bluuebunny/crossref_metadata_2025_split huggingface dataset:
MIC Related Coil Tubing Failures and Equipment Damage
Authors: Sherman Scott , Brownlee Duane , Kakadjian Sarkis 
Published: March 2015

Abstract
Microbial influenced corrosion (MIC) has been implicated in few corrosion-related challenges in the well service industry in the past. Recently, the industry is observing an influx of MIC-related equipment damage. This upsurge of MIC conincides with a switch to unconventional water sources. As fresh water for fracturing operations and well interventions becomes less available, operators are forced to use alternative water sources such as recycled flow-back water, produced water, and even ‘grey water’ from wastewater treatment plants. In some instances, recycled water is sold from one operator to another for operations on other pads. Regardless of the water source for a particular well treatment operation, the same water-hauling equipment and tanks are used for successive hydraulic fracturing operations.
This ‘communal’ use of water hauling and temporary water storage equipment is an ideal situation for bacteria to move from one water repository to another. Even if the water source used to supply water for oilfield operations is free from harmful bacteria, it may still become contaminated - in transport or temporary storage vessels - before it is pumped downhole.
This paper is an overview of premature coil tubing and other well servicing equipment failures and pumping equipment damage that is related to MIC. Metallurgical, chemical and microbial analysis of the scale as well as representative water samples have been conducted to determine if the corrosion was the result of sulfur-reducing bacteria (SRB) or merely pitting common to oil field equipment from pumping hydrochloric acid and other corrosive fluids. This paper will explore the potential source(s) of the bacteria, the impact to the equipment that was exposed to the bacteria, as well as what is being done to mitigate the problem.
Challenging Conventional Fluid Practices for Coiled Tubing Drilling
Authors: Myatt James , Lynn Stephen , Craig Steven , Murphy Stuart , Correa Pedro , Padron Tomas 
Published: March 2015

Abstract
The Buda formation in Texas presents extreme challenges to prevent formation damage during drilling operations. After using many fluid selection variations, several operators have determined that under-balanced drilling with native crude is the most optimum method. The initial startup project for coiled tubing drilling (CTD) operations in this formation has been completed, with more activity to come. However, as the preferred recirculation of the native crude drilling fluid presents two major challenges. First, the formation is up to 2% sour, and the native crude is relatively volatile with a low flash point and high vapor pressure.
Recirculation of sour crude will lead to double-sided exposure of the coiled tubing, which historically has resulted in extremely short fatigue life. The use of active fluid property testing, in addition to scavengers and inhibitors with defined mitigation plans, reduces the risk to an acceptable level. Significant laboratory testing of the fluid properties as the material degrades with time, temperature, and mixing have been completed. Additional mitigation actions are utilized in conjunction with the laboratory results to further reduce the volatility properties. Internal technical and operational reviews, along with additional sourced subject matter expertise, have challenged existing safety, operational, and technical limits. Operational procedures have been continuously monitored and adjusted to compensate for the adverse dynamic wellbore conditions encountered during the campaign.
The discussions within this paper detail the background challenges, laboratory testing, operational/HSE planning and mitigation practices to allow operations to commence. Additionally, the paper covers operational results as the wells are drilled. These results may provide a basis for future operations utilizing extreme fluid conditions in other applications within the industry due to the economic benefits from native crude.
Optimizing Memory Multidetector Pulsed Neutron Logging in Slim Horizontal Coil Tubing Drilled Wells Using a Carrier Assembly
Authors: Cedillo Gerardo , Raeesi Behrooz , Zett Adrian , Itter David , Marouby Philippe , Yonghwee Kim , Chace David , Giordanelli Henry , Martinez Carolina 
Published: March 2015

Abstract
Coiled tubing drilling (CTD) technology has been widely adopted as a cost-effective re-entry strategy to sidetrack from the existing wellbores, and drill high angle/horizontal wells to maximize recovery from remaining oil columns in the Alaska Prudhoe Bay field. The oil rim in this giant field is overlain by a gas cap and has been producing for over 36 years by various recovery mechanisms such as gravity drainage, water flood and miscible injection and hence, holds a complex fluid distribution with locally variable oil-water and gas-oil contacts.
Determining current reservoir fluid contacts using multidetector pulse neutron logging (MDPNL) technology is a crucial component in the overall strategy to maximize production from each well and identify future drilling targets. This technology has been widely used in the industry for reservoir evaluation and surveillance in open- and cased-hole environments using conventional wireline techniques in standard borehole sizes. However, logging tool conveyance in CTD wells has been challenged due to small hole size and high angle/horizontal/U- shape wells.
An innovative deployment assembly was developed by BP Alaska and Baker Hughes to acquire pulsed neutron data while tripping out of the hole during the wellbore cleanout operation, eliminating the need for a dedicated logging run, which in turn, reduces rig time costs. This deployment assembly consists of a non-magnetic stainless steel carrier and a memory adaptor that is attached to the MDPNL tool. The carrier does not limit tripping operations or wellbore circulation, and requires no wireline for data acquisition.
Another major advantage of this assembly is the additional compressional strength provided to the tool, which reduces failure rates and provides a cost-effective well logging solution in highly deviated wells.
This paper presents case studies in which this coiled tubing logging technology was applied in the Alaska Prudhoe Bay field. Various aspects of the technology are discussed, including the memory-enabled, three-detector pulsed neutron tool and carrier assembly configuration. The paper also discusses identification of reservoir fluid contacts and other petrophysical properties using the nuclear attributes extracted from MDPNL data, which ultimately provides the critical information needed for optimal perforation strategy and maximize oil production in CTD wells.
The Challenge of Gaining Access to a Suspended HPHT Subsea Well Using Coiled Tubing to Complete Full Abandonment to Current Standards
Authors: Freeman Mickey , White John 
Published: March 2015

