bluuebunny/crossref_metadata_2025_split huggingface dataset:
Challenging Wellbore Cleanouts With Coiled Tubing Made Easy With Computer Modeling Technology
Authors: Nasr-El-Din H. A. , Al-Anazi M. A. , Balto A. A. , Proctor R. J. , Saleh R. M. 
Published: December 2007

Abstract
Well bore cleanouts have been performed for many years with coiled tubing and it may be said that the cleanout operation is one of the most routine services performed in the coiled tubing industry; but until recently design was no more than a rule-of-thumb approach. Sufficient information is now available to facilitate informed decisions and achieve reliable engineering solutions, utilizing a sophisticated particle transport model.
A methodical thought process, based on extensive research and mathematical modeling, will be presented for designing specific well bore cleanouts in a challenging offshore field in the Middle East. Case histories from a number of wells are documented detailing the conclusions from each. Laboratory analysis was performed on samples collected from the cleanout operations to further optimize and validate the design process. It is the intent of this paper to demonstrate the importance of sound engineering design, aided by comprehensive computer modeling technology.
Proxy Modeling in Production Optimization
Authors: Zangl G. , Graf T. , Al-Kinani A. 
Published: December 2007

Abstract
Proxy models are becoming more widely used as they can simplify highly complex processes with reasonable accuracy. Especially in risk analysis, where complex relationships between the uncertainty parameters exist, proxy models are used in form of response surfaces to accelerate interpretation and optimization methods. However, the use of proxy models is rarely seen in production optimization.
When the data gathering from wells and surface equipment is fully automated, production optimization can be performed almost in real-time. The bottleneck in this workflow is the high computational effort of simulation models and the large number of input variables to optimize. This disadvantage can be overcome by mimicking the behavior of the system, such as the coupling of a simulation model and the surface network model, by using a computational efficient method. The requirements for such proxy models are high, since they have to capture highly non-linear trends hidden in a small number of representative samples.
This paper presents the usage of neural networks as proxy models. For the production optimization process, genetic algorithms are used. Their advantage lies in the ability to handle a large number of input variables. The neural network operates as fitness function for the genetic algorithm. The optimization result can be achieved extremely fast (within seconds), allowing optimization in near real time. A real life example is also presented in this work.
Standalone Coiled-Tubing Water-Shutoff Operations Reinstate Well on a Normally Unattended Installation
Authors: Barclay D. A. , Lawson K. , Mullins B. , Cardno B. 
Published: December 2007

Abstract
The Amethyst B1D platform is a small normally unattended installation (NUI) in the southern sector of the U.K. North Sea. A coiled tubing (CT) intervention was required on well L04 during the winter because of gas contract demands and a combination of failures on production facilities and other wells. As this horizontal well had not produced since 1996, only limited well data was available.
This paper details the entire operation, from the choice of zonal isolation material (ZIM) and the equipment selection to the preparation for the multiple run CT intervention. The intervention design was tailored to operate within the operating environment of an installation with limited deck space, compact facilities, and only a 10-ton crane lift capacity. New equipment was manufactured and tested in the provision of this solution. Trials were performed onshore to optimize the rig up. Deck layouts, lifting, and boat loading plans were generated as a result of these trials. The rig up design was improved, and the equipment specifications were reviewed.
The basis of the actual intervention was to shut off the watered-out lower completion and isolate the unsupported annulus to prevent water from coning up from the toe of the well. This required the use of inflatable plugs and packers and the placement of a suitable ZIM. This paper details the knowledge gained during the planning, operational, and post job phases. This knowledge includes the importance that the logistical aspects provided to the intervention.
The well was put on production following the water shutoff operation and is now part of Amethyst potential.
Hydraulic Pump-Down Frac Plug and Subsequent Coiled-Tubing Removal Increases Client Efficiency in Barnett Shale
Authors: Blanton E. M. , Mackenzie G. 
Published: December 2007

