bluuebunny/crossref_metadata_2025 huggingface dataset:
Tailored Cement Systems with Enhanced Mechanical Properties Designed to Eliminate Sustained Casing Pressure in Development Wells
Authors: Chekuri Pushkara Varma , Singhal Ashish , Kaura Sheraya , Dange Mikhil , Kumar Animesh , Singh Swarnima
Published: March 2023

Objectives/Scope

Oil and gas wells in the Barmer fields (Rajasthan, India) typically require a timeframe of five to seven days for well completion. The cementing process includes a wide range of challenges, including low fracture gradients, lost circulation, and sustained casing pressure (SCP). Because the baseline challenges were identified from cementing through completion phases, the target was to design a tailored, gas-tight, resilient, lightweight cement system to address wellbore integrity issues. The modelled simulations showed the rheological behaviour, equivalent circulating density (ECD), pumping rates, and maximum surface pressure, whereas the 3D model predicted the sweep efficiency of the pumped fluids. Elastomeric materials were incorporated into the designs to counter the stresses induced during well activities. Advanced laboratory testing was performed to ensure that these lightweight slurries met the requirements to address multiple issues by exhibiting suitable mechanical properties (based on finite element analysis (FEA) simulation output), gas-tight behaviour, and lost circulation curing capabilities. Three stable cement slurries were designed with the available set of additives to simplify operations.

Elastomeric additives altered the mechanical properties of the set-cement sheath to provide greater resilience than conventional cement. More than 22 wells were cemented with a varied range of densities that were designed/modified with the available chemical additives, based on the severity of the depleted reservoir zones. To ensure completion of the full process (ranging from design to completion of the cement job), multiple verifications/checks were implemented. Quality control played an important part, and all new bulk blended batches were tested for mechanical properties. The wide range of densities and sensitivity tests of the cement system assured reliable implementation.

The successful design and cemented completion resulted in the reduction/elimination of sustained casing pressure. SCP, which may have been a safety hazard, influences production rates and, in the worst case, could compromise the structural integrity of the well. Results indicated that more than 90% success was achieved in the targeted segment of the field, in terms of SCP in the B-annulus (after cementing and perforation of the wells) where the values were well below their maximum allowable limits. The returns to surface, excellent cement bond logs, microseismogram, circumferential visualization, and zonal isolation under lost circulation conditions further justified the performance of enhanced slurry designs.
Geomechanical Analyses of Hydraulic Fracturing Efficiency and Challenges in a Tight Clastic Reservoir: Experiences Over Years
Authors: Vossen Johannes , El Sherbeny Wael , Perumalla Satya , Hamid Osman , Arshad Waheed
Published: March 2023

Hydraulic fracturing experiences were gathered over the years, from a tight sandstone reservoir of Late Carboniferous to Early Permian origin to find the root causes for the persisting challenges of high formation breakdown pressures and low fluid injectivity. It was soon realized that a single root cause could not account for these challenges. Instead, a multitude of reasons acting at the same time during the injecting sequence of that particular fracturing stage could easily be responsible, and no single re-occurring pattern would explicitly repeat in the consequent stages under similar conditions. It was found that the known complex nature of the depositional environment of the targeted formation played an important role, but the overall hydraulic fracturing mechanics played an equally critical part in the success of the fracturing attempt. Having realized this complexity in deciphering hydraulic fracturing performances it became imminent that not only the fracturing execution had to be refined, but all the preceding activities from drilling operations, to well placement, to wellbore preparation, to the choice of completion equipment and its deployment. These operations critically influenced the near wellbore region. The drilling fluid properties, wellbore hydraulics, well trajectory, the wellbore clean-out procedures, and hole quality were important contributors in the geo-mechanics domain coupled with the impact of the geological setting. Thus, a workflow was developed to analyze and rationalize the root causes for the injectivity challenges with the goal of optimizing every well construction step that would enhance hydraulic fracturing and ultimately deliver optimum well productivity.
Maintaining Hydraulic Fracture Conductivity Under High Stresses Through Consolidation with DAP
Authors: Desouky Mahmoud H. , Aljawad Murtada S. , AlTammar Murtadha J. , Alruwaili Khalid M.
Published: March 2023

Acid fracturing creates conductive fractures in carbonate reservoirs through acid-rock dissolution. However, over-etching or stimulating weak carbonate formation could result in a fast decline of fracture conductivity. In addition, most models in the literature showed that rock strength has an exponential impact on fracture conductivity. In this work, experiments were conducted to mitigate this problem through rock strengthening with diammonium phosphate (DAP).

Different fracture surfaces were tested using the ACM-3000 acid fracture conductivity system to compare the conductivity of intact samples with the treated ones. The fracture conductivity of 4 pairs of weak Austin chalk samples (7in × 1.34in × 3in) with flat surfaces was evaluated by flowing nitrogen gas (200-350 cc/ min) at increasing stresses up to 1,500 psi. Half of the samples were kept intact to represent the control group to which treated samples were compared. The treatment consists of saturating vacuumed chalk samples with 1M DAP for 72 hrs at pressure and temperature of 1,000 psi and 75°C, respectively. In addition, the surface hardness of the samples was measured pre-and post-treatment, and conductivity measurements were performed to evaluate the treatment effect on the samples.

