bluuebunny/crossref_metadata_2025 huggingface dataset:
Dieta cetogénica e saúde mental – revisão narrativa
Authors:   Faculdade de Ciências da Nutrição e Alimentação da Universidade do Porto, Pereira Luísa , Matos Nuno ,   Clube Recreativo Leões de Porto Salvo, Poínhos Rui ,   Faculdade de Ciências da Nutrição e Alimentação da Universidade do Porto
Published: August 2023

As perturbações mentais estão a tornar-se mais prevalentes a nível global, e existe evidência de que a nutrição é um fator crucial no que diz respeito à sua prevalência e incidência. As abordagens de tratamento mais utilizadas, a psicoterapia e a psicofarmacoterapia, nem sempre são acessíveis, toleráveis ou eficazes no alívio dos sintomas. As dietas cetogénicas, restritas em hidratos de carbono, moderadas em proteína e ricas em gordura, são há muito utilizadas no tratamento de epilepsia refratária e, mais recentemente, têm vindo a ser investigadas no âmbito de muitas outras condições metabólicas, neurodegenerativas e do neurodesenvolvimento. Este trabalho pretende rever a evidência existente relativamente à utilização das dietas cetogénicas na prevenção e tratamento de perturbações mentais. Foi realizada uma pesquisa nas bases de dados PubMed e Scopus, de fevereiro a junho de 2022. Os estudos encontrados atribuem às dietas cetogénicas um efeito ansiolítico, antidepressivo, estabilizador do humor e antipsicótico, para além de reduções significativas na sintomatologia de várias outras perturbações, como autismo, ingestão compulsiva, hiperatividade e abuso de substâncias. Contudo, os estudos em humanos são escassos e de baixa qualidade. Em conclusão, a escassez de ensaios clínicos aleatorizados e controlados não permite traçar, neste momento, conclusões firmes sobre a eficácia das dietas cetogénicas nas perturbações mentais. No entanto, o seu carácter promissor justifica a realização de mais estudos.
Örgütsel Sinizm, Örgütsel Sessizlik, İşte Sözde Var Olma ve Sessiz İstifa Arasındaki İlişkiler: İstanbul Maltepe Belediyesi Örneği
Authors: AVCI Nuri
Published: August 2023

Günümüzde işyerinde çalışan ilişkileri, son salgının da dayattığı yeni yaşam biçimleri ve alışkanlıklar nedeniyle yönetilmesi oldukça zor ve karmaşık bir hal almıştır. Çalışanların iş yaşam dengesi sağlamalarında iş dışı unsurların ağırlıkları gittikçe artmaktadır. Bu durum çalışanlarda sinik eğilimlere uygun bir vasat sağlarken işyerinde de örgütsel sessizlik için uygun örgüt iklimi oluşmasına zemin hazırlamaktadır. Bu çalışmanın amacı; örgütsel sinizm, örgütsel sessizlik, işte sözde var olma ve sessiz istifa arasındaki ilişkileri bir yerel yönetim kuruluşu bağlamında incelemek ve bu çalışmada kullanılmak üzere sessiz istifa davranışını ölçmeye dönük ölçme aracı geliştirmektir. Araştırma nicel araştırma deseninde planlanmıştır. Araştırmanın örneklemini bir yerel yönetim kuruluşu çalışanı yüksek öğrenim mezunu 250 kişi oluşturmaktadır. Ölçme aracı olarak Örgütsel Sinizm Ölçeği, Örgütsel Sessizlik Ölçeği, Stanford İşte Sözde Var Olma Ölçeği ve bu çalışma için geliştirilen Sessiz İstifa ölçeği kullanılmıştır. Çalışmadan elde edilen bulgulara göre; çalışanların sinizm ve örgütsel sessizlik algılarının sessiz istifa davranışı üzerinde olumlu anlamlı etkisi vardır. Örgütsel sinizm algısının işte sözde var olma davranışı üzerinde negatif anlamlı etkisi vardır. İşte sözde var olma davranışı ile sessiz istifa davranışı arasında anlamlı ilişki yoktur. Geliştirilen ölçeğin yüksek içsel tutarlığa (Cronbach Alpha 0,81) ve yapı geçerliliğine sahip olduğu görülmektedir.
Kredi İvmesi ve Kredi Değişkenleri Açısından Tüketici Kredileri ile Ekonomik Büyüme Arasındaki İlişki
Authors: BARLAS Burcu , ÖZKUL Gökhan
Published: August 2023

