bluuebunny/crossref_metadata_2025 huggingface dataset:
Les manipulations génétiques : comment améliorer la croissance
Authors: HOUDEBINE L.M.
Published: August 2020

Les récents développements de la génétique moléculaire offrent désormais la possibilité d’isoler virtuellement n’importe quel gène, de le muter in vitro, de modifier ses éléments régulateurs, de le réintroduire dans des cellules ou des organismes entiers (transgénèse) et donc, de moduler à volonté une fonction physiologique donnée. Ces possibilités ont été et sont encore appliquées à la fonction de croissance. Ainsi, les gènes du GRF (Growth Releasing Factor), de la GH (Growth Hormone) et de l’IGF1 (Insulin-like Growth Factor) ont été introduits dans des embryons de divers animaux. Ces transgènes se sont exprimés et ont conduit à une accélération de la croissance et à une augmentation de la taille des animaux accompagnée d’un assez profond changement de leur métabolisme. L’incapacité de moduler finement l’expression des transgènes chez les animaux transgéniques se traduit par une sécrétion exacerbée des hormones qui, elle-même, induit une série de désordres physiologiques rendant les animaux transgéniques peu performants. La transgénèse, si elle est devenue une routine chez la souris dans un certain nombre de laboratoires, reste difficilement réalisable à grande échelle chez la plupart des animaux domestiques. Des études approfondies sur les mécanismes de contrôle de l’expression des transgènes et sur les méthodes de transgénèse doivent donc être menées à bien pour que les manipulations génétiques deviennent une réalité dans les techniques d’élevage.
The Silent Partners
Authors: Almogy Gal
Published: August 2020

Despite great advances in understanding the dynamics of viral epidemics, the emergence of rapidly spreading, highly pathogenic viruses remains a realistic and catastrophic possibility, which current health systems may not be able to fully contain. An intriguing feature in many recent zoonotic viral outbreaks is the presence of superspreaders, which are infected individuals that cause dramatically more new cases than the average. Here I study the effect of superspreaders on the early dynamics of emerging viruses that have not gained the capacity for efficient human-to-human transmission, i.e viruses with R0 < 1. I show that superspreaders have a higher chance of rapid extinction, but under crowded conditions can lead to outbreaks, causing far more cases than regular viruses. I suggest that outbreaks of highly pathogenic superspreaders are more likely when they coincide in time and space with an unrelated outbreak leading to increased hospital admission rates. These superspreader outbreaks may be difficult to detect, especially in the context of a different epidemic in progress, and can significantly affect mortality patterns observed in affected areas.
Nanomaterials in Dentistry: State of the Art and Future Challenges
Authors: Bonilla Victoria , Abalos Camilo , Herrera Manuela , Guerrero-Pérez M. Olga
Published: August 2020

The results of the bibliographic analysis show that the most explored nanomaterials in dentistry are graphene and carbon nanotubes, and their derivatives. A detailed analysis and a comparative study on their applications show that, although they are quite similar, graphene based materials seem to be more promising for most of the applications of interest in dentistry. The bibliographic study also demonstrated the potential of zeolite based materials, although the low number of studies on their applications shows that they have not been totally explored, as well as other porous nanomaterials that found important applications in medicine, such as metal organic frameworks, have not been explored. Subsequently, it is expected that the research effort will concentrate in graphene and zeolite based materials in the incoming years. Thus, present review paper presents a detailed bibliographic study, with more than 200 references, in order to describe briefly the main achievements that have been described in dentistry using nanomaterials, compare and analyze them in a critical way, with the aim of predicting the future challenges.
Operationalizing Ensemble Models for Scientific Advice to Fisheries Management
Authors: Jardim Ernesto , Azevedo Manuela , Brodziak Jon , N. Brooks Elizabeth , F. Johnson Kelli , Klibansky Nikolai , P. Millar Colin , Minto Coilin , Mosqueira Iago , D.M. Nash Richard , Vasilakopoulos Paris , K. Wells Brian
Published: August 2020

There are uncertainties associated with every phase of the stock assessment process, ranging from the collection of data, assessment model choice, model assumptions and interpretation of risk to the implementation of management advice. The dynamics of fish populations are complex, and our incomplete understanding of those dynamics (and limited observations of important mechanisms) necessitate that models are simpler than nature. The aim is for the model to capture enough of the dynamics to accurately estimate trends and abundance and to provide advice to managers about sustainable harvests. The \textit{status quo} approach to assessment modelling has been to identify the `best' model, based on diagnostics and model selection criteria, and to generate advice from that model, mostly ignoring advice from other model configurations regardless of how closely they performed relative to the chosen model. We review the suitability of the ensemble modelling paradigm to more fully capture uncertainty in stock assessment model building and the provision of advice. We recommend further research to evaluate potential gains in modelling performance and advice from the use of ensemble modelling, while also suggesting revisions to the formal process for reviewing models and providing advice to management bodies.
Pengembangan Media Paspop pada Materi SBdP di Sekolah Dasar Kecamatan Jabung
Authors: Rahayunita Cicilia Ika , Werdiningtyas Ratih Kartika
Published: August 2020

Abstract: Teachers have difficulty in linking concepts between subjects to a theme, due to the lack of thematic learning media that can help teachers in linking concepts between subjects in SDN Sidorejo 2. Teachers need paspop learning media that can support students in learning to use thematic approaches (Language Indonesia, Natural Sciences and SBdP). The purpose of this study was to develop and analyze the influence of paspop media on SBdP material in class V. The research development of the media uses the four D method (define, design, develop and disseminate). The results of the validation of media experts and material experts were 87.50% and 88% with very decent criteria. Data attractiveness of the media for students scored with a percentage of 91% categorized very well. Student learning outcomes using the media Bapang mask postpop stated that students who completed totaled 28 with a percentage of 87.5%.

