bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimized Downhole Mud Motor Delivers Outstanding Performance Improvement in Alaska Coiled Tubing Drilling
Authors: Anyanwu Okechukwu N. , Klotz Christian , Labrecque Denis , Ulrich Carl 
Published: March 2012

Abstract
For almost two decades, coiled tubing drilling (CTD) has proved to be a successful method to reach the un-swept portions of Alaska’s North Slope reservoirs. This method of drilling has evolved over the years with new technologies and efforts from contractors and operators striving to improve performance from lessons learned. Despite these improvements in equipment and processes, operators and contractors must still deal with certain inherent deficiencies of this drilling method when compared to conventional rotary drilling – suboptimal weight transfer, sometimes troublesome hole cleaning — due mainly to lack of string rotation and low flow rate range, etc. These shortcomings have the potential to induce other drilling performance problems that affect the smoothness of coiled tubing drilling operations. Severe lateral vibration and severe stalling have become acceptable evils over the years, resulting in undesirable trips for failure and unacceptable non- productive time (NPT), both undermining one of the key benefits of coiled tubing drilling – rapid pace operations compared to rotary drilling.
This paper introduces a new lower-speed downhole positive displacement motor (PDM). The technology is equipped with high-performance elastomer and was engineered to improve drilling and drill-bit performance in CTD applications. Recent field deployments in Alaska’s North Slope CTD operations proved this design by eliminating earlier performance problems for improved CTD project economics. For example, the technology’s ability to allow for about 10gal/min higher flow rates (compared to other motor designs) significantly improves hole cleaning; a key aspect in CTD operations.
Up to today, this downhole mud motor design has been utilized on 13 wells, accumulating 1,303 circulating hours, 577 drilling hours and over 20,700 ft drilled. Performance improvements in depth of cut, reduced lateral vibration, reduced amount of stalls, and other benefits were achieved. There was no trip for PDM failure in all of the 34 runs, traversing different formation zones. The corresponding paper will provide additional information on application benefits by investigating two recent field deployments.
Advances in HWO Equipment Safety Features
Authors: Harrell T. , Eberhardt M. 
Published: March 2012

Abstract
During well intervention, control of the well is dependent on the integrity of the intervention-service provider’s pressure- containing equipment. The service company’s equipment becomes a safety critical element of the duty holder’s safety case. Also, control of the pipe string being inserted into the well during HWO is critical to successful well control.
One service provider recently developed two safety devices that enhance the safety of pipe handling and pipe control during HWO activities. A pipe-handling winch tension-limiting system (TLS) was created that helps minimize the risk of accidental overload of the HWO pipe-handling ginpole and winch by retraction of the HWO jack while the pipe is connected to both the jack and the ginpole. This device helps minimize the risk associated with pipe-handling counterbalance winches that have been equipped with brakes. Also, a slip-bowl interlock system was developed that helps minimize the risk of two pipe-handling slip bowls being opened simultaneously, which could cause lost control of the pipe that is being run in hole. This new device replaces the industry norm "weevil latch," which is used widely to help reduce this risk.
This paper describes the risks that these two safety-related inventions address and the details of the development projects that brought them to fruition.
Fiber-Optic Technology Allows Real-Time Production Logging Well Campaign To Continue Where Traditional Logging Tools Fell Short
Authors: Menkhaus A. , Ryan T. , Taboada J. , Wasson C. , Webb C. , Williamson J. 
Published: March 2012

