bluuebunny/crossref_metadata_2025 huggingface dataset:
Coiled Tubing Deployed ESP Retrievable Completion Application in Algeria – A Success Story
Authors: Eren T. , Ferraro E. , Franco G. , Allal A. , Ortega Alfonzo R. , Norton M. , Craig S.
Published: March 2024

It is well known in the oil industry that on jointed tubing conveyed Electric Submersible Pump (ESP) completions there is always the likelihood of well re-completion either after the useful life or a premature failure of the ESP is reached. The re-completion becomes a significant downside versus conventional completion systems (naturally flowing wells). Most of these ESP replacement / re-interventions are usually associated with the need of a workover rig or snubbing unit and the related cost, logistics scheduling and operating time bound to it. In an attempt to evaluate a different cost-efficient alternative to address this ESP re-intervention work a Coiled Tubing Deployed ESP System / Project was initiated in Algeria to deploy the ESP systems via fit-for-purpose Coiled Tubing Deployed Retrievable ESP (CTDRESP) cable after the installation of the permanent downhole completion, with the intention to reduce the overall intervention cost, reduce the production deferment by: a) eliminating the need of having a rig on location, which have availability challenges re rig schedule) b) reducing the time required to connect the well back to production but not requiring the removal of flow lines and pipeline on the surrounding areas of the well), in a brown oil field located in an area where artificial lift systems are widely required for sustained production.

This paper documents the first fit-for-purpose Coiled Tubing Deployed Retrievable ESP completion application in North Africa region, where +/-59m (194 ft) of BHA (Tail Pipe, Seal Stack and ESP assemblies) were deployed and run into the well using 1.5in Tubing Deployed Retrievable ESP (CTDRESP) system with a specialized sub-surface safety valve installed at landing nipple at +/- 64m (209ft) successfully. Oil production was successfully resumed after ESP installation with 99% oil ratio at surface, proving this practical and cost-efficient type of ESP deployment application in a well not capable to flow naturally. With the implementation of this technology the operating company in this region has enabled an alternative method to service its ESP wells, saved operating related costs, and reduced production deferral with a safe and cost-efficient alternative that also considers reduced personnel workforce and rigless approach (rather than full scale workover rig unit).

This paper will review the project concepts, job planning, utilization of a sleeve style safety valve in the completion, well control and contingency considerations prior to reviewing the successful installation of the completion. Sharing the lessons learned will enable optimized future utilization of this technology.
Advanced Dual Electro-Optical Telemetry System Enhances Reliability in Coiled Tubing Electrical Plug Setting and Retrieval Operations
Authors: Afsal A. M. , Stephens A. Abouganem , Villagrana L. C. , Delaune J. , Fajardo S. Rondon , Tapia W. R. , Ryan R. , Langaker H. A. , Bode T. H.
Published: March 2024

This study introduces an innovative solution that utilizes a hybrid electro-optical cable within a coiled tubing (CT) pipe to enable the concurrent operation of fiber-optic and electrical telemetry systems. The goal is to facilitate the deployment of electrical tools below the smart CT bottomhole assembly (BHA), with both downhole tool and smart CT BHA having real-time telemetry communication to surface.

The new CT conveyance system and methodology involve a dedicated power line on the hybrid cable that supplies uninterrupted telemetry for the downhole tools while other downhole sensors use fiber-optic telemetry and draw power from a downhole battery module. This integrated system allows the application, for example and not limited to, of precise correlation of plugs that are used with electrical setting tools and eliminates the need for flagging the CT pipe, resolving depth offset uncertainties. Other applications include downhole cameras or linear actuators below the smart CT, providing an array of tooling that traditionally is not conveyed with correlation capability, tension and compression monitoring, or pressure and temperature measurements.

The study underscores a successful trial conducted after extensive preparations and yard tests. Subsequently, 10 isolation plug setting and retrievals were performed using this method. The downhole data allowed for improved latching, reduction of no-latch runs, observation of equalization pressures downhole, and the tension and compression data also helped to identify when the plugs are in a neutral weight for safe retrieval after the elastomer retracts and pressure is fully equalized.

The acquired downhole data significantly contributed to the well operator's ability to make informed decisions, enhancing operational safety and reliability. This technology led to substantial time and cost savings, reducing rig time by up to 30 hours per well in an offshore environment. Additionally, it lowered operational and safety risks by eliminating the need to switch conveyance methods. The study underscores the innovative nature of combining dual electrical and optical telemetry systems for maximum downhole data retrieval and its potential applications in various CT downhole operations involving electrically operated tools or diagnostic instruments.
Reassessing Barrier Placement in Through-Tubing Plug & Abandonment
Authors: Correa G. , Cornelio J. , Diaz J. , Dias C. , Freitas R. , Kenupp R. , Malouf L.
Published: March 2024

As the offshore oil and gas industry matures, the application of through-tubing operations has increased. To reduce operational risks and improve efficiency, a plugging and abandonment (P&A) strategy has become more appealing; however, it brings challenges that are inherent to the techniques normally employed for the A-annulus cement job.