Tüketici kredileri ekonomide önemli bir ivme yaratarak ekonomik büyümede itici bir rol oynamaktadır. Bu çerçevede çalışmanın amacı Türkiye’de 2006Q1-2020Q2 dönemleri arasında ekonomik büyüme ve tüketici kredileri arasındaki ilişkiyi incelemektir. Çalışmada büyüme değişkeni olarak mevsim ve takvim etkisinden arındırılmış harcamalar yöntemiyle zincirlenmiş gayrisafi yurt içi hasıla değişim oranı, kredi değişkeni olarak hacim ve tutar değişkenleri ile Biggs vd. (2009) tarafından literatüre kazandırılan kredi ivmesi (kredi akımlarında meydana gelen değişimlerin ekonomik büyümeye olan oranı) değişkeni kullanılmıştır. Literatürde yer alan kredi ivmesine ek olarak iki kredi ivmesi modeli daha geliştirilmiş ve bu modeller de analize dahil edilmiştir. Analizde değişkenlere ADF, Phillips-Perron, KPSS ve Fourier KPSS birim kök testleri uygulanmıştır. Değişkenler arasındaki nedensellik ilişkisi Fourier Granger nedensellik ve Toda Yamamoto nedensellik testi ile incelenmiştir. Fourier Granger nedensellik testi sonuçlarına göre tüketici kredisi hacmi ve yıllık reel hacim ve GSYH verileri ile hesaplanan tüketici kredisi ivmesi ekonomik büyümenin nedenidir. Toda Yamamoto nedensellik testi sonuçlarına göre ise tüketici kredisi kullandırım tutarı ve yıllık reel hacim ve GSYH verileri ile hesaplanan tüketici kredisi ivmesi ekonomik büyümenin nedenidir.
3D measurements of water surface elevation using a flash lidar camera
Authors: O'Dea Annika , Spore Nicholas , Jernigan Tanner , Bruder Brittany , Conery Ian , Straub Jessamin , Brodie Katherine
Published: August 2023

This Coastal and Hydraulics Engineering technical note (CHETN) presents preliminary results from a series of tests conducted at the US Army Engineer Research and Development Center (ERDC), Coastal and Hydraulics Laboratory (CHL), Field Research Facility (FRF), in Duck, North Carolina, to explore the capabilities and limitations of the GSFL16K Flash Lidar Camera in nearshore science and engineering applications. The document summarizes the spatial coverage and density of data collected in three deployment scenarios and with a range of tuning parameters and provides guidance for future deployments and data-collection efforts.
Demokrasi Indonesia: Antara Barat dan Islam
Authors: Khoerudin Fachri
Published: August 2023

Demokrasi merupakan sistem pemerintahan yang berasal dari tragedi bangsa Barat yang sangat menekankan akan superioritas manusia dalam pelaksanaannya. Hal ini tentu menjadi masalah, terutama apabila sistem tersebut diterapkan di negara-negara Islam yang secara filosofis sangat berbeda. Termasuk Indonesia, negara Islam lainnya juga menghadapi permasalahan yang sama tentang demokrasi sehingga tidak jarang mereka melakukan adaptasi terhadap sistem yang sudah menjadi mayoritas untuk digunakan. Alhasil, di Indonesia, muncul demokrasi baru yang secara filosofis lebih agamis, meski secara teknis tidak mengalami banyak perubahan. Tentu harus dijelaskan lebih lanjut tentang demokrasi Indonesia, apa benar demokrasi benar-benar berbeda, atau hanya sebatas akal-akalan semata agar bisa diterima dalam hati masyarakat yang pada saat itu mayoritasnya muslim. Penulis akan mengkajinya langsung lewat pemaparan dari ungkapan founding father Negara Indonesia agar ditemukan konsep yang riil terhadap masalah yang ada, lalu membandingkan mana yang lebih cocok dengan demokrasi Indonesia, nilai Islam atau nilai Barat.
Pembebasan Perempuan Qasim Amin: Telaah Kritis Pemikirannya Terhadap Hijab
Authors: Bachtiar Royyan
Published: August 2023

Diskursus mengenai perempuan di Barat selalu menjadi topik hangat. Hal tersebut dikarenakan mereka kerap mengalami kekerasan dan pelecehan. Di sisi lain, institusi agama dan pandangan masyarakat dianggap turut mendukung terjadinya sikap tersebut. Hal itulah yang mendorong perempuan Barat untuk bergerak menuntut hak dan kesetaraan dengan laki-laki, yang kemudian mereka sebut sebagai gerakan pembebasan perempuan. Karena itu, berbagai pandangan, gagasan dan konsep, hingga sebuah konvensi internasional dicetuskan, demi memberikan perlindungan dan keadilan.

            Ternyata, pandangan dan gerakan serupa juga terjadi di dunia Islam. Pandangan tersebut diperkenalkan oleh beberapa cendikiawan muslim sendiri, diantaranya Ali Asghar Engineer, Fatima Mernissi, Amina Wadud dan sebagainya. Secara umum, para pembela perempuan ini berpandangan bahwa kaum perempuan Islam juga mengalami perlakuan diskriminatif, pembatasan, dan ketidakadilan, bahkan dianggap sebagai makhluk lemah. Akibat pandangan tersebut, muncul-lah gerakan emansipasi perempuan yang menuntut kesetaraan di bidang yang diminati laki-laki, dan juga (terkadang) ada upaya penafsiran ulang atas nash yang dianggap bias gender.
Guest Editorial: How a Healthy Work Environment Drives a Healthy P&L
Authors: Harriman Matt
Published: August 2023

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People who are passionate about running businesses often talk about money or people—but not both.

Imagine, a chief operating officer at an oil company who doesn’t listen to any ideas that won’t result in more barrels or more money, right now. Many of us in the oil and gas industry know what it feels like to work in that organization.

Or the human resources leader that puts together an offsite meeting with personality tests, teambuilding exercises, and some “feel-good” work that has nothing to do with the actual work of the company.

Both examples have their place and their value, but they never work well together. It’s one or the other.

This is because of a widespread belief that what is right for a business and what is right for the people that work within one are inherently in conflict with each other.

At best, people view them as opposing forces to balance. At worst, they’re seen as incompatible ideas and there’s no town big enough for the both of them.

