bluuebunny/crossref_metadata_2025 huggingface dataset:
Cost-Effective Adaptive Inflow Technology for Sand Prevention in an Injection Well
Authors: Vimolsubsin Pojana , Wasanapradit Tawan , Khunmek Thanudcha
Published: November 2020

This paper describes the successful application of Autonomous Inflow Control Device (AICD) technology in the Nong Yao oil field located in Block G11/48 within the Gulf of Thailand. Water injection in the Nong Yao field, is often into unconsolidated sands drained at different depletion levels. This can lead to formation failure and the transportation of sand back through the annulus and tubing. This AICD bypass valve technology provides a solution by only allowing injected water into the formation but not in the opposite direction hence preventing downhole crossflow.

An AICD Bypass Valve was installed into two injection wells that were completed as Multi Zone Completions (MZC). It was planned that multiple zones would be opened simultaneously to provide ongoing waterflood support. The expectation was that the AICD technology would prevent crossflow between zones, due to pressure difference during any injection shutdowns, thereby eliminating the chance of formation failure and transportation of sand from the reservoir into the annulus and tubing.

At first, these reservoirs were produced through depletion, and waterflood of these reservoirs did not commence until reservoir pressures had reached between 5.5–7.0 ppg. This led to differential depletion across these reservoirs, hence increasing the risk of downhole crossflow immediately upon any injection shut down, which may come with sand production resulting injectivity impairment. This has been observed across other wells in the field not fitted with AICD Bypass Valves.

The concept of the AICD Bypass Valve is that the device requires a positive injection pressure differential to activate and open and allow fluid to pass through and it will close if the well is shut in due to a drop in the required pressure for valve activation. Since the installation of AICD Bypass Valves, these wells have been shut in multiple times due to platform shutdowns for rig mobilization and each time no drop in injectivity has been observed on restart, and sand production has been observed as predicted.

AICD Bypass Valves were installed into two new injection wells in the Nong Yao field, providing a low cost alternative to recompletion or redrill that may be required, if screens become plugged due to sand production triggered by crossflow between reservoirs during well shut-in. This has provided more reliable production for the field and the success in this project means that more AICD Bypass Valves will be planned for future MZC, for injection wells in unconsolidated sand.
HPHT Subsurface Barrier Valve Technology: Enhancing Reliability in Harsh Well Condition
Authors: Zhao Geng , Zuniga Jurgensen Camilo Eduardo , Batita Nabil , Arauz Grigory L , Battula Venkata Siva , Sharma Ashish , Perrotti Nicholas , Zhao Ming
Published: November 2020

Deeper reservoirs, higher pressures, higher temperatures, specific well fluids, uncertain debris-laden environments and demanding completion applications have presented very challenging well completion requirements. The reservoir subsurface barrier valve (SBV), which was developed from a fluid loss control concept, has become the key player to assist the operator to achieve safety and cost targets. In recent years, operational efficiency and overall project cost control have triggered a rapid field development approach, such as "fast-track" that includes batch drilling and batch completion. For this type of approach, the SBV is the core safety barrier for a long suspension while waiting for the production system to be ready. More and more stringent requirements on well operation safety continue to push the evolution of SBV development technology. The reliability and surveillance of the SBV, as one of the mandatory components of lower completions for subsea deepwater wells, is becoming more critical than ever for achieving a successful project.

This paper will focus on the innovation of SBV technology and will discuss in-depth the SBV design philosophy, special features and robust qualification process that ensures successful SBV performance in harsh well conditions.
Fiber Optic Liquid Leakage Detection
Authors: Baque Marc
Published: November 2020

Fiber Optic Liquid Leakage Detection (FOLLD) project has permitted of assessing on the DTS (Distributed Temperature Sensing), the DSTS (Distributed Strain and temperature Sensing) and the DAS (Distributed Acoustic Sensing) capabilities, combined with a Standard Telecom Fiber Optic Cable (FOC), for detecting small pressurized (20 barg) and pre-heated (50 °C) liquid (water) leakages on a buried dummy pipeline.

DTS/DSTS real time results demonstrated that the soil disruption, the soil and external environmental temperature variation had an influence on leakage detection results robustness. Consequently, only the first three (3) trials out of the ten (10) trials provide some comprehensive results.

Real time results shown that two (2) out of three (3) DSTS devices were able to detect a leakage up to twenty (20) km with a detection success rate of 67% in the position P1 or P2 or P3. One (1) out of two (2) DTS device detects up to twenty (20) km with a detection success rate that depends on the fiber optic position (67% for P2 or P3 and 33% for P1). Only one (1) DSTS shows a detection success rate up to fourty (40) km with a detection success rate of 67% in the position P1 or P2 or P3. DTS/DSTS real time results highlight that 100% successful detection rate can be reached up to twenty (20) km with several fiber optic cables in the position: P1/P2 or P1/P3 or P1/P2/P3. For DAS systems, the real time results shown that it was not possible to distinguish a leakage "noise" from other surrounding noise. This was especially due to the water pump noise, which was always occurring simultaneously with the leakage. Only a post processing treatment provide the leakage detection using a DAS technology.

