bluuebunny/crossref_metadata_2025_split huggingface dataset:
IRISS – Intervention Riser Integrity and Safety System
Authors: Newman Kenneth R. , Rodney Stephens 
Published: December 2007

Abstract
This paper describes a system for monitoring the maximum stresses in an intervention wellhead, BOP lubricator/riser, and injector structure. In some offshore cases the wellhead itself may be moving, causing stresses in the intervention structure. In other cases the injector support system may allow some side-to-side movement, causing stresses in the structure. This system measures the bending moment, bending direction, axial load and internal pressure at one or more points in the structure. A real-time finite element analysis is then performed by the system to determine the maximum stress in the structure. The system displays the bending moment, bending direction, axial force, and internal pressure to the operator. It also displays the maximum stresses along the length of the structure, and warns the operator when the stresses exceed a safety limit. This paper describes the development and testing of this system.
Predicting Coiled-Tubing Failure Below Injector
Authors: Zheng Andrew S. , Adnan Sarmad 
Published: December 2007

Abstract
With the increased use of coiled tubing in high-pressure wells, the collapse of coiled tubing between the injector and the stripper has received much attention recently. In high-pressure wells, the failure of this tubing section (typically less than 2 ft in length) usually occurs under the combined loadings of axial compression and internal pressure. Previous analytical models to predict failure under such loading conditions have focused mostly on the buckling behavior of the short coiled-tubing section with minor modification of yield strength to account for the effect of internal pressure. Such approaches underestimate the effect of internal pressure on the collapse failure, especially for higher internal pressure.
In this paper, a new analytical model is developed to predict the collapse of short coiled tubing under the combined loadings of axial compression and internal pressure. The analytical model first analyzes the buckling load of the short coiled-tubing section under axial compression only, and the burst pressure of the coiled tubing under internal pressure only, respectively. Then an interaction failure criterion is used to model the failure locus of the short coiled tubing under the combined loadings of axial compression and internal pressure. Experimental data are used to validate this new model.
Dynamic Excitation Tool: Developmental Testing and CTD Field Case Histories
Authors: Robertson L. , Mason C. J. , Sherwood A. S. , Newman K. R. 
Published: December 2007

Abstract
Weight transfer and helical buckling eventually leading to lock up is an issue that the industry has had to deal with since the outset of the use of coiled tubing. Limitations imposed by this restriction have reduced the number of available applications that can be carried out. The use of larger sizes, improved materials combined with friction reducers and better modelling techniques have gone a long way to understand and extend these limits.
This paper reviews a new dynamic excitation tool, which reduces frictional drag and therefore adds to available options for further extending limits and capabilities of coiled tubing.
The paper follows the tools history from developmental testing in Norway and subsequent successful Coiled Tubing Drilling (CTD) field trials in Alaska.
Results of reverse friction factor modelling are included and parameters that affect the tools ability to create dynamic excitation are also discussed.
Some "Firsts" In Coiled Tubing Inspection
Authors: Stanley Roderic K. 
Published: December 2007

Abstract
Nondestructive evaluation (NDE) of new and in-service CT is leading to higher quality (conformance to specifications), the driver being high pressure, high temperature service work. This paper outlines a number of "firsts" in NDE that have occurred at Quality Tubing. We have installed and operated an electromagnetic strip inspection device and removed many strip surface imperfections, and a phased-array ultrasound (PAUT) system for weld-seam/heat-affected zone (HAZ) inspection of new tubing for the detection of typical seam anomalies. In order to inspect butt-welds quickly and without radiation, we are investigating the use of ultrasound, and have also procedurized bias weld and seam weld prove-up procedures using UT. Further, we have "final-inspected" (i.e. NDE after hydrostatic test) numerous strings for many coiled line pipe (CLP) projects, and more recently "high-exposure" coiled tubing projects such as Sakhalin, Thunderhorse projects.
For used materials, we have NDE-inspected for cement plugs, weld locations, and typical used-tubing defects, and have assisted in the determination of API derating criteria for in-service materials.
Recently, an untethered robot, capable of inspecting CLP/CT has emerged, and is introduced here.
Real-Time Data Delivery in Coiled-Tubing Well Interventions
Authors: Cabanzo Luis Eduardo , Zhou Wei 
Published: December 2007

