bluuebunny/crossref_metadata_2025_split huggingface dataset:
Managing Asset Retirement Obligation of Nigerian Oil Companies: The Elephant in the Room
Authors: Ojukwu Kelechi Isaac 
Published: August 2020

Abstract
Asset retirement obligation (ARO) will play a vital role in the valuation of Nigerian petroleum assets, and most importantly, in providing analysts and operators with a regulatory mechanism with which to assess the ultimate value of an asset. It can also form the basis for holding the licensees accountable for their contractual obligations on environmental issues and the legislation governing field abandonment and reclamation liabilities at the end of the useful (economic) life of a project. Viewed as the potential elephant in the room, this lifecycle environmental liability can sometimes exceed terminal asset value, unless it is carefully managed by both the company and the regulator. The fact that there is no active regulatory framework currently in existence in Nigeria underscores the urgency for a system to guide oil companies in accrual and compliance obligations. Absence of such system can have significant but latent impact on what the future value can be as well as the exit or terminal liabilities. As crucial as ARO seems to be, experts believe that Nigeria's ARO liability coming from well abandonments, facility decommissioning and site reclamations may exceed $9 Billion, if properly assessed.
Establishing the ARO liability of Nigerian oil companies is one tool that the regulator needs to effectively manage accrual, amortization and contributions. It will help to enforce compliance with the laws as well as bind the licensees to their contractual obligation to Nigerian government and various lenders. To determine ARO, certain legislative, financial, technical, economic, environmental and commercial criteria must be considered in the estimation and assignment of liability. The paper aims to review existing regulatory regimes and leverage that to proffer new ways by which the government and its stakeholders can harness the best technical, financial and operational practices to improve the situation and reposition the industry going forward into the future.
This paper therefore addresses the key issues starting from ARO estimation, when does it accrue and who should implement it. It deals with fiscal or financial reliefs based on global best practices and proposes win-win schemes for Nigeria's government and operators. Implementing ARO will safeguard Nigeria's long-term economic and environmental interests, and consequently, become the cornerstone upon which an abandonment blueprint can be proactive and retroactive implemented.
Production Improvement Through Wax Management Strategy in Offshore Niger Delta Field, Nigeria
Authors: Uche Chukwunonso , Eremiokhale Obehi , Uche Jennifer , Kuku Olatunde , Sanusi Sherif , Omisore Adenike 
Published: August 2020

Abstract
Wax precipitation along oil well tubing causes deferment in production while being produced from the formation through production facilities. Existing formulations for inhibiting wax formation include, chemical injection at different dosages and depths, mechanical inhibiting forms and thermal methods used in overcoming wax formation temperature. A well in one of the Niger Delta offshore field suffered down hole wax deposition after each field shut down. A triplex pump which serves six fields was used to provide a remedial solution after an average well downtime of seven days. In order to control this challenge, crude oil pour point was determined from historical production and temperature profiles and a hot reservoir fluid circulation strategy was developed with the objective of optimizing production through reduced well downtime and minimized expenditures. The technique used shall be discussed in this work. This formulated strategy saved over a five million US dollar per annum.
An Innovative Approach to Brown Field Reservoir Management in Marginal Field Operation
Authors: Uche Chukwunonso , Eremiokhale Obehi , Omisore Adenike , Bukar Ibrahim , Uche Jennifer , Blankson Eyituoyo , Hamzat Ayomide 
Published: August 2020

Abstract
A major cause of increase in the number of well abandonments in small heterogenous formations with high geological complexities is early water breakthrough into completions which leaves pockets of bypassed oil that ultimately affects the overall recovery from such formations. This paper highlights some reservoir management strategies adopted to improve reserves from a Niger Delta formation with an API of 22 Deg. Reservoir management strategies adopted included the use of down hole gauges, inflow control devices, and detailed production/injection surveillance. Updated 3D simulation model and material balance analysis were also used for evaluation of waterflood recovery efficiency and real time Reservoir management decisions. Other Reservoir management practice helped in stimulating gas cap expansion that increased daily oil rate from this reservoir and field gas rate that helped in gas lifting wells in other heavy oil reservoirs with high BSW.
A Comparative Evaluation of Selected Correlations for Estimating Wax-Appearance Temperature of Crude Oils
Authors: Eyitayo Stella I. , Lawal Kazeem A. , Guobadia Kenneth O. , Ovuru Mathilda I. , Okoh Oluchukwu M. , Yadua Asekhame U. , Matemilola Saka 
Published: August 2020