Post treatment DTS/DSTS and DAS detection success rate are better than the real time results. This highlight the potential of both technologies.

All DTS/DSTS and DAS testing results demonstrated that the detection success rate are Supplier's dependent.
Successful Rigless Remedial Job Restores Production in a Mature Oil Field
Authors: Pelusi Luca , Lerose Marco , Pollio Pasquale , Spagnolo Salvatore , Scarso Marco , Mittiga Vincenzo , Appicciutoli Danilo , Caldarelli Riccardo , Vasquez Julio , Vitale Dario
Published: November 2020

The paper describes the execution of a successful rigless intervention solution deployed to establish well integrity and restore well production in a field in Europe. The paper will go through the planning and execution of the job highlighting the criticalities encountered and the overall benefit of the activity.

The approach used was a deep analysis of the well integrity issue from several prospectives. A new opportunity in the production optimization fluid has been identified. After an open discussion between Customer and contractor, a customized blend and detailed pumping procedure was agreed upon to reach the final scope. An injectivity test was executed to align the procedure to the reservoir and well behavior. Several pressure tests were performed to confirm the remedial job in place, and, after that, the well was re-perforated and opened to the production.

The horizontal well described in the paper, shut in during 2016 due to formation damage and depletion was selected for a new through tubing perforations interval by coiled tubing in the horizontal section. An unexpected firing head activation occurred at an unplanned depth, just above production packer. This event produced communication across the production tubing, liner, casing, and formation, which immediately induced total losses into the naturally fractured carbonate reservoir causing well control issues. The accidental perforations could have jeopardized the final scope of the project with no oil production and premature well abandonment. A successful rigless remedial intervention was immediately executed to restore well integrity by using a real time fiber optic coiled tubing acquisition and a new conformance fluid combined with a customized cement packer technique. The remedial intervention allowed the operator to resume the initial project's scope of opening the new perforation intervals, restoring an important oil production of about 150 [m3/d].

The final solution utilized a product with unique thixotropic properties which was then engineered for production optimization using a detailed pumping strategy. This novel approach added significant value, as the operator was able to restore the integrity of the well in rigless mode, avoiding the associated rig cost.
Best Engineering Practices for Asphaltenes Challenges Mitigations at Oil and Gas Production Facilities
Authors: Abbas Zafar , Punnapala Sameer , Abdulla Dalia Salim
Published: November 2020

Asphaltens presence in the reservoir fluid has great implications on downhole as well as surface facilities. These problems are not only related to production impact, but also significant integrity as well as surface facilities operational challenges are seen to affect the upstream oil and gas production facilities. Handling the asphaltenes rich fluid brings inherent challenges with it starting from well bore to the production facilities. Adequate engineering solutions need to be integrated into the design of production facilities as well as wellhead equipment which would greatly enhance production efficiency while successfully facing asphaltens challenges. The nature of asphaltens as well as their growth rate are not very well understood due to their complex chemistry with different hydrocarbons. Therefore there will not be a 100% success while managing the asphaltens, however these proactive steps would upto great extent would reduce the downtime and other asphaltene related impacts.

This paper presents an effective way to address asphaltenes challenges as faced by surface and subsurface facilities in oil and gas production operations. Best industry practices for mitigating asphaltenes related challenges, which not only sustained the production but also enhanced asset integrity performance, have been presented for experience sharing and enhancing the asphaltenes handling capability. The reservoirs with asphaltenes presence are quite difficult to handle and maintain due to complicated nature of asphaltens, which result into various problems with downhole as well as surface facilities. These problems result into scales blockage of well bore and flow lines thus causing blocked flow and in most of the cases complete seizure of wells fluid flow.
Successful Water Shut Off Based on Comprehensive Pre and Post Well Diagnostics
Authors: Skutin Vasilii , Abasher Doha , Izawa Toshihide , Watanabe Kimihiko , Nihei Shotaro , Kuramata Hideaki , Iwasaki Satoshi , Matsuda Hiroki , Nakata Nakata , Alobeidli Abdulla
Published: November 2020

This paper will describe pre and post workover well diagnostic and the successful water shut-off that has resulted. It also talks about the post workover survey. The well was recently completed to a new targeted reservoir and suffered from high water cut (80%) at the start of production. Proper diagnostics identified the source of water and helped in planning a successful remedial job. After water shut off the water cut dropped to zero. Post workover evaluation confirmed production from the targeted interval.

Comprehensive diagnostics are crucial to designing a proper remedial job. A conventional PLT survey will describe the flow characteristics and parameters inside the wellbore only. During the job under consideration, two additional services were deployed; the Spectral Noise Logging and the High Precision Temperature sensing. Their combination with the PLT allows for the assessment of behind casing flow and the identification of active streaks of the formation. The quantification of flow rate behind casing is also achieved by modelling the temperature response from the high precision sensor.