Abstract
The application of information technology (IT) tools in the exploration and production industry has extended and enhanced conventional oilfield practices by promoting better communication and technical collaboration between expert personnel and the wellsite. Effective, real-time data delivery has become a key component in improving knowledge sharing, the time-to-decision process, and performance in well interventions.
As the coiled-tubing (CT) industry expands, more-effective communication with the wellsite becomes critical to facilitating successful operations. The availability of job data allows evaluation of the design and its execution as the job progresses; optimization of the treatment; and the making of more accurate, informed decisions during the course of the operation to improve the overall execution and reduce operational costs.
CT operations have shown a significant process-improvement trend and better project economics as a result of real-time supported operations. This paper discusses the concept of real-time supported CT operations and the use of data delivery to improve decision-making in the CT industry, outlines the technology and interface involved in the data-delivery system, details the specifications required to meet the data-transfer definition, and demonstrates its target application and potential impact in the CT industry.
Inflatable Packers in Extreme Environments
Authors: Wilson Stuart , Erkol Zafer , Faugere Aude , Eatwell Bill , Espinosa Frank , Xu Ron 
Published: December 2007

Abstract
Inflatable packers are ideal for through-tubing zonal isolation, but they are rarely used in extreme environments because of the assumed risk of failure. High pressures, high temperatures, high expansion ratios, and chemical resilience are particular challenges. This paper reports on three recent case histories that demonstrate inflatable packer technology can be used in several of these "harsh" wellbore conditions.
The first case history describes a high-pressure cement squeeze job using a 2 1/8-in. packer with an expansion ratio larger than 3:1. The objective was to run the packer through a 2.313-in. restriction and set in 7 5/8-in. casing to permanently shut off a lower water zone before perforating higher in the well. The second study involves an inflatable packer used in conjunction with a butyl acetate furan resin for sand consolidation. The furan resin is known to be extremely detrimental to elastomers, so a full-scale simulation under given wellbore conditions was conducted to demonstrate its compatibility with the packer. The resin was utilized as a screenless sand-control solution that allowed fullbore production. The final case history involves pumping of a viscoelastic acid-diverting treatment fluid, used for matrix stimulation under high-pressure, high-temperature conditions. Used in carbonate formations, the fluid is ideally suited for total zonal coverage matrix simulation and high temperatures. When a through-tubing inflatable packer is used as a treating packer, individual long producing zones can be fully isolated and evenly stimulated.
Experimental Study of Aerated Mud Flows under Horizontal Borehole Conditions
Authors: Zhou L. , Ahmed R. M. , Miska S. Z. , Takach N. E. , Yu M. , Pickell M. B. 
Published: December 2007

Abstract
Extensive aerated mud experiments were performed in a unique field-scale elevated pressure and elevated temperature flow loop (6″ × 3.5″ annular test section, 73 ft length, horizontal configuration without drillpipe rotation). A view port was installed to observe flow patterns in the test section. Two nuclear densitometers were used to measure steady state mean void fraction. During test runs, the liquid and gas phase flow rates were in the range of 50-250 gal/min and 50-150 scf/min, respectively. For all the test runs, measurements of pressure drop and average liquid holdup over the entire annular section were carried out.
The two-phase flow patterns were identified by visual observations through the view port. Stratified and slug flow were the two flow patterns observed over the range of the chosen test matrix. The presence of slug flow does not justify many existing simulation practices, which assume a homogeneous gas-liquid flow.
A mechanistic model has been developed for aerated mud hydraulics based on conservation equations and existing two-phase pipe flow correlations. An extensive sensitivity analysis is presented to quantify the influence of mud properties and flow parameters on the bottom-hole pressure. Comparisons between the predictions of the model and experimental measurements show a satisfactory agreement. The present model is particularly suitable for the design of underbalanced coiled tubing applications.
Hydraulics As It Affects Our Tools – The Inflatable Paradox
Authors: Mackenzie Gordon R J , Patterson Andrew E 
Published: December 2007

