bluuebunny/crossref_metadata_2025 huggingface dataset:
Rock Mechanics Analysis of Observed Borehole Instabilities in an Ekofisk Field Extended-Reach Well
Authors: Diaz Lopez Jairo Alexander , Omdal Edvard , Rutherford James S. , Skadsem Hans Joakim
Published: March 2023

The drilling of extended-reach wells is an increasingly common practice for improving the recovery from mature fields, and for producing distant oil and gas resources using existing infrastructure. From a geomechanical point of view, the drilling and completion of extended-reach wells may become technically very challenging, as these wells often have long sections drilled at high inclinations that can be prone to borehole instability problems such as pack-offs or collapse of the wellbore wall.

The case of an extended-reach well drilled in the Ekofisk field in the North Sea where borehole stability issues were observed and eventually resulted in the loss of the well is presented. A wellbore stability assessment is performed with well-specific stress and formation strength data that explores the possible failures that may have resulted in the loss of the well. In particular, a plane of weakness model is used to model possible shear failure along the bedding of the overburden shale formations. The uncertainty in the rock matrix strength is accounted for, as well as the cohesion, friction factor and orientation of the bedding plane, on the mud window using a Monte Carlo approach. This paper focuses in particular on how the properties of the bedding plane affect the minimum required mud weight, and compare to the actual mud weight used in operation.

The generated mud window acknowledging failure along the weakness planes suggests that this type of failure was a relevant failure mechanism over the 13 1/2-in section of the well, as the mud weight employed was not high enough to avoid it. Accounting for uncertainty and the failure along the weakness planes in extended-reach wells to be drilled in the Ekofisk area may generate safer mud windows that in turn may reduce the occurrence of wellbore instability in the field.
Introducing Automated Advisory and Control Applications to a North Sea Jack-Up, Technology, Human-Centric Challenges and Resulting Performance Improvements at Scale
Authors: Forshaw Matthew , Hovda Sigve , Macpherson John
Published: March 2023

As we begin a new decade, drilling systems automation has left its primary residence of PowerPoint slides and is now seeing wider adoption. In areas, the industry sees positive return-on-investment for automation technology development; both financially, from reduction in well construction cost, and in helping meet increasingly prominent ESG targets through emissions reduction.

This paper describes a long-term case study covering the introduction of multiple automated monitoring, advisory and control systems into an already highly optimized jack-up in the North Sea. These resulted in adding incremental value, delivering a multitude of operations significantly below AFE, as well creating a trend of increasing performance spanning a full field development campaign.

In addition to quantifying resulting operational cost-out, the paper addresses several points related to challenges of adoption: –Necessity for un-biased operational needs to drive technology development. The industry is often drawn to high-end solutions to complex problems when in fact there are low-hanging fruits, such as simple business-process-automation for reporting, which are highly desired by end-users.–The notion that while there is a lot of rigor in technology development processes, there is not enough focus on the critical human element of adoption. Linked to this is the common misconception that automated systems require less training, when in-fact the opposite is true.–End-user resistance on initial introduction of a black-box system for automated directional drilling. Retroactive software development moves to more grey- or white-box systems, with an associated positive response in user acceptance.–Critically of interoperability between operator, OFS and OEM systems. How this will become more important as both closed-loop control systems, and linkages to enterprise level systems, proliferate.

This long-term case study definitively demonstrates that automated systems add value. However, due to the human-component, management-of-change must be carefully considered as we scale adoption.
Continuous or Stacked Cement Bond Logs – Does It Matter?
Authors: Lohne Hans Petter , Arild Øystein
Published: March 2023

As part of the permanent plug & abandonment of a well, the annulus casing cement sheath may be considered a barrier element provided that its integrity can be verified. Operators use a combination of data to evaluate the integrity of the casing cement sheath; cement job parameters and displacement calculations, results from FITs and LOTs, bonding logs and sustained casing pressure being the most common ones. The cement length is a key quantity for qualifying annulus cement as a well barrier element. If using the standard NORSOK D-010 rev 5 as the decision basis and provided a correct positioning, a length of 30 m MD is required when using bonding logs as the means of verification. Since the annulus cement sheath usually is considerably longer that 30 m, 30 meters of good cement can be achieved either by presenting a bond log showing 30 m of continuous good cement or by presenting a bond log that in total has 30 m of good cement.