Abstract
On average each well within the Barnett Shale play will produce from five (5) to ten (10) horizontal zones. Each zone is perforated and fractured with between 500,000 and 1,000,000 gallons of slickwater prior to isolation in order to repeat the process on the next zone. Previous to the methodology further described within this paper, the composite material frac plugs were deployed into the horizontal section of the wellbore by means of electric wireline and a tractoring system. While proving successful, this system did have limitations with respect to time and ultimately economics especially considering the average number of zones per well that required temporary isolation.
This paper will describe a system method improvement being utilized by most operators in the play whereby a Hydraulic Pump-Down Frac Plug is utilized. This cased hole temporary plug can be ‘displaced’ into the well at speeds of up to 200 feet-per-minute with surface pump rates of less than 10 barrels-per-minute. The BHA that is run consists of the Hydraulic Pump-Down Frac Plug, Wireline Adapter Kit, Wireline Pressure Setting Assembly, 2 sets of perforating guns and a firing head. After successful isolation and fracturing, the plugs are removed from the well bore in an under balanced environment by means of a coiled tubing milling assembly. The plugs have also been removed by reversing units utilizing 2-7/8" tubing and a 4-3/4" 5-bladed concave mill.
This paper will show how the development and use of this methodology has greatly increased the efficiency of completions within the Barnett Shale play by a potential reduction in time of 50% depending on the zone depth. The client costs have been significantly reduced not just in terms of time savings but also when the removal of the requirement for electric wireline with tractoring systems is taken into account.
Friction Factors for Two-Phase Fluids for Eccentric Annuli in CT Applications
Authors: Omurlu C. , Ozbayoglu M. E. 
Published: December 2007

Abstract
The gas-liquid flow phenomenon is frequently encountered during Coiled Tubing (CT) applications, especially in underbalanced drilling. In the wellbore, the flow takes place in more complex geometry than pipe flow. The determination of the pressure losses is the major concern prior to estimate the hydraulic system requirements as well as hole cleaning efficiencies and the drilling performances. The most commonly used mechanistic models are developed for two-phase pipe flow and the hydraulic diameter concept is generally applied to adapt the annular geometry to pipe flow. However, in case of two-phase flow through fully eccentric horizontal annuli, the complexity of the geometry couples with the difficulty of the physics of two-phase flow. In this study, friction factor correlations are proposed in order to calculate the pressure losses of two-phase systems flowing through fully eccentric annuli. The data used in this study, including pressure drop, flow rates, temperature and flow patterns, is obtained using the METU-PETE-CTFL multiphase flow loop. The collected data is analyzed and using statistical methods, friction factors are obtained both for considering different flow patterns as well as ignoring the flow patterns. The results showed that, the proposed friction factors for both methodologies could estimate the frictional pressure losses with an accuracy of less than 7% for all cases. The accuracy and the simplicity of the proposed methodology provide promising solutions to frictional pressure loss estimations of two-phase flow at the horizontal sections of CT.
Analysis of the Effect of Eccentricity on Flow Characteristics of Annular Flow of Non-Newtonian Fluids Using Finite Element Method
Authors: Ozbayoglu M. E. , Omurlu C. 
Published: December 2007

Abstract
One of the most difficult tasks in petrolum industry is to characterize the behavior of non-Newtonian fluids flowing through eccentric annulus. Many empirical and semi-empirical approaches have been introduced which attempt to solve this problem. Also, there are few analytical methods proposed, however, the performance of them were not promising. This study aims to approach the problem using finite element method (FEM), which became popular lately due to the developments of the computer technology. Defining a typical wellbore size commonly encountered in CT applications, three different non-Newtonian fluids were tested at three different eccentricities. Different FE mesh types were used to increase the accuracy of the results. The FEM results were compared with different conventional methods as well as experimental results which were available in the literature. The results showed that, as the eccentricity is increased, FEM can estimate the frictional pressure losses more accurately than conventinal methods. It is observed that, as the eccentricity is increased, frictional pressure loss is decreased, if all the other parameters are kept constant. Moreover, the velocity profile across the wellbore can easily be determined, which is very important to identify the hole cleaning performance of a fluid.
CT-Deployed Hydrajet Perforating in Horizontal Completions Provides New Approaches to Multistage Hydraulic Fracturing Applications
Authors: McDaniel B. W. , Marshall E. J. , East L. E. , Surjaatmadja J. B. 
Published: December 2007

Abstract
The application of horizontal completions in lower-permeability formations is continuing to proliferate on a global scale. Caused either by formation damage issues or the very heterogeneous nature of many such reservoirs, actual wells will underperform when compared to original predictions from reservoir simulations. This will continue to result in a need for effective hydraulic-fracturing stimulations for many of these wells to reach economic production levels. Horizontal completions in moderate- to low-permeability reservoirs present the challenge of cost constraints that seldom allow the use of long-proven methods such as cemented completions and individual-fracturing of numerous zones with bridge plug isolation and multiple perforating runs. Some new methods being applied to overcome this problem require expensive downhole "jewelry" and some added risks that the liner and jewelry can be entirely run to the predetermined depth. In some methods, the operator must also accept reduced completion IDs that can later restrict production rates or hinder workover operations. These increased costs and risks must be accepted even before the actual fracturing treatments are attempted.
This paper will discuss a new approach to controlled placement of multiple-stage fracturing treatments without the risks involved with packers or bridge plugs. By implementing a coiled tubing (CT) deployed hydrajet-perforating method, immediately followed by a fracturing treatment pumped down the annulus, the operator can use lower cost (and lower risk) liner completions, and delay the decision of selecting exactly where the perforated sections should be placed. In many cases, the final decisions on placement of the next perforated location can even be delayed until after the wellbore displacement of the preceding fracturing stage. By pumping the fracturing fluid slurry down the annulus of the CT and the casing the allowable frac rates can be higher than with tubing-deployed techniques. The total stimulation related costs are greatly reduced by being able to perforate/frac multiple times within the same day. Even where more than one day is required to complete the stimulation of all desired locations along the lateral, only one CT intervention and one pumping service company mobilization and rig-up will be needed, which will still improve the job economy over conventional methods. An additional benefit includes a reduction in the potential for excessive multiple fractures or near-wellbore tortuosity encountered with explosive charge perforating.
Eliminating the Human Error During Coiled-Tubing Operations
Authors: Burgos R. , Allcorn M. , Mallalieu R. , Vicens J. L. 
Published: December 2007