The conventional tubing puncher gun used to establish communication between the inside of the tubing with the A-annulus is known for potential cement displacement issues that can lead to channeling of the cement sheath or slurry contamination. The potential issues are related to the nature of the existing devices, which demands that the entire gun carrier is in direct contact with the pipe wall, creating the optimum standoff that allows the perforating charge, and that the charges are all aligned in a single phase to penetrate the tubing without damaging the casing behind it.

To mitigate the potential displacement issues, a new puncher system with a phased distribution of the perforating charges was developed. This new technology enables an even distribution of cement slurry across the entire cross section of the annulus and creates a higher flow area, favoring a much better cement sheath quality. This improved cement quality was verified by running a cement evaluation log with an acoustic map of cement distribution behind tubing. This paper describes the development of this novel puncher system.
Deciphering the Well Complexity Index for Coiled Tubing Interventions, a Unique Factor for Better Engineering and Operational Planning
Authors: Ottolina Renny , Ambrosi Giuseppe
Published: March 2024

Coiled Tubing (CT) operations complexity has increased exponentially in extended reach developments in the Middle East, and North and South America due to longer horizontals, however rig horsepower (HP) limitations compromise navigation control in the horizontal sections, leading to high tortuosity wells, which hinders CT accessibility. The CT Complexity Index (CTCI) aims to identify critical wells that may require special Extended Reach Tools (ERT), higher Friction Reducer (FR) concentrations, or multiple runs.

Computer Assisted Engineering (CAE) software is limited to 500 lines for directional input; hence, this study considers an optimized CT design methodology based on well construction factors to continue using surveys with readings every ∼100 ft. More than 20 well interventions have been analyzed to determine what factors affect the outcome, considering factors such as:

Deviation Survey Tortuosity Maximum Dogleg Severity (DLS) Horizontal length 2D or 3D wells

Based on statistics, the analyzed results contributed towards developing a CTCI to anticipate possible issues during operations, such as multiple CT runs and the percentage of success in reaching Target Depth (TD).

After analyzing data and job results, it was determined that, even though the CAE software shows that TD can be reached, it is possible that multiple runs would be required, or, on some occasions, it would not be possible to reach TD. This is a consequence of multiple factors related to drilling, completion, and CT operations, such as insufficient FR concentration, ERT failure, well tortuosity in the horizontal section, and the fact that the CAE software predicts buckling and CT-completion contact points based on mathematical models which are limited to 500 input lines on the directional survey tab. All of these lead to unaccounted friction forces, where these models can fail to identify some completion contact points affecting the predicted CT reach.

Determining a single factor such as CTCI allows the determination ahead of time of either a modified Friction Coefficient (FC) or Paslay Helical Buckling Coefficient (PHBC) to include FR and ERT selection, multiple CT run requirement, or if there is a risk of CT not reaching TD, which in turn can improve job planning.

The CTCI can be associated with an adjusted FC or PHBC, allowing more reliable CAE simulation results.

The calculation of the CTCI during the planning stage will help to address properly:

Technical challenges and solutions to reach TD Forecast operations and coordinate logistic requirements Additional resources (water, additives, BHA)

This increases efficiencies and minimizes Non-Productive Time (NPT) related to waiting for resources.
Slim Hole Thru-Tubing Casing Exit on Coiled Tubing: A Case Study Discussing the State-Of-The-Art in Casing Exits for A Coiled Tubing Drilling Project in Israel
Authors: Miszewski A. , Miszewski A. , Gemignani M. , Johnson T. , Diller C. , David A. Ben
Published: March 2024