The first survey was conducted with the conventional PLT to identify the source of water. Subsequently, a high precision temperature and spectral noise log were recorded under flowing, transient, and shut-in conditions. A crossflow behind casing from the upper unperforated intervals was identified. The main liquid production is coming from the water-bearing formation that is located 15 ft above the targeted reservoir. The cement evaluation surveys that were run previously confirmed the presence of a cement channel above of the perforated interval. Based on these conclusions a remedial job was designed and conducted successfully. Another HPT/SNL survey was conducted post workover. It confirmed the absence of any further flow behind casing and that all liquid production is happening from the targeted reservoir. Surface test data showed a rapid decrease in water production to 1% post workover.

This paper highlights the importance of complementing the current practice of running conventional PL surveys with two additional services: the Spectral Noise Logging and Temperature simulation/modelling using a High Precision Temperature measurement.
Utilization of Lithium-Ion Batteries in Offshore Platform
Authors: Qaderi S. Al , Wahedi Faisal Al , Ashqar A. Al , Kuwair M. B , Ibrahim G. M , Takieddine Oussama , R. Kamal Faris , Paul Raju , Mazumdar Sumit Kumar
Published: November 2020

This paper explores lithium ion battery as an alternative battery technology and discusses the benefits it can offer to stationary UPS application in offshore platform. A case study on utilization of lithium ion battery in Al Yasat's, Belbazem feed project is presented with an intent to implement in EPC stage and to reduce total cost of ownership.

The paper studies conventional batteries, which are used for the majority of ADNOC offshore platforms. It considers their limitations and surveys alternative battery technologies in different industry sectors. Based on industry trend, market share and technical performance, lithium ion batteries are considered as the preferred candidate. The paper also focuses on different international standards like IFC, IEEE standards for safety and other recommendations.

Conventional batteries due to large size, heavy weight, and low energy density require more space. Additionally, the performance, service life, and total cost of ownership further limit's their usefulness and advantages. Unlike conventional batteries, lithium ion batteries have emerged in recent years as small size, light weight, and high energy density solution which offers significant advantage in terms of footprint and infrastructure cost. This makes lithium ion battery as a potential candidate for offshore platform where space is premium. Under normal condition there is no electrolyte leakage and no outgassing, thus eleminating stringent ventilation requirement, minimizes HVAC energy consumption and contribute to energy optimization. Lithium-ion batteries have long life and very low maintenance requirements. There is no fluid level to measure and maintain. Lithium ion batteries require advanced battery management system (BMS) for their safety. Smart features in BMS offers an array of monitoring capabilities, including system state-of-charge and state of- health which further reduces maintenance burdens. As Lithium ion batteries offers high energy density solution they and are prone to thermal runway. The highest level of safety is ensured with sound material & process control during manufacturing, choice of stable battery chemistry, proper cell & system design and testing in compliance to industry standards.

The proposal to use lithium ion battery for stationary UPS application in ADNOC offshore is novel. It highlights strengths and discusses various aspects of lithium ion batteries which lowers total cost of ownership and ensure safer design in offshore platform. The paper presents various norms currently available in international standards, guidelines and presents manufacturer recommendations, which can be helpful to various stakeholders in specifying design requirement while considering lithium ion battery in offshore.
Waste Heat Recovery in Gas Processing by Organic Rankine Cycle
Authors: Al Ketbi Waneya , Sajjad Saqib , Al Jenaibi Eisa
Published: November 2020

ADNOC Gas Processing is looking into the energy saving opportunities to improve plants energy performance, aiming continual improvement and also for sustaining the already achieved efficiency improvement in varying operating scenarios. It is in line with the ADNOC Sustainability Strategy target for the Year 2030 which requires reducing the Green House Gases (GHG) intensity by 25% in Year 2030 considering Year 2018 as the baseline. Therefore, multiple avenues and opportunities were looked into to contribute towards this ambitious target. One of the promising contributors, having substantial potential of energy savings, is the Waste Heat Recovery. In this context, ADNOC Gas Processing has evaluated the option of utilizing waste heat from different heat sources across different plants using the Organic Rankine Cycle to generate power. Waste heat sources like exhaust gases from power generators, mechanical drive gas turbines, heaters and incinerators stacks, and low pressure steam condensers have been assessed. This opportunity of waste heat recovery exhibits substantial potential to contribute towards GHG emissions intensity reduction, reduce power import, improve energy efficiency and reduce the operating costs. The paper presents the techno-economic appraisal of the opportunity for the selected waste heat sources.
Vortex Induced Vibration for the Long Span Attachment Pipes on Jackets - An Optimized Solution
Authors: Samant Sachin , Pai Arun , Karuppusamy Kandasamy , Kamal Faris , Takieddine Oussama
Published: November 2020

Brownfield projects whether topside modifications or underwater modifications are always challenging in Offshore Industry. New facility attachments to the existing jackets in the form of J tubes, Utility Pipes, Risers etc. require clamped connections. It involves underwater removal of marine growth and installing the new clamps on existing jacket members. The allowable span lengths of these attachments pose a challenge to Engineer. Sometimes jacket members are not available to install clamps at the required location. This leads an Engineer to take misaligned and eccentric supports to satisfy the span length requirement. In few occasions this leads to the installation of the new supporting jacket member with clamped connections.

