bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Higher-Strength Coiled Tubing Developed to Extend Coiled Tubing Operating Envelopes
Authors: VanArnam W. D. , Hargis C 
Published: September 2011

Abstract
A new high strength coiled tubing grade has been developed to address the demands for improved axial strength, better fatigue performance and the ability to function at higher operating pressures. Coiled tubing service companies and operators defined several areas where existing coiled tubing grades are not considered capable of performing, including carrying heavier payloads to the well perforation zone and working in today's increasingly longer horizontal sections. Designing a coiled tubing product that meets these requirements presented unique challenges. The project goal was to develop reliable high strength coiled tubing that provides 130,000 psi minimum yield strength and predictable fatigue life. Coiled tubing strength comes from a balance of strength from the initial hot rolled strip and modifications while forming into tubing. However, some coiled tubing manufacturing operations, including welding, can influence those strength characteristics. The process controls during manufacturing, including bias welds and any tube to tube welds needed to assemble long strings; all determine the final properties of the tubing. The high strength tubing has been successfully made using existing manufacturing methods. The initial testing indicates the tubing has high strength with good ductility. Fatigue testing shows superior fatigue performance to existing grades of tubing in both cycles to failure and diametrical growth. This paper will cover the development program inclusive of strip manufacturing, tube forming, welding and other processes including the quality control necessary for assuring consistent properties. Initial application trails to verify operating characteristics will also be reviewed in the paper.
A Step Change in Circulating Technology: Increased Efficiency and Cost Reduction Through Simplifying Circulating Sub Technology and Use
Authors: Herrington D.. , Barton S.. , Clausen J.. , Billingsley J.. 
Published: September 2011

Abstract
Movement of cuttings produced while drilling is not a new issue to the drilling industry. We do however see the overall depth of wells, as well as their inclusion of extended horizontal runs ever increasing. We find the risk of differential sticking, excessive loss of pressure, and general stuck pipe situations compounded with every foot deeper we drill. The circulating sub has been a long relied upon tool in the drilling world that has aided in the acceleration of cuttings along the annulus towards the surface. When activated they can reduce build-up of debris and cuttings on the low side of the drill string through horizontal runs and in deep and ultra-deep drilling applications by increasing annular velocities. The downside to these tools has always been the constraints of the technology. Various systems for engaging and disengaging circulating subs have been designed over the years, improving on particular points such as actuation, or split flow design, but these designs have consistently relied on fishing out a drop ball or dart to deactivate, or dropping additional balls to cycle the tool. This takes costly time to pump the balls down the string and limits the total number of cycles before the tool must be pulled and serviced, potentially interrupting the run. Service companies have long been searching for a simpler, more efficient method of circulating to the annulus without the lost time and complicated cycling methods required by current technology.
Utilizing a new cycling mechanism design and an open bore (to allow for potential fishing of MWD components), drillers can now cycle an infinite number of times without regard for the tool needing to be pulled due to maximum cycling count being reached. The tool is cycled using a single drop ball and changes in flow rate alone. The tool can be launched with the ball in place, alleviating the need to pump a ball down at all, or the ball can be launched from surface during the run if fishing through the ID is required prior to activating the circulation sub.
This paper details how the development of a step change in circulating technology is assisting a major service company in reducing downtime during the use of the circulating tools in hole. This design has proven easier to operate and has reduced the overall time lost struggling with current tool designs. Supporting case studies are included to detail the increase in efficiency and reduction in costs.
First Successful Coiled-Tubing Intervention Operation on the Helideck of a Normally Unmanned Installation in Offshore India
Authors: Savenkova A. , Turner A. , Lawson K. 
Published: September 2011

Abstract
This paper describes the challenges involved with providing a coiled-tubing (CT) intervention solution from the helideck of a normally unmanned installation (NUI) in the Gulf of Cambay in offshore India.
The project began with a detailed analysis to determine if intervention was practical from the helideck of the NUI, or if barge support or a full jackup-rig intervention was necessary. Some factors in this analysis included the limited deck space, restricted crane capacity, and the existing available utilities. This led to the planning and sourcing of suitable CT, flowback equipment, nitrogen, and fluid-pumping equipment, as well as necessary downhole tools. Trials were performed onshore to optimize the rigup, stackup, and deck layout. The boat loading and lifting plans were created from these trials. The combination of the prejob planning and the trials led to the confidence to conduct this intervention with modified safety arrangements required for the platform when no helicopter operations could be performed.
The purpose of the actual intervention was to complete sand cleanout of the horizontal-well section, isolate the lower oil-producing zone, open a sliding sleeve to access the upper zone, and unload the well with nitrogen to restore production.
This paper also includes the variety of applied technologies that were either attempted or successfully used to bring the well back into production. This required the use of the latest generation of horizontal, downhole-tool solutions, slickline tractors, CT-tool deployment, and contingency operations, which involved a wide range of downhole tools. The results from the intervention and the lessons learned are presented.
HWO/Snubbing Unit Used Effectively for Subsea Flowline Fishing and Cleanout at Nansen Spar
Authors: Ford J. D. , McDaniel R. , Barbee G. P. 
Published: September 2011

