bluuebunny/crossref_metadata_2025_split huggingface dataset:
Modeling and Validating Pressure Transient Effects on Inflatable Bridge Plugs during Coiled Tubing Conveyed Perforating
Authors: Xu Ron , Shamisheva Assem , Bucher Robert 
Published: June 2014

Abstract
It is known that the performance of inflatable packer is susceptible to the pressure change after it is set. When setting an inflatable bridge plug and then perforating nearby, it was "conventionally" believed that inflatable plug would fail when subjected to the perforating gun-shock loads. A common practice to protect the inflatable from these shock loads is to place an additional barrier to absorb these loads.
During one such instance, an offshore operator required setting an inflatable bridge plug and then stimulating the zone above it. However, after the plug was set, a contingency came up as it was not possible to open SSD of this zone. In order to stimulate this zone, perforating this zone was requested by the client. Due to the time and equipment limits, placing an additional barrier above the plug to protect it from the gun-shock loading was deemed impractical and seen as an unnecessary operational delay.
In this proposed perforating operation, the risk caused by the pressure surge from perforating to the inflatable plug had to be evaluated. Risk evaluation requires the modeling of the perforating-generated pressure surge. This paper presents a methodology to simulate pressure transients reliably both in magnitude and time and evaluate the risks involved with the inflatable plug. The impact of these pressure transients on the inflatable plugs can then be analyzed during job planning. This methodology enables engineers to evaluate the job risks, mitigate these risks, and then be able to optimize the operation design.
One case study will be presented in this paper. With the ability to predict the pressure surge, a decision, such as whether or not to need an additional barrier between the perforating gun and inflatable plug to absorb the pressure surge, can be made, and a successful operation of inflatable plugs with perforation can be expected.
Successful Application of Fiber-Optic-Enabled Coiled Tubing and Inflatable Packer Used for Testing the Formation’s Upper Zone
Authors: Gonzalez Carolina , Muñoz Johana , Orozco Natalia , Higuera Josue , Nava Dubrasky 
Published: June 2014

Abstract
Floreña field, located north of the Cusiana and Cupiagua fields, has been producing since 2001. Floreña field is part of the series of thrust sheets developed as result of the Eastern Cordillera uplifting.
In order to determine pressure depletion, establish connectivity between wells, reduce the risks of geological uncertainty along the field, and meet Ministry of Mines data acquisition commitments, we performed a pressure buildup test using inflatable packers as the isolation method.
In the past, when a pressure buildup test was required in the well’s upper formation, operators had to set up a bridge plug in the lowest part of the tested formation, set up a sand plug, and finally, pump a cement plug. These extra steps increased HSE risks and project costs.
A synergistic approach using real-time down hole measurements from fiber optic coiled tubing were combined with the cased hole inflatable packer to improve operation reliability while reducing risk of failure and time.
The availability of real-time logging casing collar locator (CCL), annular, coiled tubing (CT) bottom hole pressure, and bottom hole temperature data allowed the inflatable packer to be set properly. The measurements helped ensure adequate packer inflation, monitor the maximum draw down without exceeding the packer integrity, and perform a well test to a specific formation in just one run. In addition, the BHA configuration allows a memory tool down the packer to record the lowest formation static pressure.
After the pressure buildup test was performed, the results showed well connectivity with Florena Field. The test also confirmed reservoir pressure and permeability, which helped in future job and field planning.
Optimizing Horizontal Wellbore Design to Extend Reach with Coiled Tubing
Authors: Forrester J. , Yeung J. , Marzara F. 
Published: June 2014

Abstract
There has been a recent increasing trend in the number of horizontal wells being drilled in recent years. Wellbores are being drilled with various designs that often overlook challenges faced during the completions phase of the wellbore operation. As a result, wellbore intervention has faced some challenges when servicing wells. Although well engineering programs have been developed to optimize the design of the wellbore; one of the limiting factors of wellbore design has become coiled tubing reach capability and set down force at the end of the coil. To address this concern this paper looks to examine the effect of wellbore design on the set down force provided at the end of the coiled tubing string.
Optimizing Frac Plug Mill Outs in Horizontal Wells using Coiled Tubing
Authors: Pawlik Michael , Champagne Jonathan , Whitworth Jeff , Trebing Cody 
Published: June 2014