The type of operation described in this paper has often been rejected by service companies because it is perceived to be unfeasible. This case study aims to highlight an example where detailed engineering mitigated the risks associated with the project and resulted in the execution of a previously unfeasible sidetrack, requested by an Israeli oil company which wanted to access a new and untapped section of a reservoir. This operation required passing through a 3.877" ID production tubing, featuring a landing nipple with a 3.562" ID, and drilling a new sidetrack from an existing deviated wellbore. Coiled Tubing Drilling (CTD) was the only option available for this project, given the slim-hole nature of this thru-tubing re-entry application. In addition, underbalanced drilling was required to boost production from a fractured formation. CTD is the only technique which can drill in true underbalanced conditions because it has continuous pipe and a closed-loop circulation system. Consequently, the reservoir never needs to be put in an over-balanced regime. The successful outcome of the operation validated the technology and the procedures being used and demonstrated how coiled tubing is the only option available for casing exit and milling operations on super-slim (below API recommended drift diameters) thru-tubing applications. A 3-1/2" OD whipstock attached to the bottom of a 3-1/8" OD Directional CTD Bottom Hole Assembly (BHA) had to pass through the production liner (3.958" ID) and the restriction given by the completion nipple (3.562" ID) to perform the casing exit and access the reservoir. The very small clearance posed a possible risk of getting stuck in hole. To deliver the project, a standard coiled tubing unit was converted to run e-coil. A camera run was carried out on the e-coil to inspect the tubing string and then a specially designed drift was run in hole to confirm the ability to pass the restriction, before running in hole with costly equipment. With the drift able to pass through the restriction, the casing exit operation was able to follow. The whipstock was set at the correct depth and oriented in the right direction using the real-time data from the CTD BHA. The depth of the whipstock was correlated using Gamma Ray (GR) and Casing Collar Locator (CCL) measurements. The orientation was measured using the gravity toolface and then the CTD Orienter was used to turn the toolface of the whipstock to the right setting orientation. 3.54" string mills and window mills were attached to the bottom of the CTD BHA to mill and clean out the window. The CTD BHA was run on e-coil and provided real-time feedback on the downhole conditions to the directional driller and the casing exit specialist.
First Three Thru-Tubing Sand Control Remedial Works Using Ceramic Screen in ACG Field: Design, Execution, Evaluation and Strategy for Next Jobs
Authors: Jafarov Emin , Susilo Yoliandri , Agayev Farid , Mikayilova Aydan , Gafarov Nadir , Guliyev Imran , Allahverdiyev Matin , Guliyev Ilkin , Sadigov Teymur , Hasanov Zahid , Pashayev Ahad , Eyyubbayli Turan
Published: March 2024

The Azeri-Chirag-Gunashli (ACG) is a giant field located in the Caspian Sea, Azerbaijan. The major reservoir zones are comprised of poorly sorted and weakly consolidated multi-layer sandstone formations. While Open-hole Gravel Pack (OHGP) completions have become the standard design for production wells, there are also several Cased & Perforated (C&P) wells from early field development along with some opportunistic Up-hole Re-completion (UHRC) C&P wells that were converted from OHGP. As the field matures with increasing depletion, water cut and gas/oil ratio (GOR), OHGP wells with vulnerability in the pack (incomplete pack) and C&P wells start to produce sand. Consequently, those wells are choked back resulting in sand-induced production deferral.

Several sand control remedial work technologies were evaluated for the field and ceramic screen technology was chosen due to higher erosion resistance to cope with high flow rates and GOR in ACG wells. Three thru-tubing sand control remedial works using ceramic screen has been trialed successfully, both inside C&P well and high angle OHGP wells with unpacked section at the toe which previously isolated by bridge plug. The ceramic screen bottom-hole assembly (BHA) was deployed using coiled tubing with total BHA string length up to 178m. A snap type connector was used to minimize number of runs into each well, by allowing running string of multiple sections of ceramic screen and blank pipe in one trip.

The ceramic screen installation inside C&P well demonstrated higher post-job skin compared to OHGP application, however having ceramic screen in the well allowed to produce with 3x higher drawdown at higher water cut up to ~40% with limited sand production and extend the well life considering typical C&P well failed with much smaller water cut. The ceramic screen installed in OHGP screen across unpacked section shows minimal skin change. In average there was ~2,500 bbls/day immediate incremental oil gain after each sand remediation work. This successful result demonstrates the viability of this remedial works to unlock production potential of producer wells and reduce sand-induced production deferrals in the field.

This paper primarily discusses design, execution, result and learning from the first three thru-tubing sand control remedial work that was done in the ACG field.
Increasing Efficiency in Well Abandonment Utilizing Hydromechanical Slotting Tool
Authors: Munir Waqas , Dahlberg Knut Inge
Published: March 2024

As the number of the wells designated for the abandonment or slot recovery operations increase, multiple challenges are faced during the barrier placement and removal of the casing. Achieving operational efficiency is crucial. Till now, conventional solutions included milling of the casing, throughout history, conventional solutions involved milling processes and the use of charges to establish channels for either barrier placement or cement remediation or reduction of stuck forces, thereby enhancing casing removal efficiency.

This paper will explain the new technology which includes a hydro-mechanical tool that creates the slots into the casing to allows the access behind. This innovative approach aims to significantly improve efficiency during the well abandonment phase. The tool's capability extends to breaking down the barite accumulation behind the casing or facilitating the precise placement of cement for sustained casing pressure solutions or annular cement remediation. The incorporation of this advanced technology marks a paradigm shift in addressing the challenges associated with well abandonment, offering a more streamlined and effective solution.
Safe and Successful Restoration of Wellbore Accessibility by Wellhead Gate Valve Milling
Authors: Almulhem K. F , Mubarak M. , Muhammad A. , Mansour A.
Published: March 2024

Well control has been one of the most important items in oil and gas production engineering. The wellhead plays a vital role in well control as it consists of many valves, including the master valve (MV), crown valve (CV), and wing valve (WV). The MV is the lower valve in the wellhead that is directly exposed to well pressure. Therefore, it's very important to ensure the valves holding in terms of functions tests and greasing. Passing the MV that is stuck in a partial closed position is considered a tremendous challenge, not only in well integrity but also for well intervention. The valve cannot be opened to allow for well intervention and cannot be totally closed to withstand well pressure to act as surface barrier in line with API standards. This challenge presents an opportunity to capitalize on milling the MV utilizing a gate valve drilling unit (GVDU). This paper presents a solution that addresses stuck valves across wellhead trees.