Operators have different requirements and views when it comes to stacked versus continuous. To better understand the implications in terms of sealing ability of a continuous annulus cements sheath versus a stacked annulus cement sheath we have conducted studies of both quantitative and qualitative nature. For a quantitative comparison we have used Darcy’s law and capillary pressure, for a qualitative comparison we have looked at cracks, shear failure and the effect of zones with a poor bond log.
Full-Scale Solids Control Testing of a Light Density Hollow Glass Beads Drilling Fluid
Authors: Kostov Nikolay , Penny Glenn , White James , Shoykhet Nissan , Zeilinger Sabine , Gupta V. Paul
Published: March 2023

Light density drilling fluids with hollow glass beads (HGB) are growing in applications for drilling depleted formations with minimal losses and increasing rate of penetration. However, there is a lack of studies on how best to utilize typical solids control equipment, as current practices and procedures based on barite weighted muds are inefficient. We report a systematic full-scale test program to study and optimize solids control efficiency with shale shaker, hydrocyclone and centrifuge with such fluids.

A non-aqueous-based hollow glass bead drilling fluid was formulated in the lab and a large batch (>40bbl) was prepared and tested using field scale solids control equipment. The inlet and effluent streams were monitored for density, particle size distribution, retort, rheology, and rheological properties and evaluated to determine the optimal equipment conditions to maximize solids control efficiency while minimizing loss of beads in the discharge stream. Variables included shaker screen sizes, flow rates and deck angles, hydrocyclone flowrates and operating pressures, centrifuge flowrates, differential speeds and other parameters. The amount of glass beads in the fluid was also varied.

The drilling fluid was contaminated with a variety of sized solids which mimic drill solids. Based on the data gathered, effective procedures were developed for monitoring hollow glass beads and drill solids in each stream. Through the systematic test program, conditions could be identified to achieve high solids control efficiency from the shale shaker, the hydrocyclone, and the centrifuge. This was achieved at hollow glass beads concentrations of around 11% and 22% by volume. While some previous field experiences had indicated severe challenges with centrifuge usage with these fluids, effective centrifuge operation could be demonstrated once the proper settings were identified. Overall, the testing results showed that most of the drill solids can be removed using conventional solids control equipment and fluid properties (e.g. rheology, fluid loss, etc.) can be maintained at desired levels without the loss of any significant amount of beads with the discharged solids.

Since the beads are lighter than base oil, their behavior in the solids control equipment is quite different from conventional solids. As such, equipment procedures and conventional settings had to be updated or changed. It was demonstrated that high solids control efficiency can be achieved even at high bead concentrations. This work addresses a barrier in the field application of these fluids and points towards practices that allow optimizing the application by minimizing drilling fluid dilution.
2nd Mode Shape Torsional Vibration - Observation, Identification, Mitigation
Authors: Keshiyev Sahet , Naterstad Tarje , Murray Ross
Published: March 2023

This paper investigates the drill pipe twist-offs that occurred while drilling an S-shaped well in the 12 ¼" section. The presence of the 2nd mode shape of torsional vibration was observed and linked to the failure. Conditions that lead to a 2nd mode shape being triggered and sustained are discussed in addition to recommendations to prevent fatigue failures.

2nd mode shape torsional vibration is a standing wave with two nodes created along the drill string, with the first one being the top drive and 2nd located along the drill string. The drill pipe experiences the highest torque fluctuations in the rotational nodes during torsional vibration.

A high-resolution drilling dynamics recorder was utilized to record a spectrum of torsional vibration frequencies, confirming the presence of the 2nd mode shape of torsional vibration. The multiple degrees of freedom spring-mass model was used to identify the node location, which was later compared to the locations of the actual twist-offs.

The presence of the 2nd mode torsional vibration, its transition from the fundamental mode to the 2nd mode, and the conditions for the transition to happen were observed.

Recommendations were developed on how to recognize the 2nd mode shape with the surface instrumentation, on the drill string design, and preventive inspection.

Knowing the location of the node gives a possibility of selective inspection of the drill pipes once the 2nd mode shape was observed while drilling, minimizing the risk of fatigue failures. Also, the drill string design could be revised by increasing drill pipe strength within the nodes.

The twist-off locations were found to match the calculated location of the node caused by the 2nd mode shape with a high degree of accuracy.
Low Friction Drilling Fluid Additive Technology
Authors: Akaighe Nelson , Zeilinger Sabine , Cutler Joshua , Bhandari Dhaval , Bunquin Jeffrey , Bharadwaj Nidheesh
Published: March 2023

The use of lubricants is commonplace when drilling with water-based drilling fluids. They are less frequently applied when drilling with non-aqueous fluids, as the oil-based drilling fluid is thought to impart a high lubricity.

With increased reach of the wells, lubricants are also applied in non-aqueous fluids (NAF) to reduce torque and drag at high angle, for extended reach and horizontal wells to improve drilling efficiency. However, the performance of these lubricants in NAF at extended periods of elevated temperature at downhole conditions is often inconsistent, thought to be hampered by ineffective metal binding and hydrolytic instability of the lubricant molecule. This requires frequent re-dosing and therefore higher cost to maintain performance.