Abstract
Due to the current market price of natural gas, operators have needed to reduce the overall costs associated with completing a well. Specifically, steps have been taken to significantly lower the costs associated with the mill out of composite frac plugs and frac sleeves using coiled tubing (CT). Shell’s Eagle Ford group has successfully ventured away from traditional milling procedures that included numerous short trips, sometimes referred to as wiper trips. By incorporating a scientific approach and optimizing fluids system technology and bottomhole assembly (BHA) designs, these new methods have enabled us to eliminate short trips all together and produce cleaner wellbores. Ultimately, these new practices have achieved significant reduction in cost and time.
This paper will discuss the past coiled tubing performances and the need for changes. Analysis and theories used to implement and optimize Eagle Ford coil tubing operations will be reviewed. It will review and discuss the changes made such as fluid Quality assurance and controls (QA/QC) improvements, coiled tubing selection, and BHA design. These changes resulted in significant reduction in both cost and time per well and cycle time on a multi well location. These changes are now fully implemented and are the new standard for Shell’s Eagle Ford coiled tubing operations.
High Tension Electrically Controlled Release Device Improves Reliability Of Stuck Tool Release In The Gulf Of Thailand
Authors: Surapakpinyo Kittichai , Hanchalay Chutinthorn , Fundytus Nicholas , Ford Ronald , Pakdee Sawai , Sarian Serko , Battula Arvind , Nery Nadir 
Published: June 2014

Abstract
In a tool stuck situation, wireline conveyance systems incorporate a downhole mechanical weakpoint to safely release and retrieve the logging cable during or prior to pipe conveyed fishing operations. In wells with high tension profile and long open hole sections, the weakpoint strength should be carefully selected to ensure high pulling capabilities in shallower sections of the well while not exceeding the cable safe working load (SWL) in deeper sections of the well. To overcome this limitation, electrically controlled release devices (ECRD) were introduced in the past. Release is only possible with a surface command. As such full pulling capability is maintained at all times and depths. The swap however, introduced new sets of challenges such as full tension drop requirement for mechanical release and a labor intensive tool preparation procedure. As a result non-release incident rate increased leading to high risk and costly recovery operations. To minimize this risk, clients often have to reduce or cancel wireline logging programs leading to missed critical well data.
To address the limitations of ECRD type weakpoints, Chevron Thailand E&P, LTD commissioned Schlumberger to address such challenges. The project was completed in Dec 2011 with the introduction of SureLOC 12000. Improvements include release with 1000 lbf of cable tension, 12,000 lbf (up from 8,000 lbf) of safe operating pull and substantial reduction in maintenance and redress procedures. Reliability has since improved by 75% allowing Chevron to acquire full data in wells where logging operations would have been otherwise cancelled. The improved reliability and increased operational range of the new device have allowed Chevron to safely carry out Wireline logging operations and achieving well data acquisition targets with substantial financial benefits.
Improving Post-Stimulation Coiled Tubing Drillout
Authors: Asafa Kolapo A. , Williams Brandon T. , Gonzalez Armando , Wiskofske Michael T. 
Published: June 2014

Abstract
In the last few decades, coiled tubing has been widely employed for post-stimulation drillout of composite or cast-iron bridge plugs and isolation sleeves used in multi-stage hydraulic fracture stimulation in horizontal wells. Due to its inherent capability of continual deployment, coiled tubing technology has increased in popularity for this application over conventional jointed-pipe snubbing with rig-assist snubbing units. Despite the increasing use of coiled tubing units, drillout practices have typically been based on "art" rather than science, often resulting in drilling problems such as poor fluid efficiency and hole cleaning issues, lost circulation, stuck pipe, lost-in-hole tools, and parted pipe. Unfortunately, a greater percentage of stuck pipe incidents are directly related to poor hole cleaning, and it is not surprising that the causes of these problems are often not well understood. Thus, various approaches have been utilized to prevent recurrence based on incorrect assumptions. While some of these problems have been adequately dealt with in several publications, the determination of optimum fluid properties for efficient hole cleaning as well as the effectiveness of short tripping have been given minimal attention. To a large extent, fresh water, or brine, is mixed with various additives such as friction reducer for pressure loss and pipe friction, hydrogen sulfide scavenger and inhibitor, biocide, scale inhibitor, and polymer gel while drilling plugs. A common hole cleaning practice is the use of intermittent high-viscosity gel sweeps, wiper tripping to kick-off point after drilling a predefined number of plugs, and flowing back the well in an underbalanced condition while drilling and short tripping. The effectiveness of these practices is worth questioning based on the occasional drag and stuck pipe encountered while tripping out of hole.
This paper addresses the misconceptions related to coiled tubing hydraulics and hole cleaning, as well as reviews the common drillout practices and their cost implications including coiled tubing rig up, coil size selection, bottomhole assembly, fluids efficiency, and short tripping. Various best practices are recommended for improving post-stimulation drillout, with specific emphasis on how to minimize drillout cost.
Milling on Extended Horizontal Sections, Choice of Methods: Case Histories from the Chicontepec Area, Mexico
Authors: Ortiz Jose Ramon , Montes Efren , Ramirez Luis , Gutierrez Guillermo 
Published: June 2014