This paper presents an enhanced design concept for working out the maximum possible span lengths of these pipes considering associated vortex induced vibrations (VIV). These members are checked for VIV and VIV induced fatigue to determine spacing of the supports on jacket as one of the design criteria. This paper discusses the standard methods of the VIV check and gives a more enhanced methodology by which the spans can be increased without causing VIV excitations.
API Recommend Practice 1173 Third-Party Assessment Program: Pipeline Safety Management Systems in a Global Context
Authors: Burr Alexa S. , Toth S. David , Frazier Colin M.
Published: November 2020

In 2015, the North American pipeline industry completed the development of a framework for a Pipeline Safety Management System (Pipeline SMS) designed specifically for pipeline operators. American Petroleum Institute (API) Recommended Practice (RP) 1173 is the product of a collaboration between pipeline operators, state and federal regulators, and other engaged stakeholders (e.g. gas distribution, transmission, utilities, etc.) working towards the goal of zero incidents. The API Pipeline SMS Third-Party Assessment Program is designed to identify ways of empowering stakeholders to do their operation(s) and maintenance activities in a safe way, and identifying practical steps to protect communities, employees, and the environment from the pipeline safety risks. Incidents occur not because of a lack of knowledge, but failure to use the knowledge the industry already has. Many operators think that undertaking Pipeline SMS assessments is a difficult and complicated process, and as a result, it is often misunderstood. The API Pipeline SMS Third-Party Assessment Program is a proven and consistent assessment program that enables operators to break through PSMS barriers and implementation challenges.
New Generation of HTHP Water Based Drilling Fluid Changing Conventional Drilling Fluids Solutions
Authors: Hasan Hamdan Tariq , Traboulay Vaughn Reza , Husien Mohamad , Alblooshi Salem , Awadh Alhammami Mohamed , Qassem Hussain Mohamed , El Shahat Ayman , Osama Abd El-Meguid Mohamed , Arena Carmelo , Aung Tint Htoo , Panamarathupalayam Balakrishnan , Manzoleloua Cedric , Dmello Allwyn , Eyaa Clotaire
Published: November 2020

The conventional drilling fluid to drill the high-temperature wells are non-aqueous fluid. ADNOC used high-temperature water-based drilling fluid instead of nonaqueous fluid to drill the well successfully. High-temperature water-based drilling-fluid systems hold several advantages over non-aqueous systems from financial and environmental viewpoints. However, most conventional water-based systems start to become unstable at temperatures above 300 degF. This paper details the design and implementation of specially designed water-based drilling fluids based on custom-made branched synthetic polymer that meet these temperature stability requirements. The branched synthetic polymer exhibits superior rheological properties and fluid loss control, as well as longterm stability above 400 degF. Under static conditions, the high-temperature fluid shows no gelation, resulting in lower swab surge pressures while the stability of the highly branched synthetic polymer and enhanced rheological profile minimize sag.

ADNOC required a cost-effective drilling-fluid system that remains stable under static temperatures expected to exceed 375 degF. The longterm stability of the system was critical for successful wireline logging operations. In addition, the system was required to provide shale inhibition, hydrogen sulfide (H2S) suppression and enough density to maintain well integrity while drilling through anticipated high-pressure zones. The challenging intermediate and reservoir sections were drilled and evaluated using high temperature water-based system. This paper will discuss the successful execution of high temperature water-based system in one of high-temperature well in ADNOC field.
The Hybrid Strategy of Business Continuity Management for Offshore Facilities – A Case Study
Authors: Bunjongmanomai Somsak , Homanee Setawat , Chantabutr Sirodom , Ratanatanyong Suwitcha
Published: November 2020

Business Continuity Management (BCM) identifies an organization's priorities and prepares solutions to address disruptive threats. It supports the design and implementation of detailed plans to protect the value creating operations of an organization. However, Business Continuity Plan (BCP) for offshore oil and gas facilities is not commonly developed by all Exploration and Production (E&P) companies, thus exposing some smaller (E&P) companies to significant risks arising from business disruptions.

The proposed methodology was developed in accordance with the following standards; NCEMA 7001 (2015) Guidelines adopted by UAE government entities, ISO 22301 (2012) Business Continuity Management Systems and Business Continuity Institute (BCI) Good Practice Guide (2018). This case study demonstrates the application of these standards for a marginal crude oil E&P company encompassing offshore facilities.

The paper describes the business continuity plans developed for offshore facilities, which includeWellhead Processing Platforms (WPP), subsea pipelines and the floating assets, such as the Floating Production, Storage and Offloading (FPSO) vessel, or a Floating Storage and Offloading (FSO) vessel, based on various major operational disruptive scenarios e.g. the scenarios encompassing the loss of facilities, people and/or supplies etc.

