bluuebunny/crossref_metadata_2025 huggingface dataset:
Sufragantes parroquiales y electores. La apertura relativa del mundo de la política electoral en Antioquia, 1821-1848
Authors: Vélez-Rendón Juan Carlos
Published: July 2019

El artículo trata la participación electoral en Antioquia durante los primeros años de vida republicana, con el fin de establecer el alcance de la apertura política propiciada por la puesta en práctica de la denominada soberanía popular. Se enfoca en los sufragantes parroquiales y en los electores, así como en los debates sobre méritos para acceder a cargos de representación, con el objetivo de mostrar la vigencia de antiguos poderes y valores en un ámbito político inédito creado por la influencia de las ideas republicanas y liberales.
El pasado como modelo a imitar. Relaciones entre historia y memorias, siglo XIX colombiano
Authors: Cardona Z Patricia
Published: July 2019

Este artículo analiza de qué manera escritos testimoniales como las memorias contribuyeron en la configuración de la historia de Colombia; partiendo de la diferenciación de los términos memorias, diarios e historia. A su vez, intenta elucidar el lugar del testigo como actor central y artífice de los acontecimientos durante el siglo XIX, a diferencia del testigo como víctima no merecedora de su destino, de la contemporaneidad. Entre las memorias del siglo XIX, escritas para promover la imitación, y la memoria contemporánea, narrada para asegurar la no repetición, hay un orden historiográfico que redefine el tiempo, la narración y el papel del saber histórico.
Real‐Time Imaging, Forecasting, and Management of Human‐Induced Seismicity at Preston New Road, Lancashire, England
Authors: Clarke Huw , Verdon James P. , Kettlety Tom , Baird Alan F. , Kendall J‐Michael
Published: July 2019

Earthquakes induced by subsurface fluid injection pose a significant issue across a range of industries. Debate continues as to the most effective methods to mitigate the resulting seismic hazard. Observations of induced seismicity indicate that the rate of seismicity scales with the injection volume and that events follow the Gutenberg–Richter distribution. These two inferences permit us to populate statistical models of the seismicity and extrapolate them to make forecasts of the expected event magnitudes as injection continues. Here, we describe a shale gas site where this approach was used in real time to make operational decisions during hydraulic fracturing operations.

Microseismic observations revealed the intersection between hydraulic fracturing and a pre‐existing fault or fracture network that became seismically active. Although “red light” events, requiring a pause to the injection program, occurred on several occasions, the observed event magnitudes fell within expected levels based on the extrapolated statistical models, and the levels of seismicity remained within acceptable limits as defined by the regulator. To date, induced seismicity has typically been regulated using retroactive traffic light schemes. This study shows that the use of high‐quality microseismic observations to populate statistical models that forecast expected event magnitudes can provide a more effective approach.
La diversificación y promoción turística en tiempos de “nuevas ruralidades”: de la costa atlántica al campo pampeano
Authors: Pérez Winter Cecilia Verena
Published: July 2019

En este artículo nos interesa indagar en los procesos de valorización turística de las áreas rurales -y determinados objetos y productos a ellas asociadas- en el marco de la re-estructuración productiva que algunos autores definen como “nuevas ruralidades”. Proponemos analizar el rol del estado en la configuración y extensión del turismo denominado rural, y para ello examinaremos este proceso en la provincia de Buenos Aires (Argentina). En este marco, daremos cuenta de qué estrategias se están promoviendo, quiénes participan y qué tipo de representaciones turísticas sobre la ruralidad pampeano-bonaerense se están construyendo. Nuestra investigación nos lleva a concluir que el estado provincial buscó extender el turismo hacia el interior y en este proceso promovió la modalidad rural. Para ello estableció una serie de estrategias (regionalización, rutas alimentarias e histórico-culturales y programas) que ponen en valor elementos y lugares vinculados al campo pampeano-bonaerense, activando versiones identitarias que conjugan lo local con lo nacional.
Development of an Optical Multispectral Remote Sensing System for Measuring Volcanic Surface Phenomena – Promotion Project for Next Generation Volcano Research B2 (Subtopic 2-2)
Authors: Jitsufuchi Tetsuya ,   National Research Institute for Earth Science and Disaster Resilience (NIED) 3-1 Tennodai, Tsukuba, Ibaraki 305-0006, Japan
Published: July 2019

