bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lessons on Team Integration from 2017 Bonga Turnaround Maintenance
Authors: Mustapha Adetoun , Afuba Paul , Enechi Felicia , Ejiofor Chiedu , Olasubulumi Akintunde 
Published: October 2018

Abstract
The most complex and largest Turnaround Maintenance (TAM) in the history of the Shell Nigeria Exploration and Production Company's Bonga asset was completed in April 2017. Strategic value drivers were Statutory/Regulatory, Asset Integrity, Relief Valve(RV) Recertifications, Vessel Cleaning and Upgrades. Often, Turnaround management has huge impact and directly contributes to the company's bottom line profits. However, controlling turnaround costs and duration represent a definite challenge.
This paper presents the structured process of managing the TAM project and key lessons learnt on integration with its attendant impact on project delivery. The turnaround comprises over three hundred Operations, Maintenance and Project scopes. Over ten in-field vessels were deployed, including a 600-bed Floating accommodation vessel, and over 50 Nigerian contractors and sub-contractor companies were involved while over 2,000 material deliveries were required. The workforce was over 1,000 people that cuts across 10 Functions, several Disciplines, diverse culture and mixed genders; and spread across locations. Team effectiveness and integration were identified as key elements for the team to complete the scope safely, within budget and on schedule.
Overall, several challenges were encountered during the TAM; and interventions were implemented to deepen end-to-end thinking, make performance on integrated key performance indicators visible and rally the teams to get critical steps right. This paper shares learnings on how the team was orchestrated to develop shared goals, common understanding of processes and appropriate behaviours and work effectively across organizational boundaries as ONE team. The critical scopes were delivered on schedule and below budget. The TAM therefore resulted in increased asset reliability, continued production integrity, and significantly reduced the risk of unscheduled outages or production deferments.
Comparative Study of Sand Control Methods in Selected Niger-Delta Sand Stone Reservoirs
Authors: Aroyehun Mojisola E. , Oko Francis. N. , Onyeanusi Obinna , Oguntade Tomiwa , Kabara Auwalu , Dimkpa Benson 
Published: October 2018

Abstract
Sand production is one of the major profit hurting occurrence in Niger-Delta sand stone reservoir which must be managed within permissible limit to avoid potential risk to environment, equipment and hydrocarbon recovery. Uncontrollable production of sand reduces reservoir performance and increases operational cost. The utilisation of sand control devices and reactionary approach for sand management most time exacerbates production loss. Hence there is the need for understanding the concept and selection criteria for appropriate sand control methods and devices in Niger-Delta sand stone reservoir.
This paper presents performance study on selected sand stone reservoirs in Niger-Delta field AAA operating with difference type of sand control mechanisms such as internal gravel pack (IGP), sand consolidation using chemicals (SCON) and Cased Hole Expandable sand screens (CH-ESS). Hence determining the key parameters that influence production from the unconsolidated sand stone of Niger-Delta sand stone reservoir.
The results show that the well completed with IGP produced at longer plateau rate and within permissible sand production limit than other methods presented, though the performance is less efficient in deeper interval than in shallow interval. Also the well completed with IGP is more efficient either in high or low drawdown scenario while well completed with SCON experiences high sand rate and early water breakthrough with increase in drawdown. The grain size distribution and the bean up programme at initial start-up have been identified as key factors that influence recovery, selection and durability of sand control mechanism. The results from this work will provide guidance in selection and management of sand control systems in future developments in AAA field and other Niger Delta formations.
Comparative Analysis on Rate Dependent Polymer Flooding Using Bio and Synthetic Polymers
Authors: Abdulraheem Madugu , Hamisu Tukur , Abdullahi Gimba , Oluwaseun Taiwo , Kelani Bello , Mohammed Ismail , Olalekan Olafuyi 
Published: October 2018