Abstract
From a precipitation standpoint, wax is one of the most vulnerable hydrocarbon contents of crude oil and gas condensate. As a result, wax appearance temperature (WAT) is an important consideration for the management of flow-assurance challenges in the oil and gas industry. Ideally, the determination of WAT requires laboratory analysis of representative fluid samples. In the alternative, rigorous thermodynamic models are employed. However, both the laboratory and rigorous thermodynamic methods are expensive and demanding, yet they do not always guarantee accurate results for the full range of expected operating conditions. Either as a complement or substitute to these rigorous methods, several empirical correlations are available for predicting WAT. Two of these correlations are the composition-based models recently published by Hosseinipour et al. (2019).
This paper reviews and interrogates the predictive capability of the two semi-empirical WAT models developed by Hosseinipour et al. (2019). In addition, based on some experimental datasets, a new correlation is proposed, which describes WAT as a simple function of solution gas-oil ratio (GOR). Using some WAT data obtained from different crude-oil samples in the Niger Delta, robustness of the Hosseinipour et al. (2019) and the new GOR-based correlations is examined. Compared to the experimental cases used in this study, the two Hosseinipour et al. (2019) correlations returned average absolute deviation (AAD) values of 13.0 and 3.0%. Conversely, the proposed GOR-based correlation yields an AAD of 1.0%. For the samples considered in this study, in addition to its relative simplicity, the new GOR-based semi-empirical model exhibits superior performance to both correlations from Hosseinipour et al. (2019). These results notwithstanding, potential improvement areas are highlighted for the three WAT models considered. Accordingly, an augmented form of one of the original Hosseinipour et al. (2019) models is proposed and validated.
Crude Fractionating Column Hydraulic Study with Feedstock Variation using Column Analysis Tool
Authors: Ndunagu Paschal Uzoma , Alaike Emeka Emmanuel , Joel Ogbonna Friday , Oji Akuma , Megueptchie Theophile 
Published: August 2020

Abstract
A hydraulic scenario was created for a 125,000 BPSD Crude Distillation Unit (CDU) by blending varying ratios of two crudes; A (33.62 API) and B (25.77 API) while investigating the product yield. The product specifications were implemented using the ASTM D86 95% volume cut point. The maximum allowable blend ratio of A and B for which the CDU process simulation converged was 78/22 vol%. Under this condition, the top and bottom section experienced weeping & weir overloading respectively while maintaining process conditions. To improve column performance, top pump around flowrate was decreased by 25% to mitigate weeping while the furnace outlet temperature was increased from 367.4° C to 370° C to decrease weir loading. This paper shows that refiners can meet the increased demand for heavy ends while keeping naphtha within limits to meet demand in downstream units. Existing columns can also utilize the Aspen Hysys Hydraulic tool for troubleshooting and plant optimization.
A Holistic Approach to Injectivity Decline
Authors: Harper Christopher , Michael Nnochiri , Yan Zheng , Victor Okowi , Bamisebi Adetloye 
Published: August 2020

Abstract
Key criteria such as initial skin, permeability, scaling, water quality and temperature are the typical considerations employed by most injectivity or formation damage investigations, however it is our belief that this is simply not enough.
Other mechanisms and their combined or secondary effects are typically underestimated, which leads in many cases to the application of mitigation and remediation techniques, which, although initially effective, are short lived due to an inadequate understanding of the formation damage/well communication impairment mechanisms present.
The cause(s) of injectivity decline may be numerous; and are frequently interlinked. This paper examines the considerations of a holistic workflow for defining the potential cause(s) of injectivity decline. Standard considerations of the workflow include physical and chemical water treatment process, water quality and its degradation between process and sand face, flow assurance, physical and chemical interactions with the sandface and near wellbore, mineralogical interactions, microbiological influences and completion architecture.
Such approaches have found value in defining potential causes of injectivity decline, and appropriate remediations or mitigations throughout Sub-Saharan Africa, and Europe.
Effect of Amine Structure on the Corrosivity of a Carbon Steel Natural Gas Processing Plant
Authors: Narku-Tetteh Jessica , Muchan Pailin M , Supap Teeradet , Idem Raphael 
Published: August 2020

Abstract
This work investigated and correlated the corrosiveness of different amines with their uniquely inherent structural characteristics, specifically focusing on the effect of alkyl chain lengths of alkanolamines and diamines, and the effect of the number of -OH groups in sterically-hindered amines. The amines studied were: monoethanolamine (MEA), methylmonoethanolamine (MMEA), ethylmonoethanolamine (EMEA) and butylmonoethanolamine (BMEA) for the effect of the alkyl chain length of the alkyl group attached to the amino group of alkanolamines, and ethylenediamine (EDA), trimethylenediamine (TMDA) and hexamethylenediamine (HMDA) for the effect of alkyl chain length in diamines. For–OH effect, the amines used were: 2-amino-2-methyl-1-propanol (AMP), 2-amino-2-ethyl-1,3-propanediol (AEPD) and 2-Amino-2-(hydroxymethyl)-1,3-propanediol (AHMPD). The results showed that corrosion rates reduced as the alkyl length increased as shown in MEA &gt; MMEA &gt; EMEA &gt; BMEA. For diamines, corrosion rates also reduced as the alkyl length in between amino groups increased as iluustrated in EDA &gt;TMDA &gt; HMDA. These were due to increased hydrophobicity which repelled water molecules more effectively from the metal surface, thereby protecting it from molecules that can cause corrosion. For–OH, the corrosion rate reduced as the number of–OH increased as in AMP&gt;AEPD&gt;AHMPD. In this case, the O atom, an active adsorption site that chemically adsorbs onto the metal surface, reduces the open metal surface thereby inhibiting corrosion. The results show that amines with longer alkyl length and/or higher number of–OH group will reduce corrosion rates in gas processing plants. This information will assist designers in the selection of the appropriate amines or amine blends for use in natural gas processing plants which will minimize corrosion.
Experimental Investigation on Effects of Biologically Based Corrosion Inhibitors on Flowline Material
Authors: Udoh Tinuola H. , Sunday Michael U. 
Published: August 2020