In 2016, we launched the “Promotion Project for Next Generation Volcano Research B2 (Theme B: Development of Cutting-edge Volcano Observation Technology, subtheme 2: Development of Remote Sensing Techniques for Volcano Observation), subtopic 2-2 (Development of Remote Sensing Techniques for Surface Phenomena of Volcano)” under the “Integrated Program for Next Generation Volcano Research and Human Resources Development” [1], aiming at the development of an optical multispectral remote sensing system for measuring volcanic surface phenomena. With subtopic 2-2, we are planning to develop a new observation device called a surface phenomena imaging camera (SPIC), which is technically superior to current remote sensing techniques, i.e., optical remote observation techniques used to observe volcanic surface phenomena from aircrafts or ground. We are also aiming at applying the developed observation system to quantify volcanic activities and determine volcanic eruption potentials (degrees of urgency) or branching of event trees for volcanic crises with high accuracy, contributing to better predictions of volcanic eruption transitions. To achieve the above-mentioned aims, we started the development of the SPIC by equipping it with camera-type sensors, based on preliminary analyses of the experimental observations made with the airborne spectral imaging system ARTS-SE, which consists of a pushbroom scanner and a camera system, developed by the National Research Institute for Earth Science and Disaster Resilience in FY 2015. We have already developed its components, such as the prototype filter-type multiband cameras SPIC-UC, a prototype uncooled infrared camera, SPIC-C, a cooled camera, and SPIC-SS, a visible-light camera. The SPIC-UC is a two-band camera with the function of visualizing temperature and SO2 gas concentration distributions. The SPIC-C has the function of measuring temperatures between 2 and 1075◦C with high accuracy (noise equivalent temperature difference, NETD: 16 mK); it is equipped with a sensor and a filter wheel that work in the middle wave infrared region (MWIR). The SPIC-SS is a six-lens multiband camera system that estimates the measured images from multiband spectra (6 bands) to hyper spectra (300 bands). Further, we studied a method to estimate digital surface model with a ∼30-m error. As our plan has progressed as scheduled, we intend to complete the prototype SPIC by 2020.
An Open Dialogue Approach to Volcano Disaster Resilience and Governance: Action Research in Japan in the Aftermath of the Mt. Ontake Eruption
Authors: Nakamura Hidenroi , Yamaoka Koshun , Horii Masae , Miyamae Ryoichi ,   Department of Environmental and Civil Engineering, Toyama Prefectural University 5180 Kurokawa, Imizu, Toyama 939-0398, Japan,   Graduate School of Environmental Studies, Nagoya University, Nagoya, Japan,   Department of Disaster Management, Gifu Prefectural Government, Gifu, Japan
Published: July 2019

Applied trans-disciplinary research focusing on enabling open dialogue, volcano disaster resilience, and governance was conducted in Japan after the Mt. Ontake eruption in 2014 through a three-year project. The researchers and practitioners involved in this project aimed to develop methods to reinforce volcano disaster resilience and governance at the local level. A trans-disciplinary research method of clinical environmental studies was applied. First, it was diagnosed as insufficient for local actors to intentionally coordinate with each other, keeping in mind the whole picture of volcano disaster management and the diverse positionalities of those involved in it. “Ba” (a shared time and space for emerging relationships among individuals and groups to create knowledge) development, or study meetings and workshops, functioned step-by-step to share and collate problems first, and then to share ideas of actions after the project was prescribed and executed. It was evaluated that ba development was effective for open dialogue free from positionality, face-to-face relationship building, and capacity development for local actors involved in volcano disaster management. Action research revealed that through ba development, beliefs and value systems regarding the roles of local governments and universities, as well as the relationship between these two, will be transformed within Japan: Local governments will become facilitators, and universities will function as centers of trans-disciplinary research. Universities and researchers can function as producers, coordinators, and facilitators of ba development in collaboration with local government.
Regional Distribution of Articular Cartilage Thickness in the Elbow Joint
Authors: Miyamura Satoshi , Sakai Takashi , Oka Kunihiro , Abe Shingo , Shigi Atsuo , Tanaka Hiroyuki , Shimada Shoichi , Mae Tatsuo , Sugamoto Kazuomi , Yoshikawa Hideki , Murase Tsuyoshi
Published: July 2019

Background:

During elbow procedures, reconstruction of the joint (including the articular cartilage) is important in order to restore elbow function; however, the regional distribution of elbow cartilage is not completely understood. The purpose of the present study was to investigate the 3-dimensional (3-D) distribution patterns of cartilage thickness of elbow bones (including the distal part of the humerus, proximal part of the ulna, and radial head) in order to elucidate the morphological relationship among them.

Methods:

Two 3-D surface models were created with use of a laser scanner: (1) a cartilage-bone model based on 20 elderly cadaveric elbows exhibiting normal cartilaginous conditions and (2) a bone model that was created after dissolving the cartilage. The 2 models were superimposed, and cartilage thickness was measured as the interval distance on the articular surface. Measurements were made at categorized anatomical points of the individual bones, and 3-D distributions on the entire articular surface were analyzed. The spatial relationship among individual bones was also assessed.

Results:

In the distal part of the humerus, the cartilage was thickest in the intermediate region between the capitellum and the trochlea (mean [and standard deviation], 1.27 ± 0.17 mm); in the proximal part of the ulna, it was thickest at the anterolateral edge of the coronoid (2.20 ± 0.39 mm) and the anteroproximal edge of the proximal sigmoid notch (2.49 ± 0.55 mm); and in the radial head, it was thickest at the articular zone on the rim circumference within the dish (1.10 ± 0.17 mm) and on the proximal circumference around the side (1.02 ± 0.17 mm) (p < 0.001 for all). These thicker cartilage regions gathered on the joint center, facing each other.

Conclusions:

The present study demonstrated regional variations in elbow cartilage thickness. The combined findings in individual bones showed “cartilage gathering” at the center of the elbow joint, which we believe to be a novel anatomical finding.