Abstract
This paper discusses the prejob research and eventual use of a hydraulic workover (HWO)/snubbing unit for a subsea flowline intervention at the Nansen Spar in the Gulf of Mexico (GOM). Located in a water depth of 3,670 ft (1119 m), the Nansen Spar has been in production since 2002 (Fig. 1). In 2005, a number of umbilical lines became plugged, preventing further chemical injection to prohibit hydrate and paraffin buildup. In 2009, a hydrate blockage formed in a production flowline during the course of an unplanned shut in. Initially, it was decided to perform a coiled tubing (CT) intervention to enter the flexible riser and flowline, clean out the paraffin, and remove the hydrate deposit. During the CT intervention, the pipe became stuck, thereby requiring a fishing operation. At that time, the decision was made to use a 340K hydraulic HWO/snubbing unit to fish the CT and clean out the remaining paraffin and hydrate bridges. The execution and outcome of the fishing and cleanout operation are discussed, as well as some of the challenges associated with not only working in deep water, but through a flexible riser as well. Recommendations based on the lessons learned during the planning and execution of the operation are also presented.
Bayesian Optimization Algorithm Applied to Uncertainty Quantification
Authors: Abdollahzadeh Asaad , Reynolds Alan , Christie Mike , Corne David , Davies Brian , Williams Glyn 
Published: September 2011

Abstract
Prudent decision making in subsurface assets requires reservoir uncertainty quantification. In a typical uncertainty quantification study, reservoir models must be updated using the observed response from the reservoir via a process known as history matching. This involves solving an inverse problem, finding reservoir models that produce, under simulation, a similar response to that of the real reservoir, requiring multiple expensive multiphase flow simulations. Thus uncertainty quantification studies employ optimization techniques to find acceptable models to be used in prediction. Different optimization algorithms and search strategies are presented in the literature, but they are generally unsatisfactory due to slow convergence to the optimal regions of the global search space, and, more importantly, failure in finding multiple acceptable reservoir models. In this context, a new approach is offered by Estimation of Distribution Algorithms (EDAs). EDAs are population-based algorithms, which use probability models to estimate the probability distribution of promising solutions, and then to generate new candidate solutions.
This paper explores the application of EDAs including univariate and multivariate models. We discuss two histogram-based univariate models, and one multivariate model, Bayesian Optimization Algorithm (BOA), which employs Bayesian Networks for modelling. By considering possible interactions between variables and exploiting explicitly stored knowledge of such interactions, EDA can accelerate the search process, while preserving search diversity. Unlike most existing approaches applied to uncertainty quantification, the Bayesian Network allows BOA to build solutions using flexible rules learned from the models obtained, rather than fixed rules, leading to better solutions and improved convergence. BOA is naturally suited to finding good solutions in complex high-dimensional spaces, such as those typical in reservoir uncertainty quantification.
We demonstrate the effectiveness of EDA by applying to the well-known synthetic PUNQ-S3 case with multiple wells. This allows us to verify the methodology in a well controlled case. Results show better estimation of uncertainty when compared to some other traditional population-based algorithms.
Interpreting Azimuthal Propagation Resistivity: A Paradigm Shift
Authors: Pitcher Jason , Bittar Michael , Hinz David , Knutson Craig , Cook Robert 
Published: September 2011

Abstract
In recent years, new advanced resistivity sensors have appeared in the toolboxes of logging-while-drilling (LWD) vendors. These sensors are designed for optimal well placement and accurate formation evaluation and have had a very rapid acceptance by the industry. However, their interpretation techniques and their full capability have not been fully explored or explained.
Geoscientists who use these new sensors must be able to understand and interpret the sensor responses in complex geology and in a wide range of reservoir and formation conditions. By fully examining and using the responses of these sensors with the aid of appropriate modeling tools, a much clearer insight into the rocks surrounding the wellbore can be gained. The fundamental petrophysical characteristics and geometries of the rocks can be evaluated, and the boundaries surrounding the borehole can be understood.
This paper describes the fundamental physics of the sensors, as well as many interpretation techniques. Interpretation workflows are presented to address various petrophysical concerns and methods. This paper also explains the planning, geosteering, and formation evaluation of a typical well with this new technology. Benefits and limitations, lessons learned, pitfalls, and best practices are also discussed. Finally, the paper includes field examples to show the usefulness of this new technology for well placement and formation evaluation in various types of hydrocarbon reservoirs.
Innovative Use of Inflatable Packer and ROV To De-Oil Damaged Subsea Pipeline: Case Histories
Authors: Murphy R. A. , Neves S. 
Published: September 2011