Unlike the BCP for an office location, it is shown that a hybrid strategy (standby and post requisition) is more appropriate for offshore facilities due to the inherent logistical complications of an offshore operation. A standby technique is used for short-term interruption of the facilities, while a post-incident acquisition technique is applied for longer term unavailability incidents. An appropriate recovery strategies is developed for all case studies to achieve the Minimum Business Continuity Objective (MBCO) prior to the operation's full recovery. Finally, this approach facilitates the validation of the BCP.

Business continuity management is emerging as an essential part of sound corporate governance, but knowledge and experience in BCM by E&P companies is not yet widespread. The case studies presented in this research provides valuable guidance on the development of business continuity plans in accordance with international standards, and demonstrates how the implementation of BCM alongside an effective Emergency Response Program (ERP) increases the level of business resilience of an organization.
Extreme Extended Reach Drilling Depths with Ultra High Torque Drill Pipe
Authors: Awad Ahmed , Musleh Osama , Bordet Laurent , Baryshev Dmitry , Prim Matthew Thomas
Published: November 2020

A world-leading extended reach drilling (ERD) project in the UAE has successfully made a breakthrough, drilling several of the longest wells in the world from artificial islands offshore Abu Dhabi. A key enabling technology for efficiently delivering such wells has been the use of a single size string of ultra-high torque drill pipe throughout the entire well construction process. The drill pipe incorporates specially designed threads and tubular geometry to overcome technical challenges and enable ERD depths beyond 40,000 feet (12,000 m).

The drill pipe design is fit for purpose, incorporating the latest in thread technology to enable ultra-high operational torques. The connection pushes the limits of thread design with make-up torques (MUT) in excess of 70,000 ft-lbs for a 6½-in. connection and 5½-in. tubular body. Design considerations allow for fishability in an 8½-in. hole while accounting for equivalent circulating density (ECD) and standpipe pressure restriction that might otherwise limit the achievable drilling depths.

The drill pipe design was successfully used to drill more than 1,000,000 ft (300 km) across seven rig lines since the tubular entered service in early 2018. As of February 2020, zero failures related to the drill pipe have occurred. The incredibly high operational torque is continuing to allow wells to reach out further and further, with multiple wells now among the top 10 longest worldwide.

The drill pipe being of a single size has tremendously reduced the amount of tubular handling that must occur as it is no longer necessary to lay down and pick up other tubular sizes on each well. Hydraulic design considerations have proven to be sufficient.

This paper details the comparative evaluation of two drill pipe designs that enabled the operator to drill wells that are among the longest in the world. Insight into the operational benefits obtained by shifting to the new tubular design are also detailed.
Remote Activated Sliding Sleeves Improve Efficiency and Introduce Operational Flexibility to Offshore Lower Completion Design
Authors: Edwards Andrew , Tuffy Declan , Sweeney Kieran , Glennie James , Babazade Farrukh , Robertson Bruce , Murdoch Euan
Published: November 2020

This paper will portray the development and deployment of remote-activated sliding sleeve devices commissioned for use in a two-stage completion North Sea project. The sliding sleeves are required within the lower completion to provide access to the reservoir, protection to a control line and act as part of the fluid-loss envelope. Remote activation technology has been implemented to the sleeve designs to improve efficiency and introduce operational flexibility.

Three variants of sleeves were designed and deployed to facilitate well objectives. The first variant is run-in-hole (RIH) Open to provide a circulation path and subsequently closed post displacement activities. The second variant is RIH Closed and is distributed across the reservoir. These sleeves are remotely opened post Xmas tree installation and provide the tubing/annulus communication for production or injection. The third variant is again RIH Closed, but this is a purely mechanical sleeve to allow further access to compartments or different reservoir units later in the well's life. A variant of open-hole anchor with bypass capability was also developed and tested.

Remote-activated sliding sleeves were prototyped and qualified to API 19AC. In addition to the standard requirements of API 19AC, open/close cycles were also performed with lost circulation material-laden (LCM) fluid along with low hydrostatic pressure function testing. This latter testing is to allow for sequential functioning without having to shut in or choke back the well, instead functioning while the well is flowing or even under full operational drawdown. Three wells have been completed to date, two producers and one injector. The RIH Open sleeves have successfully acted as a replacement to a traditional fluid loss valve and the RIH Closed sleeves have allowed zonal isolation, selective water shut-off and reservoir management. The use of open-hole anchors has also been standardised, in producers to support future stimulation operations and in injectors to combat thermal contraction. Across all three wells the RIH Open sleeves have all been actuated successfully via Radio Frequency Identification (RFID) tag carrier or timer and the RIH Closed via pressure sequence and / or timer. The second producer also saw the first implementation of the staged clean-up functionality with sleeves opening at four different intervals over a period of 17 days.
Using Agile Saturation Distribution to Turn the Models into Democratic Knowledge for Faster Clastic Subsurface Characterization
Authors: Sugiharto Yudiyoko Ega , Ralphie Benard , Johare Dzulfadly
Published: November 2020

Although papers comparing some standard functions with saturation models have been published, no consistent review exists comparing the performance of most of the universal saturation-height function quantitatively. The universal SHF is fast and straightforward, but robust enough to account for limited data and while another full data acquisition and advanced analysis are in progress (partially obtained). The method can help the subsurface team in understanding the water saturation nature in quick turnaround time before the completion of ongoing volumetrics estimation. Two best practices of this workflow are rapid and robust.