The conventional practice is to utilize either a workover (WO) rig or coiled tubing (CT) to mill the MV and secure the well to change a defective MV. However, it is more challenging when the well does not meet the minimum barrier requirements and the operation is costly. A new generation of GVDU has been deployed to especially mill such a stuck/defective MV, with no need to utilize (CT) unit nor a wireline (WL) unit -.

A 15K pneumatic GVDU has successfully been demonstrated and proven its ability to mill the gate valves to safely restore and gain wellbore accessibility. During the planning phase of this operation, several elements were considered to ensure safe and efficient execution, including conducting a series of peer reviews, comprehensive risk assessments along with well integrity and well intervention peer review team members. During the operation, several challenges have arisen such as rising pressure because of the compressed gas while run in hole (RIH), which was tackled by a modification of the gas bleed-off needle. Moreover, killing the well was challenging due to the fact the MV was in stuck position. Thus, a circulation path was added through pumping water,. Nonetheless, there were three main advantages through utilization of a GVDU; one of which was the easy and light rig-up. Second was safe and quick operation, which was completed in only 2.5 hours. Third was the cost optimization unless idea is to indicate that no cost was involved?

This success of this operation has unlocked the well potential after regaining wellbore accessibility. It also resolved the well integrity/control challenge in a safe, an extraordinary expedited intervention, a cost-effective method, and an environmentally safe and minimal environmental footprint.
First Rigless Intervention in Bonga Deepwater
Authors: Okosun Augustine , Ugbor Ifeanyi , Ezeokafor Tobechukwu
Published: March 2024

In the Bonga Deepwater project, while exploring subsea well intervention and stimulation campaign opportunity, the subsea Rigless intervention strategy, which has been in the SNEPCo team's technology maturation funnel for some years, re-surfaced. In the first quarter of 2017, the Shell Nigeria Exploration and Production Company (SNEPCo) Deepwater team led the industry to deploy the first ever riser-less technology for well intervention operations in Nigeria. The main objective was to prove the rigless intervention concept and capability in the Bonga Deepwater project. The team focused on improving production enhancement and sustaining well integrity on the Bonga Main Project by minimizing well-intervention cost without compromising process safety, achieving incident free operation, and delivered the project at 50% less than what this scope of work would have cost using a Mobile Offshore Drilling Unit (MODU). Additionally, the acid stimulations added 9,200 barrels of crude oil per day to the company's production.

As with every new project, several challenges were encountered, and new ideas were developed. The team acquired a lot of learning from the planning phase, vessel mobilization to execution. These learnings have been integrated into the team's standard operating procedure and shared with other stakeholders. Additionally, the knowledge and learnings gained from this project have been harnessed in collaboration with the service provider and Original Equipment manufacturer (OEM) to modify and upgrade an existing in-house well intervention well control package (EDP/LRP) for riserless intervention access in the Bonga Deepwater project.
Automation – Continuing to Improve Service Delivery of Coiled Tubing Operations
Authors: Craig S. , Pinero L. , Terry A. , Lindsey B.
Published: March 2024

Coiled tubing operations become ever more complex to meet the demands within the industry. A worldwide challenge is a smaller group of highly qualified field personnel to meet these expectations and without such can lead to a potential compromised service delivery. To alleviate this our focus is on the increased level of unit automation providing the unit operator with greater monitoring, feedback, technical advice and, if needed, intervention on the unit to prevent failures.

The combined solution is derived from three main areas: automatically update the CT force limits, continuous monitoring of key parameters to provide operational advice, and if required to prevent a potential failure, automatically intervene with control of the appropriate injector functions. Core to the system has been taking a highly complex CT flow and force model and transferring it to run automatically with only minimal intervention from field operators or specialists.

The paper will detail the multiple system capabilities and the associated historic service delivery issues that created the need for the automated system. For example, the injector control system utilizes five different limit measurements to auto stop the injector to prevent failure. This includes the ability to auto monitor downhole force measurements during logging operations, which liberates wireline personnel to attend to other tasks during CT deployment and recovery. System enhancements such as the ability to easily recalibrate force modeling by adjusting friction and surface loads will be detailed. The system has further enhanced the ability for field crews to track expected vs actual loads and take preventative action without the need for a field engineer to be present.

The system is being utilized across the service provider's fleet of units. Statistics on reduction of incident rates will be presented.