Clinical Relevance:

An enhanced understanding of elbow cartilage geometry will provide additional insights into elbow procedures in elderly individuals, such as hemiarthroplasties, in which anatomical contours could help to restore normal joint function and improve postoperative outcomes.
Optimising Candidate Well Selection for Matrix Stimulation-IPR Approach
Authors: Amarfio E. M. , Adusu P. T.
Published: July 2019

The selection of appropriate candidate wells for a stimulation operation is the most vital step for the economic success of the process. The selection criteria include assessing the well damage and choosing the appropriate approach to stimulate it. Most selection approaches consider the effects of damage and their corresponding treatment methods neglecting the economic influence of the process. This research, therefore, presents a detailed approach to candidate well selection for matrix stimulation using Vogel’s Inflow Performance Relationship (IPR) curve analysis. A non-linear mathematical optimisation model was developed in Microsoft Excel using this analysis. This model requires certain input parameters for each well in order to generate results which could be analysed for the right decision. To validate the model, data from four wells on the Nero Field were used as input parameters. The results show that Well N3 has the highest total post-stimulation production of 12 833 886 barrels of oil and therefore should be considered for the stimulation operation. Sensitivity analysis was also conducted on Well N3 to see the performance of the well when certain independent variables such as price of oil, discount rate, and stimulation time are varied. The results show that the post-stimulation well performance is positively influenced by oil price, increasing as the oil price increase. The post-stimulation well performance, however, show a negative influence from both the discount rate and stimulation time, decreasing as those two parameters increase
Utilizing Surface Parameters in Determining Periodic Chemical Injection Treatment Intervals for Aged Water Disposal Wells
Authors: Onwuemene Onyeka Chiazor , Deele Happiness , Numbere Otokini
Published: July 2019

Following the last couple of years marked by a drop-in oil price, there has been a requirement to optimize costs for operating and maintaining existing and ageing facilities and equipment and Water disposal wells are no exception.

Case study considered onshore wells which were initially completed as oil producing wells in the mid-1970s to early 1980s and in their later life converted for water disposal after the Ultimate Recovery (UR) of the associated reservoirs had been reached and produced water injectivity for wells positively ascertained.

The need to initiate this method of produced water management was to ensure its proper and efficient disposal in line with best practices, government regulations and associated cost efficiencies.

As these wells stay long in service, they witness several impairments that affect their injectivity. These impairments amongst others include oil slippages, suspended solids, fine sand, corrosion products, microbial activity and carbonate scale particles. These in turn create blockage around perforations which reduce the effective path area for movement of water molecules into subject reservoirs.

One of the key actions in maintaining ‘old’ water injection wells is periodic chemical treatment to ensure optimal injectivity. Chemical treatments maybe conducted routinely as a preventive and corrective maintenance activity.

As a view to optimising costs we looked to change this to a "Just-in-time" treatment philosophy to manage its overall impact on operating costs and schedule for execution. A surveillance program was developed for older water injection wells which do not have sophisticated sub surface gauges, by relying on surface parameters and associated equipment condition monitoring to schedule chemical treatments for the water injection wells. Some of the surface parameters that was utilized are Water Injection Pump Discharge Pressures, Injection Tubing Head Pressure (ITHP), Injection Flow Line Pressure (IFLP).

Following analysis, an empirical system has been developed that enables the prediction for chemical injection treatment without the need to conduct sub-surface investigations using Coil Tubing equipment.

This paper discusses a simple, cost effective and easy to use methodology which can be adopted as a first step towards ensuring the adequacy of water injection surveillance program.
Lignin As a Potential Additive For Minimizing Surfactant Adsorption On Clay Minerals In Different Electrolyte Concentration
Authors: Tumba Jibril , Agi Augustine , Gbadamosi Afeez , Junin Radzuan , Abbas Azza , Rajaei Kourosh , Gbonhinbor Jeffrey
Published: July 2019

The use of surfactants in chemical enhanced oil recovery can recover more oil trapped in the reservoir. However, the loss of surfactant due to adsorption on porous media renders the process ineffective and economically unfeasible. In this study, the adsorption of sodium dodecyl sulfate (SDS) and 4-octylphenol polyethoxylated (TX-100) on different clay minerals (kaolinite, montmorillonite, illite and quartz) as a function of the surfactant concentration, pH and salinity has been investigated. Besides, the use of lignin alkali as a sacrificial agent to reduce adsorption of surfactants in the reservoir is proposed. Surfactant adsorption on the different minerals was determined using the surface tension technique and batch equilibrium adsorption process with lignin as sacrificial agent. The experiment was conducted at varying pH and electrolyte concentrations. Furthermore, oil displacement test was conducted in a sandpack to determine the amount of oil recovered by the surfactant before and after pre-flush with lignin alkaline. Experimental result reveals that SDS adsorbed more on kaolinite while, TX-100 on montmorillonite. The decrease in pH increased the adsorption of SDS on kaolinite and illite, meanwhile, the adsorption of TX-100 on montmorillonite increased significantly at low pH. The optimum salinity concentration for both surfactants was at 20,000ppm for all the minerals except for kaolinite which was at 30,000ppm. Lignin alkaline reduced the surfactant adsorption by 50% and 53.2% for SDS and TX-100 respectively. Oil displacement test with SDS and TX-100 surfactants after water flooding had additional recovery of 7.44% and 4.18% respectively while, after pre-flush the recovery increased by 2.2%.
Using Reservoir Navigation Service and Formation Pressure Testing to Meet Drilling Objectives in Offshore Niger Delta
Authors: Imomoh Victor , Ndokwu Chidi , Amadi Kenneth , Toyobo Oluwaseun , Nwabueze Ikechukwu , Okowi Victor , Ajao Oyekunle , Okeke Genevieve , Dada Yemi , Jumbo Sandison , Aina Soji
Published: July 2019