The chalk samples used in this study are naturally weak with low average surface hardness (i.e., 3 GPa compared to 15 GPa for Indiana limestone). However, The DAP solution can remarkably boost the surface hardness of soft chalk, increasing it by nearly double its original value. The chalk hardness increase reduced the normal deformation and increased the yield stress of the treated samples. The untreated sample exhibited lower endurance to loading and developed cracks at lower stresses. Also, the results showed that the normalized conductivity of the treated flat samples is at least double the untreated ones. The chemical treatment makes the chalk stiffer with less deformation when stressed, which leads to enhanced conductivity at higher stress.

In this paper, an additional stage is suggested in acid fracturing to harden the surface of carbonate rocks chemically after acid injection. Successful application of such treatment in the field can extend fracture life and substantially reduce the need for re-fracking jobs.
Multifunctional Cementing Additives, A Way to Improve Rig Time Saving and Annulus Fluid/Gas Migration During Cement Placement
Authors: Frittella Francesco , Santos Auribel Dos , Jallad Hussam , Hartanti Stephanie , Sundblom Andreas
Published: March 2023

Controlling gas migration in the annular space during cement placement involves several challenges; especially in deep wells where temperature contrast leads to longer wait-on-cement (WOC) time, widening the window where fluids can migrate. Such extended setting is caused by the lower temperature in upper sections which impacts compressive strength build-up while also leads to higher rig time costs. In this paper, the authors focused on key aspects of slurry design to minimize these problems.

Among the factors that contribute to the invasion and migration of gas and other fluids into the annular space, are insufficient hydrostatic pressure, poor slurry design, inefficient mud removal, problems during cement hydration, or defective cement-formation-casing bonding. For this study, an experimental method was followed to evaluate specific additives and their impact in gas control performance. Different slurry formulations were evaluated at a temperature range between 50°C and 110°C (120°F -230°F) while pressure kept at 5300 psi to minimize variables.

The laboratory evaluation included tests for determining thickening time, rheology, compressive strength, fluid loss and gas migration. The slurry design involved the use of a novel retarder based on synthetic polymer with carboxylic acid functionality as well as a colloidal silica dispersion. The results showed that the selected additives allowed the slurries to achieve the targeted thickening time with a right-angle set, a short transition time and quick build up in compressive strength. In addition, the migration tests indicated excellent gas control under evaluated conditions. The studied additives performed well individually and even better combined, with a synergistic effect when preventing gas migration and accelerating compressive strength build-up.

The additives evaluated showed multifunctional attributes that are beneficial not only to prevent gas migration and retard slurry setting, but also to accelerate compressive strength, a cement feature which allows significant savings in rig time costs.
Advanced Hole Cleaning in Horizontal Wells: Experimental Investigation Supported by a Downhole Clamp-On Tool
Authors: Skenderija Jelena , Koulidis Alexis , Sanchez Domingo Lattanzi , Ahmed Shehab
Published: March 2023

Up to 80% of stuck pipe events are hole cleaning related in the case of high-angle wells. Therefore, significant attention should be given to understanding hole cleaning as it is crucial to restricting stuck pipe-related non-productive time (NPT). In order to optimize hole cleaning efficiency, the fundamental objective of the proposed paper is to experimentally investigate cuttings transport supported by a downhole clamp-on tool.

This work approaches existing challenges by designing and building a custom flow loop that recreates the drilling environment of horizontal wells. The study provides additional steps and new ideas in developing a reliable experimental setup for a proper hole cleaning investigation. Accordingly, the process includes comprehensive dimensional analysis, detailed design, and building a desired experimental flow loop setup. A unique mechanical design allows pipe rotation while achieving a closed-loop system. A clamp-on tool assists in agitating the cuttings to reduce accumulation at the bottom of the borehole. Experimental performance with various cuttings compares scenarios with and without pipe rotation.

Among the key factors influencing cuttings transport in horizontal wells are drill pipe rotation (RPM), flow rate (Q), mud rheology, cuttings size, flow regime, and penetration rate (ROP). This research focuses on the mechanical removal of solid cuttings. Experimental work emphasizes cuttings' behavior showing different patterns for their movement in deviated wells by utilizing image processing. Drillstring rotation proves to be a crucial factor for efficient hole cleaning. The specific shape and dimensions of the clamp- on tool affect the efficiency of the hole cleaning process and impact the distance covered by the agitated cuttings downstream of the tool. The concept of the tool depends on blades that agitate cuttings as it rotates. Optimum tool design considers the physical properties of the fluid and the cuttings. The results show that as the tool agitates cuttings and moves them into the higher velocity region, the cuttings advance with the flow, which improves cuttings transport and reduces bedding formation. Assuming low flow rates, tool application increased average particle velocity within the tool more than four times (372%) and twice after the tool. In addition, differential pressure (Δp) shows a significant decrease while the tool operates, indicating improvement in hole cleaning.

