a much larger radial response that delivers distance and direction to the nearest change in resistivity within a formation, in addition to the resistivity of each of the formation layers.
A case study is presented onshore Abu Dhabi field of the United Arab Emirates, where information from the deep directional propagation LWD tool, together with near-the-bit direction and inclination measurements enabled to take proactive and timely corrective drilling actions to optimize the placement of the well path. A team from Petroleum Development and Drilling was formed with specific objectives to maximize reservoir exposure and minimize drilling risk and to insure 24 hours communication and real time data transmission between service and operating companies. The result was a well with 100% of its length in the desired reservoir. It was possible to achieve the field production target for this gas reservoir, drilling only 5 of the 7 wells originally planned.
Underbalanced Drilling Technology Adds Reserves and Enhances Ultimate Recovery
Authors: Babajan Salar , Qutob Hani 
Published: March 2009

Abstract
The current world petroleum industry situation is that: ➢Exploration is difficult and costs are increasing.➢The majority of hydrocarbons being exploited today are found in existing pressure depleted or complex and lower quality reservoirs➢Current oil prices are at their highest
Thus, world circumstances have forced today's petroleum industry to rethink both its operating methods and technologies aiming at improving recovery and reducing cost. It is believed that adoption of new technologies is the most important factor in adding reserves, enhancing recovery, reducing cost and increasing revenue. Underbalanced drilling technology is now seen as the way to achieve these objectives.
Introduction
Underbalanced Drilling – UBD- main objectives are: ➢Preventing formation damage and improving Reservoir Benefits.➢Improving Drilling Performance & Preventing Conventional Drilling Problems.
This paper discusses in details the reservoir benefits part of underbalanced drilling technology.
What is Underbalanced Drilling?
Underbalanced Drilling is the intentional reduction of the drilling fluid density causing the hydrostatic pressure in a well bore to be lower than the pore pressure within a formation thereby permitting reservoir fluids to be produced while drilling.
Underbalanced Drilling benefits the reservoir by simply adding reserves through: ➢Discovery of new zones➢Reducing formation damage and increasing intra-zone contribution➢Lowering abandonment increasing well drainage area➢Accessing challenging reservoirs➢Providing real time reservoir evaluation / characterization.
Although UBD has many advantages, it is not a magic potion for all fields, wells or drilling problems. Poor execution and planning would result in an over-enthusiastic misapplication of the technology, and possibly failure. Several real results and case studies will be presented and discussed in this paper.