Oil and gas drilling has fully embraced the practice of drilling horizontal and extended-reach wells in place of deviated wells to avoid multi-platform drilling and increase hydrocarbon recovery. However, the producer is still faced with multiple challenges that include lateral facies change, lateral variation in reservoir properties and structural uncertainties. Consequently, it is paramount that continuous advancement is achieved in combining fit-for-purpose, real-time logging-while-drilling (LWD) solutions to assist further in the enhancement of hydrocarbon recovery.

Reservoir navigation services (RNS) involve predicting the geology ahead of the bit to place the wellbore correctly in the zone of interest in a horizontal or near-horizontal path. LWD data, obtained from downhole drilling suites, transmitted in real time through mud pulses to a surface computer where the data are interpreted and used to steer the well in the desired direction. Formation pressure while drilling (FPWD) is a process of acquiring reservoir pressures downhole and this is done with a specialized downhole LWD pressure-testing tool. The use of RNS in Well-MX played a significant role in the drilling project – landing Well-MX in the targeted M reservoir bed and drilling the lateral section. The major geosteering technologies used are the at-bit resistivity and azimuthal propagation resistivity, which provides geostopping capability, reservoir bed boundary mapping and accurate distance to bed boundary calculation. These technologies helped in keeping the wellbore within the hydrocarborn unit of the M reservoir. Performing formation pressure testing in realtime, the team was able to carry out a reservoir gradient analysis which helped with reservoir fluid identification, fluid contact determination, and connectivity of hydrocarbon zones before drilling was concluded.

Well-MX is a horizontal well located in the Mirum field of the Niger Delta Basin, offshore Nigeria. The well was drilled to target the deep multi-lobed M reservoir to a total hole depth of 11,307ft MD. By using Well-MX as a case study, this paper discusses how the combination of reservoir navigation service and real-time formation pressure sampling helped meet drilling objectives for this well. Some of the challenges encountered includes vertical seismic interpretation uncertainty, poor reservoir quality along the drain hole section, change in depth of oil to water contact and undulating bed boundaries. Other challenges and decisions taken to successfully geosteer the well will be reviewed in this paper.
Simple Guidelines for Screening Development Options for Oil-Rim Reservoirs
Authors: John Idoko Job , Matemilola Saka , Lawal Kazeem
Published: July 2019

Given various competing alternatives, the rigorous evaluation of development options for oil-rim reservoirs can be challenging and computationally intensive. For quick and robust decision-making, an efficient screening method that accounts for the relevant static and dynamic properties of the reservoir of interest is desirable. Based on controlled numerical simulation experiments, this paper proposes simple screening guidelines for oil-rim reservoirs under the mutually exclusive development scenarios of (i) sequential oil-then-gas (OTG); (ii) concurrent oil-and-gas (COG); and (iii) gas-only development (GOD).

For simplicity, a two-level factorial design was used to create 17 experiments from a set of static and dynamic reservoir properties. A generic reservoir box model was then developed and used to conduct a total of 51 experiments. For each of the three development options, normalised surrogate models were developed for hydrocarbon recovery factor (RF) as a function of these static and dynamic properties.

For the specific box model and the parameter space examined, it was found that the performance of the OTG option is most sensitive to oil API (viscosity), vertical anisotropy, oil relative permeability and liquid offtake rate. The COG case showed oil API, vertical anisotropy, liquid offtake rate and oil relative permeability as the heavy hitters, while the GOD option returned oil rim thickness, relative permeabilities and gas offtake rate as the key drivers of reservoir performance.

Performance comparison of the three development options reveals that when reservoir properties are favourable to oil flow, OTG is the preferred oil-rim development option, while the GOD option is the most attractive when the reservoir is naturally less favourable to oil mobility. Although these guidelines provide indications of the most promising option, the final decision should be premised on further detailed studies, while considering both technical and non-technical factors that are peculiar to the specific project in question.
Impact of Geological Interpretation on Reservoir 3D Static Model: Workflow, Methodology Approach and Delivery Process
Authors: Agi Augustine , Gbadamosi Afeez , Junin Radzuan , Kampit Stanley Jaul , Abbas Azza , Gbonhinbor Jeffrey
Published: July 2019