Lab-scaled flow loop development aims to simulate drilling conditions with drillpipe rotation and different downhole clamp-on tool geometries. The results show different flow patterns from experimental observations of liquid-particles flow in the horizontal wellbore, assisted by the proposed downhole clamp- on tool. The innovative tool design is a promising step in reducing hole cleaning issues with mechanical- assisted tools.
Utilizing Drilling Data and Machine Learning in Real-Time Prediction of Poisson's Ratio
Authors: Mutrif Siddig Osama , Elkatatny Salaheldin
Published: March 2023

Rock elastic properties influence drilling performance, estimation of in-situ stresses, and hydraulic fracturing design. Therefore, having complete and accurate information on rock properties is essential. While those properties are conventionally measured experimentally or using well logs, this work proposes to estimate the Poisson's ratio (PR) from parameters available while drilling.

Various machine learning techniques were employed, such as artificial neural network (ANN), support vector machine (SVM), and random forest (RF). The dataset utilized contains more than 5800 data points, each of them has a value of PR and six drilling parameters such as rate of penetration (ROP), rotary speed (RPM), and weight on bit (WOB). The dataset was divided into three parts, two were fed to the algorithms for training and testing the models, while the last group (around half of the dataset) was hidden to be used to validate the models later.

The models had a good fit with the actual PR values with correlation coefficients as high as 0.99 and errors as low as 1%. Among the used algorithms, ANN and RF yielded the best accuracy in all datasets with no significant difference between the training and the validation performance which indicate good generalization without an overfitting problem.

Using drilling data to predict rock mechanical parameters allows building a complete geomechanical model at an early time. It also saves the time and cost associated with laboratory tests.
Lost Circulation Material Design for Highly Inclined Or Horizontal Well Sections
Authors: Nguyen Kien , Mehrabian Amin , Santra Ashok , Phan Dung , Bathija Arpita
Published: March 2023

The use of particulate lost circulation material (LCM) is common in treating lost circulation events of subterranean drilling. LCM isolates the wellbore pressure from fracture tip by forming an impermeable agglomerate inside the wellbore fractures. Fracture width estimation is the center piece of designing the particle size distribution (PSD) of LCM blends. State-of-the-art practice for width estimation of wellbore fractures has been predominantly associated with assumption of axial fracture development from wellbores. However, this assumption is not valid for all wellbore orientations. Shallow vertical wellbores and highly inclined or horizontal wellbores in a normal faulting regime are example configurations where axisymmetric wellbore fractures develop transverse to the wellbore axis. The change in fracture geometry yields a substantially different width estimate for transverse fractures compared to the axial ones. This study aims at demonstrating this disparity and the impact that it would have on the LCM blend design. For this purpose, a linear elastic fracture mechanics solution is applied to the fractured wellbore to estimate the fracture width. Results indicate that an axial model of the fracture could substantially overestimate the fracture width depending on the wellbore inclination and in-situ stress magnitudes. Application of the solution in selecting the composition of a three-component blend from selected LCMs via a blend particle size criterion is shown. The discrepancy between the LCM blends PSDs obtained from the axial and transverse models of the wellbore fracture are thoroughly discussed.
Water Injection Optimization Using Geomechanics and PWRI Fracture Modeling, South of Sultanate of Oman
Authors: Al-Busaidi Salim , Al Zadjali Ruqaiya , Yuan Roger , Ghafram Hamid , Al Amri Mohammed
Published: March 2023

In the quest to increase production in parallel with reservoir pressure maintenance and to reach the ultimate recovery factor, PDO has been developing the fluvial stacked sandstones using water injection concept under matrix condition. The reservoir is good quality sandstone formation with average porosity (14-24 %) and permeability (20-500mD). The reservoir has weak aquifer support and develops with peripheral water injection. The target VRR is 1 was maintained fairly well in the area in the past few years, until Aug 2020 when few water injectors faced injectivity issues mostly related to the formation itself rather than water quality, so there is a need to compensate for the low cumulative voidage replacement ratio (VRR). Previous study done in year 2015 recommended matrix injection in peripheral mode with possibility to go for controlled fracture injection mode with the need to understand the timeline for fracture propagation to reach the producer wells.

Geomechanical modeling results were integrated with well and reservoir management (WRM) activities and surveillance technologies to optimize the injection strategy for improved waterflood performance. Formation fracture pressure data were used to provide guidance on maximum allowable injection pressure in injectors to manage the risk of induced fracture growth. A Produced Water Re-Injection (PWRI-FRAC) fracture modeling and analysis was performed to determine the potential fracture dimensions to provide input to development decisions of injection rate and water quality.