Abstract
This paper details a case history of a recent HPHT CT well intervention operation to gain access to a suspended subsea well, in order to finally abandon the well including wellhead removal from seabed. There was a need to mill out the shallow set environmental cement plug to allow section milling and cement plug setting on well that had been originally suspended in 1997. The absolute worst case predicted pressure trapped below the shallow set cement plug was 12,500psi. This paper will take the reader through the full life cycle of the CT well intervention project. Starting with the initial feasibility study that lead to the selection of CT as the most viable option, moving onto the two sets of trials on test wells verifying the milling parameters and BHA selection. There will then be details on the 15,000psi live well intervention landing string that had to be manufactured to act as a conduit for the milling operations and also having the capability to shear the 2″ QT1000 0.203″ CT. The paper covers a review of the actual versus planned operations and captures high level lessons that would benefit future similar operations. The requirement to enter old wells that have been previously suspended / abandoned to fully abandon to current standards is an area of increasing interest. The use of CT to re-enter a HPHT subsea well has proven its versatility in comparison to alternatives such as costly relief well or HP interface equipment to allow jack up operations that could facilitate a snubbing unit.
Is Well Clean Enough? A Fast Approach to Estimate Hole Cleaning for Directional Drilling
Authors: Zhang Feifei , Miska Stefan , Yu Mengjiao , Ozbayoglu Evren , Takach Nicholas , Osgouei Reza Ettehadi 
Published: March 2015

Abstract
In spite of many recent technology improvements in drilling, hole cleaning remains a significant challenge, especially in deviated and horizontal wells. Inadequate hole cleaning can lead to a series of problems such as stuck pipe, fractured formation, high drag and torque, premature bit wear, decreased ROP, logging, and casing and cementing difficulties.
Hole cleaning is a complex issue that is affected by many drilling parameters. The major approaches of hole cleaning evaluations include experimental correlations and mechanistic models. But these techniques frequently require complex computations or numerical iterations to get the solutions.
In this paper, a set of charts is developed to allow the drilling engineer to quickly estimate the cuttings volumetric concentration in the wellbore. From previous cuttings transport studies, we know that well inclination angle, drilling fluid velocity, fluid rheology, fluid density and drill pipe rotation have the most important effects on hole cleaning. These parameters are divided into several ranges based on their sensitivity to cuttings concentration in the wellbore. The charts are obtained by running a hole cleaning simulator, which is based on a large number of experimental and modeling studies of cuttings transport.
The results of the charts are verified by experimental data. The difference between the charts' prediction results and experimental data are within 20%. Instead of solving complex equations in cuttings transport models, drilling engineers are able to quickly estimate the cuttings volumetric concentration by looking up the charts and conducting very simple calculations. This paper is also helpful in guiding the driller to quickly choose proper operational parameters during drilling operations.
Surpassing the Challenges of CT Interventions in a Trilateral Extended Reach Well in the Arabian Gulf
Authors: Issa Faiz , Zorbalas Konstantinos , Pardo Rolando , Zavala Eduardo , Chrysovulou Christina 
Published: March 2015