In order to identify a better-performing lubricant, it was necessary to better understand the fundamentals of lubrication in a drilling fluid. For example, what portion of the well contributes most to torque and drag? What is the frictional regime that dominates the lubricity between a drill pipe and its contact points?

Looking at theoretical analysis and modeling, it was found that the horizontal portion is dominated by the boundary and mixed layer friction regime, which is a combination of surface forces and fluid viscosity. Additionally, understanding of tribology from other industrial applications was employed to better design a molecule that can deliver optimum lubricity in a NAF.

This new understanding led to identifying an optimized lubricant for NAF. A lubricant derived from a plant-based raw material was specifically designed to be chemically and thermally stable, binding strongly to metal surfaces, and providing a tenacious film that reduces metal-to-metal friction factors during drilling, casing run and other completion operations.

The identified lubricant was tested for compatibility with NAF, including effects on rheology, elastomers, and formation damage potential. Coefficients of friction and fluid rheology comparisons and research-related field trials are presented. The results show significant (20%) reduction in the coefficient of friction after treatment, especially after hot-rolling, indicating thermal and oxidative stability of the product.
Problems to Solve to Achieve Cost Efficient CO2 Injection Wells
Authors: Manum Henrik , Borgerud Line Kristin , Stokke Ragnar
Published: March 2023

This paper reviews particular challenges for offshore CO2 injector wells, and how these can be mitigated by improving tools, methods, and best practices. Further, challenges with assessment of leakage risk through existing wellbores is reviewed. Finally, a possible cost reduction path for offshore CO2 injection by simplifications in well design is given.
4D Radar Imaging of Wellbore Geometry While Drilling
Authors: Øy Lars , Bye Inge , Lauritzen Magne , Herbert Mike , Grunwald Kamil , Grunwald Kamil , Rød Anne Mette , Kane Danny
Published: March 2023

Despite advances in Measurement-While-Drilling / Logging-While-Drilling (MWD/LWD) technologies, the oil & gas industry has until recently lacked viable technologies and tools to measure wellbore geometry in large hole sizes (>12-1/4″) while drilling and subsequently the ability to visualize and describe the borehole shape and size in an intuitive way.

A direct mechanical measurement solution such as used on wireline, e.g., multi-finger tools, is not feasible to implement on MWD/LWD tools due to the nature of the drilling operation. Conventional technologies and methods, including acoustic- and density-based measurement methods have been used with reasonable results in smaller hole sizes (≤12-1/4″) when combined with low mud weights. However, many commercially available tools within the industry have low vertical and azimuthal resolution due to sparse sampling or sparse storing in its internal downhole memory of such caliper measurements, resulting in limited use of such data for borehole shape and size purposes. Such conventional technologies and methods have not been, or very seldom used in large hole sizes, primarily due to lack of available technologies and tools, resulting from challenges related to the sensor to wellbore interface standoff distance.

A novel Logging-While-Drilling Caliper tool based on impulse radar technology has been developed to overcome the challenges related to mud weight, sensor to wellbore standoff in oil-based muds and at the same time addressing challenges related to sparse datasets. This tool enables the oil and gas industry to accurately image borehole shape and size with both high vertical and azimuthal resolution, including within large hole sizes where there has not been any viable solution whilst drilling. The high sampling rate together with a large downhole memory (128 GB) allows the industry to evaluate the borehole shape and size as a function of time (timelapse).

An Impulse Radar Caliper tool has been pilot tested in several wells on the Norwegian Continental Shelf (NCS), in borehole sections ranging from 12-1/4″ to 17-1/2″. During the pilot testing, the Impulse Radar Caliper tool acquired wellbore shape and size measurements while drilling, and some intervals while pulling out of hole. Several wellbore features, not previously imaged in such large hole sizes, have been identified and their time-dependent development studied in detail. The results from this pilot campaign are discussed in this paper together with the 3D/4D tunnel-view visualization used to assess the processed caliper measurements.
Autonomous Directional Drilling Simulator Development for the Drillbotics 2021-2022 Virtual Competition
Authors: Fernandez Berrocal Miguel , Shashel Alina , Usama Muhammad , Hossain Md Akber , Baris Gocmen Emre , Tahir Ali , Sui Dan , Florence Fred
Published: March 2023

The work focuses on the drilling control algorithms as well as Artificial Intelligence (AI) technique implementation into an in-house real-time drilling simulator developed by the Drillbotics® Virtual Rig Team from the University of Stavanger, the winner of 2021-2022 Drillbotics Competition.