The traditional method of geologic modelling requires the interpretation of geological sections during digitization. But this traditional method has its limitations, the main limits are; it is usually time consuming and the model produced is unique to each individual geologist interpretation and may not be easily replicated by others. This study proposes an alternative workflow method for modelling, constructing and interpreting 3D geologic static model with multi-source data integration. The volume base method (VBM) was used to construct the 3D model. The combination of deterministic and probabilistic methods was used to model the facies workflow process to capture the geometrics of depositional environmental element. The truncated Gaussian simulation method was used with vertical trends option to obtain vertical transitional lithofacies in most of the reservoirs. Verification of results and detailed discussion of the proposed workflow and methodology is based on comparison with the conventional method. The saturation height function (SHF) equation applied to the water saturation model and permeability model improved the 3-D properties modelling workflow. The pillar gridding process was identified as the stage that increases the timeframe in 3-D modelling workflow. The results have proven to improve the overall timeframe and maximize the value of the field studies. The proposed method can be applied to a broad and complex geologic area. And is useful for marginal field development, by contributing economically and improving the deliverability of the entire project.
Performance Evaluation of Cashew Nut Shell Liquid CNSL as Flow Improver for Waxy Crude Oils
Authors: Eke William Iheanyi , Achugasim Ozioma , Ofordile Samuel E. , Ajienka Joseph .A. , Akaranta Onyewuchi
Published: July 2019

Use of chemical additives for the control of wax formation and to improve flow properties of waxy crude oil is increasingly being adopted by oil industry operators. Most of these additives, such as pour point depressants, wax crystal modifiers or wax inhibitors are synthetic polymeric compounds, with poly acrylates and methacrylates, poly(alkylmaleate-co-α-olefin), poly(styrene-co-alkylmaleamide) and poly(ethylene-co-vinyl acetate) constituting the dominant chemistry. The high specificity of pour point depressant formulations to oil wells and the considerable expense incurred by industry operators on chemical injections continue to increase the interest for the development of better and cheaper chemical solutions to the wax formation problem. The present work reports the application of natural Cashew Nut Shell Liquid (CNSL) as a flow improver for waxy crude oils and its potential as a veritable resource for the development of new pour point depressants for waxy crude oils. CNSL was solvent-extracted from the shells of Cashew Nut (Anacardium Occidentale L.) using a soxhlet extractor. The physico-chemical properties of CNSL were determined. Functional group characterization was carried out by Fourier Transform Infrared Spectroscopy (FTIR). Rheological evaluation of CNSL at temperatures ranging from 10°C to 60°C using a coaxial cylinder rotational viscometer showed Newtonian behavior. Two Niger-Delta waxy crude oils were characterized to determine their API gravity, water content, kinematic and dynamic viscosity, pour point, Wax Appearance Temperature, wax content, asphaltene content and paraffin carbon number distribution. Wax formation in neat and CNSL-dosed crude oil was studied using cross-polarized microscopy. The pour point of a test crude oil dosed with CNSL at 4000ppm was depressed by 6°C. CNSL reduced the viscosity of the two waxy crude oils by 60% and 35% respectively during couette flow at a temperature of 10°C. CNSL can function as a pour point depressant and viscosity reducer for waxy crude oils and holds promise as a renewable chemical feedstock for the production of pour point depressants and other oilfield chemicals.
Effect of Temperature and Salt Concentration on Rheological Behaviour of Surfactin
Authors: Salihu S. M. , Abubakar A. J. , Meisam B. , Emmanuel U. A. , Hassan K. Y. , Aminu A. Y.
Published: July 2019

Behavioural changes of surfactants due to temperature fluctuations, and its interaction with saline environment, is very common during oil and gas operations. Exhibition of transient or permanent flow behaviour is one form of these changes. Therefore, effect of temperature and ionic concentrations (salinity) on flow behaviour of sodium surfactin was experimentally investigated. ORCADA® software-controlled OFITE viscometer (Model 1100) was used to conduct steady-shear study, at 23–50 °C temperature, 0.1–1.5 molar (M) salt concentrations and 0.025–1.0 % surfactin dosages. Sodium surfactin behaves as non-Newtonian fluid, with a pseudoplastic pattern exhibited in aqueous and 0.25-1.5M saline media. Effect of changes in temperature and salinity on apparent viscosity of surfactin was surfactant-dosage dependent. Furthermore, shear-thickening effect set in at a critical shear rate of 680.9 s-1, signifying flow-induced self-aggregation. Surfactant dosages 0.075 and to a lesser extent 0.1% were minimally affected by changes in temperatures, salinity and rate of shear not exceeding 680.9 s-1. The findings suggest pumpability and dispersion characteristics of the biosurfactant.
On the Characterisation of the Flow Regimes of Drilling Fluids
Authors: Ajayi Oluwaseun E. , Lawal Kazeem A. , Ukaonu Cyril E. , Alabi Tunde , Okoh Oluchukwu , Igbokwe Obianuju
Published: July 2019

Drilling fluids are vital elements in the safe, efficient and effective construction of wells. Their key functions include transporting drill cuttings to the surface, cooling and lubrication of drill string, cleaning build-up deposits on drill bits and tools, as well as stabilisation of the borehole and pressure control. Because they are often a complex mixture of different solids and fluids, the rheology of drilling fluids is usually complicated. As a result, they typically exhibit non-Newtonian flow behaviours. While the traditional practice is to use critical velocity to describe the flow regimes of drilling fluids by discriminating between laminar and turbulent conditions, this paper explores the applicability of Reynolds numlber (NRe), which is a more robust and universal dimensionless quantity to characterise flow regimes.