Abstrak: Guru kesulitan dalam mengaitkan konsep antar mata pelajaran pada suatu tema, karena kurang tersedianya media pembelajaran tematik yang dapat membantu guru dalam mengaitkan suatu konsep antar mata pelajaran di SDN Sidorejo 2. Guru membutuhkan media pembelajaran paspop yang dapat mendukung siswa dalam belajar menggunakan pendekatan tematik (Bahasa Indonesia, IPA dan SBdP). Tujuan penelitian ini untuk mengembangkan dan menganalisis pengaruh media paspop pada materi SBdP di kelas V. Penelitian pengembangan media tersebut menggunakan metode four D (define, design, develop dan disseminate). Hasil validasi ahli media dan ahli materi sebesar 87,50% dan 88% dengan kriteria sangat layak. Data kemenarikan media bagi siswa memperoleh nilai dengan persentase 91% berkategori sangat baik. Hasil belajar siswa  dengan menggunakan media paspop topeng Bapang menyatakan bahwa siswa yang tuntas berjumlah 28 dengan persentase 87,5%.
Penerapan Teori Belajar Van Hiele Untuk Meningkatkan Aktivitas Dan Hasil Belajar Siswa Pokok Bahasan Luas Persegi, Persegi Panjang, Dan Segitiga
Authors: Pratiwi Farisia , Sugiarti Titik , Hutama Fajar Surya
Published: August 2020

Tujuan dalam penelitian ini adalah untuk meningkatkan aktivitas dan hasil belajar siswa kelas IV SDN Kepatihan 05 Jember melalui penerapan teori belajar van Hiele.  Jenis penelitian yang digunakan adalah Penelitian Tindakan Kelas (PTK). Penelitian ini dilaksanakan sebanyak dua siklus. Setiap tindakan meliputi perencanaan, pelaksanaan, pengamatan, dan refleksi. Teknik pengumpulan data yang digunakan adalah observasi, wawancara, tes hasil belajar, dan dokumentasi. Subjek penelitian ini adalah seluruh siswa kelas IVA SDN Kepatihan 05 Jember yang berjumlah 28 siswa. Hasil penelitian ini menunjukkan bahwa persentase aktivitas belajar siswa mengalami peningkatan. Pada siklus I menunjukkan hasil sebesar 56,29 persen dengan kriteria cukup, sedangkan pada siklus II sebesar 76,66 persen dengan kriteria baik. Rata-rata hasil belajar siswa juga mengalami peningkatan. Pada siklus I menunjukkan hasil sebesar 55,74 dengan kriteria cukup, sedangkan pada siklus II sebesar 75,71 dengan kriteria baik. Berdasarkan hasil penelitian, maka dapat disimpulkan bahwa penerapan teori belajar van Hiele dapat meningkatkan aktivitas dan hasil belajar siswa kelas IVA SDN Kepatihan 05 Jember.
Slow Release of Surfactant Using Silica Nanosized Capsules
Authors: Alsmaeil Ahmed W. , Enotiadis Apostolos , Hammami Mohammed A. , Giannelis Emmanuel P.
Published: August 2020

Engineering and scaling-up nanocarriers for the controlled release of surfactant are imperative for enhanced oil recovery (EOR). Herein, using silica-based nanosized porous capsules to slowly release surfactant in saline water is reported. The results indicate that the silica shell ensures the stability of the protected surfactants in the cores under harsh conditions. Almost negligible release was noticed in salt-free brine [deionized (DI) water]. In saline brine, the particles slowly released surfactant molecules. Forty-six percent of the total surfactant encapsulated was released after 12 days as quantified by the remaining organic content after mixing with brine. Scanning electron microscopy (SEM) analysis confirms the stability of the surfactant incorporated particles in saline water that contains 56 000 mg/L salts.
Fractional Flow Behaviour and Transport Mechanisms During Low salinity and Protein Enzyme Bio-surfactant EOR Flooding
Authors: Morgan Anthony , Akanji Lateef , Udoh Tinuola , Mohammed Shaibu , Anumah Prosper , Kyeremeh Sarkodie Justice
Published: August 2020