The designed simulator consists of a topside model capable of calculating block position, surface hookload, surface torque, and bottom hole pressure. To achieve drilling efficiency, a formation-based rate of penetration (ROP) optimization module is running in real-time, where the safe-operational windows are considered to reduce/avoid drilling accidents, like stick-slip, axial vibrations, poor hole cleaning, and low efficiency etc. The obtained optimal WOB and RPM by solving such ROP optimization are used as setpoints and then fed into the rotary steerable system module (RSS module) to steer the bit following a planned path. Such path is designed with multiple Bezier curves that can pass given target coordinates and maintain low dogleg severity (DLS). Furthermore, the high-tech AI methodologies are integrated to the simulator to smartly manage downhole pressure via perceiving and interpreting the data, learning through the trial, training through given policy, and taking optimal actions offered by the AI-agent.

The simulator is demonstrated to be a powerful and user-friendly tool for path design and optimization, real-time path control, and drilling performance optimization. It provides interactive and automatic operations of steering a bit passing multiple given target points and optimizing drilling behaviors to achieve high efficiency and low costs. From the results, the simulated (real-time) trajectory steered by the automatic RSS module integrating with surface drilling/control modules has small deviations from the planned trajectory. In the meanwhile, the simulator can precisely detect formation changes, accurately control the downhole pressure, and automatically optimize the drilling speed.

The progress of the whole simulation can be followed through the web-based graphical user interface (GUI) remotely, where the depth-base data view, time-base data view and 3D graphical wellbore trajectories are visualized. After drilling, data analytics is conducted so that useful information from operational drilling data can be extracted and subsequently evaluated for post well-analysis.
A Water-Base Drilling Fluid for Controlling Deep-Reservoir Extreme Conditions in an Abu Dhabi Gas Shale Play
Authors: Manescu Gabe , Veer Balazs
Published: March 2023

Drilling for hydrocarbons in the extreme reservoir pressure and temperature remains one of the most challenging operation, especially related to drilling fluids. A combination of excellent teamwork and fluids technology proved to be the recipe for successfully drilling in these extreme conditions for TotalEnergies shale-gas play, onshore Abu-Dhabi, United Arab Emirates.

The success on drilling deep (6,200mMD), long lateral displacement (2,000m) wells with an integrated global operator is a balance, dependent on frequent and transparent communication between the team members, of excellence in well planning, extensive laboratory testing, procurement and supply of resources, flawless field execution, and a diligent post-well review with the operator. More commendable is this success was achieved while dealing with operational challenges amplified by the pandemic restrictions on personnel and materials movement.

The design of the environmentally and economically acceptable aqueous fluid met stringent fluid design criteria, wellbore and temperature stability for drilling and data acquisition performance goals. The high-density HT drilling fluid is designed to have the minimum amount of solids by using a Sodium Chloride combined with a Sodium Bromide brine, weighted up with ultra-fine grind barite. Viscosity and fluid-loss are controlled with a unique additive, a dual-function, branched synthetic polymer.

The environmentally acceptable aqueous drilling fluid delivered a barite sag-free operation in these highly deviated wellbores, delivering a balance between a low-equivalent circulating density and excellent hole cleaning, compatibility with the reservoir formation, and long-term stability to enable logging with no formation closure in a deep, high temperature drilling environment. Additional achievements of the fluid were the low HPHT filtration, good lubricity for increased rate of penetration, and reusability on the subsequent wells thus improving the sustainability profile by reducing disposal. Successful coring and extended wire logging the reservoir section was an excellent test for this fluid.

The balance between a brine base, filtrate-loss, and viscosity-increase additive for fluid design, coupled with excellent field engineering provides the long-term thermal stability of a drilling fluid able to tackle drilling a reservoir reaching a depth past 6 kilometers.
Extended Reality and Gamification for Drilling
Authors: Chatar Crispin , Lokesh Rajat , Kamboj Vineet , Saetern Danny
Published: March 2023

The video game industry grew from about 10 billion in 2007 to more than 135 billion in 2018. Many industries including the oil and gas industry have been monitoring new and emerging technologies in this space as the capability evolves. The result of years of research, investigation into latest technologies, and proving the use cases for our industry have been a fit-for-purpose design. Key collaboration enabled the utilization of gamification for training, increased data visualization, improved operations, and the ability to create virtual twin of worksites. These improved capabilities increase safety and efficiency. This paper aims to share lessons learned and key points to consider when utilizing gamification and extended reality (XR) to deliver these solutions. This will be done by discussing several technologies investigated and their application to real cases. Specifically, products in use today as well as many proof-of-concept projects already in production will be highlighted.

Gamification is not about creating video games. Gamification is about adding gaming elements to nongaming environments. Gamification can engage consumers, employees, and partners to inspire, collaborate, share, and interact. Gamification has the potential to address specific industry concerns. The industry can translate technologies previously thought only to be of value to the gaming industry into valuable energy industry applications. Like many other industries now utilizing gaming technology to adapt their own solutions, it is time for the energy sector to realize the potential applications of gamification. The potential upside to gamification is billions of dollars saved, and immeasurable increases in safety and operational efficiency. One example of this will center around training.