Abstract
The Chicontepec basin in the northern region of Mexico has experienced an increase in the application of completion technologies using fracturing sleeves (FSs) activated by baffles in long, extended horizontals. Because of the oil’s high viscosity in that zone and the inherent decrease in initial production, the milling of such FS baffles has become a necessity. Milling jobs have proven to be difficult using conventional coiled tubing (CT) milling methods, tools, and processes. Analysis of previous variables, well constructions, CT strings, and CT equipment led to the development of an unconventional work method that has been applied with success in more than 12 wells in the region.
CT milling operations rely heavily on two variables—the amount of effective weight on bit (WOB) that is applied over the obstruction and the torque generated by the tool. An intervention in a long, extended horizontal using CT implies the following constraints:
Normal force of CT in the extended section. Friction caused by the previous normal force. Friction pressure loss resulting from limited CT diameters and lengths.
While observing the long time intervals involved with most interventions and a few events in which the CT became stuck, a new intervention method was developed. Highlights of this method include the following:
Specific bottomhole assemblies (BHAs) for milling and cleaning of debris generated. Static friction reducers. Pressure friction reducers. Staged milling/cleaning work method of the total amount of FSs.
The first deployments of the combined work method were observed with caution and were not fully supported by the customer. The staged milling was supposed to increase the operating times in these interventions. However, by the time the third well was milled using this method, this perception began to change because of comparisons between the time lost during unwanted events, such as the tool becoming stuck and difficulty during milling. Previous events had reduced the occurrence of these issues in the last 12 wells and the use of associated FSs.
The importance of this work method is evident by the observed reduction in overall intervention time, delivering production earlier with no quality issues for the Chicontepec area.
Beyond Logging: Slickline Operations Can Now Provide a More Efficient and Cost Effective Alternative to Traditional Intervention Operations
Authors: Loov R. , Billingham M. 
Published: June 2014

Abstract
Digital Slickline’s capability and flexibility is providing operators with the opportunity to re-think traditional well intervention methodology. The technology provides both traditional mechanical Slickline services in addition to a range of real time downhole measurements enabled by a coated conventional slickline. Digital Slickline does enable multiple services such as production logging and perforating on demand but further significant value is being found when used performing conventional mechanical operations.
This paper will discuss carefully planned and engineered solutions where Digital Slickline was used. In one example it provided a means to accurately correlate the depths of completion components, allowing for the accurate setting of a mechanical isolation plug. The integrity of the plug isolation was verified by use of downhole pressure and temperature measurements. Additionally the upper zone sliding sleeves were located accurately, opened successfully and resulting desired production well flow verified by conducting pressure and temperature logging passes. In another example the technology was again used to prevent separate runs to perform leak detection. Mechanical plugs were set on the same run as logging passes for leak detection. In both examples the well intervention operation lead to a reduction in planned operational time and significant cost savings for the client compared to traditional workover rig operations.
Coiled Tubing Material Selection for Velocity Strings in Sour Brine Service
Authors: Ward I. , Lynn C. , Shaw R. , Hervo S. 
Published: June 2014

Abstract
Installing coiled tubing velocity strings is a common deliquification strategy used in gas wells in which the flowrate has dropped below the critical rate required to remove produced liquids from the well. Initially in Shell’s Groundbirch unconventional gas development, a standard carbon steel coiled tubing grade was used for these applications. Due to elevated levels of chlorides, carbon dioxide and in some cases H2S, a long-term inhibition schedule was then needed to minimize corrosion. Recently, however, a special CRA material has been employed, that Shell had previously helped develop for subsea applications (Li et al, 2002), which has eliminated the need for costly long term inhibition. This paper outlines the selection process and implementation of this material change.
Standard 13Cr alloys are well known in the industry but could not be used in the Groundbirch fields due to the high chlorides levels of the produced water as well as H2S levels sometimes above NACE thresholds. On this basis, higher chromium coiled tubing materials were evaluated based on their ability to resist corrosion, sulphide and chloride stress cracking, as well as their mechanical properties. A fit for purpose material testing program was used, combining standard NACE test protocols with unconventional specimen shapes and crevice corrosion assessments in simulated well environments. Factors such as the direction of primary loading stresses, mechanical deformation during installation, as well as coiled tubing manufacturing characteristics such as the longitudinal seam, bias welds, and orbital (butt) welds were also considered.
From this fit-for-purpose testing, not only was the preferred corrosion-resistant material, Nitronic 19D duplex-steel, selected for the coiled tubing strings, but an operating envelope has been developed for it, as well as manufacturing specifications have been defined for the strings for optimum performance. Installation guidelines to reduce the mechanical damage inflicted on the strings have also been created. Although the campaign startup was delayed due to manufacturing issues, once the campaign did start, the installations have been efficient, with future campaigns planned.
By selecting a single, robust material grade for CT Velocity String material for a variety of potential conditions (high salinity, CO2, H2S), and also developing some guidelines for their use, installations can be done efficiently in Groundbirch in large campaigns, with long term cost savings from eliminating the need for continuous inhibition. Furthermore, the long term integrity of the strings should benefit, ultimately leading to longer completion life, less production deferment, and less intervention issues due to corroded and failed CT strings.
Journey of a Coiled Tubing Catenary Operation: Best Practice at South China Sea
Authors: Wan Mohd Fablillah Wan Mohd , Abdul Ghani Sushila Siti , Ishak Mohd Fakhrurazi , Kasim Mohamed Heikal 
Published: June 2014