Many operating companies are fully engaged and supportive of the journey to operational automation/remote monitoring and service delivery improvements. The majority of the features covered above have never been presented in a technical paper. This paper would provide valuable industry insight into the current and future expectations of technology that will aid the operating companies’ goals.
Fit-For-Purpose Heavy-Duty Fishing Equipment Designed to Safely Retrieve a Damaged Wireline Cable from an Active, Sour Gas Well Located Offshore
Authors: Amri M. N , Macaulay R , Aboelnaga S , Abouganem A , Al Dahhan M
Published: March 2024

Wireline operations play a crucial role in the oil and gas industry, facilitating essential tasks like well maintenance, data collection, and intervention. These operations involve deploying substantial downhole tools and large cables into the wellbore, but this endeavor is not without its challenges. Particularly, when a wireline cable breaks downhole, it poses significant risks.

Unplanned wireline breakages result in demanding heavy-duty fishing operations when they occur in challenging offshore environments and unfavorable downhole conditions. In this work, strategic planning and execution were applied in a complex e-line cable recovery in a live, sour gas well without the need for well kill operations. This undertaking necessitated a unique approach to safety and setup, starting with a thorough assessment of the challenging well conditions. A comprehensive fishing plan was then developed to embrace all potential scenarios. The operation involved the use of advanced heavy-duty fishing tools and solutions specifically designed to withstand the well conditions.

The success of this endeavor is evident in the completion of two recovery operations, all resulting in the successful retrieval of the wire. This first achievement enables customers to restore wellbore access and proceed with their planned interventions. One of these operations involved recovering ~ 4000ft of 5/16in Eline cable and upper section of the fish using mechanical wireline and coiled tubing.

While SPE-218323-MS (ICOTA A. Abouganem 2024) provides details about the first recovery, this paper aims to present a more comprehensive overview of the second recovery. Specifically, this recovery involved retrieving a 0.350-in Polymer encapsulated wireline cable using a 5/16-in Heavy Duty braided wireline cable within a 7-in. tubing., representing the first occurrence of such a cable recovery on a global scale. The paper delves into the specific techniques employed and the substantial effort and planning invested in successfully recovering this distinctive cable, recognized for its unique shape characterized by elevated breaking strength and rigidity. The distinct nature of this recovery necessitated the utilization of specialized tools and techniques for both latching and recovery.
An Artificial Intelligence Model to Synthesize Measurements While Drilling Sensors for Coiled Tubing Drilling
Authors: Urdaneta C. , Jeong C. , Zheng A.
Published: March 2024

This paper presents a comprehensive methodology for developing an artificial intelligence (AI) model to synthesize downhole measurements as a digital backup for measurement while drilling (MWD) sensors, ensuring uninterrupted drilling in coiled tubing drilling operations (CTD). The MWD tool plays a pivotal role in CTD, acquiring critical measurements for safe drilling operations. These measurements are critical for decision-making, monitoring, and managing the drilling process. One significant challenge faced during CTD is the occurrence of sensor failures in MWD tools, which hinders the real-time assessment of downhole conditions. Such failures can lead to operational downtime due to the need to trip out the bottomhole assembly (BHA) for sensor replacement. To address this issue, an AI based model using synthesized downhole measurements as backup for MWD tools has been developed for CTD. The proposed AI model leverages custom regression models for each MWD sensor, using various machine learning techniques such as Random Forest, Gradient Boosted Trees, and more to predict sensor values when a sensor fails. The model is continuously updated with new data and uses predefined thresholds and AI-based models to detect sensor failures and assess the uncertainty of predictions. To evaluate the model's effectiveness, various machine learning models are compared using metrics such as mean absolute error (MAE), and r-squared score (R2). The results indicate high accuracy in predicting sensor data, even in the absence of failed sensors, for annulus pressure, pipe pressure, and weight on bit (WOB). This approach could reduce nonproductive time (NPT) and costs associated with sensor failures in CTD operations. It provides a robust framework for using AI to maintain uninterrupted drilling operations by synthesizing sensor data when needed, ensuring the seamless execution of drilling operations.
Through-Tubing Snake Tool Installation Enables Remedial Intervention in a Niger Delta Condensate Gas Well
Authors: Osode P. I , Soro A. O , Olugbade O. R , Alake S. A , Uwakwe R. O , Samaila I. A , Nwadiogbu L. C , Nicoll D. A , Ugboaja C. C , Iyamah A. I , Shehu A. H , Aworanti O. A
Published: March 2024

Single string-single interval completion design has been traditionally adopted for high-rate Niger Delta condensate gas wells because of ease of the large-size tubing installation and integrity of the bottom production packer assembly. Following the incident of leaking packer and the loss of safety barrier above the bottom completion interval, wells were re-entered with workover rig for integrity repair. A pragmatic approach taken was to install a new production string and packer after tubing cut and retrieval with the old packer stump assembly remaining in hole.