Abstract
When a well is abandoned the flow line contains well effluent which must be recovered before abandonment is completed -this can present problems, especially in deepwater sub sea wells. In a well in the Campos Basin, Offshore Brazil, in a water depth of 624 meters (2067 ft.), pigs were pumped from the wellhead to the production facility to flush the flexible line, however they became stuck leaving some 1400 meters (4593 ft.) of 4 inch ID flow line filled with production fluid. To clean the balance of the flow line it was decided to cut the line downstream of the pigs and insert a flexible deployment flow line from surface to seal inside the cut and thereby facilitate the continued displacement of the flow line. It was agreed that the use of an inflatable packer deployed by a Remote Operating Vehicle (ROV) would offer the best chance of success, however two problems existed which could affect the adequate sealing of the packer element:
• The ID of the flexible flow line contained a continuous spiral groove 1/16inch deep.
• The sea floor temperature at the mud line was 39°F.
To evaluate this, lab tests were initiated and successfully performed to confirm viability of the seal in this situation. The packer was then made up with a 1″ hose to a 4″ ID flexible deployment line located on a work barge, run to bottom and inserted into the flow line cut using the ROV. It was set, the setting plug sheared and 862bbls of sea water were pumped through the line to clean it out. Upon completion of the job the packer was left in place and recovered along with the flow line.
In this paper the authors will describe the testing of the concept, its subsequent successful use with the ROV and the problems which were encountered with inserting the packer into the flow line. They will go on to describe two further such operations in which the lessons learned from the first operation were taken into account. All the operations were successful, allowing recovery and subsequent reuse of the flow lines.
High-Temperature Downhole Motor Facilitates Cleanout of Obstructed Thermal Well, Saving Production Downtime
Authors: Thompson J. , Rossing M. 
Published: September 2011

Abstract
Certain wells in the Peace River region of Alberta, Canada, produce heavy crude oil along with H2S and CO2. The heavy crude oil is normally recovered with enhanced production methods involving thermal wells whereby the crude is heated to very high temperatures to facilitate production. One such well became plugged by scale deposits and efforts were made to clean out the obstruction using coiled tubing (CT) intervention techniques. However attempts to do so with jetting tools and acidisation proved to be ineffective and the only alternative left was to run a mill with a downhole motor. A major problem was posed by the bottomhole temperature of 300° C (572°F) which precluded the use of standard motors. The operator was thus faced with the probability of having to make an extended shut down to allow the well temperature to decline to an operable temperature level where standard equipment could be used, or look to alternatives.
In an attempt to avoid this extended downtime it was decided to run a non elastomeric high temperature downhole motor, which uses a positive displacement principle with a stainless steel stator and rotor system with no elastomers, which as a result is rated to 260°C (500°F). The 2-7/8″ OD motor was run with a 3-9/16″ OD mill on 2″ OD CT to try to mill out the obstruction in the 4-1/2″ slotted liner while circulating KCl fluid at the rate of 50 litres/min (13gallons/min) and Nitrogen at 30 standard cubic meters/min (1100 standard cubic feet/min). The obstruction was encountered at 820.6 meters (2,692ft) and successfully milled to 929m (3048ft) where the mill broke through and was run to bottom at 945m (3100ft) to circulate clean before pulling out. The whole operation took a total of 9 hours.
In this paper the authors will review the well conditions and the motor design and explain the decision to run it at downhole temperatures in excess of its rating. They will go on to detail the milling operation which was successful in returning the well to production at a considerable saving in production downtime when compared to the available alternatives.
New Innovative Top-Side Solutions To Provide Beneficial Offshore Well Intervention
Authors: Torgersen K. I. 
Published: September 2011