This can be achieved with a game engine to create the learning environment and target a specific set of goals. All the tools to create a gamified system can be achieved with the right technology, but strong collaborations with technology leaders in other fields are necessary. Today, with the support of game engine partners, we can push the exercise to any platform be it mobile, desktop computer or virtual reality (VR). The gamification process can greatly enrich two-dimensional and three-dimensional experiences. We can easily use a tablet for three-dimensional learning experiences. A personal computer can be used for the most in-depth training process. Virtual reality can be an option to add muscle memory to the learning process as well. Collaboration is another example of an important function we will showcase. We will show the solution built as a multiuser experience that can bring experts from many domains together in one workspace on their platform of choice. In this example, we will show how these functions can be integrated with already existing software.
Modeling of Axial Rotary Drilling Dynamics as a Step Towards Drilling Automation
Authors: Whitlow Zackary , Mahjoub Mohamed , Auld Sonny
Published: March 2023

Analysis of low frequency axial drilling dynamics from block velocity input to surface weight on bit (SWOB) or differential pressure outputs, shows significant regional variation. This range in dynamics poses a robustness challenge for automated drilling control systems. Many factors influence drilling dynamics such as pipe stiffness, mud properties, tortuosity, friction, bit design, and BHA geometry. A simple analytic model representing axial drilling dynamics is described and compared to a finite element drilling model and to drilling data. The analytic model shows that axial drilling dynamics may be represented by a first-order transfer function with a time constant dependent on axial stiffness and drillabillity.
A Short Summary of Retrofit Multilateral Technology Implementation
Authors: Berge Frode , Fathi Marcus , Rød Anne Mette , Fjelde Tomas
Published: March 2023

On the Norwegian Continental Shelf there are many fields and wells in late life production. There are also many nearby drilling targets with limited volumes to add. This situation requires new mindset in order to optimize tie-ins of new reserves to existing infrastructure. Retrofit multilateral well solutions are regarded as one enabeler in this context since they enable tie-in to existing producers from nearby targets through deep sidetrack operations.

There are many pre-requisites that must be in place for such solutions to be suitable. In addition, the risk of partial success involves loss of an existing producer.

A few such wells have been constructed by the operator in the last couple of years. The requirements and challenges are discussed. The implementations show that it is technically feasible to use conventional multilateral technology in ways that enable installation in producing wells. Improvements to existing solutions are sought in order to facilitate future implementations and to improve robustness of this technology.
Detailed Dynamics Modeling Helps to Assess the Effect of Stabilizer Design on Drill String Vibrations
Authors: Nguyen Khac-Long , Mahjoub Mohamed , Dao Ngoc-Ha , Menand Stéphane
Published: March 2023

Various stabilizer types are used in the industry, such as bladed stabilizers with straight or spiral blades, roller-reamers, and other emergent forms. Their designs are proved, via many in-field measurements, to have a significant impact on vibration levels. Although experimental data is extremely valuable to rank the available design options, testing the different stabilizers can be costly and sometimes risky. In addition, in-field conditions can be difficult to control making the comparisons between stabilizers even more complicated. Assessing the design impact using numerical simulations represents an interesting alternative to provide objective comparisons based on tests in a controlled environment.

When a stabilizer is rotating, the contact forces between its different blades and the wellbore are transient. A static approach like torque and drag or directional models is then insufficient to properly investigate the stabilizer's design characteristics. Therefore, a time-domain dynamics approach is adopted in this work. A detailed modeling of bladed stabilizers including the blade geometry (number of blades, spirality, and blade width) and friction characteristics are introduced in an existing time-domain model. These characteristics are used to compute the contact forces between the wellbore and each individual blade.

This numerical model is applied to quantify the effect of stabilizer design in terms of vibration, from straight blades to highly spiraled blades. First, a parametric study of blade design and wellbore inclination effects on stabilizer vibrations is presented by considering different stabilizers in straight well conditions. Simulations of an actual drill string configuration in an unconventional well is discussed. For vertical, curved, and horizontal sections, the acceleration levels, contact forces, and rotation speeds are investigated. These analyses can constitute guidelines about stabilizer design to minimize vibrations.

The novelty of this work is to introduce the geometry details of the stabilizers in the time-domain dynamics to differentiate designs in terms of likelihood to trigger vibrations.
A Full Laboratory Study on the Physical and Mechanical Properties of a Bismuth Plug
Authors: Hmadeh Lewaa , Elahifar Behzad , Sangesland Sigbjørn , Abrahamsen Andreas Elmer
Published: March 2023

Well plugging and abandonment can be very expensive, time consuming and problematic. This is because it is the least considered process during a well's life cycle. Setting a plug downhole in an efficient and successful manner is governed by several factors, one of which is the type of sealant used. Portland cement, a commonly used sealing material, turned out to be an inadequate barrier material due to its porous and permeable properties, as well as its insufficient long-term sealing integrity.