Models to estimate NRe of drilling fluids are explored for Bingham and power-law types of drilling fluids, including development of models for other non-Newtonian behaviours such as shear-thinning and shear-thickening. More important, the models provide a veritable basis to compare the hydraulic characteristics of a drilling-fluid mixture against its Newtonian counterparts under similar conditions. In addition, these models would facilitate the exploitation of the concept of dynamic similarity to improve the design and benchmarking of the flow characteristics of different drilling fluids in different systems and under diverse conditions. Examples are provided that show the robustness of using NRe as against critical velocity, to identify flow regimes of drilling fluids.

The applicability of the proposed models and ideas are not limited to drilling fluid hydraulics. The findings are relevant in other areas of transporting non-Newtonian fluids such as polymer for enhanced-oil recovery and multiphase mixtures such as emulsions, waxy crudes and general pipeline transport. Additionally, the principles and insights should be of interest to other industries such as food processing and chemical manufacturing.
The Future of Petroleum Engineering in an Emerging Renewable-Energy World
Authors: Lawan Zainab M. , Lawal Kazeem A. , Ukaonu Cyril E. , Eyitayo Stella I. , Matemilola Saka
Published: July 2019

The global energy demand is constantly rising due to urbanisation and population growth. Consequently, the petroleum industry has been ensuring affordable supply to match demand through exploitation and production of oil and gas. Nonetheless, there is increasing drive to shift towards renewables being an energy source that is ‘inexhaustible’, while decreasing the intensity of anthropogenic greenhouse gases as well as mitigating other negative environmental impacts of hydrocarbon field development. However, this shift is a threat to the upstream sector of the petroleum industry, specifically to petroleum engineering (PE), given its potential to lower hydrocarbon demand while raising carbon taxes of oil and gas companies.

Against this background, this paper takes a closer look at what lies ahead for PE in an emerging renewable energy (RE) world. It is shown that RE can be integrated into some conventional PE activities such as the use of solar energy for thermally enhanced-oil recovery and the application of its skillsets to advance the body of knowledge in geothermal engineering.

Despite RE's comparative advantages, it faces challenges in energy storage and intermittency of supply. The paper examines the influence of PE in some industries that depend on its products and relevant skill sets. It also explores the interplay between PE and other apparently remote industries is explored.

In conclusion, the future of PE is considered promising, though it needs to continuously re-invent itself. The reality is that it contributes not only to energy production, but many aspects of daily life. Compared to petroleum derivatives, the alternative products are yet to attain sufficient maturity for sustained large-scale utilisation. In principle, the breadth and depth of challenges that RE faces suggest that the world's dependence on PE is not likely to shift dramatically in the next couple of decades.
Gas Lift Optimization within Field Capacity Limitations
Authors: Ifeanyi Uche Chukwunonso , Esieboma Samuel , Uche Jennifer
Published: July 2019

Optimizing oil production with facility constraints has become a challenge to most E&P companies even as they pursue sustainable resources. The innovative gas lift technique overcomes this challenge. The conventional gas lift well system has long been in use, but the design most times is limited by gas availability and pressure which limits the depth of gas lift injection for improved production rates. This challenge may not be evident in matured producing fields with gas compressors installed with available non-associated gas source wells, but truly such challenges arise in new fields especially owned by indigenous companies where much uncertainties at an early field life unavoidably allows you to be more stringent in expenditures towards development of a field gas lift project. A new gas lift concept was developed and studied in Field A in an offshore field of the Niger delta in the absence of gas compressors. This design has been proven to be suitable because it was used to bring four closed wells online even when those wells were removed from the company annual forecast. The original design consists of a minimum of two unloading valves and an orifice at a deeper depth, but because of the absence of scrubbers and gas compressors in the facility, pressure depletion in the reservoirs caused four flowing wells to be closed. The new design then sets dummy at shallow mandrels and uses a modified size of orifice to optimize available pressure and gas required to open the closed wells and still sustain other gas lifted wells connected to the same gas lift manifold. This campaign resulted to an additional 7000Bopd which is the primary discussion of this paper.
Physicochemical Characterization of Starch from Unripe Artocarpus heterophyllus Lam Pulp as a Low-Cost Starch Source for Oilfield Applications
Authors: Adewumi C. N , Achugasim O , Ogali R. E , Akaranta O
Published: July 2019