The resulting gap between the top and bottom completion configuration has hampered through-tubing tool conveyance into the sump during subsequent rigless remedial intervention. To overcome this challenge, a tubing conduit (snake tool) with maximum possible internal diameter was configured to be stabbed into the lower completion tubing stump and hung-off at the landing nipple profile within the top completion. The snake tool was made of conformable material for the corrosion risk environment due to presence of corrosive CO2 gas in the produced condensate gas and existing downhole completion string made of 13Cr tubing plus accessories. Reliability and robustness of the tool was evaluated based on the expected well operating envelope including analysis of the mechanical strength, stresses, and erosional risks at expected downhole conditions.

The 3.78-inch snake tool was able to restore seamless wellbore access to the lower tubing break, approximately 25ft below. This tool will facilitate planned through-tubing remedial activities such as perforations, mechanical water-shut off, zonal isolation and chemical stimulation interventions. The wireline snake tool deployment which took only 6 days has proven to be highly cost efficient given the elimination of a rig workover.

This paper enumerates the investigation and preparation of the snake tool application from the design stage to the field execution in the 10,700-foot-deep gas well. It is expected that this low-cost repair technique will be extended to many other similar gas wells in the region.
Advancing Pipe Integrity Assessment in Multi-Barrier Well Completions: Full-Scale Test with Seven Pipes
Authors: Dai Junwen , Sheng Huiwen , Fouda Ahmed E. , Saada Mahmoud , Ostermann Neil , Roy Sushovon
Published: March 2024

Well completions typically involve a series of multiple barriers that serve as the structural foundation for both production activities and safeguarding aquifers against contaminants. Monitoring the integrity of these completions holds immense importance for the reliability of oil and gas production as well as environmental preservation. In instances where wells experience diverse pressure gradients, geological complexities, or corrosive settings, the number of barriers might extend beyond five, seeking heightened protection. This intensifies the complexity of assessing pipe integrity within such wells. Even if the tubing could be pulled out, the presence of several permanent barriers exacerbates the challenge for existing non-destructive testing methodologies to accurately evaluate metal loss within each barrier. In this paper, we demonstrate how a new technology based on a multi-frequency multi-spacing electromagnetic tool is used to estimate the individual wall thicknesses of up to seven barriers. A full-scale fixture comprising seven pipes with outer diameters ranging from 2-7/8″ to 24″ was built. The pipes have non-uniform machined defects to mimic realistic metal loss profiles akin to ones caused by corrosion. The tool's efficacy within well scenarios featuring seven pipes is showcased through the utilization of both the yard test and real field data. These tests substantiate the tool's precision in accurately determining the extent and position of corrosion within each individual barrier up to seven simultaneous pipes.
How a New On-Command Downhole Control System is Breaking the Efficiency and Sustainability Paradigm in Multilateral Stimulations
Authors: Ramondenc Pierre , Molero Nestor , Hofacker Mark
Published: March 2024

Over the past two decades, coiled tubing (CT) has been the preferred intervention method in multilateral wells, given its ability for deeper reach, smaller displacement volumes, more controlled placement, and flexibility on the scope of work. Nonetheless, as the lateral mapping and entry processes have relied on hydraulically actuated downhole tools, interventions tend to be lengthy and fluid consuming, requiring more than 400 bbl of water per lateral just for mapping purposes.

Stimulation treatments in multilateral wells are usually preceded by wellbore conditioning on each lateral. The placement of the treating fluids is conducted through a high-pressure jetting module that, when activated permanently, isolates the multilateral entry components of the hydraulically actuated toolstring. Therefore, interventions with cleanout and stimulation scope of work cannot be conducted in a single run, extending the overall intervention time. The recent introduction of an acid-resistant, electrical multilateral entry tool with direction and inclination measurements allows lateral entry on the first attempt. The system also features a downhole on-command, electrically actuated circulation valve (EACV), which redirects fluid to either exit jetting nozzles or to downhole tools, thus avoiding isolation of any toolstring component.

A dual-lateral carbonate water injector well, completed as a 6 1/8-in. open hole, was selected for the first implementation of the acid-resistant, multilateral entry assembly. The CT string was equipped with a hybrid electro-optical cable that provides continuous downhole power and enables dual telemetry (optical and electrical) capabilities for a virtually unlimited operational time. Following cleanout work on the main lateral (L-0), entry into the second lateral (L-1) was completed on the first attempt. In both cases, the wellbore conditioning stage was conducted by circulating fluids through the jetting nozzles of the EACV. Before the matrix stimulation of each lateral, the flow path of the EACV was switched, redirecting the flow through a high-pressure jetting tool. Close to 5,000 bbl of reactive fluids were pumped throughout the stimulation stage with an average pumping rate of 3.5 bbl/min. The entire scope of work was completed in a single CT run, saving more than 48 hours of operating time. The optimized intervention workflow saved more than 1,000 bbl of water and reduced CO2 emissions by nearly 25%.