Field data utilized to generate different scenarios of PWRI-FRAC fracture model containment and uncontainment in which the contained fracture scenario indicates that injection higher rates >400 m3/day and TSS=140 ppm, would result in fracture half-length exceeding 1/3 of PI distance towards the end of field life. For small thickness units, models show low risk of fracture growth for rates 100 and 200 m3/Day and TSS=18 and 80 ppm. The rate of fracture growth is primarily influenced by water quality and injection rate. Mapped well spacing for critical wells are around 800-1000m away with orientation towards NE-SW direction, fracture growth modeling results give indication that water injectors are less likely to interact or result in short circuiting with producers if injection with a rate is less than 400 m3/Day and less than 140 ppm of TSS and this is also in line with SH max direction (NE-SW) as seen from drilling induced fractures interpretation from borehole images.

Fracture injection is feasible as long as the injection rate and water quality are operated under recommended limits (rates <400 m3/Day and TSS< 140 PPM) and this will significantly impact the field waterflood performance. Results provided inputs to reservoir simulations and injection rate envelope. The study benefits the field to minimize risk of injector producer short-circuiting for improved waterflood management.
Optimization of Rheological Models for Invert Emulsion Drilling Fluids using Novel Algorithms
Authors: Gucuyener Ismail Hakki , Gurcay Onur Kazim , Yanik Abdüssamed , Ay Ahmet , Seydibeyoglu Elif Alyamaç
Published: March 2023

Invert emulsion drilling fluids (IEDF) are recognized as the highest-performing fluid systems available, providing invaluable benefits in drilling operations. This study uses conventional and novel algorithms to improve the fitting ability of three and four-parameter rheological models for IEDF. Linear regression (LR), quasi-linear regression (QLR), Gold Search Section (GSS), Generalized Reduced Gradient (GRG), Trust Region (TR), and Gauss-Newton (GN) methods are employed to determine optimal rheological model parameters. The analysis utilizes an extensive field database from five different sources. In optimizing the model parameters, a symmetric mean absolute percentage error-based objective function is used, eliminating the statistical problems experienced in conventional objective functions. Average symmetric mean absolute percentage error (SMAPE) and the number of best fits (NBF) is used for selecting the most appropriate rheological model. In the performance comparison of the models, the ranking index, which is defined as the symmetric mean absolute error percentage and the arithmetic mean of the best fit number, is also used. The symmetry of the error distribution giving the balance between the overestimated and underestimated errors is predicted by the average overestimated and underestimated symmetric percentage errors.
Successful Application of a Novel High-Pressure High-Temperature (HPHT) Quartz Crystal Microbalance (QCM) Set-Up to the Evaluation of Asphaltene Deposition Inhibitors
Authors: Ghaffoori Abeer , Anderson Ross , Hoopanah Mohsen , Tohidi Bahman
Published: March 2023

Asphaltene deposition is a major flow assurance challenge in oil production. Changes in fluid temperature, composition, and particularly pressure, can all lead to solid asphaltene precipitation. This may deposit in the formation, wellbore, or production lines, causing reduced flow or even complete blockage. The objective of this work was to evaluate a recently developed, novel high-pressure high-temperature (HPHT) quartz crystal microbalance (QCM) set-up for the testing of asphaltene deposition inhibitors.

Developed within a joint industry project (JIP) aimed at improved asphaltene inhibitor testing and deposition modelling, the variable volume (50 to 450 ml), HPHT QCM set-up can operate at pressures up to 410 bar (6,000 psi, extendable to 690 bar / 10,000 psi), allowing measurements on live oil / re-livened oil (dead oil made live again by gas addition) systems for real production pressure-temperature (PT) conditions / scenarios. In this work, the HPHT set-up has been used to evaluate several commercial asphaltene inhibitors for two re-livened oil systems in terms of AOP pressure and relative mass asphaltenes deposited versus blank (inhibitor-free) cases. For comparison, traditional heptane titration tests were also carried out for the same dead oil ± inhibitor systems using an atmospheric QCM apparatus.

Results demonstrate the HPHT QCM to be a very promising tool for asphaltene inhibitor evaluation, with clear variations in anti-deposition performance seen for different chemicals. Furthermore, while findings show that atmospheric pressure dead oil titration results often agree well with those for re-livened HPHT tests, there are significant differences for some inhibitors, meaning the former may not always be representative of real conditions, while the latter should presumably be more so. These observed differences may go some way to explain problematic discrepancies between traditional laboratory test approach results and real-field chemical treatment performance, i.e., where an inhibitor performs well in the laboratory, but not in the field.