The focal point of this project is to investigate and assess the potentiality of an enhanced waterflooding process by a naturally generated surfactant (Protein-Enzyme bio-surfactant). The effect of low salinity (LSW), and LSW combined with a bio-surfactant (Protein-Enzyme) in a tertiary mode flooding comparatively. A high salinity water (HS) (0.75 M) was used to flood in the secondary mode after aging the crude saturated core with an initial water saturation of 19%, a recovery of 68.15% oil initially in place (OIIP) was recovered until no further recovery. Upon flooding with a LSW (90% dilution of HS), a further incremental recovery of 11.1% OIIP was produced. Enhancing the LSW with bio-surfactant in a third flooding sequence, an additional 3.75% OIIP was recovered. Analysing the mechanism of LSW bio-surfactant with fractional flow, a high recovery of 0.583 PV (pore volumes) at breakthrough was estimated. Thus, an alteration in ionic strength (salinity) by a 90% dilution and combination of bio-surfactant, saw an incremental recovery, which indicates the potential of LSW bio-surfactant on recovery of residual oil saturation.
Water Injection in Complex Geology: A Case Study of a Field in the Niger Delta
Authors: Ihebuzor Valentine , Onyeneke Obinna , Obasi Ogbonnaya
Published: August 2020

Water injection is a secondary recovery mechanism often initiated when the primary drive of a reservoir / field is not enough to maintain pressure. Injected Water supports the pressure of the reservoir through voidage replacement, which in the process stimulates production by displacing oil from the reservoir towards the well. Apart from the objective of maintaining pressure and enhancing production, water injection can also be employed as a means of produced water disposal. However, most water injection projects fail on account of poor reservoir conceptualization in the modeling process, the skill of the evaluator, complex geology leading to poor sweep efficiency, water compatibility problems leading to scaling and failure of surface equipment. This paper showcases how a water injection project failed due to poor understanding of the reservoir / field geology, the lessons learnt and what was done differently to successfully conceptualize and execute another water injection project in the same field. To understand the reason why the water injection project failed, attributes were extracted, a conceptual static model was developed, and pressure plots were made, which allude to stratigraphic compartmentalization and poor positioning of the injector as the main culprit. Three (3) scenarios were tested, considering the geologic complexity of the reservoir. Scenario 3 shows a recovery factor of 48.1% and a recoverable volume of about 25.4MMSTB and was adjudged the best development scenario for the reservoir.
A Comparative Analysis of Upward and Downward Pressure Gradient Behaviour in Vertical Gas-Liquid Two-Phase Flows in a Large Diameter Pipe Facility
Authors: Almabrok Almabrok Abushanaf , Aliyu Aliyu M. , Baba Yahaya D. , Ribeiro Joseph X. , Archibong-Eso Archibong , Lao Liyun , Yeung Hoi
Published: August 2020

Pressure gradient (PG) is vital in the design/operation of process equipment e.g. in determining pumping requirements and has direct effect on capital and running costs. Here, we report a gas–liquid experimental study using a large diameter pipeline system. Pressure was measured at two locations of each section of the upward and downward flowing sections. PG was then determined for a wide range of superficial velocities: usg = 0–30 m/s and usl = 0.07–1.5 m/s. We found varying trends in pressure gradient behaviour between upward and downward flow under similar conditions: from bubbly to annular flow. We give a theoretical account due to the different physical mechanisms. PG values based on prevailing conditions and flow direction were compared. We show that the satisfactory prediction of PG is highly dependent on flow direction and limits of experimental conditions. These factors can have important implications for the design and operation of fluid pipelines in the process, nuclear and oil and gas industries.
Mineralogical Characterization of Ririwai Biotite and its Weighting Effect on Drilling Mud Rheology
Authors: Salahudeen Nurudeen , Mohammed Umar , Yahya Muftahu
Published: August 2020

This study investigates the effect of application of a locally mined drilling mud weighting agent from Ririwai in Doguwa Local Government Area of Kano State. Mineralogical characterization was carried out using X-ray diffraction (XRD). The specific gravity of the material was determined using density bottle apparatus. Water-based drilling mud was prepared using commercial bentonite according to the API 13A Standard. Effect of gradual addition of Ririwai weighting agent; 0 – 100 wt%, on the mud density and rheological property were studied. XRD analysis showed that the material was biotite mineral. The specific gravity of the Ririwai biotite was determined as 2.40. The optimum composition of the drilling mud was 40 wt% Ririwai biotite as weighting agent. The optimum composition gave mud density and plastic viscosity of 9.0 lb/gal and 3 cp respectively. At the optimum composition, the weighting agent increased the mud density by 2.3% while the plastic viscosity decreased by 50%.
Reservoir Characterization, Machine Learning and Big Data – An Offshore California Case Study
Authors: Ojukwu Chima , Smith Kevin , Kadkhodayan Nadia , Leung Mark , Baldwin Kimberly
Published: August 2020

In order to robustly characterize a reservoir and make reservoir management decisions, it is paramount that an integrated and comprehensive study use all available static and dynamic data including petrophysical, geological, geophysical, engineering, and production data sets. These large vintage data sets are often available but are typically underutilized because of poor data management practices and lack of forward-looking data strategies.

This paper presents the results of a supervised classification machine learning (ML) algorithm that accurately identifies reservoir quality associated with the most favorable production trends. The algorithm was trained and tested using log curves, seismic attributes, production, and sidewall core sample data sets.