Abstract
One of the fundamental things we are taught as part of our industry training is how to calculate pressures as they interact with our systems and tools. Any number of training materials have been produced for us both in-house and externally to better understand the concepts of pressure. The tool service providers will provide pressure rating guidelines to allow their end users to very precisely define the limitations of pressure across their intervention devices. In the strictly mechanical arena the calculation of allowable differential pressures, both in terms of pressure reductions (such as drawdown) or applied pressure (such as testing) is a relatively simple process following the basic principles of what we have been taught. The mechanical solution supplies us with a very two dimensional platform on which we have to base our calculations. The paradox comes when the same age old, tried and tested principles are attempted to be utilized when dealing with an inflatable solution to the well operation. A new third dimension is introduced whereby not only must pressure differentials across the device itself be considered, but also differences from the inside of the inflatable element to the outside of the element must be analyzed. One of the biggest precursors to the success of planning an inflatable operation is the understanding and acceptance of this third dimension pressure characteristic and its application to not only the performance of the inflatable tool when the operation is being conducted, but in the case of long term deployments, its performance throughout the cycles of the well while the inflatable element is in situ. This paper will attempt to describe and explain in detail the differences in calculation methods required across inflatable type packing elements and highlight these differences in such a way as to inform as to the criticality of getting these calculations correct and applying them to both the planning and implementation stage of both temporary and long term inflatable isolations.
New Technologies Allow Small Coiled Tubing to Complete the Work Formerly Reserved for Large Coiled Tubing Units
Authors: Portman Lance 
Published: December 2007

Abstract
Coiled tubing has been used as a well intervention tool since the early 1960's. Since its introduction, the diameter of coiled tubing available has steadily increased, driven by demands for higher flow rates as well as larger push and pull forces. However, bigger coiled tubing sizes require larger equipment and in many cases, the simple physical size of the equipment becomes unworkable, particularly for offshore applications.
Some of the most common reasons for not using coiled tubing are:-
The platform and/or platform crane is not big enough for coil tubing size thought to be required. The available or manageable coiled tubing size cannot access the bottom of the well. Insufficient pull or push is available using the available or manageable coiled tubing size. The low fluid rates achievable through the available coiled tubing make the job time too great.
This paper addresses each of the above arguments put forward against the use of coiled tubing. The paper shows how advances in technology have, to a large extent, removed these perceived barriers, most notably for the most common coiled tubing activities, these being fill cleanouts, gas lifting and acidizing/stimulation. Several technologies have emerged recently that enable small, light coiled tubing units to be used where previously larger units were thought necessary.
Field Launch of a Safer, More-Efficient Coiled-Tubing Unit in North Sea for Valhall Stimulations
Authors: Andreassen T. , Langeteig B. , Amaravadi S. , Mallalieu R. , Polsky Y. 
Published: December 2007

Abstract
Safety and efficiency have always been the primary performance measures in the coiled-tubing (CT) industry. This paper describes the feasibility study, development objectives, field test, and launch of a new-generation CT unit in the Norwegian sector of the North Sea. This automated, modular system with its distributed system architecture is designed to improve safety in CT operations, with 15% operational efficiency gain and 30% offshore personnel reduction targeted.
A typical completion on Valhall is a horizontal well completed with 5 to 12 proppant-treated fractures per well in the soft chalk formations. The operations and logistics are complex and involve repeated sequences of perforating with CT, proppant fracture treatment with stimulation vessel, and a combined cleanout/perforating run with CT. On a 24-hour operation offshore, a 13-member crew operate the conventional CT spread comprising the unit, reel, and power stand; well-control equipment; two high-pressure, positivedisplacement pumps; shakers; choke; and a CT tower with the injector head.
The requirements and specifications of the new unit were finalized after a detailed study of operations, platform requirements, and local regulations. Efficiency gains were targeted in the rig-up and rig-down times, and in the overall zone cycle times (operational efficiency). Health, safety, and environmental improvements are achieved by reducing manual handling and lifting operations on board. Distinguishing equipment characteristics are as follows:
Preassembly and integration of components on skids to enable quicker rig-up and reduce manual handling. For example, offshore rig-up typically involves 54 lifts; the new unit cuts this number to 36. Distributed-control architecture to reduce the number of rig-up connections required. For example, the system design allows a total rig-up with only 36 hydraulic connections instead of the usual 84. Ability to run larger and heavier pipe (6,000-m length, 2⅞-in. diameter, 90,000-psi yield) at faster rates enables easier completion of difficult wells and reduces the overall zone-cycle time. It also eliminates handling of friction-reducing chemicals while maintaining cleanout efficiency. Planned reduction in crew through the utilization of automated process control, The benefits of this include the following: ▫ All controls for the choke, shakers, CT unit, and pumps are centralized in the CT unit's control cab. Many equipment controls-related tasks that conventionally were hands-on tasks are performed by the control system to allow the operator to focus on treatment efficiency. ▫ Automated safety features are incorporated into process-control software to reduce safety exposure, particularly in areas prone to human errors. ▫ Cab ergonomics allow the operator to oversee the entire operation and react to any situation quickly and efficiently.
Further Developments for Coiled Tubing Floater Operations
Authors: Lode J. E. , Møller R. , Nesvik K. T. , Buchanan A. , Myklebust J. 
Published: December 2007