The reported HPHT QCM approach is novel in that it can be used to investigate asphaltene inhibitor performance for live / re-livened fluids for real production PT conditions/scenarios.
Successful Casing-While-Drilling Operation in West Kuwait Saves 17 Rig Days and Reduces Well Delivery Time and Well Cost
Authors: AL-Hajri Nasser , Al-Khaldy Ali Dawood , Hassan Jassim , Gupta Satya , Dashti Reham , Abdel Kader Mohammed , Al-Buloushi Zainab , Homi Jokhi Ayomarz , El Kady Mahmoud , Al-Saad Naser , Al-Muzaini Shahad , Al-Houti Mariam , Al-Harbi Saad , Al-Kanderi Naser , Herrera Delimar , Halma Jeremy , Ibrahim Sameh , El Sheikh Omar
Published: March 2023

Drilling the 16-in. section in Umm Gudair field in western Kuwait faces a lot of challenges while drilling. Challenges include drilling through severe loss conditions, destabilized shale, and deteriorating hole conditions. These conditions can result in hole collapse or lost in hole of the drill string that requires sidetracking. The objective of project presented in this paper was to develop an engineered solution to drill through the difficult zones, lessen nonproductive time, and reduce the total well cost.

The solution proposed was to use casing-while-drilling technology with a drillable bit and drill through the fractured dolomitic limestone and sandstone formation while simultaneously setting casing. The drillable casing-while-drilling bit was specifically designed and engineered to conform to the formations in the field. The drillable casing-while-drilling bit is manufactured with a material that can be drilled out with either conventional roller cone or fixed cutter bits. A plastering process was used, which smears the cuttings generated by drilling against the borehole wall, seals the pores or fractures in the formation, and helps reduce fluid losses while maintaining well integrity.

The successful implementation of 16 × 13.375-in. casing-while-drilling job in Umm Gudair field reduced well delivery time for the operator and saved 17 rig days with cost savings of 450,000 US Dollars considering rig rate only. The section was drilled successfully while encountering total mud losses through fractured dolomitic limestone and sandstone formations. Preventing the risk of losing the bottomhole assembly in the hole and alleviating the use of multiple cement plugs saved additional cost for loss-cure plugs to heal the loss-prone formations. After reaching the target depth, cementing, pressure testing of the casing were carried out successfully. Lesson learnt from the first job were applied in the subsequent job completing the section with faster ROP with substantial savings to operator. For both the jobs, drillout of the drillable casing-while-drilling bit using a fixed cutter bit and Rotary Steerable bottom-hole assembly were performed successfully, the drillout bit continued drilling to section TD in one run.

With the successful implementation and the savings obtained by using this casing-while-drilling technology in the West Kuwait field, there is the potential for substantial annual cost savings, aiding the operator deliver wells in less time, and eventually increase production by increasing the number of wells drilled per year.
Numerical Simulations of the Flow Past Crescent Cylinders – Flow Monitoring
Authors: Noui-Mehidi Mohamed Nabil
Published: March 2023

The flow characteristics of the vortex shedding system behind two cylinders that have a crescent cross-section, were numerically studied using a lattice Boltzmann approach. Two configurations ate considered, in one the crescent is facing the flow and in the other facing the flow downstream. The system of vortices formed behind the crescent cylinders was compared to the classical case of a circular cylinder for the same geometrical, physical and dynamic conditions at varying Reynolds numbers. The flow properties from all three cases studied have revealed that the crescent shape affects strongly the shedding mechanism. The numerical results showed that the flow past the crescent facing downstream of the flow was very similar to that of the circular cylinder, whereas there were remarkable differences when compared to the crescent cylinder facing the flow upstream.
Optimizing Directional Drilling by Enhancing Bottom Hole Assembly Design in Complex Well Profiles
Authors: Hussain Sajid , Baghdady Waleed , Al Khalifah Ahmed , Hussein Zeyad
Published: March 2023

Enhanced drilling efficiency is key to improve performance in the challenging long and highly deviated well profiles which are now common in the oil and gas industry. This paper details the inception and testing of a combined BHA and Fixed Cutter Drill bit solution. Utilizing the Flow-Activated Friction Reduction (FAFR) tool reduces drilling issues in these applications such as torque, drag, weight stacking and buckling. This paper also explores how the utilization of unique cutting structures and shaped Polycrystalline Diamond Compact (PDC) cutters built onto drill bits with low aspect ratio enhances weight transfer, reducing energy consumption and eliminating the need for expensive drilling solutions. Reducing the required energy to drill also decreases the overall stress on the drilling system, reducing tool fatigue and the chance of wellbore issues.

The FAFR tool converts the hydraulic energy of the drilling fluid into gentle axial mechanical oscillations which break the static friction and convert it to dynamic friction. This reduces borehole friction factor and enhances the weight transfer to the bit. Simultaneously, a light set cutting structure coupled with a V-shaped PDC cutter induces higher stress per unit energy input, optimizing point loading thereby improving drilling efficiency in both rotating and sliding drilling modes.

This paper presents the results of utilizing the FAFR tool and the engineered drill features to drill the 12¼, 8½, and 6⅛ inch directional sections. The combined solution helped reduce torque and drag and, as a direct result, improve weight transfer to the bit. Direct benefits were improved bit life and enhanced drilling performance / higher ROP when compared to offset wells.