Lessons learned show the importance of managing data in a way that is complementary to machine learning. In addition, a flexible and forward-looking data strategy provides for rapid and efficient evaluation of reservoir characteristics. These quantitative machine learning results can be factored into field development strategies and help optimize efficiency and capital allocation. Integrating this machine learning workflow supports resource conservation efforts by ensuring optimal production of offshore hydrocarbon resources while minimizing impacts to the environment.
The Impact of Corporate Governance on the Development of Marginal Oil Fields in Nigeria
Authors: Oruwari Humphrey Otombosoba
Published: August 2020

Nigeria position in the international financial landscape, especially in terms of the good governance is affecting business negatively in the country. The study evaluates the impact of corporate governance on the development of marginal oil field in Nigeria. The qualitative method of data collection through literature review and case study were used in the study. Data were analyzed using thematic analysis. The findings of the study revealed that good governance is positively related to the development of marginal oil field. This is because good corporate governance increases investor’s confidence and transparency in the award of marginal oil field contract. Transparency has three-sided paradigm, openness, acceptability, and inclusion or participation. The practical significance of the study is that it will act as planning tool for decision makers. The study established several recommendations namely provision of enabling environment, adequate legal and regulating frame work and good governance.
Multivariate Analytics on Economic Impact of Oil and Gas Price Swing: Nigerian Outlook
Authors: Abdulkadir Usman , Abdullahi Mohammed , Abubakar Mahmud
Published: August 2020

Oil prices have fallen dramatically to the average range of USD $30 to $60 per barrel and are expected to stay in this average range through 2015 and beyond. Historically, crude oil producing countries seemed to be more concerned on the risks and uncertainties associated with fluctuations in crude oil price economic wise globally. This was evident both in times of rising and falling price, imposing serious challenges to them. Moreover, Natural gas also contributes to Nigeria’s GDP resulting from global industrialization and more swing from crude oil price. The implications of these swings significantly influence the economy of the country in question (Nigeria), shaping the narrative around it.

Statistical methods are distinctive in their ability to provide insights into correlations where thresholds exist, building a predictive statistical data-driven model for analyzing the economic impact of swings in crude oil and gas prices with corresponding output has been of great interest in the oil and gas producing countries primarily because of its successful implementation in several industries. The analytics behind the predictive models are described through mathematical functions that rely on monthly and yearly averaged spot oil and gas prices and total oil and gas produced from 2015 to 2019 data range. This research work evaluates the extent to which these variations on crude oil and gas prices with respect to their production effects on Nigerian economy thereby impose a need for a well fitted analytical model for future forecasting based on statistics. The Statistical-analysis tool used to clean and examine the data sets were Multiple Linear Regression Analysis (MLRA) coupled with analysis of variance (ANOVA) where calculations took place in data analysis add-ins tool pack of Microsoft office Excel work sheets using the functions set out by the methodology. Thorough analysis of the results showed that some of the models build to be highly fitted and statistically significant, evident from R-squared values, adjusted R-Squared, standard errors, other hypothesis and statistical assumptions detailed in the results and analysis shows that the basic objective of this research work is achieved.
OML-42 Ramp Up: Reaping Low Hanging Fruits, Pitfalls and Gains
Authors: Awani Oludewa , Owarume Michael , Oton Enoto , Ezuka Ifeanyi
Published: August 2020

Production ramp-up from aging assets poses several challenges, substantial oil gains and attendant learnings.

The scenario for OML-42 was complicated by prolonged production shutdown, associated wells and facility vandalization occasioned by over nine (9) years shutdown by the former operator. Most wells were illegally operated and mis-managed by oil saboteurs during the nine years shutdown.

On acquisition of OML-42, the new investor conducted sequential field Re-entry activities, facilities repair, wells revamp and aggressive production ramp-up campaigns in the fields within OML-42, to minimize Re-entry cost, optimize production and profit.

This paper focuses on production ramp-up initiatives deployed in OML-42 fields to grow production from a pre-reentry rate of50kbopd to 70kbopd, without any rig-based activity. It also elaborates unfamiliar difficulties and learnings derived from the ramp-up campaigns.
Formulation of Imidazolium-Based Ionic Liquids for Methane Hydrate Dissociation
Authors: Sulaimon Aliyu Adebayo , Masri Asiah Nusaibah , Shahpin M. Hazri , Salleh Intan Khalida , Sulaimon Abdul-Azeez Oladimeji , Bello Kelani Olafinhan
Published: August 2020