I call nonsense.

What’s Good for People? Elimination of Frustration

Whether it’s the fabled “TPS Reports,” jammed printers, or (multiple) inept bosses, we all have things at work that make our days worse. Some of them are minor annoyances like an extra copy/paste step, but many of them cause damage to our focus, ability to make decisions, and overall efficacy at our jobs.

What is one of the worst? Poor communication. Usually, small teams are not too bad at communication. But cross-department collaboration (or the lack thereof) is almost always an area where companies of all sizes can find room for improvement.

Give Them a Reason To Care

Obviously pay and benefits are a good reason to care about your work. But there is a big difference in your attitude if you are simply “here so I don’t get fired” vs. truly caring about your work, your company, and the people you work with.

This is what people mean when they talk about “employee engagement.”

What makes someone care about their work beyond a paycheck? It varies, but here are a few high-probability ideas:

- Ensuring they understand the impact of their work on the big picture.

- Supporting their personal growth goals, i.e., leadership growth, skill development, new challenges.

- Fostering a fair work environment. Involve employees in decisions for the company.

What’s Good for Business? A Smooth Process

A process that is effective, efficient, and integrated and one that is “not too bad” are worlds apart.

Everyone knows that process problems cause wasted time and resources. But many people underestimate the real cost—the missed upside. That time spent dealing with bad process is time that should have been spent driving better decisions or improving the business. If you make good people do both by working more than they want to, they will leave.

And here’s a hint to the punchline: improving a process looks a lot like eliminating frustrations.
BP’s Argos FPU Offers Fresh Lessons for the Future of Deepwater GOM Projects
Authors: Wright Blake
Published: August 2023

Tipping the scales at well over 60,000 tons, BP’s Argos platform is a giant among giants in the deepwater US Gulf of Mexico (GOM). Standing 27 stories tall, the platform has a deck the length and width of an American football field and is one of BP’s largest in the region. One-time KBR subsidiary GVA designed the semisubmersible, the centerpiece of the supermajor’s $9 billion Mad Dog II project built to unlock additional production potential of the Miocene-aged reservoirs estimated to hold more than 5 billion bbl of oil in place.

But that wasn’t always the plan.

Over a decade ago, BP’s Mad Dog II looked quite different. On paper, the producer was looking at an all-subsea development tied back to another large spar platform—dubbed Big Dog—to host the additional reserves. The development plan envisioned a massive truss spar. Its topsides would need to be installed via three separate offshore lifts then fully integrated at the field site. Any offshore heavy lift is an execution risk. In 1998, an accident while lifting the south module onto Texaco’s Petronius compliant tower in the GOM resulted in the loss of that section of the topsides and delayed the project for a year and a half. That module weighed 3,600 tons.

Another hesitation for BP? The price tag. All-in, the spar-based Mad Dog II solution was estimated to cost around $19 billion. That included 30-plus wells. Ultimately, the spar concept was scrapped, and BP moved back to square one and a blank sheet of paper.

“The reserves were there,” said Chris Ruthven, project general manager, Mad Dog II. “We knew the reserves were there. In fact, ironically, the team developed the field with the smallest of the four big platforms that BP did back at that point in time: Thunder Horse, Holstein, Atlantis, and Mad Dog. It was the smallest, but ultimately, it was the second-biggest field. It turned out to be huge. All that appraisal showed we’ve got a lot of reserves. So, we went back and went with an analog to Atlantis. Atlantis was seen as a good fit requiring much less offshore integration work. Operations loved the asset, and it was a very safe design. We landed on that concept, and we tried to keep it almost pretty much the same in terms of the overall layout of the facility, but it’s a little bit bigger footprint.”

Mad Dog proper was discovered in 1998 via an exploration well in over 6,100 ft of water located in Green Canyon Block 826. The well was drilled to a measured depth of 22,410 ft and encountered around 215 ft of hydrocarbon-bearing Miocene reservoirs. The discovery was followed by a 1999 well drilled to a total depth of 22,410 ft and a further successful appraisal well in February 2000.

Mad Dog, covering Green Canyon blocks 825, 826, and 782, was sanctioned as a spar-based development in 2002. The project came online in early 2005.
Technology Focus: Reservoir Simulation (July 2023)
Authors: Abraham Anson
Published: August 2023

As 2022 drew to a close, we saw the emergence of ChatGPT, a development that left me both fascinated and slightly apprehensive. Initial posts on LinkedIn and similar platforms focused on its impressive capabilities, yet it wasn’t long before discussions of its inherent biases began to surface.

Artificial intelligence (AI) and machine learning (ML) technologies have rapidly progressed and have significantly affected traditional reservoir engineering, bringing innovative methodologies to reservoir simulations. However, it is essential to understand that these AI and ML technologies are only as effective and trustworthy as the data they are trained on. Limiting the data we feed these systems might inadvertently restrict their predictive power and the scope of their solutions.

As we increasingly rely on these data-driven tools for decision-making, we must be cautious of the conclusions they draw and the narratives they generate. These can subtly shape our viewpoints, highlighting the need for a firm understanding of fundamental principles. I am reminded of a term coined by Daniel Yang: the “Nintendo Engineer,” an engineer whose thought process is guided by simulations rather than the other way around.