Abstract
Exploration and exploitation of the shale formations in the United States has continued to accelerate since the early 2000's. Once considered to exist only as a cap rock, shale is now proving to be one of the most important reservoir rocks in North America and throughout the world. The demand for production logging (PL) in these reservoirs has increased due to the desire to better understand the basis behind higher stimulation efficiency and increased production results. Data collected via production logs can be used to evaluate efforts to enhance production through better zonal targeting, modifications to completion/hydraulic fracture design and/or alternate zonal isolation procedures.
Drilling extended reach horizontal wells has allowed for more efficient exploitation of these formations but has also increased the number of potential obstacles to overcome in order to obtain complete and accurate production logs. Some of these obstacles include: severe doglegs which interfere with logging tool bending capability, substantial wellbore debris and/or added friction surface contact impacting depth of data capture, and completion configurations that limit equipment options and ease of logging. This paper will identify these critical factors and address proper candidate well selection and job preparation. It will also illustrate a multi-well logging campaign in the Marcellus shale, which highlights the benefits of fiber optic technology as a suitable alternative to traditional production logging techniques.
Practical Cementing Technique To Repair Severe Casing Damage
Authors: Cirer David , Arze Erick , Moggia Juan Manuel , Soto Ruben Hector 
Published: March 2012

Abstract
We introduce a new way to repair the casing affected by severe damage, even long rupture casing. These techniques consist to pump cement through a special design of cement retainer and fiber pipes call ERFV (Epoxy Reinforced Fiber Glass), to fill the annular space between the casing and ERFV pipes. The ERFV are used as a guide for a special pilot mill (a mill with a nose of smaller diameter). Thus, achieve the integrity, the passage and the continuity of the well.
This paper will explain the method to repair severe casing damage and show the results of wells repaired.
Effect of Coiled Tubing Buckling on Horizontal Annular Flow
Authors: Asafa K. A. , Shah S. N. 
Published: March 2012

Abstract
Over the last few decades, coiled tubing technology has found increasing applicability in oilfield operations, including well intervention, well logging, coiled tubing drilling, perforation and fishing operations. Significant attention has been given to the prediction of friction pressure loss of various fluids pumped through coiled tubing and the annular space between the tubing and the wellbore. The importance of such prediction cannot be underemphasized, as adequate knowledge of the anticipated friction pressure is useful for determining the required pump horsepower and developing hydraulic programs during the operational planning stage.
However, a coiled tubing string can buckle under its own weight when the axial compressive load acting on the string exceeds a certain threshold, known as critical buckling load. In long extended reach wells, the extent of buckling, as well as its effect on fluid flow hydraulics can be significant, especially in the annulus between the tubing string and the wellbore. Despite the frequent occurrence of tubular buckling in many oilfield operations, previous publications on annular flow have traditionally considered flow in concentric and eccentric annuli, mainly discussing the effects of diameter ratio, fluid rheology and eccentricity on the friction pressure loss observed in such conduits.
The present numerical and experimental study examines the characteristics of steady-state isothermal laminar flow of non- Newtonian (Power-law) fluids and turbulent flow of Newtonian fluids in annulus with a non-rotating buckled inner tubing string. Numerical modeling results of fluid flow in various three-dimensional annular geometries using Computational Fluid Dynamics (CFD) are presented, ranging from a uniformly eccentric annulus to an annulus consisting of "corkscrewed" inner tubing - a helical buckling state, whereby the coiled tubing is permanently deformed when the prevailing bending stresses exceed the yield stress of the tubing. In addition, extreme cases of "arbitrarily" buckled coiled tubing annulus were evaluated for each size of coiled tubing considered. An interesting observation is the increase in annular friction pressure loss with increasing buckling extent. The CFD simulation results have been verified experimentally using a field-scale flow loop comprising of a helically buckled tubing annulus and an equivalent uniformly eccentric annulus. Practical empirical correlations have been developed, taking into account certain buckling parameter, to improve the accuracy of annular friction pressure loss predictions in coiled tubing operations involving a considerable level of buckling.
Case History: Pilot Project With Coiled Tubing Drilling in Offshore South China Sea
Authors: Abdul Rahman A. A. , Hamzah N. E. , Ahmad Fauzi N. , Safiin N. , Khalid M. Z. , Syaifullah N. , Jenie J. R. , Hariry H. E. 
Published: March 2012