Formation of gas hydrates in oil and gas production systems constitutes a major flow assurance challenge and the consequences to the smooth production operation could be catastrophic. Recently, there is a shift of focus from total hydrate prevention to risk management which is more economical with reduced storage and injection facilities. Therefore, we have formulated two novel imidazolium-based Ionic Liquids (IM-based ILs) for thermodynamic methane hydrate inhibition. Heating, insulation, and addition of thermodynamic or kinetic inhibitors are strategies to prevent hydrate formation. The COnductor-like Screening MOdel for Realistic Solvents (COSMO-RS) was used to screen and rank several potential IM-based ILs based on their hydrogen bonding energies. 1-ethyl-3-methylimidazolium glutamate (EMIM-GMT), 1-butyl-3-methylimidazolium glutamate (BMIM-GMT) and 1-(3-cyanopropyl)-3-methylimidazolium glutamate (CPMIM-GMT) with hydrogen bonding energies of −62.01 KJ/mol, −61.46 KJ/mol and −67.21KJ/mol respectively were selected and synthesised for performance evaluation. Methane gas of 99.995% purity was used with deionised water to conduct thermodynamic dissociation tests using the SETARAM micro-Differential calorimetry (μDSC 7 Evo-1A). The μDSC was calibrated by comparing the offset dissociation temperature data of deionised water with published data from the literature. Thereafter, the dissociation profiles were obtained at pressures 30, 50, 75, 100, 125, and 150 bars. Results show that for 0.1wt% of the three IM-based ILs, the dissociation temperature increases with pressure and a good thermodynamic inhibition with temperature shift in the range from 0.87 to 1.14°C was observed. The EMIM-GMT achieved the highest geometric average temperature shift of 1.14°C while the CPMIM-GMT and BMIM-GMT shifted the hydrate dissociation envelop by 0.91°C and 0.87°C respectively. Thus, the thermodynamic inhibition performance of EMIM-GMT is better than most of the current EMIM- and BMIM- Halide groups of IM-based ILs with the individual and combined average shift of less than 1.0°C. In this study, we have shown that the effectiveness of an IM-based IL as a thermodynamic methane hydrate inhibitor is largely a function of its hydrogen bonding energy between the water molecule and the IL ions. The relative order of performance of the three IM-based glutamate ILs is EMIM > CPMIM > BMIM.
Post-Drill Pore Pressure and Fracture Gradient Analyses of Y-Field in the Offshore Tano Basin of Ghana
Authors: Ahedor Moses Kofi-Nani , Anumah Prosper , Sarkodie-Kyeremeh Justice
Published: August 2020

A post-drill pore pressure and fracture gradient analyses were conducted on a field in the Tano Basin of Ghana with the primary objective of predicting as accurately as possible the pore pressure, fracture pressure and the overburden pressure from the well logs data of two wells. The wells were drilled offshore in water depths of about 95.4 m and 124.4 m.

Eaton's method coupled with depth-dependent Normal Compaction Trendlines (NCT) and Mathews and Kelly method were used in determining the pore pressure and fracture gradient. The results indicate that average pore pressure gradient, fracture pressure gradient and overburden pressure gradient for the first well are 1.423 psi/m (8.34ppg), 3.514psi/m (20.6ppg) and 4.299psi/m (25.2ppg) respectively whiles values for the second well are 1.423psi/m (8.34ppg), 3.85psi/m (21ppg) and 4.299psi/m (25.2ppg) respectively. These values were predicted to be required to maintain the stability of the wells using accurate mud weight.
Wax Removal and Prevention in an Old Well — Lessons learnt
Authors: Anyanwu Chinedu , Agbo Ejimofor , Olusola Bukola , Olowoyeye Oluwasola , Njoku Ben
Published: August 2020

Wax deposition in producing wells is one of the most challenging flow assurance issues which is worsened when not addressed during well design. EC-40 being the first and only well completed on reservoir X1.0, was completed without provisions for wax inhibition. It produced about 1,100BPD with intermittent mechanical wax cutting intervention every 6 months. However, as production continued, the start-up rate, FTHP and the duration of production continued to reduce thus increasing the frequency of the wax cutting until it became uneconomical. In this paper a combined approach involving the use of chemical solvent and a Wax Inhibition Tool (WIT) was used to remove and prevent wax formation. A Xylene – Diesel chemical solvent was used to dissolve the entire wax in the tubing and restore the well to production while the WIT which prevents wax deposition, was installed at the XN-Nipple of the tubing. The well was opened up to a potential of 1,000 BPD after successfully removing the wax and installing WIT and produced for about 4 months before getting waxed up again. This paper illustrates the lessons learnt from the case study and based on results proposes an optimized way of re-installing the WIT or a retrofit chemical injection valve for wax prevention.
Automated Production Network Model Calibration and Optimization in Agbami Field
Authors: Fagbowore Olufisayo , Okpani Olu , Oyewole Anthony
Published: August 2020

Agbami Field is a deepwater producing asset off the coast of the Niger Delta region in Nigeria. The production system comprises of 26 subsea production wells, 8 subsea production manifolds, subsea flowlines and subsea risers respectively. The production wells are intelligent completions made up of 22 dual zone well completions and 8 single zone well completions. Dual zone well completions are equipped with Interval Control Valves (ICVs) for zonal control & isolation. They are also equipped with several pressure/temperature (P/T) gauges from the sand-face completion to topsides for real time measurement.

Production commenced in 2008 and peak production was achieved a year later in 2009. Field production remained at peak for about 8 years. The stellar field performances have been achieved through several reservoir management best practices. These include, but not limited to, robust initial field development strategy, infill development, acid stimulation operations, Real Time Reservoir Management (RTRM) and production optimization using Intelligent Well Completion (IWC).