Abstract
In the last decade, several successful initiatives have been introduced to mitigate the risk of coiled tubing pipe failure while performing interventions in oil and gas wells. Through the use of reasonably accurate computer modeling, the industry has seen a marked reduction in the number of pipe failures associated with material fatigue due to the constant plastic deformation occuring during pipe tripping operations. Similarly, the judicious practice of employing off-line pipe quality inspection tools, as well as the availability of real-time monitoring of pipe geometry through a variety of devices has contributed to a more predictable and more favourable pipe performance.
A study of root causes for coiled tubing (CT) pipe failures over a five-year period indicates that a substantial percentage of incidents were attributed to human error. This type of incident involves the application of excessive overpull resulting in pipe necking or complete parting of the pipe due to tensile failure. Similarly, too much snubbing force will cause pipe buckling and compressive failure. Both have the undesirable result of a damaged CT string (at best) or a compromised well control security (at worst). Using a properly trained and fully competent crew can minimize such events. However, the ardous and stress-filled nature of live-well CT operations will limit the elimination of this human element.
This paper presents an effective means for eliminating the possibility of human error becoming a factor in conditions that could result in a pipe failure during normal CT operations. Through the incorporation of a specialized system in the coiled tubing unit controls, a safety device is put in place to provide a shutdown feature when specific job designed setpoints are exceeded.
This paper provides a discussion of the features and capabilities of such a system. It cites details of recent experiences demonstrating the benefits with use of the device in actual CT interventions.
Deployment of a Formation Dynamics Tester with Coiled Tubing
Authors: Herrera H. G. , Moreno A. , Maldonado R. , Dubost F. X. , Foinquinos C. I. 
Published: December 2007

Abstract
In their effort to continuously improve operations through the development of new and innovative technology, East Mexico operators have focused on optimizing operating times and reducing costs during the completion process by conducting in-situ characterization of gas fields. The challenges encountered when attempting to perform such tests are generally associated with the characteristics of the well completion, the length of open hole (OH) section below the shoe, the type of mud used and the high deviation profile.
These issues have prompted the design of an alternative coiled tubing (CT) conveyed technique. This paper presents the experience of the first deployment of a modular formation dynamics tester (MDT) on CT. This was used to perform several "point pressure tests" and achieve formation characterization of a gas well in the Lizamba Field, State of Veracruz, Mexico. With this new application, the operator was able to significantly reduce time and costs by performing the characterization survey following a conventional CT logging (CTL) operation.
The success of this technique has led to the enhancement of general OH CTL operations by the use of well control equipment at surface to provide formation characterization at slightly over-balance conditions. The greatest challenge is to have effective risk-mitigation procedures to avoid pipe sticking from differential pressure or problems with the small annular clearance between the tool and the wellbore. It has also been extremely important to have an effective contingency plan prepared to recover the toolstring if the stuck-pipe situation does arise.
This paper provides a discussion and analysis of these issues with reference to recent experience with CT- conveyed wireline tools in open hole.
Unique Coiled-Tubing Unit Design Improves Surface Efficiency for Performing Well Interventions in Algeria
Authors: Adil A. R. , Burgos R. , Howell R. L. , Samir A. 
Published: December 2007