The paper reviews three of the universal saturation-height methods, namely those proposed by Choo, Kyi-Ramli, and K-Function. The comparisons between modelled and measured capillary pressure measurements over the most common functions and through different reservoirs are discussed. The advantages and drawbacks of each method are highlighted. Each technique is compared by investigating how accurately they model the saturation-height profiles of several wells from Offshore Malaysia. The work was carried out to independently assess which equations should be tested first during saturation-height studies. The differences for each capillary pressure between the water saturations estimated using the equations and those measured on the samples are examined in both graphic and quantitative terms.

The results of this study show that Choo (2010) model is one of the better performing saturation-height functions. However, the best results are achieved using this function, but this method is also the most challenging to execute in petrophysical and static modelling software. Of the conventional equation-based approaches, the K-Function model appears to have the most utility and are recommended as first choice saturation-height models to test. It only has two inputs for the modelling comprising of RQI and HAFWL.

This study continues the extended concepts of Adams (2016) and Harrison (2001) to describe quantitative comparisons between modelled and measured capillary pressure measurements over the functions and through different reservoirs.

The review presented could not include all possible equations, but shows which of the most frequently cited functions, is likely to be of utility. Areas for future improvement are also highlighted.
The Persistence of Child and Adolescence Mental Healthcare: Results from Registry Data
Authors: Dijk Hermien , Freriks Roel , Alessie Rob , Mierau Jochen
Published: November 2020

Background: Previous studies on the persistence of child and adolescent mental healthcare do not consider the role of time-invariant individual characteristics. Estimating persistence of healthcare using standard linear models yields biased estimates due to unobserved heterogeneity and the autoregressive structure of the model. This study provides estimates of the persistence of child and adolescent mental healthcare taking these statistical issues into account. Methods: We use registry data of more than 80,000 Dutch children and adolescents between 2000 and 2012 from the Psychiatric Case Registry Northern Netherlands (PCR-NN). In order to account for autocorrelation due to the presence of a lagged dependent variable and to distinguish between persistence caused by time-invariant individual characteristics and a direct care effect we use difference GMM-IV estimation. In further analyses we assess the robustness of our results to policy reforms, different definitions of care and diagnosis decomposition. Results: All estimation results for the direct care effect (true state-dependence) show a positive coefficient smaller than unity with a main effect of 0.215 ( p < 0.01), which indicates that the process is stable. Persistence of care is found to be 0.065 ( p < 0.05) higher for females. Additionally, the majority of persistence of care appears to be associated with time-invariant characteristics. Further analyses indicate that (1) results are robust to different definitions of care and (2) persistence of care does not differ significantly across subgroups. Conclusions: The results indicate that the majority of mental healthcare persistence for children and adolescents is due to time-invariant individuals characteristics. Additionally, we find that in the absence of further shocks a sudden increase of 10 care contacts in the present year is associated with an average of less than 3 additional care contacts at some point in the future. This result provides essential information about the necessity of budget increases for future years in the case of exogenous increases in healthcare use.
MSCs‑derived exosomes attenuate ischemia-reperfusion brain injury and inhibit microglia apoptosis via exosomal miR-26a-5p mediated suppression of CDK6
Authors: Cheng Chang , Chen Xiuying , Wang Yuhan , Cheng Wenchao , Zuo Xuzheng , Tang Weiju , Huang Wen
Published: November 2020

Background: This study aims to explore the role of mesenchymal stromal cells (MSCs)-derived exosomes (MSCs-Exo) in the cerebral ischemia-reperfusion (I/R) injury.Methods: Exosomes were isolated from MSCs of adult C57BL/6J mice by the gradient centrifugation method. The expression of miR-26a-5p and CDK6 in MSCs-Exo and mice brain tissues were evaluated by qRT-PCR and western blot. MiR-26a-5p mimics and miR-NC were transfected into MSCs, and exosomes were isolated from the stably expressing MSCs. Then MSCs-Exo-miR-26a-5p mimics or MSCs-Exo-miR-NC was injected into mice through the tail vein, or added into medium to stimulate BV-2 cells. Cell viability was evaluated by CCK-8 assay. Cell apoptosis was detected by flow cytometry. The apoptosis in brain tissues was evaluated by TUNEL staining assay. Bioinformatics analysis and luciferase reporter assay were performed to determine the relationship between miR-26a-5p and CDK6. Results: MiR-26a-5p was downregulated and CDK6 was upregulated in MSCs-Exo of MCAO and OGD model. MSCs-Exo-miR-26a-5p mimics significantly reduced cell apoptosis of OGD-injured BV-2 cells. MSCs-Exo-miR-26a-5p mimics significantly reduced infarct volume of MCAO-induced mice. Luciferase reporter assay revealed that CDK-6 was a target of miR-26a-5p. In addition, MSCs-Exo-miR-26a-5p mimics significantly decreased the expression of CDK6 in both OGD-induced BV-2 cells and MCAO-treated mice brains. Conclusion: Our results indicated that MSCs‑Exo attenuated I/R injury in mice by inhibiting microglia apoptosis via exosomal miR-26a-5p mediated suppression of CDK6. Our study shed light on the application of MSC-Exo as a potential therapeutic tool for cerebral I/R injury.
Estimating the number of people who inject drugs in Cherokee Nation using capture-recapture methods
Authors: Feder Molly , Winters Amanda , Essex Whitney , Mera Jorge
Published: November 2020