The experience gained from the first implementation of the acid-resistant, multilateral entry assembly validates the technology as a step-change for enhanced CT multilateral intervention. This technology paves the road for new intervention workflows leveraging optical and electrical CT downhole telemetry with the EACV acting as the key building block to provide full control of the selective actuation of part of the hydraulic bottomhole assembly.
NDR-UNet: Segmentation of Water Bodies in Remote Sensing using Nested Dense Residual U-Net
Authors: Surekha Jonnala , GUPTA NEHA
Published: March 2024

The identification and accurate delineation of water bodies in remote sensing satellite images have significant implications for scientific research and various applications such as natural disaster forecasting, drought and flood detection, and monitoring disappearing water bodies. However, this task poses challenges due to complex spectral variations caused by factors like aquatic vegetation, different colors of lakes/rivers, mud along the sand, and shadows from surrounding plants.To address these challenges and improve water body extraction from high-resolution and moderate high-resolution remote sensing images, we propose a method called D3net (Nested Dense Residual Network). The Adam optimizer is employed to train the satellite images, minimizing the associated losses. The activation function and the number of nodes in each layer are optimized to achieve the best performance.To ensure data integrity and protect the identified water bodies during transmission, we utilize the Elliptic Curve Digital Signature Algorithm as a security component. This algorithm creates a digital signature for the projected area of water bodies, providing data protection.For our study, we used a dataset consisting of 5682 Sentinel-2 satellite images, including 2841 images and their corresponding masks. The masks were generated using the Normalized Water Difference Index (NWDI) for a specific geographic location in Europe. The suggested model achieves a performance IOU (Intersection over Union) of 93.27% and a recall rate of 95.60%. Additionally, the model can be applied to tasks such as edge detection, blurry image recognition, and low-resolution image detection. It exhibits reliability and accuracy in its predictions, although it may require more memory due to the utilization of high-resolution and moderate high-resolution images for segmentation.
Cultivating a Continuous “I Don’t Know”: Four Supervisory Mentoring Practices that Support Online Doctoral Students’ Academic Writing
Authors: Becker Sandra , Jacobsen Michele , Friesen Sharon
Published: March 2024

Academic writing in both face-to-face and online environments is often a challenging experience for many faculty and students and can be fraught with tension and emotion. Thus, the quality of doctoral students’ online academic writing experiences can be a difference maker in successful completion of programs. Building on our earlier work identifying five enabling factors of successful online doctoral supervision, this study explores practices that enable factor five: Cultivating a collaborative online community of support for academic writing. Using a comparative case study approach, we analyzed the data from interviews with five recently completed doctoral graduates to determine the mentoring practices that cultivated for them, effective online doctoral student academic writing relationships. Findings identified four supervisory practices: (a) engaging in regularly scheduled meetings with iterative cycles of mentoring and scaffolding; (b) engaging students in a trusting, supportive community of practice; (c) using coursework and program structures as a springboard for writing; and (d) providing diverse models of academic writing. Central to the effectiveness of these practices was the notion of trust. Most of the doctoral students trusted their supervisor to engage in the four practices to support them. Through the provision of timely and thoughtful feedback and feedforward strategies from their community, doctoral students were able to develop their academic writing as a tool for communication, as a tool for thinking and creating new knowledge, and for developing their academic identities.
A new species of Anthopleura (Cnidaria: Anthozoa: Actiniaria) from the Mexican Pacific
Authors: VASSALLO-AVALOS AURORA , GONZÁLEZ-MUÑOZ RICARDO , MORRONE JUAN JOSÉ , ACUÑA FABIAN HORACIO , DURÁN-FUENTES JEFERSON ALEXIS , STAMPAR SÉRGIO NASCIMENTO , SOLÍS-MARÍN FRANCISCO ALONSO , RIVAS GERARDO
Published: March 2024

Anthopleura is one of the most numerous genera within the Actiniidae family. This genus is particularly characterized by its members having both verrucae on the column and acrorhagi on the margin. In the region of the Baja California Peninsula, in the Mexican Pacific, six species of Anthopleura have been documented, which are relatively well defined by their morphological characteristics and coloration patterns. During recent visits to the intertidal zone of Cerritos, in Baja California Sur, we found individuals of Anthopleura displaying a variety of colorations that do not agree with known species for the region. We collected and examined specimens of four morphotypes of Anthopleura, analyzing them by integrating information about their external and internal anatomy, as well as their cnidome. Additionally, we obtained and analyzed genetic sequences from mitochondrial and nuclear markers through phylogenetic analyses. Our results reveal that the four morphotypes belong to a single, and undescribed species of Anthopleura. We provide a detailed description of the species Anthopleura variata sp. nov., including images of the key taxonomic characteristics defining it. Anthopleura variata sp. nov. is the 49th species in the genus and the seventh species of Anthopleura documented for the Mexican Pacific.
This article is registered in ZooBank under http://zoobank.org:pub:25688E38-5374-42EB-84EA-4728930988B5
Adherence to self-care management for patients with permanent pacemaker and their efficacy in daily living activities
Authors: Elsaka Dina , Abdelkader Hayat , Bodaddy Elsaid , shahin Eman
Published: March 2024