Abstract
The sustained and relatively high value of oil and natural gas has resulted in an unprecedented level of drilling activity and implementation of innovative methods to recover as much hydrocarbon as possible, and as quickly as possible. The resulting demand for conventional drilling rigs for programs has forced the rates high and the availability low, making use of the units difficult to justify for use in declining fields with less significant amounts of recoverable product. The by-passed reserves remaining accessible in these depleted fields exist in volumes worthy of pursuit, but must be done economically.
In many fields, operators, either intentionally or unintentionally, bypass pay zones during initial development by focusing only on the best zones. Accessing bypassed thinly laminated formations can be economically attractive but poses several challenges, especially due to aged platforms and completion string in place, also offshore environment is adding its own challenges.
Coiled Tubing Drilling (CTD) has yet to establish itself in an offshore environment. Numerous one-off projects have been tried, but commitment was never made to a number of wells to see through the learning curve and realize the potential of the application. Offshore South China Sea have a huge quantity of candidates on existing installations, installations that, due to water depths and sub sea conditions require large, expensive rigs to drill or re-enter wells. Technically the wells can be accessed with coiled tubing with drilling parameters seen regularly in other projects. The challenges for this pilot project will be equipment specification and set up, efficiently exiting the casing, and management of wellbore stability in open hole drilling and completion techniques.
The main objective of this pilot project is to bring proven technology to offshore environment to access small bypassed reserves economically and provide an alternative to conventional drilling. The well candidates were selected with strict work scope to avoid going beyond the regular CTD application to ensure learning curve and lessons learned can be implemented throughout the project and achieve the objective.
This paper will described the preparation, execution, achievement and lessons learned from this 4 wells pilot project in offshore South China Sea.
Coiled Tubing Reduces Stimulation Cycle Time by More Than 50% in Multilayer Wells in Russia
Authors: Yudin A. , Burdin K. , Yanchuk D. , Nikitin A. , Bataman I. , Serdyuk A. , Mogutov N. , Sitdikov S. 
Published: March 2012

Abstract
Traditionally, coiled tubing (CT) in Russia has had very limited service diversity. Its use has been concentrated at wellbore cleanouts and nitrogen kickoffs after fracturing treatments.
We used coiled tubing equipment and technologies to supplement stimulation operations in one of the world’s largest oil fields, Priobskoe, which has up to five separate layers per well. Conventionally, well completions here have involved complicated workover operations with tubing, packers, and wireline perforating after each stimulated layer. Average wells with three layers took 30 days to complete. CT provided a significant improvement in completion efficiency, reducing the cycle time to just 10 to 12 days.
The first option of the completion and stimulation technology assumed "through casing" operations, eliminating the use of frac strings and a packer, which is a significant achievement under Russian regulations. This was done with a 4-in.-OD perforator and casing with increased strength. A year later, a second option for the technology was introduced to operate on regular strength casing through tubing. A slimmer abrasive perforator that could fit into the packer’s internal bore developed for this option was particularly effective for sidetrack and horizontal completions.
In total, 95 wells were analyzed with more than 250 stimulation stages. This includes an operational and technical review of the tools and techniques used to compare the efficiency of the whole cycle of completion, resources requirements and amount of risks and non-productive time associated. Also a productivity comparison of CT combined with fracturing technology versus standard process of wireline/workover/stimulation sequence will be given.
Case Story: Rigless Debris Removal From a Subsea Safety Valve With a Wishbone Honer Brush on Electric Line
Authors: Higa Rogelio , Saavedra Percy A. 
Published: March 2012

Abstract
Subsea safety valves (SSSV) are safety-critical when a well has sufficient reservoir pressure to flow naturally. Among other things, they are used to secure offshore wells during hurricanes to prevent pollution in the unlikely event the wellhead sustains damage. They are tested regularly and must be reliable.
While testing a SSSV in one of its wells in the Campeche Bay, a major Latin American Operator discovered scale deposits that prevented the SSSV from sealing shut. The operator was looking for an alternative mechanical solution, since pumping acid into its wells had not been effective. A downhole tractor service provider approached the operator and after carefully studying the case, presented the wishbone honer brush design run on a well tractor and electric line to repair the valve in situ and avoid costs associated with mobilizing a rig and removing well components. It was the first time this technology was used successfully for this application.
The operator deployed the cleaning equipment in August 2011 and performed the work in 18 hours operating time. The SSSV tested successfully on the following day and the well was returned to production. The operator estimated that the selected technology saved more than a week of deferred production at 7500 BOPD and direct costs of rig mobilization. The wishbone honer brush tool run on a well tractor and electric line proved to be the alternate solution they were seeking and it is now the operator's preferred technology for this application.
This paper will present the operational challenges as well as the results of this successful, rigless cleaning operation on an important producing well.
Risk Reduction and Efficiency Gains in Well Intervention Operations Through the Application of Real-Time Digital Slickline Services
Authors: Murchie S. , Billingham M. , Evans S. , Bautheas M 
Published: March 2012