Abstract
The number of new subsea-completed wells is increasing rapidly. At the same time, existing subsea field developments are entering more challenging phases of production with wells demanding a higher intervention frequency in order to maintain production and/or increase recoverable reserves. Consequently the demand for performing coiled tubing (CT) interventions in such wells is increasing. As an indication of this trend, one operator in Norway has seen a doubling of CT interventions in subsea wells in 2003 compared to previous years.
Today the most common installations available to perform CT interventions on subsea wells are semisubmersible rigs that are primarily designed for drilling and completion activities. The challenges of interfacing with and performing CT operations from these "semisubmersibles" are well documented (1). Such challenges relate mainly to restricted access and space around the hoisting systems and, even more importantly, to the relative motion (primarily heave) that exists between the "fixed" wellhead/riser and the moving installation.
This paper describes newly introduced equipment and techniques that are now considered field tested to improve coiled tubing, semisubmersible operations by
Reducing personnel exposure to safety hazards Reducing equipment exposure to damage hazards Increasing efficiency and the operational window with respect to heave conditions
Items to be described and discussed in this regard are:
A latest generation lifting frame with integrated stripper crash frame and stabbing guide Revolutionary use of a new slip joint system that effectively cancels out the effect of heave during critical phases of the operations
Coiled-Tubing Drilling Reentry: Case History from East Kalimantan
Authors: Wright H. J. , Aristianto B. , Gan R. G. , Jenie J. R. , Kyaw H. A. 
Published: December 2007

Abstract
As oil and gas developments mature, reservoir depletion reduces field output and fewer opportunities exist to drill new wells. Drilling new wells as the sole means of increasing field production often becomes less profitable, and it presents greater operational risks. Economic risks are also greater as the chance of completing good wells is getting less and the higher capital investment required.
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 and low-permeability zones is economically attractive but poses several challenges.
Several techniques were used to achieve sustainable commercial production from the bypassed zones in East Kalimantan. Hydraulic fracturing and underbalanced perforations were tried, with inconsistent results. Drilling new horizontal wells was not economical.
Coiled-tubing (CT) drilling was the solution that provided a cost-effective alternative to the use of a conventional drilling rig. The advantages were a smaller location footprint, shorter trip times, ability to drill underbalanced, competitive rates of penetration, and through-tubing reentry.
Because only a few CT drilling campaigns have achieved both operational and production successes, a campaign was proposed that used conventional well design and drilling programs. Previous lessons learned worldwide were used to reduce the drilling risk and enhance the chance of success. This was especially important in drilling a deviated hole through the coal zone of the subject well.
This paper will describe three wells from the design phase through post-job evaluation. Lessons learned and improvement plans are also incorporated in this paper.
Investigation of Polymeric and Mixed Metal Oxide Fluids for Use in Well Intervention Operations
Authors: Hodder M. , Michel C. , Kellingray D. , Bailey L. 
Published: December 2007

Abstract
This paper describes an investigation into the characteristics of various biopolymer and mixed metal oxide fluids for potential application in well intervention operations. Poor hole cleaning is experienced on many well intervention jobs with coiled tubing and even with hydraulic workover units because of lower circulation rates compared with conventional drilling operations. This can lead to stuck pipe (illustrated by two case histories) and is an expensive problem worldwide. Currently used products are poorly characterised in terms of their viscosity at elevated temperature and at the low shear rates encountered under the pipe in deviated, eccentric annuli.
The investigation involved rheological measurements on xanthan, welan, diutan and scleroglucan polymers on a Bohlin rheometer at shear rates of 0.001–1000 s-1 and temperatures 50-175°C. Two mixed metal oxide fluids were also tested as a comparison. The fluids were tested on a Chan rheometer (with identical geometry to the common Fann 35) to investigate correlations.
These experiments were complimented by hydraulics analysis and by tests to determine the resistance of the various fluids to contamination by cement. A simple suspension test was also performed using material simulating common cuttings produced in well intervention operations.
We also describe the results of treatments designed to break the viscosity of the various fluids prior to flow through the production separators. Finally, a case history is presented of a successful well intervention operation on a high-temperature well using viscous mixed metal oxide pills.