With this in mind, returning to the foundational principles underpinning our field is crucial. This approach could counterbalance our reliance on AI and ML technologies, helping us maintain a well-rounded perspective.

The papers I am recommending for your reading embody this mindset.

The first paper highlights these technologies’ practical challenges and constraints, offering valuable insights for reservoir engineers. The authors emphasize the need for a balanced approach that combines these advanced techniques with informed decision-making.

They also highlight that only some optimization problems can be solved with a plug-and-play approach and that the engineer has to frame the problem in a manageable and meaningful way.

The second paper addresses the limitations of the conventional Stone II three-phase permeability model and presents a novel, robust alternative. It takes a fundamentals-based approach to develop an alternative model for the three-phase relative permeability model. Inherent in this recommendation is my bias toward heavy oil because it is the area I currently work in.

The third paper showcases the remarkable potential of AI in supplementing traditional reservoir simulation. The paper’s real-world application demonstrates the practicality and adaptability of AI in reservoir engineering and simulation.

I hope you enjoy reading this selection of papers and find them enlightening.

Recommended additional reading at OnePetro: www.onepetro.org.

URTEC 2021-5549 Use of Machine Learning Production Driver Cross Sections for Regional Geologic Insights in the Bakken Three Forks Play by T. Cross, Novi Labs, et al.

SPE 214219 Business Intelligence Dashboarding Application in Reservoir Simulation by Ke Wang, ADNOC, et al.
Approach Improves Vertical and Areal Sweep in Tengiz Platform Sour-Gas Injection
Authors: Carpenter Chris
Published: August 2023

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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 203995, “Injection and Production Optimization for Tengiz Platform Sour-Gas Injection by Reactive and Proactive Conformance Completions Control,” by Shusei Tanaka, SPE, and Matthieu Rousset, SPE, Chevron, and Yousef Ghomian, SPE, Tengizchevoil, et al. The paper has not been peer reviewed.

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Sour-gas injection (SGI) operations have been implemented in the Tengiz field since 2008 and will be expanded in a future project. Because of limited gas-handling capacity, production at a high gas/oil ratio (GOR) has posed a challenge, resulting in potential well shutdowns. The objective of the study described in the complete paper was to establish an efficient optimization work flow to improve vertical and areal sweep, thereby maximizing recovery under operational constraints. This will be achieved through conformance-control completions that have been installed in many production and injection wells.

Introduction

The Tengiz field is in northwestern Kazakhstan on the northeast shore of the Caspian Sea. The reservoir extends 20 km2 with an oil column of approximately 1.6 km in a carbonate buildup structure at 3850 m subsea. Tengiz produced oil has a specific gravity of 47 °API with approximately 13% of hydrogen sulfide (H2S) and 3% CO2 in produced gas. At initial reservoir conditions, the GOR was 2,242 scf/STB and oil viscosity was 0.22 cp. At the time of writing, the production strategy follows gas-injection processes in the central to north platform area while depletion drive exists at the platform margin to the slope, where fractures appear to dominate flow dynamics. The production area is maintained above saturation pressure based on surveillance data for both the platform and slope zones.

Tengiz SGI With Vertical Conformance Control

The authors write that 20% of produced gas at Tengiz field is reinjected into the central platform area, which consists of the Bashkirian (Bash), Serpukhovian (Serp), and Visean A (VisA) formations. As the volume of injected gas increases, the neighboring producers observe gas breakthrough with increased GOR. The high-GOR wells need to be shut in to achieve maximum oil production in the plant. As the number of shut-in wells increases, however, it becomes challenging to meet plant capacity because of a lack of active producers, resulting in loss of production.

To avoid production loss, zonal-production and injection-control capability were introduced through conformance-control completions and use of swell packers and sliding sleeves. With completions closed at a high-GOR interval, oil production is expected to be maintained while gas production from the well is reduced.

With the extension of the SGI project, capability will exist to control vertical conformance with the planned completion strategy in 38 producers. In addition, 17 injectors also will have vertical conformance-control capability for selective zonal injections.
Mangrove Restoration and Conservation Effort in Niger Delta Used as Carbon Offset Option
Authors: Carpenter Chris
Published: August 2023

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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 207725, “Mangrove Restoration and Conservation as a Carbon Offset Option: a Case Study in the Niger Delta Region,” by Gustavo C.D. Estrada, Jason Sali, and Patrizio Piras, Eni, et al. The paper has not been peer reviewed.

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Mangroves have gained attention as a carbon offset option because of their high carbon-storage capacity and diverse social and environmental benefits. Carbon stock in mangroves is approximately four times higher than in terrestrial forests and contributes to almost 10% of the global terrestrial carbon pool. In 2017, the Nigerian Agip Oil Company (NAOC) launched an initiative to restore mangroves to promote social and biodiversity benefits while contributing to offsetting its greenhouse-gas (GHG) emissions. The complete paper details the methodology and results of this initiative.

Introduction

Mangroves are coastal ecosystems mainly composed of typical tree and shrub plant species possessing adaptations to unstable, low-oxygen soil; high-salinity water; and frequent submersion. Fauna equally adapted to the unique environmental conditions observed in the mangroves also are considered part of the ecosystem.

Mangrove forests are recognized globally to be of extreme ecological, economic, social, and cultural importance because of the variety of goods and services they provide. Some of these include the protection of the coastline from the energy of the winds and waves and conservation of fishing and biodiversity in coastal and adjacent estuarine waters.