This paper demonstrates the development of an automated system which performs Production Network Model calibration and assessment of production optimization opportunities. The key considerations for automated calibration and optimization system workflow development will be presented. Since deployment, the automated calibration and optimization system has reduced the manhours spent with manual model calibration and optimization assessment by 85%.

Lessons learned during the development and deployment of the automated system as well as production gains realized from the solution will be highlighted.
Sustaining Production in Brownfield Assets by Adapting Existing Rigless Workover Technology to Create Well-Specific Solutions
Authors: Haastrup Adeyemi , Adeyinka Adeboye , Ajakaiye Olayinka , Fatile Olufemi , Aina Soji , Adegoke Oluwagbemiga , Aliyev Shahin
Published: August 2020

The changing landscape of global energy and fluctuations in commodity prices have driven companies to get more efficient means to sustain their businesses. With companies seeking more from their assets via rigless interventions, the trend has been that the low-hanging opportunities have been executed. The opportunities left are either too complex for rigless interventions or the expected production is too small to make major-rig workovers economic.

We discuss such complex opportunities that were revisited to ensure sustained production from mature fields. The first case study discusses a gas-lift opportunity that was suspended when tubing leaks were discovered. The three holes posed a challenge since they were quite shallow and not suitable to be used as the injection-point of the gas. The work-around was to use a tubing patch to cover the holes without significantly reducing tubing ID as much as a pack-off would to allow for future well re-entry.

The second case study discusses a well with a tubing restriction that prevented perforation addition. The job stalled when a gauge cutter (similar OD as the available gun) barely passed through the restriction during a dummy run. Even if the gun passed through and was detonated, the expended gun would be swollen and irretrievable due to the restriction. A modified perforating gun that disintegrated upon detonation was used, eliminating the need to retrieve the expended gun.

The third case study was a well completed with mud five decades ago. The mud had caked; preventing any chance of executing a poor boy gas lift. The solution was to adapt the cement-bond-log technique to identify regions of moveable mud in the annulus with the mud subsequently displaced out by pumping.

The lesson learned is that opportunities that have stalled due to their complexity can still be executed via rigless workovers by leveraging on existing technologies with slight adaptations to create well-specific solutions.
Re-positioning Mature Fields for Sustainability: Deriving Additional Value by Applying the Internet of Things via Remote Well Monitoring
Authors: Adeyinka Adeboye , Tsakporhore Abraham , Oduwole Ajibola , Jumbo Sandison , Odusote Femi , Aliyev Shahin , Adegoke Oluwagbemiga , Lapham John , Eme Titi
Published: August 2020

Mature fields typically require a considerable amount of attention and manpower to keep their production going. Typical daily operational challenges include identifying wells that quit, reactivating such wells and gathering wellhead/casing pressure data that are used for well integrity, surveillance and optimization studies.

These challenges are further compounded for mature assets that have a significant number of wells spread across wide geographical areas, leading to a never-ending cycle of data gathering while reactively chasing wells that have quit to minimize lost-production opportunities (LPO).

One way to manage these challenges is to install sensors that leverage on the Industrial Internet of Things (IIoT) on wells to achieve remote well monitoring. The sensors are used to monitor critical well parameters (pressures, temperatures) remotely, thereby reducing Opex incurred via helicopter trips to diagnose well problems. The solution was also configured to report shut-in wells via email/texts helping to narrow down the culprit well, reduce reaction time and minimize LPO.

More value can be derived beyond gathering surveillance data and reducing LPO reaction time. The data can be delivered real-time to the Asset Engineers in the office to drive engineering analysis on wells. Such analysis could lead to proactive solutions such as optimizing wells that are already on gas-lift or quicker decision-making to initiate gas-lift on a well just before it quits.

In this paper we demonstrate the value that was created by implementing remote well monitoring in mature fields using case-studies that capture the daily field operational challenges and how they were resolved leading to significant cost savings.
Log Hierarchy and Calibration with Other Data for Net Sand Definition in Poorly Developed Reservoir with Limited Log Data Within Niger Delta Depositional Environment
Authors: Anyaehie James , Iyowu Olakunle
Published: August 2020

Huge hydrocarbon volumes in the Niger Delta are potentially screened out as non-reservoirs due to conventional net sand definition that precludes complex lithologies (silty, laminated and heavy mineral formations). The situation is usually prevalent in reservoirs with legacy logs (vintage wells without Density, Neutron, NMR, etc.). Netsand determination is one of the key uncertainties when evaluating resource volumes. This uncertainty elevates in complex lithologies especially with limited suite of logs.

This report unravels the steps to adopt in selecting/ ranking input logs for net sand definition, its validation with reservoir production data (Production log), reservoir sampling (formation fluid & pressure) core data (full bore and/wall sample) drilling cutting etc. In addition, two case studies (fields with vintage and another with more recent well data set) resulting in circa 450% and 40% increase in HCIIP from a recent evaluation with application of the hierarchical process. This translated to increase in ultimate recovery and improved project economics (Net Profit Value and Uith Development Cost).
Investigating How Capillary, Viscous and Gravity Forces Impact the Matrix–Fracture Transfer Mechanisms in Fractured Oil – Gas Systems
Authors: Abubakar Mahmud , Abdulkadir Usman
Published: August 2020

By investigating how capillary, viscous and gravity forces impact the matrix–fracture transfer mechanisms in fractured oil – gas systems, this paper aims to deepen our understanding on the modeling of fractured reservoirs with the intention of creating more predictive and more realistic dual porosity – dual permeability reservoir simulation models.