Background: Injection drug use is an important public health issue in the United States, and estimates indicate that American Indian and Alaska Native people are disproportionately affected. Injection drug use is also the leading cause of Hepatitis C virus (HCV) infection in the United States, attributable to over half of all cases, and contributes to 44% of human immunodeficiency virus (HIV) acquisition in American Indian and Alaska Native females. Existing estimates of American Indian and Alaska Native people who inject drugs are limited. We aimed to estimate the number of people who inject drugs in Cherokee Nation.Methods: A two-sample, capture-recapture approach was used. The first data source was an abstraction of Cherokee Nation Health Services electronic medical records from February 2017 through December 2018. The second data source was an abstraction from Cherokee Nation’s HCV Elimination Program Database from August 2015 through December 2018. Individuals were included in the abstractions if they were asked if they had injected drugs in the past six months during their health visit. The indirect prevalence estimate of people who inject drugs was calculated in accordance with the UNAIDS/WHO Guidelines on Estimating the Size of Populations Most at Risk to HIV.Results: In total, 198 individuals across both data sources reported that they had injected drugs within the past six months. This included 123 unique individuals from the first source, 69 individuals from the second source, and six individuals who were included in both sources. Capture-recapture calculations indicated an estimate of 1,613 people who inject drugs (95% CI: 1,530.27, 1,694.7). Conclusions: This study was the first attempt at estimating the number of people who inject drugs in Cherokee Nation, and one of the few existing studies to estimate the number of American Indian/Alaska Native people who inject drugs in the United States. Gaining knowledge about the prevalence of people who inject drugs in Cherokee Nation will inform strategies to support addiction care and treatment among people who inject drugs living in Indian Country.
Case Reports of Cerebral Sinus Venous Thrombosis in COVID-19 Patients
Authors: Sitanggang Prysta Aderlia , Tini Kumara , Susilawathi Ni Made , Wijaya Ida Ayu Sri , Dewi Putu Utami , Samatra Dewa Putu Gde Purwa
Published: November 2020

Background: The outbreak of Coronavirus disease 2019 (COVID-19) has started in China since December 2019 and expanding worldwide rapidly with cases of respiratory tract infection and multiple system involvement. Neurological manifestations are not exempted following the reports from various sources about Ischemic and haemorrhagic stroke related to COVID-19, but the reports about cerebral sinus venous thrombosis (CSVT) are still rare.Case presentation: We would like to report two cases of cerebral sinus venous thrombosis in COVID-19 patients following the respiratory manifestations with profound haematological and coagulation disarrangement triggered by COVID-19 and these are assumed as underlying mechanism. These two cases also have different course of disease and outcome which are interesting.Conclusions: CSVT is one of neurological complication and COVID -19 manifestation that can have grave prognosis, if this involves the brainstem venous drainage. Thrombogenesis and coagulation cascades are prolonged despite successful alteration to negative result of severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) reverse transcription polymerase chain reaction (rt-PCR) test. Therefore, monitoring neutrophil to lymphocyte ration (NLR), D-dimer level, fibrinogen and C-reactive protein (CRP) is paramount as well as indicators of poor prognosis.
Epidemiology and management of endometrial cancer: experience of International University Hospital Cheikh Khalifa and Mohammed VI Center for cancer treatment at University Hospital Ibn Rochd Casablanca, Morocco
Authors: Bouziyane Amal , Benaguida Hicham , Lamsisi Maryame , Khoaja Ayoub , Benayad Samira , Ennachit Mohammed , Elkarroumi Mohamed , Benhessou Mustapha , Ennaji Moulay Mustapha
Published: November 2020

Background

Endometrial cancer is the fourth most common cancer in women in high-income countries and its incidence has increased over the past 20 to 30 years. In Morocco, the incidence is close to those found in developing countries, but it is lower than those found in Western countries. To determine some epidemiological aspects of endometrial cancer in Morocco, we conducted a prospective study over 43 months at the International University Hospital Cheikh Khalifa and the Mohammed VI Center for Cancer Treatment at the Ibn Rochd Casablanca University Hospital, Morocco. 93 cases of endometrial cancer were included.
Results