The literature suggests that more than 812,000 ha of mangrove areas, spread over 106 countries or territories, show potential for restoration. Furthermore, mangroves have been lost globally at a rate of 1–2%/year, which may account for an annual emission of approximately 0.09–0.45 GtCO2eq/year that could be avoided through conservation.

Because the dispersion of mangroves propagules (seeds that have germinated while attached to the mother plant) is driven by ocean and estuarine currents, natural recolonization can occur and mangroves recover successfully by secondary succession during a period of 10–15 years if conditions are ideal. However, ecosystem function may take more than a century to be fully reinstated. Understanding the autoecology, hydrological patterns, and factors impairing natural regeneration is key for a successful restoration project. Several examples exist of restoration programs that were unsuccessful for, among other problems, having failed to acquire these key prerestoration data.

During the last 10–15 years, a community-based ecological mangrove restoration effort has emerged based on the recognition that ecological science is not enough to assure successful restoration of mangroves and that social and economic issues must also be integrated.
Technology Focus: Formation Evaluation (August 2023)
Authors: Chen Zhiming
Published: August 2023

Fractures, whether natural or hydraulic, serve as crucial pathways for fluid flow within rock formations. Because natural and hydraulic fractures are generated hundreds of meters underground, their parameters always seem to be a black box. Their influence on pressure propagation and well productivity, however, cannot be overstated. So how well are we doing in fracture evaluation and modeling?

Fracture evaluation can be regarded as an inverse problem, wherein the structural characteristics of a system are deduced based on input and output signals. Our objective is to ascertain the distribution, orientation, connectivity, and properties of fractures through the mathematical and physical methods applied to field data. Generally, we can use fracture-evaluation techniques such as surface tilt fracture mapping, downhole tilt fracture mapping, microseismic fracture mapping, tracer testing, temperature logs, production logs, borehole image logs, downhole video, caliper logs, production analysis, and well testing.

In parallel to fracture evaluation, fracture modeling assumes a computational approach to simulate fractures within subsurface reservoirs. We have various methodologies such as analytical, semianalytical, or numerical approaches to develop fracture models, including dual-porosity models, discrete fracture models, embedded discrete fracture models, and flow-net models. By means of fracture simulations, we can glean valuable insights pertaining to transient pressure behaviors, optimal production schemes, and estimation of ultimate recovery.

Despite the significant progress made, a gap still exists between theoretical advancements and practical field application in fracture evaluation and modeling, because underground fractures are often more complex than initially expected and nonunique solutions for fracture evaluation are commonplace. Thus, fracture evaluation and modeling represent complex and interdisciplinary fields, requiring expertise in geology, reservoir engineering, geomechanics, simulation, and related disciplines. We also need continuous research endeavors and advancements in fracture evaluation and modeling techniques to augment our understanding of fracture behavior and reservoir performance in the oil and gas industry, as demonstrated in the selected papers and recommended additional reading.

Recommended additional reading at OnePetro: www.onepetro.org.

SPE 212296 A Simple Analytical Model for Oil Production From Partially Fractured Reservoirs To Estimate Size of Finite Fracture Networks by Sait I. Ozkaya, Consultant

SPE 209624 A Flow-Net-Based Method for History Matching and Production Prediction of Shale or Tight Reservoirs With Fracturing Treatment by Hui Zhao, Yangtze University, et al.

SPE 209293 A Hybrid Embedded Discrete Fracture Model and Dual-Porosity, Dual-Permeability Work Flow for Hierarchical Treatment of Fractures in Practical Field Studies by Mun-Hong Hui, Chevron, et al.
Subsea Injection Systems Enable Carbon Capture and Sequestration
Authors: Carpenter Chris
Published: August 2023

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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 32460, “Subsea CO2 Injection Systems for CCS Applications: Themes, Challenges, and Opportunities,” by Julian P. Tucker and Kamaldip Randhawa, Baker Hughes. The paper has not been peer reviewed. Copyright 2023 Offshore Technology Conference. Reproduced by permission.

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The complete paper presents a discussion of challenges and opportunities relating to subsea system design for CO2 injection in carbon capture and storage (CCS) applications. The scope of the text includes field development considerations, systems operation and control, intervention, monitoring, and barrier testing. A global review of existing and planned CCS developments is used to identify common system characteristics and core functional requirements. The paper reviews topics associated with CO2 transportation, injection, and storage across multiple disciplines to provide holistic guidance and commentary specifically for subsea system design relating to CO2 injection for CCS applications.

Value Drivers

For widespread adoption of CCS, dedicated geologic carbon storage (GCS) must be a commercially viable activity. Simply put, the cost of storage per tonne of CO2 must be less than the price that can be charged for storage as a service.

Financial incentives also must be present to support the carbon price for development to take place. Transitional incentives to close the gap between costs and the low value of CO2 emissions reduction also may be required to support development.

In all cases, however, the common denominator is that the cost of storage per tonne must be as low as possible. This is driven by the capital expenditure and operating costs of a project (as well as post-injection-period obligations), which include the cost of CO2 transportation and injection systems and associated equipment.

Types of Transportation and Storage Networks

For dedicated GCS, several types of offshore storage systems are available that are linked to different types of emitters, transportation networks, and value chains.

Storage systems linked to natural gas processing facilities may be considered single-point emitters. The overall architecture of these systems, however, will depend on where the CO2-rich production stream is processed and separated before reinjection.