The hypothesis of this study is that first order differential equations may be able to capture and approximate the total transfer realistically, however it has to be known to which extent the individual forces influence the total transfer. Complex, higher order, non-linear differential equations are able to capture the combined influence of the forces, however their formulation and implementation are extremely challenging.

To investigate whether the total matrix – fracture transfers can be expressed as the sum of the individual forces multiplied with appropriate coefficients, two dimensional models were created using ECLIPSE 100 Black Oil simulator and Eclipse 300 for the study compositional effect.

The results showed that the models can realistically capture the effect of capillary-, gravity- and viscous forces individually. These scenarios can serve as a solid basis for further quantitative analysis regarding the extent, to which the individual forces influence matrix – fracture transfers.

In this study we determined the Minimum Miscibility Pressure (MMP) of CO2 using slim-tube test, we also carried out sensitivity studies of important operational CO2-EOR parameters to determine how they will affect oil recovery factor and displacement efficiency in a single matrix block surrounded by fractures. To ensure miscibility CO2 was injected at a pressure above minimum miscibility pressure.

A significant improvement in CO2 EOR processes and CO2 storage can be achieved by applying the findings of this research in dual porosity – dual permeability models in fracture-matrix systems. These findings not only result in a technical advancement, but could be of high significance from an economical point of view as well.

A slim tube model was set up and used to determine the Minimum Miscibility Pressure (MMP). Seven components (CO2; N2-CH4; C2-NC4; IC5-C7; C8-C12; C13-C19; C20-C30) were presented in the model to compare the rate of dissolution and displacement efficiency. Understanding the process and applying this knowledge to enhance recovery of hydrocarbons, CO2 Capture and Storage can have a significant economic and environmental effect.
Integrated Planning IP in TEPNG - JV District: The Transformation Process
Authors: Akande O. , Iwegbu M. , Dike O.
Published: August 2020

The use of different fragments of planning's existed across entities in Total E & P - JV District but these planning were neither integrated nor centrally coordinated which resulted in: poor visibility of inter-relationship with other entities, making it time consuming to identify clashes and concurrent activity issues; inability to optimize/align activities with production shortfalls; use of different planning tools/templates which resulted in duplication of data/activities & planners spending much time in data entry and generating reports; and difficulty with linking Integrated Planning (IP) to organizational business model/budget which gives a poor overview of the operational cost/efficiency and resources optimization.

These prompted the IP transformation project, where a review of the situation along with its limitation were discussed during workshops organized with entity schedulers and their management. Return on experience from other affiliates on Implementation of IP were also reviewed and data gathered/feedbacks from entities were used to develop the new IP deliverables. A central enterprise planning software was adopted, schedulers were selected, trained and processes, rules were equally defined and developed.

We now have a single centrally coordinated IP database that now enables the identification of anticipate clashes and Synergies, proper POB management, enhancement of Contracts and Procurement to better anticipate required resources (materials), follow progress, Improved communication and transverse approach across the Total E & P JV-District, arbitration and report when required and incorporation of IP in established JV business processes.

The scope of the transformation project includes HSE, Production, Maintenance, Drilling and Completion/Well Services, General Services, Events, Inspection, Engineering/Construction and Projects, Contracts and Procurement, Shutdown, Campaign of Works, Technical Logistics and General Activities. These entities can now extract planned activities with varied time scales with deliverables ranging from weekly, 4monthly, 1 yearly (work program) and 24 monthly.
Wringing Value from a Mature Reservoir: An Offshore Niger Delta Case Study
Authors: Ogbuagu Frank , Okani Nnamdi , Silpngarmlers Lynn , Strebelle Sebastien
Published: August 2020

The objective of this paper is to share lessons from an intensive study of a mature reservoir and highlight its results. This study also aims to demonstrate the value that can be obtained from a mature conventional oil reservoir when the appropriate assessment processes are utilized.

The case study is an offshore oil reservoir with over 50 years of production with waterflooding for almost a decade. The dynamic simulation model from an earlier assessment of the reservoir showed significant deviation following years of waterflooding, as it became more challenging to understand the water front movement, predict water cut changes and deliver more reliable liquid production forecasts. The reservoir had historical challenges with water production and matching the water-cut from producing wells emphasizing the deviation of the existing simulation model from actual data. As a result, a cold-eye review of all available data without anchoring on prior interpretations was required.

An updated reservoir characterization and earth modelling methodology was applied during the study with attendant improvements in structural and stratigraphic representation of the reservoir. A full-field assessment methodology was employed in the study both for the fault framework and model building, ensuring the inter-reservoir connections and dependencies were captured. Additional scrutiny was applied to initial fluid contacts, leading to the resolution of longstanding uncertainties.