Starches serve as vital raw materials in many industrial applications especially in food, textile, pharmaceutical and petroleum industries. In petroleum industry, chemically modified starches are used in water based drilling mud to enhance fluid loss and viscosity in the formation during drilling. Most starches used for these applications are obtained from food sources such as corn, potato and cassava and this affects the overall production cost. Artocarpus heterophyllus Lam (AHL) is a tropical tree with large bulb (fruit) containing pulp and seed. In Nigeria, this tree grows in the wild or homes but its fruit is not seen as a food source and thus allowed to waste. Starch was extracted from the pulp of unripe but matured AHL using wet milling method, and the extracted starch was examined for its proximate composition and physicochemical properties. Starch extraction from the unripe pulp gave a starch yield of 44.12±1.13% and the physicochemical characterization shows that the starch has high amylose content (24.09±0.11%), water absorption capacity (116±0.18%), gelatinization temperature (71°C) and the swelling power increases with increase in temperature. The thermal behavior of the starch studied with differential scanning calorimeter (DSC) demonstrated a distinguished endothermic peak with distinct onset, peak and conclusion temperatures. The scanning electron microscope (SEM) result showed that the starch granules are small sized and aggregate together with high tendency of forming network of granules. The results obtained from the physicochemical characterization of unripe AHL pulp starch shows that it has high potential for oilfield applications.
Complex Reservoir Re-Development in a Deep Offshore Maturing Field: Akpo Field Case Study
Authors: Adeyemi Adeoye , Uwerikowe Gabriel , Tyagi Tapesh , Oukmal Jed , Usman Musa
Published: July 2019

With increasing complexity of reservoir developments, there is often a marked deviation from the field development plan (FDP), thus, requiring complementary developments with infill wells. This paper addresses this necessity whilst using the Akpo field reservoir B as a case study. Our case is an oil-bearing, highly faulted turbidite channel-levees system. The reservoir comprises three different units (Upper, Middle and Lower) with gross interval of about 140 m and good porosity and permeability values. The hydrocarbon-water contact (HWC) varies across fault blocks with little certainty about reservoir connectivity. It was assumed in the initial FDP that two producers located around the top structure would be supported by two injector wells located on the flanks near the HWC. In 2011, the first producer (Akpo-XP) was completed in the three units and equipped with an inflow control valve (ICV). From fluid samples collected and the selective acquisition of dynamic data from these intervals, results showed that the Upper unit was disconnected from the Middle and Lower units. Consequently, Akpo-XP was forced to produce only from the Middle and Lower units in order to be supported by a northern injector (Akpo-YW) in the same interval. To complete the initial development, another pair of wells (producer-injector) was drilled and completed in the upper unit. All wells were equipped with down-hole pressure gauges for connectivity assessment.

In 2015, a seismic monitor was acquired, processed and interpreted whilst integrating production, injection and pressure data. The 4D seismic data confirmed specific fluid movements in the reservoir and a reservoir re-development could be sanctioned with two infill wells (one producer and one injector) with estimated increase in up to 16 Mboe of reserves and incremental production of 13 kbopd.

A post-mortem analysis of these two infill wells showed a combined incremental production slightly above expectations.
Formulation of Bio-Waste Derived Polymer and Its Application in Enhanced Oil Recovery
Authors: Fadairo Adesina , Adeyemi Gbadegesin , Onyema Obioma , Adesina Adedapo
Published: July 2019

Polymers are substances considered to have their molecular structure being built up majorly from a large amount of similar smaller units bonded together, for instance synthetic organic materials used as plastics and resins. It has been stated that due to reservoir heterogeneity and capillary forces affecting the water flood process causing low oil recovery after a particular interim, the technique of implementing polymer flooding as a chemical flooding mechanism has been introduced and is rapidly gaining attention in the oil and gas industry. The study describes primarily the formulation of a specific bio-polymer product and examining its performance in Enhanced oil recovery. The musa paradisiaca derived bio-polymer solution was formulated and injected at different concentrations by performing simultaneous experiments at certain operating conditions using a reservoir permeability testing equipment (RPT). Core sample flooding experiment was performed on three core samples of varying porosity and permeability. The bio-polymer is flooded through core sample at different pore volumes using the RPT as the flooding equipment. The bio-polymer solution has the ability to lower mobility by reducing the relative permeability to water as well as increasing its viscosity (an index of mobility ratio improvement), which reduces the mobility of the driving phase, hence causing an increased mobility of the driven phase(oil). From the experimental procedure performed in this study, the results indicate that the injection of newly derived bio-polymer solution into oil strata enhanced oil recovery where the incremental oil recovery attained for each core sample were 16.71%, 25.58% and 14.55% of the respective original oil in place (OOIP), indicating an average incremental oil recovery of about 18.94% for entire experiment performed. The results obtained from the flooding of newly derived bio-polymer solution proved a better performance in oil recovery percentage when compared with flooding of gum arabic polymer solution.
Estimation of Reservoir Permeability Using Analogue Core Data for Green Field: Case Studies from Niger Delta
Authors: Das Anindya , Anijekwu Chinedu , Maguire Kelly , Wood Mark , Akinrolabu Segun , Adenaiye Olaniyi , Iyowu Olakunle , Duvbiama Omolara , Ozoemene Uche , Amrasa Kefe
Published: July 2019

Permeability is one of the most important parameters of reservoir rocks; it defines the capacity of rocks to transmit fluids in pore spaces. Permeability prediction is of extreme importance in deciding the field development strategy for green reservoirs. The reservoir rocks are made up of grains, cement and pore network. The pore network is made up of larger spaces, referred to as pores, which are connected by small spaces referred to as throats. The pore spaces control the amount of porosity, while the pore throats control the movement of fluids and the quantity of rock permeability. Generally, the sources of permeability measurements in green field are from core data, well test data and Nuclear Magnetic Resonance (NMR) data. However, core information, well test information and NMR information are usually very limited due to high cost of acquisition making justification usually difficult. The consequence is that we have very low ratio of cored to the total reservoirs in the Niger Delta.