Abstract
Real time digital slickline services have been used increasingly in the Gulf of Mexico by a number of customers. Through its telemetry enabled capabilities and the purpose built tools that complete the platform, digital slickline services can deliver a number of safety and efficiency gains to all types of slickline operations.
Material presented in this paper will be from actual operations, examples being perforation, tubing punching and cutting, plug setting and cement dump bailing, and will demonstrate the operational efficiencies being delivered.
Enhancement of the slickline service comes from real time surface readout of in situ tool operational status, the critical core measurements of downhole toolstring movement, deviation head tension and shock, and the depth precision now offered through gamma ray and CCL sensors. Optional tools such as a pressure / temperature gauge bring yet further visibility on the impact of the downhole actions undertaken. Expansion of the slickline service capabilities come from the telemetry enablement and core tools, coupled with a range of specific tools and sensors that have been developed to run on this slickline platform, namely a electro-hydraulic setting tool, an explosive triggering device, a monobore lock mandrel, and a production logging suite.
The real time data that is delivered to the slickline operator removes the need for assumptions that often have to be made during conventional slickline operation, and allow for a more efficient and reliable slickline operation to be undertaken. This results in a reduction in operation time, and a reduction in unnecessary trips out of the well to check on the tool status or to validate depth. Furthermore, since digital slickline is able to carry out both slickline well preparation work and a range of remedial or measurement work often carried out on memory or eLine, these operations can often be conducted entirely utilizing digital slickline crew and equipment. This optimizes pre- and post-job logistics, equipment rig up and rig down, and the job execution itself. In addition to the obvious cost savings, with a slickline wire comes a simplification of the pressure control and a well control recovery situation.
Comparison of glomerular filtration rate determined by use of single-slice dynamic computed tomography and scintigraphy in cats
Authors: Schmidt David M. , Scrivani Peter V. , Dykes Nathan L. , Goldstein Richard M. , Erb Hollis N. , Reeves Anthony P. 
Published: March 2012

Abstract
Objective—To compare estimation of glomerular filtration rate determined via conventional methods (ie, scintigraphy and plasma clearance of technetium Tc 99m pentetate) and dynamic single-slice computed tomography (CT).
Animals—8 healthy adult cats.
Procedures—Scintigraphy, plasma clearance testing, and dynamic CT were performed on each cat on the same day; order of examinations was randomized. Separate observers performed GFR calculations for scintigraphy, plasma clearance testing, or dynamic CT. Methods were compared via Bland-Altman plots and considered interchangeable and acceptable when the 95% limits of agreement (mean difference between methods ± 1.96 SD of the differences) were ≤ 0.7 mL/min/kg.
Results—Global GFR differed < 0.7 mL/min/kg in 5 of 8 cats when comparing plasma clearance testing and dynamic CT; the limits of agreement were 1.4 and −1.7 mL/min/kg. The mean ± SD difference was −0.2 ± 0.8 mL/min/kg, and the maximum difference was 1.6 mL/min/kg. The mean ± SD difference (absolute value) for percentage filtration by individual kidneys was 2.4 ± 10.5% when comparing scintigraphy and dynamic CT; the maximum difference was 20%, and the limits of agreement were 18% and 23% (absolute value).
Conclusions and Clinical Relevance—GFR estimation via dynamic CT exceeded the definition for acceptable clinical use, compared with results for conventional methods, which was likely attributable to sample size and preventable technical complications. Because 5 of 8 cats had comparable values between methods, further investigation of dynamic CT in a larger sample population with a wide range of GFR values should be performed.
Evaluation of a midazolam-ketamine-xylazine infusion for total intravenous anesthesia in horses
Authors: Hubbell John A. E. , Aarnes Turi K. , Lerche Phillip , Bednarski Richard M. 
Published: March 2012