Abstract
The oil industry in the UAE is striving to advance both onshore and offshore operations to address technological challenges that will allow for increased oil production in a safe and efficient manner. Offshore, artificial islands are being built for the purpose of accommodating up to 300 wellheads on a single island, with the wells themselves comprising multiple, extended-reach horizontal laterals. These ground breaking projects present new and exciting challenges for coiled tubing (CT) interventions, which require extensive planning and the use of innovative technologies.
Specific challenges were identified during the design phase of intervening on a trilateral, extended reach well and applying several technologies enabled us to overcome these challenges to allow successful execution of a stimulation treatment on the well. Techniques used included accessibility modelling and CT string selection to achieve maximum reach.
The methodology used and the testing conducted were designed to ensure that the multicomponent CT bottomhole assembly (BHA) allowed for selective engagement of each lateral and subsequent horizontal accessibility of each extended-reach lateral. Operations were performed in the context of the completion restrictions, diameter of the openhole and cased-hole laterals, and the requirement to pump large volume acid treatments. Each of these factors added a layer of complexity to the final CT BHA selection and setup, which had to operate within a limited range of activation pressures and rates.
Finally, the lessons learned during the execution phase have been captured and recommendations formulated for moving forward with CT intervention in similar types of multilateral and extended reach wells. These lessons contribute to subsequent studies of maximum reservoir contact wells and form the basis of future development and intervention plans for the offshore and islands projects in the UAE.
Successful Offshore Coiled tubing Well Intervention in Mega-Reach Wells in the Russian Caspian: A 4-Well Case Study
Authors: Burdin K. , Mazitov R. , Bravkov P. , Lobov M. , Kichigin A. , Stepanov V. , Eliseev D. , Zemchihin A. , Byakov A. 
Published: March 2015

Abstract
Korchagin oilfield is located in the northern part of the Caspian Sea. Drilled wells are mega-reach (MD/TVD ratio greater than 3.0) with measured total depth (MD) up to 23,622 ft [7,200 m] and vertical depth of only 5,118 ft [1,560 m]. This presented a great challenge for coiled tubing (CT) well intervention even with the help of state-of-the-art hydraulic tractors. Limited working area, weight restrictions, challenging well geometry, completion features and lack of experience in offshore CT operations in the North Caspian Sea, required complex pre-job activities to optimize job design, select proper downhole tools and prepare a robust layout plan. This paper will illustrate the project preparation challenges, on-the-job troubleshooting and workflow, supported by the well case studies and results from the first CT operation in Northern Caspian Offshore. Lessons learned from the project, where all defined objectives were achieved with zero HSE (health, safety and environment) incidents, were also captured to assist in future campaigns with similar operational environment.
Improving Well-Work Efficiency and Mitigating Risk Exposure by Utilizing Digital Slickline in the Kuparuk River Unit, North Slope, Alaska
Authors: Wiese T. , Yoakum V. , O'Dell B. , Loov R. , Milazzo B. , Nemec J. 
Published: March 2015

Abstract
With approximately 1,200 wells and 47 developed drill sites in the Kuparuk River unit (KRU), North Slope, Alaska, a variety of well intervention services are required to keep wells in safe operating condition. Historically, conventional slickline and electric line services have performed a large portion of the non-rig diagnostics and repairs. With slickline operations generally limited to mechanical interventions and electric line required for depth-critical logging operations, both services are commonly required to complete a given well-work program. Because the intervention units are a shared resource, and the well-work schedule is priority based, there are often delays between slickline operations and the electric line diagnostics that follow.
Digital slickline services are being used in the KRU to improve overall well-work efficiency by completing intervention programs without the need for separate slickline and electric line services. Digital slickline services are being used to mechanically prepare wells for diagnostics, perform logging operations that would normally require electric line, and ready wells for repair without the need of additional service units. The enhancements linked to incorporating real-time surface readout data while performing mechanical interventions has reduced uncertainty and provided information for effective workover decisions. Using digital slickline technology has also mitigated risk exposure, as fewer crew hours are spent traveling and handling surface equipment. Examples of intervention work that have been completed with digital slickline services in the KRU include setting retrievable tubing patches, well integrity diagnostics and conventional slickline operations. The operations in the KRU have provided lessons learned and an understanding of the challenges associated with the technology.
Fishing Coiled Tubing With Internal Weld Seams and Failed BPVs in a Live Well Environment Using Hydraulic Workover (HWO)
Authors: McDaniel Ralph 
Published: March 2015

Abstract
This paper examines techniques necessary to fish coiled tubing (CT) with internal weld seams in a live well environment without back pressure valves (BPVs) using a hydraulic workover unit (HWO). The challenges of placing barriers in internal seamed CT verses using the slip and shear method is addressed.
The discussed onshore operation was completed August 2013 in North America. Using the techniques described, a 14,000-ft (4267 m) 2-in. (50.8-mm) CT fish was successfully removed from a well with an average surface pressure of 5,500 psi. This was achieved by first opening the blind rams, snubbing in, and dressing off the CT fish. Next, the CT fish was latched with an overshot and a pull test was performed, pressure was equalized, and the slip and pipe rams were opened. Following, the CT fish was picked up and moved to a desired location in the blowout preventer (BOP) stack (approximately 51 ft 4 in.). The slip rams were then closed and a weight check was performed. The pipe rams and inverted rams were then closed. The CT fish was shear/cut, the pipe was picked up and the blind rams were closed. This was concluded by laying down the fish and the process was repeated 276 times with an average cut of 50 ft. The HWO fishing procedures consisted of 541 hours without any health, safety, or environment (HSE) incidents, accidents, injuries, or job failures.
Coiled Tubing Completes Unique High-Pressure Well Abandonments in Remote Alaska Field
Authors: Webb Brendon , Cahill Peter , Broady Chad , Williams Paul , Greene Tim , Penrose Bill 
Published: March 2015