This resulted in the delivery of a new dynamic simulation model with a much better water cut history match compared to the previous study. Fluid contact tracking over time was also better matched using the new model. The new model indicated an increase in original oil in place of 38% leading to the identification of 2 new infill producer opportunities with total estimated ultimate recovery of several millions of oil barrels.
Screening Criteria for Waterflood Projects in Matured Reservoirs: Case Study of a Niger Delta Reservoir
Authors: Imuokhuede Peter Ibiezugbe , Ohenhen Ikponmwosa , Olafuyi Olalekan Adisa
Published: August 2020

One important process for revitalization and optimisation of mature reservoirs is secondary recovery by waterflood. However, some engineers do not understand the science and, consequently, without proper plan lose millions of dollars of investment because they target reservoirs for waterflood secondary process which do not possess appropriate characters.

This paper presents screening criteria for waterflood projects in a matured field in the Niger Delta region of Nigeria. Data set for a field X in the Niger delata was simulated. Sensitivity analysis was carried using different scenario and their results were reported.

Six parameters which can be used to screen reservoirs for water flood potential were proposed in this paper.The result of the evaluation showed that waterflood are best applicable for reservoirs with residual oil saturation of less that 33%,gas saturation of greater than 15% and API gravity of less than 30cP.
Delivering Best in Class Wells: A Case Study
Authors: Okoli Ugo’ , Numbere Otokini , Ntiwunka Greg , Ifediora Emmanuel , Nwagu Chike , Aigbedion Prince , Okubor Eleanor , Salami Hassannah
Published: August 2020

It is possible to conduct a drilling and completion operation, sustaining a high operational performance and ensuring low Non-Productive Time (NPT) throughout a well drilling and completion campaign. The results from a recent onshore drilling campaign proves that with the right people, planning and process, a hitch free drilling and completions campaign can be achieved. In this case a perfect campaign was defined as;

Delivering the planned work-scope (5 wells) within the approved Authority for Expenditure (AFE) cost and duration. Drill to the specified Total depth, penetrating all the subsurface targets within the stated tolerances specified. Achieve less than 15% overall non-productive time. Deliver the planned work-scope without Fatalities (FAT), Loss Time Injuries (LTI), Restricted Workday Cases (RWC), or uncontrolled discharges to the environment. Deliver wells without well control issues, Stuck-pipe incidents or any train wrecks. Deliver wells with minimal formation damage. Maintain technical and operational integrity by complying with statutory regulations and company governance documents always.

In order to avoid previous problems encountered while drilling the appraisal wells, critical sections of the Well delivery process were thoroughly reviewed and optimized as required. These include: The Well Design, Rig selection/certification and acceptance, Safety, and drilling operations and logistics. The optimization methods are extensively discussed in this paper. The improvement and close optimization of the mentioned facets of the project helped to save circa $14MM from the project. When compared with other land projects in the same terrain (Niger Delta), the campaign was observed to be a top performer in the P-10 region of the performance percentile.
Parameterization of Fault Seal Analysis as Input to In-Place Volume Assessment
Authors: Adenaiye Olaniyi
Published: August 2020

This paper presents an integrated approach for addressing uncertainty in hydrocarbon column based on fault seal analysis and column-height prediction for a target reservoir ‘F’ in a field in the Niger Delta area.

The target field is in the shallow offshore of the Nigerian delta, about 20km south of the present-day coastline. The field was discovered in the sixties by an exploration well; Further appraisal wells confirmed hydrocarbon in a footwall block, but with uncertainty in fluid contact.

‘F’ reservoir is a highly faulted collapsed crest structure sandwiched between regional and counter regional faults. Numerous antithetic and synthetic faults dissect the reservoir to form several compartments. Seismic data covering the area was shot in the late nineties and is deemed to be of relatively low quality leading to suboptimal imaging of the faults.

To address structural framework uncertainty, two structural model realizations were built for ‘F’ reservoir, focusing on the trapping mechanism, namely, a fault assisted 3-way dip closure (i.e. closure is bound by a major antithetic fault). This trapping mechanism has major impact on the hydrocarbon column height that can be held by the fault.

The column heights for the model realization was estimated from two different fault seal analysis methods: – i.) Bretan et al., 2003; and ii.) Yielding et al., 2010. The results viz., column heights from each of the two methods for the structural model realization were presented as one of the input parameters for the volumetric uncertainty assessment carried out to determine an optimal development plan for the reservoir.
Investigation On the Effect of Change in Relative Permeability On Oil Recovery
Authors: Ezeaneche Obinna , Wobo Monica , Uzoho Chidinma , Onyekonwu Mike
Published: August 2020

The knowledge of relative permeability is key in oil production mechanism as it affects multiphase flow which is vital to producible reserves in petroleum reservoirs. In this study, the impact of altering end point saturation on relative permeability curve and how it influences oil recovery was investigated on field X in Niger Delta, Nigeria. The saturation end points obtained after a simulation study was used as a start point to predict oil production. These end points saturation of water and oil were altered and varied according to facies. The eclipse simulation tool was used in conducting the prediction runs. The result obtained showed wide variation from actual production forecast (i.e. ≥ 25%) when end points were varied with no guided limit from experimental data. This study reveals the need for an accurate determination of residual oil saturation as it was seen to have an impact on forecast and history match.