Background: Self-care management is an important part of patient education and can improve long-term pacemaker function and improve follow-up treatment adherence. Self-care is also important for improving the effectiveness of everyday activities, improving outcomes, and reducing unnecessary hospitalizations.
Aims: to explore the correlation between adherence to self-care management for patients with permanent pacemaker and their efficacy in daily living activities.
Method: The methodological approach is a correlational design. A purposive sample of 94 patients with permanent pacemaker that were available within 6 months was used according to inclusion and exclusion criteria from a cardiac outpatient clinic in Al-Nasr Hospital in Port-Said city.
Result: The result of the present study shows that 89.4% of the studied patients had an unsatisfactory level of self-management behavior. While the mean score of daily living activities among patients with permanent pacemaker was 17.9±1.24.
Conclusion: The present study concluded that no statistically significant correlation existed between the total level of self-management behavior and daily living activities among the studied patients.
Pre-existing parasympathetic dominance seems to account for heart rate slowingafter six months of Fingolimod-treatment in patients with multiple sclerosis
Authors: Hilz Max J. , Canavese Francesca , Leal Carmen de Rojas , Lee De-Hyung , Linker Ralf , Wang Ruihao
Published: March 2024

Purpose: Vagomimetic Fingolimod effects cause heart-rate (HR) slowing upon treatment-initiation but wear off with Sphingosine-1-phosphate-receptor downregulation. Yet, prolonged HR-slowing may persist after months of Fingolimod-treatment. We evaluated whether cardiovascular autonomic modulation differs before and six months after Fingolimod-initiation between RRMS-patients with and without initially prolonged HR-slowing upon Fingolimod-initiation.
Methods: In 34 RRMS-patients, we monitored RR-intervals (RRI) and blood-pressure (BP), at rest and upon standing-up before Fingolimod-initiation. Six hours and six months after Fingolimod-initiation, we repeated recordings at rest. At the three time-points, we calculated autonomic parameters, including RRI-standard-deviation (RRI-SD), RRI-total-powers, RMSSD, RRI-high-frequency-[HF]-powers, RRI- and BP-low-frequency-(LF)-powers, and baroreflex sensitivity (BRS). Between and among patients with and without prolonged HR-slowing upon Fingolimod-initiation, we compared all parameters assessed at the three time-points (ANOVA with post-hoc testing; significance: p< 0.05).
Results: Six hours after Fingolimod-initiation, all patients had decreased HRs but increased RRIs, RRI-SDs, RMSSDs, RRI-HF-powers, RRI-total-powers, and BRS; 11 patients had prolonged HR-slowing. Before Fingolimod-initiation, these 11 patients did not decrease parasympathetic RMSSDs and RRI-HF-powers upon standing -up. After six months, all parameters had re-approached pretreatment-values but the 11 patients with prolonged HR-slowing had lower HRs while the other 23 patients had lower parasympathetic RMSSDs and RRI-HF-powers, and BRS than before Fingolimod-initiation.
Conclusion: Our patients with prolonged HR-slowing upon Fingolimod-initiation could not downregulate cardiovagal modulation upon standing-up already before Fingolimod-initiation, and six months after Fingolimod-initiation still had more parasympathetic effect on HR while cardiovagal modulation and BRS were attenuated in the other 23 patients. Pre-existing autonomic dysregulation may cause prolonged HR-slowing upon Fingolimod-initiation.
Multi-view graph learning for deciphering the dominant cell communication assembly of downstream functional events from single-cell RNA-seq data
Authors: Ji Boya , Wang Xiaoqi , Wang Xiang , Xu Liwen , Peng Shaoliang
Published: March 2024

Cell-cell communications (CCCs) from multiple sender cells collaboratively affect downstream functional events in receiver cells, thus influencing cell phenotype and function. How to rank the importance of these CCCs and find the dominant ones in a specific downstream functional event has great significance for deciphering various physiological and pathogenic processes. To date, several computational methods have been developed to focus on the identification of cell types that communicate with enriched ligand-receptor interactions from single-cell RNA-seq (scRNA-seq) data, but to the best of our knowledge, all of them lack the ability to identify the communicating cell type pairs that play a major role in a specific downstream functional event, which we call it "dominant cell communication assembly (DCA)". Here, we proposed scDCA, a multi-view graph learning method for deciphering DCA from scRNA-seq data. scDCA is based on a multi-view CCC network by constructing different cell type combinations at single-cell resolution. Multi-view graph convolution network was further employed to reconstruct the expression pattern of target genes or the functional states of receiver cells. The DCA was subsequently identified by interpreting the model with the attention mechanism. scDCA was verified in a real scRNA-seq cohort of advanced renal cell carcinoma, accurately deciphering the DCA that affect the expression patterns of the critical immune genes and functional states of malignant cells. Furthermore, scDCA also accurately explored the alteration in cell communication under clinical intervention by comparing the DCA for certain cytotoxic factors between patients with and without immunotherapy. scDCA is free available at: https://github.com/pengsl-lab/scDCA.git.