Abstract
Coiled tubing (CT) has been used in Alaska for over 20 yr as a low-cost alternative to a workover rig to complete a variety of well interventions in Arctic conditions in an effort to increase oil production. The majority of these operations are performed on wells that have a maximum anticipated surface pressure (MASP) that does not exceed 5,000 psi and are considered low-pressure wells. The working pressure of the lowest-rated component in the well control stack, including the operator's wellhead, is typically 5,000 psi. Therefore, CT interventions in Alaska on wells where the MASP exceeds 5,000 psi must be well planned far in advance of the job date to ensure that a thorough review of the equipment requirements, job design, and other aspects of the job are completed so that the operation can be executed safely.
Given current Alaska Oil & Gas Conservation Commission (AOGCC) regulations, an operator decided to re-enter five wells in the remote Point Thomson field area that contain hydrocarbons such as diesel or “arctic pack” (gelled diesel) in the wellbore to remove the hydrocarbon fluids and plug and abandon (P&A) the wells. There were several key challenges associated with this operation; these included the well's high MASP (7,900 psi), low ambient temperatures (−50°F), performing CT milling operations in large casing (9 5/8 in.), and cement placement through CT in zones with very low bottomhole temperature (29°F). The low-temperature cement system used was designed so that volumes of cement in excess of 200 bbl could be placed in the well through CT. In addition, a pressure and fluid management system for controlling pressure and removing solids and gas from the working fluids was used to manage high well pressures and reduce fluid costs. CT operations were completed safely. The application of CT to meet the requirements of these unique well abandonments allowed the operator to complete the P&A of all five wells.
Degradable Alternative to Risky Mill-Out Operations in Plug and Perf
Authors: Aviles I. , Dardis M , Jacob G. 
Published: March 2015

Abstract
With hundreds of thousands of well stages completed in 2014, the “plug and perf” technique is the number one stimulation method used in unconventional reservoirs. This technique relies on the use of metal or composite plugs to isolate sections of the reservoir to be hydraulically fractured. After all the stimulation operations are complete, plug removal is required to enable production to begin. A motor and a mill assembly must be conveyed into the well, usually by coiled tubing, to eliminate the plugs used during the stimulation.
In wells with low reservoir pressure or long horizontal sections, plug mill-out can prove very challenging. Returns do not easily reach the surface, and fluid is often lost into the recently created fractures. Even with the use of nitrogen to assist with cleaning operations, debris from the plugs removed can accumulate in the horizontal section, posing a risk of getting the coiled tubing stuck during the operation. In addition to this significant risk, the economic impact of such operations increases under these conditions because operations tend to be lengthier and more complex than traditional plug mill-outs.
A new plug-and-perf technology has been developed to address the problems mentioned above. This method relies on degradable technology to eliminate the need to remove plugs. During fracturing, this new technology follows the same process as traditional plug and perf, but no plug removal is required after stimulation. Seat assemblies serve the function of plugs, and after all stages are completed, these seats remove themselves by simple contact with flowback water. Immediate production is possible, and the well is left with a fullbore ID. No restrictions are left in the well that would prove problematic during any future workover intervention. This restriction-free environment also allows for the full production potential of the well to be achieved, as no chokes to production are left in the well.
The operational sequence of the new fully degradable isolation assembly for plug and perforate technique have shown a seamsless integration into current best practices for Eagleford operatiors, where the technology has been applied.
Pt Nanoparticles via Oil-in-Water Microemulsions Stabilized by a Technical Grade Surfactant: An Economical and Ecological Approach
Authors: König Ramona Yvette Genevieve , Stubenrauch Cosima 
Published: March 2015

Abstract
This study deals with the synthesis of Pt nanoparticles via oil-in-water microemulsions formulated with the technical grade surfactant BIODAC® 510. For this purpose we studied the influence of the Platinum precursor dimethyl(cyclooctadiene)platinum (Pt(COD)Me2) on the phase behavior of the base microemulsion. It was found that the addition of Pt(COD)Me2 has nearly no effect on the phase boundaries even at relatively high concentrations. Small angle X-ray scattering data confirmed that the addition of the metal organyl also does not influence the size of the microemulsion droplets. According to transmission electron microscopy (TEM) the size of the resulting platinum nanoparticles is independent on the amount of Pt(COD)Me2 in the templating microemulsion. This result was rather surprising since it indicates that a greater amount of precursor in the o/w-microemulsion leads to more rather than to larger nanoparticles.