The most common method of CO2 transportation to offshore locations is through a subsea pipeline, which enables a continuous flow of CO2 and a high system availability. It is worth mentioning that some developments also have considered transportation to offshore storage sites by ship, with injection through an intermediate floating storage vessel. Once installed, a pipeline provides continuous injection with high availability, whereas a vessel will be affected by transit time, weather conditions, downtime caused by maintenance, and high operating costs owing to fuel use. Furthermore, challenges with field expansion also may result.
Hybrid Power-Generation Concept Incorporates Offshore Wind
Authors: Carpenter Chris
Published: August 2023

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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 204901, “Hybrid Offshore Power Generation,” by Izleena Md. Iqbar, SPE, Fauzi O.B. Othman, and Hasmi Taib, Petronas, et al. The paper has not been peer reviewed.

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The operator has developed an offshore hybrid power-generation concept to leverage and optimize wind-turbine systems for power generation in weak-wind areas such as Malaysia. In this concept, one gas-turbine generator is replaced by an offshore wind turbine adapted to low wind speeds. This lowers maintenance costs and carbon exposure. Additionally, the fuel gas will be diverted to sales gas, thereby improving economics and making offshore renewable power generation feasible for oil and gas platforms.

Background

Malaysia is situated in a weak-wind area. Most of the operator’s oil and gas platforms are in water depths of more than 60 m, which are considered deep water for offshore wind-turbine systems. Offshore wind-turbine systems generally are expensive and not cost-effective for low-wind-speed areas where the annual average wind speed at hub height is less than 6.5 m/s. For economic reasons, offshore wind turbines are multimegawatt turbines designed for sites of International Electrotechnical Commission Class I or II only. However, a need exists to install CO2-effective, renewable electrical generators with high power density to support industrial plants that cannot follow the wind but are bound to local offshore oil and gas resources.

In view of these challenges, specific criteria have been identified for this project, namely specific rated power, maintenance costs, risk of hazards, capability of a black start (the ability of generation to recover from a blackout), and offshore capability.

Hybrid Offshore Power-Generation Project

From preliminary studies, it was concluded that a reasonable value for specific power is less than 200 W/m² to achieve high-capacity factors in a weak-wind region. The need for low maintenance costs calls for a solution with little technical complexity and a minimum of components. Capability for a black start in an island situation requires storage and parameters for the generator or invertor system of the wind power plant. At the time of writing, no wind turbine can be bought off the shelf for the purposes mentioned. A wind turbine found closest to these criteria is provided by a European manufacturer based in Estonia.

The offshore wind-turbine system consists of a customized wind turbine adapted to harness the energy from the weak-wind area and a microgrid system to integrate the wind turbine with the turbine generators, which are housed on a tension-leg-platform (TLP) floating structure. This floating platform is held by a gravity anchor.
Technology Focus: Gas Production (August 2023)
Authors: Veeken Cornelius (Kees)
Published: August 2023

The demand for natural gas remains unabated and with it the need to further develop and disseminate gas-production-related expertise. A few of the common themes that emerge from recent SPE publications are elaborated upon here.

The recovery of condensate from gas condensate depletion drive reservoirs is much lower than the recovery of gas from the same reservoirs because of condensate dropping out below dewpoint pressure. Besides pressure maintenance, no field-proven methods are yet available to mobilize this trapped condensate. Most papers present model or laboratory results without mentioning field data. The same applies to inflow impairment because of condensate dropout; many modeling studies lack validation against field data. Case in point: Pressure/volume/temperature testing generally does not venture below 500–1,000 psi pressure while many reservoirs reach (near-wellbore) pressures well below that range.

Reducing emissions of natural gas or CO2 has become a key deliverable of most projects. Some papers present dedicated technology, while many others emphasize emission reduction as an important side benefit.

Artificial intelligence (AI) is permeating the exploration and production business, as it does society at large, and features in many recent papers. So far, most applications use advanced data analysis to achieve higher derived data accuracy. This appears to be very successful as long as the evaluated data is within the domain of the training data. It is not always clear how well the AI models perform outside of their training domain. A relevant question is whether complex AI techniques applicable within a restricted domain can or should be used to replace simple, well-established engineering relations. Time will tell how deep and wide AI will affect day-to-day gas production applications.

Recommended additional reading at OnePetro: www.onepetro.org.

SPE 210136 The Reversible Relationship Between Choke Management and Liquid Yield Trends in Shale Reservoirs by Yalda Barzin, Repsol, et al.

SPE 210099 Innovative, Cost-Effective, and Zero-Flaring Solution to Clean Up and Start Up New Wells in a High-H2S Field in Kazakhstan— The Vital Step Forward Toward Net-Zero Carbon Footprint by Timur Tankiyev, Karachaganak Petroleum Operating, et al.

SPE 209745 A Data-Driven Approach To Predict the Critical Gas Flow Rate in Gas Wells by Ehsan Rahmati, Ambyint, et al.
Water Shutoff With a Thixotropic Treatment in Offshore Well Increases Gas Production
Authors: Carpenter Chris
Published: August 2023

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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 209889, “A Successful Water Shutoff Using a Thixotropic Treatment in a Subhydrostatic and Highly Aromatic Well Results in Increased Gas Production of 30% and Reduced Water Production of 63% in Vietnam,” by Tuanangkoon Daohmareeyor, Tran Thang Nguyen, and Reawat Wattanasuwankorn, Halliburton, et al. The paper has not been peer reviewed.