Bismuth, an alternative sealing material, demonstrated several distinctive characteristics, such as being non-porous, expanding after cooling, and corrosion resistant. In this study, samples of bismuth-tin metal alloys were deployed and allowed to solidify in carbon steel pipes. For comparison, cement plug samples were also prepared under the same conditions; the only prevailing difference was the plug length where that of cement was longer than that of bismuth. Both bismuth and cement samples were subjected to extensive physical, hydraulic, and mechanical push-out tests after curing. Leakage tests using nitrogen gas were also carried out on cement and bismuth samples.

As a safe, economical, and environmentally friendly alternative to cement, bismuth appears to be a promising material. Preliminary results clearly manifest the weakness of cement, where high leakage flow rates and early plug breakdowns were witnessed during the tests carried on it. It was observed that short plugs of bismuth were able to withstand a higher differential pressure compared to longer cement plugs. Another interesting finding was that the bismuth plug kept on building up its strength with time even after solidifying. However, the trend of this "strength-build-up" eventually became minimal with time. Hence, the optimal curing time of the bismuth plug was concluded to be somewhere around 24 hours, unlike that of a cement plug which must be left a minimum of 5 days to cure.

The aim behind the conducted laboratory experiments is to understand the sealing ability of bismuth to a steel pipe and compare its sealing performance to that of cement. This paper represents the first part of an extensive research which at later stages will be tackling the sealing performance of a bismuth plug in the annulus and its interaction with the surrounding formation.
Sealing Ability of Barrier Materials for P&A Application: Investigation of Casing-Barrier Interface
Authors: Moreira Paulo , Khalifeh Mahmoud , Govil Amit
Published: March 2023

The bonding properties between a sealant and steel casing are an important component of well barrier. However, there is no consent about how sealing materials should be tested and qualified, and the understandings around the bonding interface and its mechanisms of failure remains uncertain. A custom setup and a systematic interface analysis procedure was established to test the hydraulic bond sealing properties of different sealants, and to investigate their interface with a L80-Cr13 steel casing. The results of hydraulic bond sealability was correlated with macro and microstructural evidence of the bonding interface to understand the behavior and the performance of class G cement and a geopolymer recipes. The geopolymer recipe showed improved sealing performance in relation to class G cement. The interface analysis suggests that, in addition to the mechanical interlocking mechanism, the geopolymer sealant has a strong bond with the coating of the steel casing, as a secondary adhesion mechanism. Understanding the interface and the mechanisms of failure may be the key to further develop current and future sealants, and to reduce risk of leak and to reduce cost with well intervention in P&A operations.
Applied Well Testing Analysis Considerations in Channel Reservoir Coupled with Dynamic Simulation Model
Authors: Mesdour Rabah , Aboubakar Coulibaly , Almalki Faisal
Published: March 2023

In this paper will describe the integrated workflow between two well-known reservoir engineering approaches PTA and 3D dynamic simulation. This workflow provides significant help to understanding the channel sand reservoir properties, predict possible well interference and provide consistent well's production prediction forecast. The available geological background, seismic data to map the combined channels, and even well by well Petrophysical correlation showed limited capabilities to characterize the channel heterogeneity due to the reservoir continuity change consistently, and for most of the cases the channels features are unpredicted. Giving these limitations, it is necessary to consider using other engineering approach; e.g. Pressure Transient Analysis (PTA), Rate Transient Analysis (RTA), Dynamic Simulation models to narrow down the uncertainties for better understanding of the reservoir quality.

This customized workflow was completed and used in this study to cover all uncertainty parameters during the calibration and prediction of the wells’ performance. It consists to calibrate the geological model using Pressure transient Analysis (PTA) and dynamic simulation model output to enhance the geological model calibration assessment under uncertainty. As results; multiple geological realizations were obtained to cover the possible uncertainty ranges for each parameter. Furthermore, the Well prediction scenarios were performed to evaluate the range of wells’ production prediction forecast under multiple geological realization uncertainty to be more confident in predicting the wells performance under different well constrains and come up with minimum and maximum values. The main challenge associated with the development of channel tight gas sand reservoirs is how to predict the channel attributes and location; e.g. channel width, height, and how to quantify their effect on the well's long-term performance. This workflow will help to quantify the channel properties, interference between wells, and it will guide you on how to select the new well locations for better business planning.
Chelating Chemicals: A Solution to End the Battle with Calcium Sulfate Scale
Authors: Alotaibi Fares , Almubarak Tariq , Alhamad Luai , Al Moajil Abdullah
Published: March 2023

Calcium sulfate inorganic scale deposition is a major challenge that can block tubulars and hinder flow assurance during hydrocarbon production and water injection operations. This scale can form when high sulfate water gets in contact with water containing high content of calcium ions. Dissolving calcium sulfate is problematic due to its low solubility in water and common inorganic acids. Many scale dissolvers exist in the industry; however, the dissolving performance varies significantly when applied to calcium sulfate field samples. The main objective of this study is to evaluate the efficacy of three commercial calcium sulfate dissolvers for possible applications in the field.