Abstract
Polymer play a key role in several EOR processes such as polymer flooding, surfactant-polymer flooding and alkaline-surfactant-polymer flooding due to their critical importance of mobility control in achieving high oil recovery. This high oil recovery is dependent on polymer properties and the rate of flooding.
This paper presents the results of polymer flooding of an unconsolidated porous media using the locally available Gum Arabic in its natural and Modified states. Commonly used polymers Xantham Gum and Hengfloc were also used for comparison. The effective flooding rate was established using Modified Gum Arabic as the polymer. The established flow rate was used in polymer flooding for other polymers. Different concentration of each polymer was used to achieve similar viscosity of polymer solutions used for each flooding. The brine, oil and porous media properties were also kept constant.
The results from these studies favoured a low injection rate. More oil up to 90% of original oil in place was recovered. The result from the oil recovery using the established effective rate on other polymers showed that the Modified Gum Arabic recovers approximately 10% more than the natural Gun Arabic, Xantham Gum and Hengfloc. The recoveries were 90.2%, 81%, 79.5% and 80.2%, respectively.
It was also observed that the oil retention time in polymer mixture is lower in Modified Gum Arabic and Natural Gum Arabic when compared to Xantham Gum and Hengfloc.
Determination of the Degree of Contaminants of Different Refined Products From Kaduna Refinery
Authors: Egu Daniel Ikechukwu 
Published: October 2018

Abstract
Contamination of petroleum products at source has been a major setback in the downstream in Nigeria. Several mechanical crashes in the air, roads, and water ways have also been traced to cases of possible contaminated refined petroleum. There are no enabling laws to prevent these excesses. The aim of this study however, is to carry out a detailed simulated experimental procedure using different percentages of petroleum products from the Kaduna refinery as contaminants. The objective is to conduct several laboratory tests on the product sample for traces of mixtures with other products, in order to establish possible cases of unintentional contamination during handling at the refinery, to mix several products together and test for the possible traits from the mixture as well as the effect of such trait in the containing fuel and to determine the degree of contaminants in each of the mixture and to what extent it influences the individual characteristics of each product present in the mixture base on the degree of contamination. Materials used are PMS, AGO and DPK. They were contaminated with 85%, 90% and 95% of each product. Results show that for 85% DPK with 15% AGO had the highest SG at 15/4°C. This blend also had the highest distillation IBP at 175°C and EBP at 328°C with a flash point of 62°C, the cloud point, viscosity, colour and sulphur content were not recorded. For 95% DPK with 5% PMS had the highest SG at 15/4°C, distillation IBP at 95°C and EBP at 248°C, it has no flash point because PMS is very volatile, the cloud point, viscosity, colour and content were not recorded. The same procedure was applied for all the samples and compared with results from a few dispensing stations in Kaduna with some variation of impurities. It is recommended that handling of petroleum products and particularly the blending processes in our refineries should as a matter of fact be very thorough with proper re-examination of products using appropriate laboratory procedures before dispensing them to the public.
Laboratory Foamed-Cement-Curing Evolution Using CT Scanning: Insights From Elevated-Pressure Generation
Authors: Dalton Laura E. , Brown Sarah , Moore Johnathan , Crandall Dustin , Gill Magdalena 
Published: October 2018