This paper discusses a methodology for accurately estimating permeability using analogue fields/reservoirs core data in green reservoirs. The main factors to consider in choosing a suitable analogue includes Facies classification, relative depth of the reservoirs, average porosity and histogram of the Gamma ray values between the subject and analogue reservoirs. This selection is usually an integrated effort between the teams Geologist and Petrophysicist.

In this study, two fields were selected where permeability prediction was based on analogue core data.

A robust Niger delta wide analogue selection process was applied first to identify the analogue field where core data exists. After selection of the analogue field, facies-wise poroperm transform was built. This poroperm transforms were then validated in one of the fields where real core measurements were available post study. This blind test with real core permeability data indicated an excellent match with analogue based permeability model. In the other field, the analogue based permeability was validated against NMR and mobility data acquired in some of the reservoirs.

This workflow establishes the robustness of using existing analogue data to reduce the subsurface uncertainty and justify an integrated workflow of estimating permeability in the green field rather than acquiring a new data to support development decision.
Efficient Placement of Relief Well Using Combination of Tools
Authors: Pedro Abiye Iyalla , Feltracco Davide , Pasquale Antonio , Gravante Elpidio
Published: July 2019

A Well with plug set in both tubing was sabotaged and even after initially capping the well, it was observed that attempting to kill the Target Well via surface pumping was abortive.

Therefore, in order to achieve well control, drilling a relief well became imperative and required some critical decision to be taken. This include location selection, type fluid to be used in drilling, the casing setting depth, downhole measuring tools for use, as well as contractors needed in achieving success in a suitation of incomplete well survey data.

This paper presents how this keys needs were met in drilling the Relief Well planned for 97days trouble free and performed in 107days from spud to hitting Target Well. The success was on single attempt in spite of it having an incomplete survey record acquired 49 years earlier.
Realtime Aaquisition of Formation Pressure Data For Reservoir Characterization and Safe Drilling
Authors: Umeonaku Loretta , Adegboye Philip , Ubadigha Emmanuel , Ibrahim Hamza , Anwana Francis , Omale Gabriel
Published: July 2019

Formation Pressure data is a key parameter for in-depth characterization of a reservoir's potential and capacity to produce hydrocarbon. Pressure data are analyzed to confirm fluid interface, fluid type as well as to understand reservoir connectivity/isolation and compartmentalization if any, needed to finalise on the completion strategy to be utilized for optimal production. Acquisition of this data while drilling provides early and reliable information for decision making in optimising the drilling process.

This paper demonstrates the use of Formation Pressure While Drilling (FPWD) tool to acquire formation pressure data. It examines the successful wellsite execution of FPWD service deployed in 3 deepwater wells in the Gulf of Guinea. It discusses operational sequence, quality of the results and how the operator utilized acquired data. In Well A, the test objective was to establish reservoir connectivity between a producer and an injector. For Well B, acquired pressure data was crucial in finalizing completion strategy. Well C shows how the direct pressure measurements were utilized to update the mud program in real time while drilling.

Finally, this paper reemphasizes the value of FPWD by outlining how acquired pressure data met clients objectives by providing valuable quality data which provided great insight in reservoir characterization and safely drilling the wells to Total Depth.
A Computer-Aided Hydrate Management System
Authors: Lawson-Jack Databa , Odutola Toyin , Chukwu Ogbonda Douglas
Published: July 2019

In this study, a computer-aided system for effective hydrate management is presented. A flowchart was developed to suggest possible intervention approaches to follow in the event that hydrates are restricting flow in flowlines. Using VBA® in Excel, a worksheet was developed to serve as a direct means of proposing an intervention approach to adopt after confirming the cause(s) of hydrate formation in the flowline that is monitored. The worksheet created suggests intervention approaches in a matter of seconds after a series of prompts to input the identified causative agents. The main causative agents considered were hydrate formation temperature (HFT), hydrate formation pressure (HFP) and Sufficient Gas/Water. Six scenarios of causative agent occurrences were considered. Scenario 1 was a combination of HFT, HFP and sufficient gas/water, the proposed intervention was to depressurize, heat flowline, carry out chemical inhibition and dehydrate. Scenario 2 was a combination of HFP and HFT, the intervention proposed was to depressurize, heat flowline and carry out inhibition. Scenario 3 was HFP only, the intervention strategy proposed was to depressurize and carry out chemical inhibition. Scenario 4 was a combination of HFT and sufficient gas/water, the proposed intervention was to heat flowline, carry out chemical inhibition and dehydrate. Scenario 5 was HFT only, the proposed intervention strategy was to heat flowline, carry out chemical inhibition. Scenario 6 was a combination of no HFP, HFT or sufficient gas/water, the proposed intervention was that the causative elements be checked again since hydrate presence in the flowline had been previously confirmed.