Abstract
In the Malay Basin area, 18 offshore oil and gas fields are operated by PETRONAS Carigali Sdn. Bhd (PCSB). Years after years of production, the challenges in managing these matured assets are becoming more and more complex. PCSB performs well intervention, integrity operations and maintenance on different type of platforms comprising of more than 800 strings. Allocation of sufficient resources is inevitable in ensuring continuous performance of our daily well intervention works. To sustain and enhance the production rate at some wells, it requires extra resources for well intervention works to occur especially related to small or satellite platforms in the region. The small and satellite platforms limit the normal coiled tubing operation in term of deck loading capacity, crane limitation and accommodation during the operation.
In year 2008, PCSB has experienced a significant breakthrough by conducting CT barge assisted operations for the first time in their operation and in Malay Basin of South China Sea. During that time, team faced a lot of hurdles at preparation and execution stage due to limited experience thereof. Many lesson learnt had been documented for future operation improvements.
The journey since 2008 until now has seen the total of four CT barge assisted operations at PCSB platforms in Malay Basin which involved cement packer, acid stimulation, nitrogen kick off & sand management operations. All the objectives of these four operations were successfully met and increased the total production of oil at about 2500 bbls/day and 30 MMSCF/day. Determined to improve the quality of each operation at the preparation and execution stage, the team has taken an approach to capture lessons learnt & best practices from one project and applied them in the subsequent projects.
A wide range of engineering and project assessments from each of the activities have been developed to help the next CT catenary operations to achieve the most optimized time, cost and quality. Furthermore, the findings of this study are valuable for identifying strength and weaknesses in current approaches. The paper will focus on the specific of each of the project’s operational challenges; lesson learnt and devised best practices which have allowed development of specific guidelines that now allow effective execution of CT catenary operations in different challenging conditions found in South China Sea waters.
A Systematic Approach to Horizontal Well Perforating With Coiled Tubing in the South China Sea, Malaysia
Authors: Tapia W. R. , Jenie J. R. , Sorman I. 
Published: June 2014

Abstract
For many years perforating in horizontal wells under variable conditions has been one of the biggest challenges in the South China Sea area. Being a critical step during the cycle of a well, operators have to identify the best perforating method to achieve desired results in the safest manner whilst remaining cost-effective. Perforating using coiled tubing (CT) conveyance provides a range of flexibility as an attractive method to convey long sections of guns in a single run; however, whether this technology can be considered the most appropriate solution in light of available alternatives developed in recent years, remains in question.
One of the operators in Malaysia faced this situation when preparing its first perforating campaign in a field with complex extended reach wells, where the main target was to produce the maximum quantity of gas available whilst avoiding sand production. The campaign was performed with a rig present and any delay due to failure meant a huge cost impact. The operator solicited a detailed technical design and a systematic evaluation of all available options in the market to perforate the pay zones successfully.
The solution implemented was based in part on the experience obtained during previous years in the Area, where different methods were used. An exhaustive statistical analysis was performed to determine the critical parameters to be the focus of the design and the selection of the most reliable technology to address the various scenarios that the campaign presented. Hydraulically actuated CT tractors, friction reducers, sterling beads, and creative use of buoyancy effect, together with using state-of-the-art CT technology were among the combinations proposed to overcome CT lockup and successfully convey the oriented guns to total depth (TD) in all wells.
The intent of this paper is to provide a strong guide to CT perforating under variable conditions in horizontal wells through a thorough requirements analysis, risk evaluation and proper selection of technology. A review of the results and lessons learnt are also included. The engineering process, which has since become the benchmark in the area, can be applied with confidence as evidence by the success of the campaign.