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An offshore operator in Vietnam faced high water production in a subhydrostatic and highly aromatic gas well. In addition to low productivity, the high water cut also strained the water-treatment facility. Previous treatment attempts to shut off the high-water-producing zones have been unsuccessful because of challenging well conditions. A customized solution using a thixotropic organically crosslinked polymer (TOCP) with extensive laboratory testing was found to be the most suitable treatment design for this well. The new placement technique provided prevention of losses to the depleted zones. The thixotropic treatment provided higher viscosity when pumping stopped, allowing the polymer to seal off at the target zone.

Introduction

Excessive water production in mature wells is a major challenge for oil and gas operators worldwide, causing numerous economic issues for hydrocarbon production. In this case, the operator faced concerns with handling the water at the production facility, which had almost reached its capacity limit and would soon result in well abandonment. Furthermore, the well discussed in the complete paper was one of the highest-producing gas wells on the platform. The trend of gas production in this well was decreasing year over year, however, and the previous chemical water-shutoff treatment was not successful because of reasons that included the following:

- The highly depleted formation created difficulties for well-intervention activities and treatment placement.

- A complex well-completion setup was not ideal for well intervention, especially for mechanical isolation applications.

- High aromatic content from the reservoir created incompatibility with mechanical isolation packer elements, risking operational failure.

To achieve a shutoff objective, prejob considerations should include proper candidate selection, root-cause investigation, placement selection, tailored treatment design, and risk-mitigation planning, all of which are important factors of a successful operation. The complete paper presents the design and operational execution to serve as a guideline for future wells with similar issues. The operation’s objective was to shut off the top interval (Interval A) of five intervals in the well to reduce water production and increase gas production.
Exploring Shear Strength of Concrete: A Novel Z-Test for Direct Shear Testing of Plain and Fiber Reinforced Concrete
Authors: Sahlab Ziad Nabil , Volpatti Giovanni , Diaz Jorge Camilo , Zampini Davide
Published: August 2023

With the advent of new concrete materials and advances in structural design, the shear strength of concrete has become increasingly significant. However, the lack of a standardized shear characterization process impedes full utilization of the inherent shear strength of these novel concrete mixes. This paper aims to address this by introducing a novel direct shear test for plain concrete (PC) and fiber reinforced concrete (FRC) that uses standardized samples and loading method. The shear behavior of PC and FRC samples was thoroughly captured using the test. Furthermore, the study observed the effect of fibers on the shear strength and found it to be primarily dependent on the fiber dosage, with samples with higher dosages exhibiting greater shear strength. Additionally, residual strength was found to depend on both the fiber dosage and type, with longer fibers exhibiting slightly better performance and higher ductility. The paper also introduces a validated numerical model to describe the pre-peak behavior of the samples. The combination of experimental and model results provides a quantitative tool to describe the shear behavior of concrete samples and investigate the effect of different parameters on shear strength. In general, this study contributes to the advancement of shear strength characterization in concrete and provides valuable information on the behavior of plain and fiber-reinforced concrete under shear loading, potentially facilitating the direct use of concrete shear strength in the design and construction of new concrete structures.
Short-term recurrence rate of male urethral stricture and its predictors after treatment with optical internal urethrotomy: Prospective Cohort Study at a tertiary center in Ethiopia
Authors: Issack Feysel Hassen , Tefera Alemayehu Tegegne , Teshome Henok , Hassen Seid Mohammed , Gebreselassie Kaleab Habtemichael , Mummed Ferid Ousman
Published: August 2023

Background:Even though, one of the managements options of urethral stricture, popular among the urologists in view of its simplicity, safety and shorter learning curve is optical internal urethrotomy , urethroplasty should be offered as the gold standard treatment option for urethral stricture. The main aim of our study is to determine the one-year recurrence rate of urethral stricture after treatment with optical urethrotomy and identify predicting factors of urethral stricture recurrence at a tertiary centre in Ethiopia.
Materials and Methods: A prospective observational cohort study was conducted on 80 male patients who underwent optical urethrotomy from November 2019 to August 2020 G.C. in a tertiary center in Ethiopia. Logistic regression was used to analyze the association between dependent and independent variables. A p-value of <0.05 was considered statistically significant.
Results: The mean and median age (± standard deviation) of patients at the time of the procedure were 54.76 (± 14.74) and 58 years with a range [20-78], respectively. Urethral discharge was the most common etiology identified in 39 (48.75%) of patients. Eleven (13.75%) patients had no identifiable etiology for their urethral stricture disease.
Majority of patients presented with at least one voiding lower urinary tract symptoms .
Sixty-eight (85%) patients out of the total had single stricture and 12 (15%) had multiple strictures. The location of stricture was in the bulbar urethra on cysto-urethrography in 83% of the patients. The one-year recurrence rate of urethral stricture after optical urethrotomy was 35% in our study.
Number of strictures and presence of hypertension were independent predictors of recurrence of urethral stricture within one year after treatment with optical urethrotomy [AOR=15.35(2.92-80.61) at 95% CI; P=0.00] and [AOR=19.47(2.11-178.98) at 95% CI; P=0.01], respectively.
Conclusions
Our study identified that multiple strictures, and presence of hypertension are associated with increased recurrence rate in the first post-operative year.
Clinical course of COPD patients with exercise-induced elevation of pulmonary artery pressure or less severe pulmonary hypertension presenting with respiratory symptoms and the impact of bosentan intervention— prospective, single-center, randomized, parallel-group study
Authors: Kashiwada Takeru , Tanaka Yosuke , Tanaka Toru , Okano Tetsuya , Saito Yoshinobu , Seike Masahiro , Hino Mitsunori , Kimura Hiroshi , Gemma Akihiko
Published: August 2023