By maximizing energy delivered to bit combined with an optimized bit design, it has become possible to push the drilling boundaries to achieve longer, faster wells and accomplish all directional requirements and achieve lower dogleg severity.
A Renewed Focused on Cementing Design Has Improved the Cement Bond Log in Shorter Time Wait on Cement Time
Authors: Al Ruqaishi Abdullah Saud , Al Sulaimi Jamal , Al Shuely Ahmed , Al Battashi Qais , Al Sabti Hashem
Published: March 2023

Challenging Low Oil Prices environment and LEAN maturity in PDO provided the impetus to boost performance and optimize cost. PDO has identified Waiting On Cement (WOC) before performing cement quality logs and Perforation as one of the major cost contributor and hence, an area of focus. Extensive laboratory works on cement slurry designs were carried out and ended by identifying a fit for purpose cement design reducing the WOC time by 50%.

Relatively low bottom hole temperatures (BHT) made the design of high and fast developed compressive strength (CS) cement for shallow wells more difficult as cement CS development at this range of temperature is slow. After extensive laboratory testing on different slurry designs, PDO team, along with cementing service companies managed to design a fit for purpose cement slurry, which does not only develop enough CS in a very short time but reduces WOC by 50%.

The systematic approach in designing the cement slurry and technical input helped to achieve the outstanding results. The field trials and extensive Cement quality evaluation using CBL/VDL USIT logs have also demonstrated an excellent cement adherence to casing which is even better than the quality of conventional slurries. Four CBL/VDL USIT logs were run out of seven wells after 20 hours WOC to evaluate the cement quality behind the production casing and the results were excellent. Three out of seven wells were perforated within the required 20 hours WOC frame with no well integrity issue nor impairment on the quality of the produced fluid.

This paper explains the design approach and shows how earlier CS can be achieved at low BHT and with excellent cement bond evaluation. This improvement in cement design enabled to cancel scrapping operations, saving time and money, reducing the risk exposure, and achieving faster well delivery.
Production Analysis on Wells Producing with Flow Thru Plugs to Optimize the Usage of HPCT Milling Operations
Authors: Alsulaim Abdullah , Alajmi Fahad , Aldawsari Mudhish , Guzman Javier , Amjad Bilal
Published: March 2023

One of the main used completion techniques in the gas wells Plug and Perf for proppant or acid stimulation, where the flow through frac plugs are commonly installed to provide isolation between the planned stages to be stimulated. Once the stimulation is completed, the well is flowed back where gas is produced thru the internal diameter restriction in those frac plugs, then all plugs are milled to clear any downhole restriction. The objective of this paper is to evaluate the need of milling frac plugs by simulating the behavior of the Production Index affected by downhole restriction in frac plugs considering those are not milled.

The proposed evaluation will investigate the real need of milling the flow thru plugs in the well after the frac operations, as the milling operation has a high cost and complexity. The preferred method is to flow the well without milling operation. However, if the effect of the plugs was significant on the productivity of the wells throughout the years, there will be a need to perform milling operation on the wells to ensure full wellbore accessibility. On the other hand, if the effect was not significant on the future production, the flow thru plugs can be left in the well downhole to avoid the milling operation complications. It is worth to note that milling multiple plugs in a well is a very lengthy and extremely expensive operation looking at the CT and Sand Management System (SMS) daily charges as well as the highly nitrogen consumption (Nunez et al. 2021).

The analysis in this paper is split in two parts, where initially Well-A is simulated in PROSPER to compare the production performance in a Plug and Perf completed well with plugs installed or milled. Second part of the analysis is to compare 2 offset wells with real-time data: Well-X with flow thru plugs and Well-Y with flow thru plugs being milled. The results of these analysis as well as the operation total cost and complexity will help in identifying most economical way to apply.
OEE-AODV – Optimized Energy Efficient Routing Protocol for Reliable Data Transmission in FANETS
Authors: Mohanakrishnan usha , Sathiamoorthy J , Nishanth R Bhagavath , Ashween R
Published: March 2023

FANETs are the new means of communication and have been aiding domestic and military applications for a long time now. FANETS are supported by UAV (Unmanned Autonomous Vehicles) which carry out the task of transmitting and receiving data. FANETs are still susceptible to challenges and issues that ad hoc networks usually face. Because of the lack of infrastructure, FANET related issues need to be addressed before applying any strategies or protocols over the network. Routing and effective transmission are two major challenges faced in FANETs. This objective of a FANET is not aided in any way by the high mobile AUVs in the network scenario. Packet loss and routing failures are common occurrences in a FANET. Node and route links are not permanent and may lead to a lot of transmission related issues. The performance of any network is gauged by its successful delivery rate. Effective delivery is made possible by carefully planned routing strategies. Setting up an optimal path right from the originating source to the delivery address is quite the challenge in a FANET. FANETs also fall victim to various network attacks, primary of which is the black hole attack. Black hole attacks are more common in a FANET and this is closely associated with the AUVs’ high mobility. Data may be completely lost during a black hole attack. Our proposed protocol will address the challenge of effective routing while addressing black hole attacks. Our Eagle optimized Energy Efficient Ad hoc On demand Distance Vector (OEE-AODV)routing protocol focuses primarily on selecting an optimized and secure route towards the destination node .Network factors like trust degree, priority queue, network delay, hop count and the level of energy consumption are taken into consideration in formulating a routing strategy for the proposed protocol. The outcome is an efficient routing strategy that can oversee the successful delivery of the data. The proposed protocol works in two phases. In the first phase, it focuses on setting up an optimal route with select nodes, while in the second phase it enhances the security level of the network by foiling potential black hole attacks with the use of the RREP packets. The nodes along the discovered route will be made up of nodes which are scrutinized and determined as trusted nodes. The OEE-AODV protocol assures the successful delivery of data with the help of an optimal and trusted routing path. The proposed OEE-AODV protocol is assessed against AODV and AODV-V2 protocols to assess its performance. OEE-AODV achieves maximum PDR and throughput while conserving the network energy by minimizing the network delay.
Welding fault detection and diagnosis using One-Class SVM
with distance substitution kernels and random convolutional
kernel transform
Authors: Amine Melakhsou Abdallah , Batton-Hubert Mireille , Casoetto Nicolas
Published: March 2023