Abstract
Objective—To evaluate the use of midazolam, ketamine, and xylazine for total IV anesthesia (TIVA) in horses.
Animals—6 healthy Thoroughbred mares.
Procedures—Horses were sedated with xylazine (1.0 mg/kg, IV). Anesthesia was induced with midazolam (0.1 mg/kg, IV) followed by ketamine (2.2 mg/kg, IV) and was maintained with an IV infusion of midazolam (0.002 mg/kg/min), ketamine (0.03 mg/kg/min), and xylazine (0.016 mg/kg/min). Horses underwent surgical manipulation and injection of the palmar digital nerves; duration of the infusion was 60 minutes. Additional ketamine (0.2 to 0.4 mg/kg, IV) was administered if a horse moved its head or limbs during procedures. Cardiopulmonary and arterial blood variables were measured prior to anesthesia; at 10, 20, 30, 45, and 60 minutes during infusion; and 10 minutes after horses stood during recovery. Recovery quality was assessed by use of a numeric (1 to 10) scale with 1 as an optimal score.
Results—Anesthesia was produced for 70 minutes after induction; supplemental ketamine administration was required in 4 horses. Heart rate, respiratory rate, arterial blood pressures, and cardiac output remained similar to preanesthetic values throughout TIVA. Arterial partial pressure of oxygen and oxygen saturation of arterial hemoglobin were significantly decreased from preanesthetic values throughout anesthesia; oxygen delivery was significantly decreased at 10- to 30-minute time points. Each horse stood on its first attempt, and median recovery score was 2.
Conclusions and Clinical Relevance—Midazolam, ketamine, and xylazine in combination produced TIVA in horses. Further studies to investigate various dosages for midazolam and ketamine or the substitution of other α2-adrenoceptor for xylazine are warranted.
Effect of head and neck position on intrathoracic pressure and arterial blood gas values in Dutch Warmblood riding horses during moderate exercise
Authors: Sleutjens Janneke , Smiet Esmee , van Weeren René , van der Kolk Johannes , Back Willem , Wijnberg Inge D. 
Published: March 2012

Abstract
Objective—To evaluate the effect of various head and neck positions on intrathoracic pressure and arterial oxygenation during exercise in horses.
Animals—7 healthy Dutch Warmblood riding horses.
Procedures—The horses were evaluated with the head and neck in the following predefined positions: position 1, free and unrestrained; position 2, neck raised with the bridge of the nose aligned vertically; position 4, neck lowered and extremely flexed with the nose pointing toward the pectoral muscles; position 5, neck raised and extended with the bridge of the nose in front of a vertical line perpendicular to the ground surface; and position 7, neck lowered and flexed with the nose pointing towards the carpus. The standard exercise protocol consisted of trotting for 10 minutes, cantering for 4 minutes, trotting again for 5 minutes, and walking for 5 minutes. An esophageal balloon catheter was used to indirectly measure intrathoracic pressure. Arterial blood samples were obtained for measurement of Pao2, Paco2, and arterial oxygen saturation.
Results—Compared with when horses were in the unrestrained position, inspiratory intrathoracic pressure became more negative during the first trot (all positions), canter and second trot (position 4), and walk (positions 4 and 5). Compared with when horses were in position 1, intrathoracic pressure difference increased in positions 4, 2, 7, and 5; Pao2 increased in position 5; and arterial oxygen saturation increased in positions 4 and 7.
Conclusions and Clinical Relevance—Position 4 was particularly influential on intrathoracic pressure during exercise in horses. The effects detected may have been caused by a dynamic upper airway obstruction and may be more profound in horses with upper airway disease.