Abstract
Various types of coiled tubing (CT) units have been in operation throughout the petroleum industry for over 30 years. Despite the introduction of desirable improvements in the quality of materials and components, the principle layout and operation of a coiled tubing unit (CTU) package has not changed much over time.
The geography of Algeria presents a very challenging environment for any oilfield operations. For example, less than favorable conditions exist from the extreme heat, hazardous routes must be traveled during equipment transport, restrictions in personnel movement are brought about by concerns involving security and local operating practices limit most of the operations to daylight hours only. To overcome these problems a light, efficient and fit for purpose CTU is needed. The CTU would have to be operationally efficient thus reducing the number of personnel to run and support the unit operation. This alone would minimize any potential safety issues by reducing the exposure of personnel to heat stroke and/or the handling and stepping hazards associated with rig up activities.
Using modern technology and a fit for purpose design of CT surface equipment, great improve-ments can be realized in safety, efficiency, reliability, and operating cost of CT operations. Since introduction to Algerian operations in 2002, a uniquely designed CTU has shown significant advantages over conventional unit designs. The equipment rig up process has been made safer and more efficient through improved design and the integration of various components. Process control of the whole well site operation allows the operator to focus on the down-hole treatment rather than surface logistics. A reduction in the number of trucks and personnel required to perform basic CT operations offers some significant efficiencies in operating costs.
This paper examines the facts and figures of this unique CTU in the Algerian area of operations including a comprehensive discussion of its features and why they have been beneficial in this challenging environment.
Well-Intervention Challenges to Service Wells that "Can Be Drilled"
Authors: Blount C. G. , Mooneyt M. B. , Behenna F. R. , Stephens R. K. , Smith R. D. 
Published: December 2007

Abstract
Drilling rigs are continually setting new records in measured depth versus true vertical depth ratios, horizontal section lengths, and delivering sophisticated versatile yet often operationally complex completions.
Experience suggests that common well intervention technologies including slick line, electric line, e-line tractors, Coiled Tubing (CT) tractors, pump-down services, and CT and CT enabling technologies may have difficulty fulfilling all the possible intervention needs of the wells that can and are being drilled and completed.
This paper will present an overview of available well intervention technology, outline limitations of each technology, and use numerous case histories from challenging interventions performed in Alaska to support the discussions and conclusions.
A Web-Based Integrated Project-Management System Supporting Teamworking and Decision Making on Field-Development Projects
Authors: Piantanida M. , Rossi P. , Gaudioso G. 
Published: December 2007

Abstract
Following the reengineering of ENI's Development Management System, which occurred in the early 2004, ENI has developed an IT integrated Project Management System to support Field Development Projects.
ENI's Development Management System promotes a stage&gate approach to the development of a field, starting from the assessment of the value of the field, the identification of the viable development scenarios, the definition of the selected development strategy and the execution of the project (including the construction of the facilities and the hand-over to operations). At the end of each stage, a predefined set of data and documents have to be prepared by the project team to be submitted to a Decision Gate in order to support an informed decision by ENI's executives and authorize the start of the following phase. The IT system has been developed with a Web Portal technology and it assists:
○ the multidisciplinary team involved in the project (geologists, reservoir and drilling engineers, facility & construction specialists, HSE consultants) in the daily work. In fact, it provides web based tools to share and verify project documents; develop and control the schedule baseline of the project; automatically track cost expenditures against budget values; document and review risks and lessons learned; manage milestones, issues and project changes; ○ the executives involved in decision making. In fact, it provides a high level dashboard with an integrated visualization of the last updated schedule and cost figures for the project, as well as direct access to the main project documents relevant for the Decision Gate of the current project phase.
The system integrates the document management capabilities of Domino; extends the planning and control functions of MS Project; automatically imports the budget/actual expenditures from SAP R3; authorizes and profiles users according to their role. It has been used to support 50 project phases across 34 projects.
Application of Global Optimization Techniques for Model Validation and Prediction Scenarios for a North African Oil Field
Authors: Griess B. , Diab A. , Schulze-Riegert R. 
Published: December 2007

Abstract
This paper presents a case study in which a Multipurpose Environment for Parallel Optimization is applied to assisted History Matching. Experimental Design techniques are used in order to investigate parameter sensitivities. Different global optimization methods are integrated into a workflow controlling a large number of reservoir simulations. For increased efficiency, simulations are run in parallel. Results are analyzed and compared to traditional History Matching to identify potential added value and increased efficiency. The reservoir engineer is in full control over the optimization process and interacts frequently with the History Matching process, while acquiring more information and improved understanding of existing uncertainties of the simulation model.
The history matching objective was defined to emphasize selected key wells where traditional history matching had proven to be difficult. The importance of a large number of input parameters was investigated, and an optimization scheme was set up to generate one or more alternative history-matched realizations of the simulation model. Alternative simulation models are determined by differences in model parameters as well as varying match qualities on a well-bywell basis. Selected results are used as input for alternative prediction scenarios.
The study was used to evaluate the economic potential for new infill wells, potential side-track locations and ESP candidates. The case study demonstrates the improvement in assessing reservoir uncertainties for an OMV-operated North African oil field. A structured process was implemented for assessing uncertainties related to oil in place volumes in selected regions of the field with a large impact on alternative prediction scenarios.