Abstract
Oil reserves being more and more expensive to develop, which makes it more and more important and beneficial increasing oil recovery on existing fields. To do so, drilling of new wells and side tracks are done, but taking care of existing wells, keeping them healthy and optimum producing, is often the most beneficial method for increased oil recovery.
This paper will focus on what can be done to increase benefit by doing cost efficient well interventions, at the same time as HSE measures are improved, on offshore installations and vessels. The paper will highlight the IOR issue, the potential for increased well intervention work, and focus on what we can do to make this happen.
The paper will present solutions for well intervention from existing well head platforms with or without drilling rigs, and for subsea wells. For existing platforms with drilling rigs, the potential for working in parallel will be described. For subsea wells, main focus will be the increasing need and the limited number of floating rigs, and how we can sort this out in a cost-efficient manner.
Traditional thinking have more or less been: what can we do with what we have - now it must be changed to: what do we need to achieve best results? Main intention with this paper will be to engage oil- and service- companies to innovative IOR thinking, and for inspiration the paper will include some examples of what has been both possible and beneficial.
Coiled Tubing Milling Operations: Successful Application of an Innovative Variable-Water Hammer Extended-Reach BHA to Improve End Load Efficiencies of a PDM in Horizontal Wells
Authors: Castaneda J. C. , Schneider C. E. , Brunskill D. 
Published: September 2011

Abstract
Horizontal completions continue to increase in popularity throughout the industry. In North America the majority of horizontal wells are drilled in shale gas formations. These formations require fracture stimulation for economic production. The majority of these stimulations are completed by fracturing four to six clusters of perforations simultaneously at high rates followed by a mechanical isolation with a composite bridge plug. As the horizontal wells increase in length the number of plugs required increases, with up to twenty plugs not being uncommon. These plugs are removed with a positive displacement motor (PDM) and mill run on either coiled tubing (CT) or jointed pipe. In longer-reach horizontal completions, plug removal using CT becomes more challenging as the efficiency of surface end loads transmitted to the mill are reduced. Quite often the deepest plugs can not be reached with standard coiled tubing, instead requiring larger-diameter, more costly, coiled tubing or jointed pipe. The need to extend the operating depth to effectively operate PDMs and reach the deepest plugs has led to development of several tool systems.
This paper will discuss the engineering, design, testing and initial field trial results of a variable fluid hammer extended-reach tool; how it was used to improve plug milling performance, to give superior control of weight on bit, to extend coiled tubing reach in the horizontal section and to reduce operational time. These field results will be compared with results using other methods of friction reduction, such as pipe-on-pipe friction reducers.
Coiled-Tubing-Conveyed Perforating in Shale
Authors: LaGrange T. , Barton J. , Andrich L. 
Published: September 2011

Abstract
This is a study of the development and ultimate use of the CT (Coiled Tubing) Firing Transfer System used in three different scenarios and is a comprehensive examination of what specifically is required for use and the contrast between past and present methods in order to quantify perforating efficiency. The Coiled-Tubing-Conveyed CT Firing Transfer System has greatly improved Coiled Tubing perforating efficiencies when multiple zones are to be perforated during a single run in a well. Cost, capability and time, (cost of time) have always been limiting factors in bringing oil or gas to market profitably. The CT Firing Transfer System has been used in many hundreds of wells. An estimated 15,700 individual CT Firing Transfer Systems and perforating guns have fired over 90,000 perforating charges with a very high degree of reliability. The savings at the well site are substantial in direct imbedded equipment and maintenance costs savings to the end user over a period of just 3 years. The simplicity and methods of its use in many different scenarios have been developed and are in use successfully. Although originally developed for Coiled Tubing, the CT Firing Transfer System has also been used for Tubing Conveyed Perforating (TCP) applications.
Light Well Intervention Scale Milling Enables Reservoir Access
Authors: Larkins B. M. , Mitchell D. A. 
Published: September 2011

Abstract
This paper will present a record North Sea electric line milling operation carried out during March 2010, the success of which enabled access to the reservoir section, with subsequent interventions leading to a significant uplift in production.
The Operator was experiencing high water cut in one of its wells; previous interventions in other wells connected to the same reservoir indicated a high probability of scale. The plan was to log, isolate the watered out zone and then re-perforate in order to increase oil production rate. Electric line Tractor Milling equipment was mobilised as contingency, should well access be an issue, which happened to be the case.
In order to keep the bit clear during milling, cuttings were flowed back to surface. Progress was made until the surface choke packed off and flow was no longer achievable, the toolstring had to be retrieved whilst choke and lines were cleared. The scale sheath was eventually broached and the decision made to continue in hole in order to drift, as well as providing the capability of dealing with any further scale that may be present; the Tractor Miller was started once more with a minimum of resistance encountered. Target depth was attained, all Tools were then retrieved to surface with no issues.
The overall objective was achieved, resulting in a significant increase in production. One hundred and twenty one (121 metres, 390 feet) of calcium carbonate scale was removed during the operation, validating the use of light well intervention techniques when removing scale.
This paper will discuss the technical aspects of e-line milling and challenges overcome during this particular operation.