Summary
Computed-tomography (CT) scanning has become a mainstay among scientists (Wildenschild and Sheppard 2013) because it enables nondestructive observation of material processes and formation in real time. Foamed cement is a high-strength, low-density material containing nitrogen gas, and is used to stabilize wellbore casings both onshore and offshore. In-situ foamed cement is subject to pressure changes because the slurry is pumped downhole and cures at depth. To correlate the influence of pressure to the gas-void size and the curing evolution of a foamed cement, two laboratory foamed cements were generated and CT scanned as they cured. One cement was generated following the American Petroleum Institute (API) industry standard API RP 10B-4 (2015) at atmospheric conditions using a blender, and the other cement was created using a foamed-cement generator (FCG) (resembling that of de Rozières and Ferrière 1991) to produce a sample at an elevated pressure. FCG-generated cement qualities (in the range of 20, 25, 30, 35, and 40%) were scanned at their cured state for comparison. From the CT-image time series and the single FCG scans, the volumetric void properties were characterized and compared. The time-series blender voids were an order of magnitude larger than the FCG voids, and void growth was stagnant after a curing period of 100 minutes, whereas the FCG voids gradually increased in volume after 100 minutes. The Hsü-Nadai plots (Brandon 1995) reveal that the FCG and blender voids are weakly prolate, and all FCG voids, regardless of generation quality, relax to a greater final-magnitude strain than the blender voids. These findings confirm that both the void size and the curing process are influenced by the pressure at which a foamed cement is generated.
Controlling the Extent of Oil Spill Using Modified Oil Digesting Microbes
Authors: Panwar Aashish 
Published: October 2018

Abstract
It's an era of new innovations that have been helpful in decreasing the complication while drilling, and transportation of crude oil the need for Cutting edge technologies is growing at a high pace.
The sole objective of the Paper is to make use of the modified microorganism (having altered DNA) to digest oil if accidentally Oil Spill occurs during transportation, in order to reduce Environmental Pollution.
The paper describes about the new approach that is based on combination of the DNA of Oliespira (Highly efficient deep sea oil digester that cannot work in saline conditions) and Neptumonas (Poor Oil Digester that can work in saline conditions). Using DNA Recombination Technique through which we can alter the DNA of the bacteria so that we can get single bacteria having both the desired characters (i.e. a bacteria containing both features of High efficiency and can work in saline water). These modified bacteria's can be exploited by making the use of asexual reproduction and unfavourable conditions for increasing the no. of bacteria and helping in the more effective digestion of oil during oil spill.
The modified bacteria developed will be having both the desired traits i.e. Digestion of Oil in sea water and deep sea levels will help in solving the problem of environmental pollution. The results would be mind boggling as a single microorganism would serve as the solution for various problems related to Oil Spill. The microorganism at normal or low temperature it will act as an Oil Digester which can work in sea water. With the use of these modified microorganisms we will be able to protect our environment and hence control extent of oil spill.
Exemplary management and proper working of these genetically modified bacteria's would be a boost for the industry. With the use of these modified microorganisms (bacteria's) we will be able to protect our environment and also avoid the harmful effects caused by the Oil Spills.
Aspects of Well Productivity Deterioration for Unconventional Wells
Authors: Linderman Daniel 
Published: October 2018

Abstract
Diagnostic plots of production decline of wells producing from unconventional reservoirs provide a particularly interesting field of study, given the fast-growing unconventional completion methods in the United States. In this paper, we present a method for analyzing fracture quality in horizontal wells with multiple stages of fracturing draining unconventional reservoirs. Our method, which explains a plausible cause for reduced production and rapid production decline, includes a log-log plot of the inverse production rate change vs. time. This diagnostic plot was used to analyze forty oil-producing wells drilled in the Bakken formation and ten gas wells producing from the Marcellus formation. From these graphs, we first observed that regardless of the number of fracturing stages, a plot of a system of fractures behaves as one equivalent fracture. Second, we noted that in some cases; a bilinear flow is observed, indicating strong support of the induced fractures by the formation. This is followed by a linear flow period. Furthermore, the duration of fracture linear flow indicates the quality of the induced fracture system in the formation. Crossflow among the induced fractures is noted. This can explain the deterioration of well productivity. A summary of these observations and the appropriate explanation behind this analysis method is presented. This diagnostic method used can help in monitoring causes of low production quality and low recovery factor from individual wells and in seeking solutions.
Modeling, Application, and Optimization of Engineered Water Injection Technology in Carbonate Reservoirs.
Authors: Adegbite Jamiu Oyekan 
Published: October 2018