Welding defect detection is still often performed by the human visual inspection or with non destructive tests. These quality inspections methods can be time consuming and can have an important error rate. In this paper, we propose an approach for the detection of welding faults through the detection of abnormal subsequences of the welding voltage signal. The approach is based on the One-Class SVM with distance substitution kernels. The One Class-SVM has been used in many works for the detection of abnormal subsequences. However, often after transforming the subsequences into a set of features. Nevertheless, finding the relevant features for anomaly detection may be challenging. Dealing with the raw subsequences in distance-based approaches, on the other hand, are known to be effective and can generalize well to different problems but they often suffer from high computational cost, which may restrict their application, especially with the need of real time predictions in an industrial context. We show in this work that the One-Class SVM can be successfully used directly with the raw subsequences. This is achieved by employing distance substitution kernels. These class of kernels has not yet gained widespread adoption for time series anomaly detection. The results show that the approach is both accurate and fast, which makes it more suitable for real-time welding monitoring. We further propose an approach for automatic diagnosis of welding defects.
Safety and Efficacy of phosphodiesterase-5 (PDE-5) inhibitors in fetal growth restriction: a systematic literature review and meta-analysis
Authors: Liu Ying , Un Ella Man-Wai , Bai Ying , Chan Man Keong , Zeng Luo Xin , Lei Sut Leng , Li Junjun , Ung Carolina Oi Lam
Published: March 2023

Background
The efficacy and safety of phosphodiesterase-5(PDE-5) inhibitors in the management of fetal growth restriction (FGR) remains inconclusive and new evidence continues to emerge. This study aimed to evaluate the most recent evidence about the clinical outcomes and safety profiles of PDE-5 inhibitors used to manage FGR.
Methods
Eight databases were searched for articles published in English and Chinese from the database inception to 30th September 2022. Randomized controlled trials (RCTs) reporting the use of PDE-5 inhibitors in FGR were included. Odds ratio (OR) and mean difference (MD) (95% confidence intervals) were pooled for analysis.
Results
From 229 citations identified, 16 studies involving 1492 pregnant women met the inclusion criteria. Only sildenafil (15 RCTs) and tadalafil (1 RCT) were investigated for their use in FGR. Sildenafil use was associated with an increase in birth weight (MD:164.07, 95%CI:61.55-266.59), pregnancy prolongation (MD:6.09,95%CI:2.15–10.03) and umbilical artery pulsatility indices (MD: -0.24, 95%CI: -0.32 - -0.15). However, sildenafil also had an increased risk of pulmonary hypertension in newborns (OR:4.37, 95%CI:1.49–12.80), as well as headache (OR:5.57, 95%CI:2.89–10.72) and flushing/rash in mothers (OR:5.11, 95%CI:2.08–12.53). No clinical differences in gestation age, perinatal mortality or major neonatal morbidity, stillbirth, neonate death, infants admitted to neonatal intensive care unit, intraventricular hemorrhage and necrotizing enterocolitis in infants were reported with the use of sildenafil. There was no evidence of any increase in the risk of pregnancy hypertension and gastrointestinal side effects in mothers. Subgroup analyses by age showed similar significant effects of sildenafil on birth weight for mothers younger than 30 years old (MD:198.6, 95%CI:19.95-377.25) and those aged 30 years or older (MD:82.73, 95%CI:7.14-158.32). However, no significant effect was observed for pregnancy prolongation.
Conclusions
The evidence from this review indicates that PDE-5 inhibitors improve birth weight and duration of pregnancy without causing severe maternal side effects. However, it has been shown that sildenafil can also increase the risk of neonatal pulmonary hypertension. It remains uncertain whether the benefits of PDE-5 inhibitors in FGR outweighs the risks and further investigation with larger studies is warranted.
Tilt Angle Filter Effect on Noise Cancelation and Structural Edges Detection in Hydrocarbon Sources in a Gravitational Potential Field
Authors: Hosseini Seyed Aliakbar , Khah Nasser Keshavarz Faraj , Kianoush Pooria , Arjmand Yaser , Ebrahimabadi Arash , Jamshidi Emad
Published: March 2023