Background: The data on bosentan were lacking for the treatment of exercise-induced elevation of pulmonary artery pressure (eePAP) or less severe PH in COPD. This study was conducted to investigate long-term efficacy and safety of bosentan for the treatment of eePAP or less severe PH in COPD.
Methods: COPD patients diagnosed at this hospital as having COPD (WHO functional class II, III or IV) with eePAP or less severe PH whose respiratory symptoms were stable but remained and gradually progressed even after COPD therapy were randomly assigned in a 1:1 ratio to receive either bosentan or no PH treatment for two years and assessed at baseline and every 6 months for respiratory failure, activities of daily living (ADL), lung and heart functions by right cardiac catheterization, and other parameters.
Results: A total of 29 patients who underwent RHT for detail examination were enrolled in the current study between August 2010 and October 2018.No death occurred in drug-treated group (n = 14) for 2 years; 5 patients died in untreated group (n = 15). Significant differences were noted between the 2 group in hospital-free survival (686.00 ± 55.87 days vs. 499.94 ± 53.27 days; hazard ratio [HR], 0.22; P = 0.074) and overall survival (727 days vs. 516.36 ± 55.38 days; HR, 0.11; P = 0.048) in all causes of death analysis, but not in overall survival in analysis of respiratory-related death. Bosentan was not associated with increased adverse events including requiring O2 inhalation.
Conclusions: This study suggested that the prognosis for COPD patients with eePAP or less severe PH presenting with respiratory symptoms was very poor and that bosentan tended to improve their prognosis and suppress ADL deterioration without worsening respiratory failure.
Trial registration: This study was registered with UMIN-CTR Clinical Trial as UMIN000004749.
(https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000005654).
First trial registration at 18/12/2010
Disentangling effects of anthropogenic disturbance and community structure on multi-pathogen dynamics in tropical cave-dwelling bat communities
Authors: Vicente-Santos Amanda , Ledezma-Campos Paula , Rodríguez-Herrera Bernal , Corrales-Aguilar Eugenia , Czirják Gábor , Civitello David , Gillespie Thomas
Published: August 2023

Cave-dwelling bats' persistence in degraded habitats provides a unique opportunity to examine the dual effects of community structure versus habitat degradation on disease prevalence. To evaluate how disturbance and cave complexity influenced bat community composition and the prevalence of multiple pathogens in bat communities, we conducted surveys of 15 caves in Costa Rica along an anthropogenic disturbance gradient. Collecting samples from 1,238 individuals, representing 17 species from four families, we determined the prevalence of four common and divergent pathogens: Bartonella (19.7%), Leptospira(22.7%), Trypanosoma (32.0%), and microfilaria (6.6%). Cave complexity, but not disturbance, predicted bat community composition—however, degraded habitats sustained smaller populations. For bat richness, we found a negative association with Bartonella prevalence, but a positive association with Trypanosoma and microfilaria and no association with Leptospira. Using a multi-host, multi-pathogen system, our work provides insight into the complex patterns of pathogen dynamics and bat community ecology in changing environments.
The development of a set of key points to aid clinicians and researchers in designing and conducting n-of-1 trials
Authors: Chatters Robin , Hawksworth Liv , Julious Steven , Cook Andrew
Published: August 2023

Introduction:
n-of-1 trials are undertaken to optimise the evaluation of health technologies in individual patients. They involve a single patient receiving treatments, both interventional and control, consecutively over set periods of time, the order of which is decided at random. Although n-of-1 trials are undertaken in medical research it could be argued they have the utility to be undertaken more frequently. We undertook the National Institute for Health Research (NIHR) commissioned DIAMOND (Development of generalisable methodology for n-of-1 trials delivery for very low volume treatments) project to develop key points to assist clinicians and researchers in designing and conducting n-of-1 trials.
Methods
The key points were developed by undertaking a stakeholder workshop, followed by a discussion within the study team and then a stakeholder dissemination and feedback event. The stakeholder workshop sought to gain the perspectives of a variety of stakeholders (including clinicians, researchers and patient representatives) on the design and use of n-of-1 trials. A discussion between the study team was held to reflect on the workshop and draft the key points. Lastly, the stakeholders from the workshop were invited to a dissemination and feedback session where the proposed key points were presented and their feedback gained.
Results
A set of 22 key points were developed based on the insights from the workshop and subsequent discussions. They provide guidance on when an n-of-1 trial might be a viable or appropriate study design and discuss key decisions involved in the design of n-of-1 trials, including determining an appropriate number of treatment periods and cycles, the choice of comparator, recommended approaches to randomisation and blinding, the use of washout periods and approaches to analysis.
Conclusions
The key points developed in the project will support clinical researchers to understand key considerations when designing n-of-1 trials. It is hoped they will support the wider implementation of the study design.