Abstract
Engineered / low-salinity water injection (EWI/LSWI) technology is one of the latest and promising technology for improving recovery in both sandstone and carbonate reservoirs. In this paper, the mechanism, modeling, application, and optimization of EWI in carbonate reservoirs are discussed.
Firstly, an EWI model based on multi-ion exchange is proposed and validated through history-matching of coreflood data. This proposed model is later tested on field-scale by upscaling the coreflood model to three 5-spot reservoir models including homogeneous, heterogeneous with channeling, and heterogeneous with gravity underride. Afterwards, a sensitivity and optimization studies are conducted using the machine learning and artificial intelligence tools in CMG-CMOSTTM.
The results showed an improvement in both displacement and volumetric sweep efficiencies after engineered water injection, which was supported by mobility ratio and tracer method analyses. For the sensitivity study, oil price, tax rate, and initial oil saturation are among the most significant design parameters on EWI-NPV for the model investigated. More so, secondary EWI was recommended as opposed to tertiary injection due to the favorable recovery efficiency and profitability with respect to an NPV of $1.44 million and a payback period of about 2 years after the optimization study. This study gives more insight into understanding the EWI technology through which field-scale developments can be performed with more certainty and lower risk.
System Analysis of Liquid-Assisted Gas-Lift Unloading
Authors: P Coutinho Renato 
Published: October 2018

Abstract
This study describes the concept of Liquid-Assisted Gas-Lift (LAGL). This concept includes three main parts: two-phase downward flow in annulus, two-phase flow through orifice Gas-Lift Valves (GLVs), and upward two-phase flow in pipes. The latter part is well described in the literature and will not be investigated in this work. However, there is a lack of studies on two-phase downward flow in annulus and through GLVs. Therefore, these two topics are investigated in this work.
An experimental and numerical study on two-phase flow through orifice GLVs is presented. The experimental results are compared to predictions using a numerical model published in the literature for two-phase flow through restrictions. It is observed that the mechanistic model could successfully characterize two-phase flow thorough gas-lift valves with errors lower than 10%. A flow regime map of downward two-phase flow in the annulus is used to analyze the flow regimes observed during field-scale experiments of LAGL unloading. It was concluded that the intermittent and bubbly flow are preferred to minimize injection pressure during LAGL unloading operations.
A commercial flow simulator is used to perform sensitivity analysis of the LAGL system and to perform unloading of a well using the LAGL concept. The unloading simulation results indicated that the use of LAGL has the potential to decrease the injection pressure requirement in more than 50% when compared to the conventional single-point gas injection. The simulation model is shown to be a useful tool to perform system analysis and optimization of LAGL.
Confinement Affects Phase Behavior of Petroleum Fluids in Shale Reservoirs
Authors: Luo Sheng 
Published: October 2018

Abstract
Different from the conventional reservoirs, the liquid-rich shale reservoirs are known to possess a broad pore size distribution. In macropores and fractures, the porous geometries are in the size of micrometers. However, in organic matter, a significant amount of porosity consists of nanopores. In the nanopores, the fluid phase behavior deviates from the bulk-scale phase behavior due to the nano-confinement effect. The deviated phase behavior results in significant challenges in evaluating oil and gas in-place and understanding reservoir fluid depletion mechanism.
In this paper, the nano-confinement effect on hydrocarbon phase behavior in shale reservoirs is studied in three steps. Firstly, the bubble point temperatures of hydrocarbons in multiple sizes of nanopores are measured using the laboratory approach of differential scanning calorimetry (DSC). Secondly, a pore-size-dependent equation of state (PR-C EOS) extended from Peng-Robinson equation of state is completed with the experimental data. The PR-C EOS models the phase diagram with an extra dimension of pore size and the modeling results agree well with the experimental data. Thirdly, a multi-scale PVT simulator is developed to calculate the PVT of reservoir fluids in the shale pore size distribution systems. The whole pore size distribution is discretized into specific sizes of pores and PR-C EOS is used to describe the fluid per pore. The simulated multi-scale PVT provides a realistic picture of fluid phase behavior in liquid-rich shale reservoirs with macro-to nano-scale porous geometries and sheds light upon GOR behavior during production history.
Application of Machine Learning for Closure Pressure Determination
Authors: Nande Soumitra 
Published: October 2018