Field scale samples were characterized using X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy (XRD/SEM-EDS) to determine its composition. The HPHT aging cell was used to conduct the experiments at a temperature ranging from 77 to 300°F to evaluate the performance of several calcium sulfate dissolvers. The testing involved static dissolution tests to identify the optimal dissolver, scale dissolver to inorganic scale ratio, temperature influence, surface area influence, and the appropriate soaking time. Compatibility and thermal stability tests were also explored to avoid formation damage issues during the removal treatment. Additionally, corrosion tests were performed using low carbon steel metal coupons to assess the dissolver corrosivity at 200 and 300°F.

The scale dissolvers compatibility and thermal stability were presented up to 300°F. The performance of the dissolvers generally increased as the temperature and soaking time increased. The scale dissolver chemistries were tested at high pH conditions and most of the tests exhibited a low corrosion rate of < 0.05 lb/ft2 with no significant pitting at 200°F or 300°F for the duration of the soaking time. One of the tested scale dissolvers failed the corrosion test at 300°F and two dissolvers thermally degraded when exposed to high temperature.

This work is derived from testing actual inorganic scale field samples and shares the difficulty of dissolving such scale samples. The work also systematically compares three commercial scale dissolvers to resolve this issue.
Dynamic Characteristics of Supercritical CO2 Injection in Depleted Carbonate Oil Reservoir for its Sequestration Potential: An Experimental Study
Authors: Zhou Xianmin , Yu Wei , Wu Yu-shu , Al-Abdrabalnabi Ridha , Khan Sarmad Zafar , Kamal Muhammad Shahzad , Elsayed Mahmoud
Published: March 2023

To reduce the amount of CO2 in the atmosphere and mitigate the severe consequences of climate change, capturing, utilizing, and storing CO2 has become very important for human survival. For utilization of CO2 in reservoir engineering practice, CO2-enhanced oil recovery (CO2EOR) as a mature technology has been widely applied in several types of reservoirs such as sandstone, carbonate, and shale gas/oil reservoirs, and the focus of concern is to study oil recovery efficiency and its influencing factors over the past few decades. Recently, more and more researchers are paying great attention to the geological storage of carbon dioxide in depleted oil reservoirs where scCO2 is injected as a displacing agent for secondary and tertiary oil recovery. Unfortunately, there is a lack of laboratory research on scCO2 sequestration in such reservoirs in terms of capacity, two-phase flow (the mixture of scCO2 and residual oil and water), injectivity of scCO2, and permeability loss of rocks. In this study, we evaluate the dynamic characteristics mentioned above subjective is based on laboratory results.

Several experiments, including different injection modes such as horizontal and vertical injections, and their effects on displacing residual oil and water by scCO2 after water flooding has been performed using reservoir carbonate rock, live crude oil, and seawater under reservoir conditions.

As a result of this study, the experimental methodology to obtain the scCO2 storage capacity of the depleted oil reservoir was proposed for the first time, and the calculation of scCO2 storage capacity assumes that the scCO2 dissolves into residual water and oil after scCO2 injection. This study found that the main scCO2 storage mechanism is pore space storage (structural trapping) for depleted oil reservoirs. Based on experimental results, the storage efficiency is found to be closely related to the permeability of rocks. In addition, the scCO2 injectivity and permeability loss of the rock were evaluated for a depleted carbonate reservoir, which was displaced by scCO2 injection at the final stage of the oil recovery process. The experimental results show that the scCO2 injectivity is not strongly affected, although the relative permeability to scCO2 slightly decreased after the scCO2EOR process. The experimental results can be applied directly for the evaluation and strategy of scCO2 storage and can be used to simulate the performance of the injection process of scCO2 storage.
Leveraging the Ability of the Online Health Information Seekers to Find Credible Online Sources
Authors: Hassan Radwa Ibrahim Ali , Sabry Hend Aly
Published: March 2023