Noise cancelation is the process done to remove out-of-range anomalies and make better edge boundaries interpretation. One of the most challenging issues in describing gravitational maps is separating the anomalies related to shallow sources from the deep ones. Furthermore, Existing noise can make it arduous to separate shallow blurred boundaries. In this study in SE Iran, gravitational surveying was carried out in shallow areas from the west of Qeshm to the Hormuz islands in a regular network with a distance of one kilometer. The range of gravitational Bouguer was -297 to -330 mGal. Modeling and determining geometrical parameters revealed five negative anomalies from salt penetration. The residual gravity was computed by deducting gravitational effects related to deep sources from measured gravitational data. The hyperbolic tangent function was preferred by comparing the results and employing the tilt angle filter on different gravitational field maps using numerical coding. Correspondingly, estimating the boundary and edge of the subsurface masses will be better than local filters, and anomalies will be highlighted with more intensity. Furthermore, three major fault systems in the Zagros basin were determined as the primary origin of activity and expansion of Hormuz salt. Sensitivity analysis was employed utilizing analytical signals and maps of tilt angle filtering, which both revealed the same satisfying results of -297 to -330 mGal. In this article, the effect of the tilt angle local phase filter on a synthetic model was accomplished through numerical coding. Then the results were analyzed on the gravity data.
How do trial teams plan for retention during the design stage of the trial? A scoping review
Authors: Murphy Ellen , Gillies Katie , Shiely Frances
Published: March 2023

Background
Retention to trials is important to ensure the results of the trial are valid and reliable. The SPIRIT guidelines (18b) require “plans to promote participant retention and complete follow-up, including list of any outcome data to be collected for participants who discontinue or deviate from intervention protocols” be included in trial protocols. The evidence for inclusion of this retention information in protocols is absent. The purpose of our scoping review is to establish if, and how, trial teams report plans for retention during the design stage of the trial.
Methods
A scoping review with searches in key databases (MEDLINE/PubMed, Scopus, EMBASE, CINAHL (EBSCO), and Web of Science from 2014-2019 inclusive) to identify randomised controlled trial protocols. Quantitative and qualitative methods were used to synthesise results.
Results
Eight-hundred and twenty-four protocols met our inclusion criteria. Definitive RCTs (n=722) and pilot and feasibility trial protocols (n=102) reported using the SPIRIT guidelines during protocol development 35% and 34.3% of the time respectively. Of these protocols, only 9.5% and 11.4% respectively reported all aspects of SPIRIT item 18b “plans to promote participant retention and to complete follow-up, including list of any outcome data for participants who discontinue or deviate from intervention protocols”.
Of the definitive RCT protocols, 36.8% included proactive “plans to promote participant retention”. Most protocols planned ‘combined strategies’ (48.1%). Of these, the joint most commonly reported were “reminders and data collection location and method” and “reminders and monetary incentives”. The most popular individual retention strategy was “reminders” (14.7%) followed by “monetary incentives- conditional” (10.2%). Of the pilot and feasibility protocols, 40.2% included proactive “plans to promote participant retention” with the use of ‘combined strategies’ being most frequent (46.3%). The use of “monetary incentives – conditional” (22%) was the most popular individual reported retention strategy.
Conclusion
There is a lack of communication of plans to promote participant retention in trial protocols. Proactive planning of retention strategies during the trial design stage is preferable to the reactive implementation of retention strategies. Prospective retention planning and clear communication in protocols may inform more suitable choice, costing and implementation of retention strategies and improve transparency in trial conduct.
Rule-based Reinforcement Learning for Lane Change Decision-making: A Risk Assessment Approach
Authors: Xiong Lu , Zhong Danyang , Xu Puhang , Tang Chen
Published: March 2023

To solve problems of poor security guarantee and insufficient training efficiency in the conventional reinforcement learning methods for decision-making, this study proposes a hybrid framework to combine deep reinforcement learning with rule-based decision-making methods. A risk assessment model for lane-change maneuver considering uncertain prediction of surrounding vehicles is established as a safety filter to improve the learning efficiency while corrects dangerous actions for safety enhancement. On this basis, a Risk-fused DDQN is constructed utilizing the model-based risk assessment and supervision mechanism. The proposed reinforcement learning algorithm sets up a separate experience buffer for dangerous trials and punishes such actions, which is shown to improve the sampling efficiency and training outcomes. Compared with conventional DDQN methods, the proposed algorithm improves the convergence value of cumulated reward by 7.6\% and 2.2\% in the two constructed scenarios in the simulation study, and reduces the number of training episodes by 52.2\% and 66.8\% respectively. The success rate of lane change is improved by 57.3\% while the time headway is increased at least by 16.5\% in real vehicle tests, which confirms the higher training efficiency, scenario adaptability and security of the proposed Risk-fused DDQN.