Abstract
Hydraulic fracturing is a method in which fluid is pumped at elevated pressures to break down the formation, and create a conductive pathway for production of hydrocarbon fluids. Understanding the stress environment of the rock is critical for a better design and successful execution of a fracturing treatment. More often than not, a formation breakdown pressure is equal to or in close approximation of minimum horizontal or in-situ stress, also termed as closure pressure.
Various analytical methods such as G-Function plot, G-dP/dG plot, square-root of time plot etc. are used for the determination of closure pressure, and have been implemented since the inception of hydraulic fracturing as a way to better design fracture treatments. These methods are prone to have subjectivity due to the experience and knowledge of the person analyzing the data, which calls for a need to more objectively analyze such data, in order to better predict the closure pressure.
Machine learning is a method to teach computers to implement a predesigned algorithm and execute tasks without having to explicitly program them. It helps create significantly complex mathematical models which automate processes based on critical learning parameters, and predict within a certain acceptable degree of accuracy.
In this paper, Artificial Neural Networks (ANN), a machine learning methodology, has been applied in order to minimize the subjectivity in predicting the value of closure pressure. Artificial neural networks, similar to neural networks of the brain, are a system comprising of various neurons. These neurons are organized in layers namely input layer (consisting of input neurons), output layer (consisting of output neurons or results) and multiple hidden layers. The number of input, hidden and output neurons depend on the parameters affecting the end-result. An ANN has been designed, taking into consideration critical parameters on which closure pressure depends. The model identifies and learns from the patterns in the data and predicts the required output. This output is then compared with the actual results in order minimize the error. The objective is to minimize the error so as to get a close match for the given data. In this paper we have kept the ratio of learning to testing at 80:20, which means that of all the available data, 80% is used for training the model and the rest 20% is used for testing the model.
Results from this work point to the fact that the ANN was able to predict the closure pressure with reasonable accuracy.
Development of Models for Filtration Simulation in Nonlinear Media
Authors: Nevmerzhitskiy Yan 
Published: October 2018

Abstract
The paper contains numerical simulation of nonisothermal nonlinear filtration in a porous medium. Two-dimensional unsteady problem of heavy oil, water and steam flow is considered. Oil phase consists of two pseu-docomponents: light and heavy fractions, which can vaporize like the water component. Oil exhibits viscoplastic rheology, its filtration does not obey Darcy's classical linear law. Simulation considers not only the dependence of fluids density and viscosity on temperature, but also improvement of oil rheological properties with temperature increasing.
To solve this problem numerically, we use the streamline method with splitting by physical processes, which consists in separating the convective heat transfer directed along filtration from thermal conductivity and gravitation. The article proposes a new approach to streamline method application, which allows to correctly simulate nonlinear filtration problems with temperature-dependent rheology. The core of this algorithm is to consider the integration process as a set of quasi-equilibrium states that are results of solving system on a global grid. Between these states the system is solved on a streamline grid. Usage of the streamline method allows not only to accelerate calculations, but also to obtain a physically reliable solution as integration takes place on a grid that coincides with the fluid flow direction.
In addition to the streamline method, the paper presents an algorithm for non-smooth coefficients accounting, which arise during simulation of viscoplastic oil flow. Applying this algorithm allows keeping sufficiently large time steps and does not change the physical structure of the solution.
Obtained results are compared with known analytical solutions, as well as with the results of commercial package simulation. The analysis of convergence tests on the number of streamlines, as well as on different streamline grids, justifies the applicability of the proposed algorithm. In addition, the reduction of calculation time in comparison with traditional methods demonstrates practical significance of the approach.