The average age was 64. 36.5% of our patients had early menarche. 17.2% had menstrual cycle abnormalities. The nulliparous patients represent 40.8℅. 3 patients in our series underwent medical hormone treatment. 46.2% of patients claimed to have taken oral contraception during their period of genital activity, 79.5℅ were obese, 62.3% of the patients are diabetic and 49.4% are known to be hypertensive. 9.6% of patients are on hormone therapy with Tamoxifen. Metrorrhagia is the first symptom encountered in 62.2% of cases. Ultrasound was performed on all of our first-line patients and pelvic MRI was the most relevant examination in the pre-therapeutic assessment of endometrial cancer. Endometrial adenocarcinoma of the endometriotic type (81.72%) was the most prominent histological type. The therapeutic attitudes practiced were: Extended total colpohysterectomy for 17 patients. Total hysterectomy with bilateral salpingo-oophorectomy for 93 patients. Omentectomy was performed for 11 patients. 78 patients had undergone pelvic lymph node dissection, while 51 patients had undergone an associated lumbarortic dissection. 44.08℅ of cases were diagnosed at stage (IA) and 18.27℅ of cases at stage (III). At the time when we stopped our study, 42 patients had received radiotherapy as adjuvant treatment, ie 45.1% of cases.
Conclusions

Local and locoregional epidemiological studies should be multiplied to shed light on the interest of prevention by promoting a healthy lifestyle. Besides, genetic studies must be conducted to better understand the place of racial factors as risk factors for this cancer.
Pharmacodynamics of efavirenz 400 mg in treatment-naïve Chinese HIV-infected patients in a prospective cohort study
Authors: Xu Ling , Peng Wenxiu , Song Xiaojing , Li Yanling , Han Yang , Zhu Ting , Fu Qiang , Du Xiaoli , Cao Wei , Li Taisheng
Published: November 2020

Background: The plasma concentration of patients treated with efavirenz (EFV) 600 mg was found to exceed the upper limit of the proposed therapeutic window in most Chinese HIV-infected individuals; thus, dosage reduction of EFV to 400 mg daily warranted consideration. This study aimed to assess the pharmacodynamics of EFV 400 mg for HIV-1-infected patients in China.Method: Twenty cART-naïve individuals were enrolled in this study. EFV 400 mg combined with tenofovir (TDF) and lamivudine (3TC) as an initial antiretroviral regimen was administered for 48 weeks. EFV concentration and T cell subsets as well as HIV RNA load were evaluated at baseline and at 4, 12, 24, and 48 weeks. Moreover, neuropsychiatric adverse effects were also assessed by the Hamilton depression (HAMD) scale and Pittsburgh sleep quality index (PSQI).Results: Eighteen males and two females whose median age was 26 (interquartile range [IQR]: 23-32) years completed 48 weeks of follow-up. The median EFV concentrations were 1.88 (IQR: 1.54-2.42), 1.74 (IQR: 1.36-1.93), 1.93 (IQR: 1.66-2.22), and 1.85 (IQR: 1.54-2.14) mg/L at weeks 4, 12, 24, and 48, respectively. The viral load was 4.59 (IQR: 4.10-5.19) lg copies/mL at baseline, and it decreased by 4.6 (IQR: 3.98-5.18) lg copies/mL from baseline to week 48. Three of 20 (15%), 10 of 20 (50.0%), 17 of 20 (85%), and 18 of 19 (95%) participants had a plasma viral load less than 50 copies/mL at weeks 4, 12, 24, and 48, respectively. The median CD4 cell count was 330 (IQR: 237-410) cells/µL at baseline, and it increased to 473 (IQR: 344-574) cells/µL at 48 weeks. The HAMD score was 5 (IQR: 3-9.8) and 3 (IQR: 2.25-4) at baseline and 48 weeks, respectively. The PSQI score was 4 (IQR: 2-5.8) and 3 (IQR: 2-4) at baseline and 48 weeks, respectively. Dizziness was the most common event, occurring in 70% of patients within the first two weeks of treatment.Conclusion: Patients prescribed EFV 400 mg-containing agents demonstrated favourable virological and immunological responses. The plasma EFV concentration was within the recommended therapeutic range, with fewer adverse reactions than with EFV 600 mg. EFV 400 mg was effective and safe in Chinese HIV-infected patients.Trial registration: NCT04596488; Registered 21 October, 2020; Retrospectively registered
LncRNA URHC promotes cell proliferation by regulating a miR-5007-3p/DNAJB9 axis in hepatocellular carcinoma
Authors: niu kunwei , Qu Shibin , Zhang Xuan , Dai Jimin , Wang Jianlin , Nie Ye , Zhang Hong , Tao Kaishan , Song Wenjie
Published: November 2020

Background: To investigate the underlying mechanisms of lncRNA URHC in HCC. Methods: RT-qPCR, FISH staining, EdU, colony formation, and tumor xenografts experiments were used to identify localized and biological effects of URHC on HCC cells in vitro and in vivo. The Bioinformatics analysis, Dual- luciferase reporter assay, and rescue experiments revealed the potential mechanism of URHC. Results: We found that URHC was mainly localized in the cytoplasm. URHC silencing may inhibit the HCC cells proliferation. And URHC positively regulated the level of DNAJB9 by sponging miR-5007-3p. Conclusion: Together, our study elucidated the role of URHC as a miRNA sponge in HCC, and shed new light on lncRNA-directed diagnostics and therapeutics in HCC.