Background: The spread of misinformation about different health issues, has become a growing threat nowadays. The process of identifying credible information became a real problem of high urgency. It took a new dimension with the creation of numerous web platforms and the ubiquity of internet coverage.
During the current pandemic of COVID-19, misinformation is not the only challenge, the infodemic is another serious consequence of growing digitization. Infodemic is defined as an excessive amount of information about a problem that is typically unreliable, false, or misleading, spreads rapidly, and makes a solution more difficult to achieve. This causes anxiety and mistrust in health authorities, leading to decrease capacities for decision-making and undermining public responses, especially during disease outbreaks or pandemics.
Aim: The current study was designed to evaluate the effect of implementing a digital intervention training module, to educate participants about choosing credible online health information, according to the quality standards and protocols.
Methods: This is a quasi-experimental study with pre/post-assessment comparisons. It took place between October 2019 and May 2020 with the recruitment of a group of 480 medical students, from the 1st, the 2nd, and the 3rd academic years, at the Faculty of Medicine. They were assigned to an intervention and a control group. The intervention group attended the digital health module, which was conducted online with both its theoretical and practical components. Participants responded to the pre- and post-online questionnaire through google forms, in addition to a post-intervention assessment.
Results: Results showed post-assessment significant improvements in all items related to seeking online health information and the ability to check the credibility of such information, among the intervention group in comparison to the control group with p-value< 0.05.
Conclusion: The infodemic caused by COVID- 19 pandemic, with all its associated psychological pressure and panic due to misinformation, made it crucial to disseminate awareness about credible digital information sources. Targeted digital health interventions regarding online health information quality and credibility, are highly promising, due to the safe outreach and accessibility without any physical contact, especially during the pandemic time.
Serotonin sensing by microglia conditions the proper development of neuronal circuits and of social and adaptive skills
Authors: Roumier Anne , Albertini Giulia , D'Andrea Ivana , Druart Mélanie , Béchade Catherine , Nieves_Riveira Nayadoleni , Etienne Fanny , Magueresse Corentin Le , Rebsam Alexandra , Heck Nicolas , Maroteaux Luc
Published: March 2023

The proper maturation of emotional and sensory circuits requires a fine tuning of serotonin (5-HT) level during early postnatal development. Consistently, dysfunctions of the serotonergic system have been associated with neurodevelopmental psychiatric diseases, including autism spectrum disorders (ASD). However, the mechanisms underlying the developmental effects of 5-HT remain partially unknown, one obstacle being the action of 5-HT on different cell types.
Here, we focused on microglia, which play a role in brain wiring refinement, and we investigated whether the control of these cells by 5-HT is relevant for neurodevelopment and spontaneous behaviors. Since the main 5-HT sensor in microglia is the 5-HT2B receptor subtype, we prevented 5-HT signaling specifically in microglia by conditionally invalidating Htr2b gene in these cells. We observed that abrogating the serotonergic control of microglia during postnatal development impacts the phagolysosomal compartment of these cells and their proximity to dendritic spines, and perturbs neuronal circuits maturation. Furthermore, this early ablation of microglial 5-HT2B receptors leads to adult hyperactivity in a novel environment and behavioral defects in sociability and flexibility. Importantly, we show that these behavioral alterations result from a developmental effect, since they are not observed when microglial Htr2b invalidation is induced later, at P30 onward.
Thus, a primary alteration of 5-HT sensing in microglia, during a critical time window between birth and P30, is sufficient to impair social and flexibility skills. This link between 5-HT and microglia may explain the association between serotonergic dysfunctions and behavioral traits like impaired sociability and inadaptability to novelty, which are prominent in psychiatric disorders such as ASD.
Integration of Fractal Geometry and Correspondence Analysis Reconnaissance for Geochemically High-Potential Promising Areas NE Iran
Authors: Hosseini Seyed Aliakbar , Khah Nasser Keshavarz Faraj , Kianoush Pooria , Ebrahimabadi Arash , Shirinabadi Reza
Published: March 2023

In geochemical exploration, in order to highlight the local anomalies, the background Anomaly separation is required. Most geochemical and geostatistical analysis in mining exploration requires removing regional trends in order to obtain local anomalies. In this paper, Khusf stream sediment was studied based on fractal geometry and correspondence analysis methods. This paper conducted a chemical analysis of fluvial sediments to find high-potential areas of Pb, Cd, and As elements in the Khusf area of South Iran's Khorasan province using fractal anomaly separation technique. Correspondence analysis with 170 samples through 20 elements concentration values in each sample was performed. According to correspondence analysis, among one or several elements in the study area was separated which the highest concentration relative to the variables Pb, As, and Cd elements. The correspondence analysis revealed that in the Khusf area at some locations Pb, Cd, and as elements have been accumulated anomalously. After the correspondence analysis, the best variogram for the Khusf area was obtained. Elemental concentration maps was then produced through estimating the values using kriging method. Therefore using the fractal method, between three statistical sets of elements, it was concluded that the third set showed the anomaly for Pb, Cd, and As elements. Local anomaly values are respectively determined as 55, 7.2, and 0.88 ppm. Finally, it is suggested that this region has the possibility of Basic Metals occurrence and suggests further geophysical operations on a local identification scale.