Abstract
In this paper, the potential of azadirachta indica and enzyme as corrosion inhibitors on mild steel was investigated. Effect of salinity, different concentrations of these corrosion inhibitors and their corrosion rate control were measured based on weight loss method over a period of 576 days. The results show that the rate of corrosion of mild steel does not change significantly after 400 days of continuous exposure to fluids. Also, a linear decrease in corrosion rate was observed with increase in azadirachta indica concentration while, increase in enzyme concentration makes no significant changes in corrosion rate beyond the initially reduced rate. Finally, the results show that corrosion inhibition capacity of azadirachta indica was only enhanced at high concentration of 10 wt.% while enzyme generated high corrosion control at all investigated concentrations except at high concentration of 10 wt.%. This study presents novel potential of biological based corrosion inhibitors application to flowline.
Optimization of Intermittent Gas Lift Surface Injection Pressure in High Water Cut Oil Well
Authors: Abdullahi Mohammed Bashir , Abdulkadir Usman , Aliyu Ahmad Musa , Shehu Bashir Umar 
Published: August 2020

Abstract
Gas lifted oil wells contributed substantially worldwide during the production life of the oil reservoir. The intermittent gas lift optimization process leads to an overall reduction of OPEX and increases the NPV from the asset. When the reservoir pressure is insufficient to produce the desired rate, consequently the oil well productivity declines and the percentage of water cut increases. The well level optimization is one of the practical strategies employs to optimize well parameters especially surface injection pressure of intermittent gas lift. A sensitivity study was implemented on surface injection pressure using IPM Prosper. Gas lifted oil rates were analyzed at several surface injection pressures from 1000-5400psi. The optimum surface injection pressure of 1300psi at an oil rate of 140 STB/day was achieved with 6 injection valves (4 operating valves and 2 safety valves) at a depth of total valves of 7316ft producing 80% water cut.
Optimized Production of Bioremediation Agent for Application in the Eco-Recovery of Oil Spill Site
Authors: Agbaji Joseph Egwoyi , Nwaichi Eucharia Oluchi , Abu Gideon Orkwagh 
Published: August 2020

Abstract
This study investigates the application of an optimization process in the formulation of a bioremediation agent modelled to mimics bioaugmentation and biostimulation and that offers a short half-life high degradation efficiency less intrusive and benign to petroleum spill-threatened biodiversity. Several optimized methods and processes were followed to harness the plethora of rhizobacterial isolates from aged oil contaminates sites, screening, and selection of isolates with potential for hydrocarbon degradation based on their specific enzymes activity and catabolic gene assay. One Variable At a Time (OVAT) is applied to screen and select the best agrowaste materials with limiting organic nutrients to support high throughput rhizobacterial isolates cultivation and for which the isolates showed a high substrate utilization affinity. The Monod model was used to establish the optimum organic nutrient capacity as estimated from their agrowaste materials proximate assay. These led to the selection of four rhizobacterial isolates and three agrowaste materials that constitutes the independent factors in the enhancement of petroleum hydrocarbon removal from contaminated soil. To further optimize this process, a multivariate statistical technique of the Box-Behnken method of 15 runs design having the independent variables of bacterial consortia (Pseudomonas fluorescens, Achromobacter agilis, Bacillus thuringiensis, and Staphylococcus lentus) of 5 to 7% inocula size, nitrogen nutrient (corn steep liquor) of 0.331 to 0.662 mgkg-1 and phosphorus nutrient (poultry droppings) 39.4 to 197.4 mgkg-1 was adopted and the model resulted in the randomization of nutrients and consortia in ratios designed to formulate a bioremediation agent. To this composition, a rich potassium source (plantain peels char) of 22.0 mgkg-1 was added. A bioremediation application study was set-up to follow the Box-Behnken modelled results and was monitored for 56d with initial Total Petroleum Hydrocarbon (TPH) content of 9744 mgkg-1 and Total Hydrocarbon Content (THC) of 964 mgkg-1. The model response from the treated sample shows a half-life of 6d, with degradation efficiency of 89.6% and 88.7% for TPH and THC removal after 21d of the study. This study established the feasibility of the application of an optimization model in the development of an efficient bioremediation agent suitable for the eco-recovery of oil spill sites.
Unlocking Potential in Mature Brown Field with Complex Configuration in the Niger Delta- The OML26 Success Story
Authors: Ageh Ebenezer , Isiba Ezinwanneakolam , Okoruwa Immaculate , Ajao Wale , Yebusika Idalla , Onopkise Amos , Oke Oluwatobi , Agbaroji Victor , Okon Willie 
Published: August 2020

Abstract
Managed by a joint operating team tagged the Asset Management Team (AMT), the OML 26 Asset has undergone a total transformation in all ramifications of the oil and gas operations.
Within the space of three years, the Asset has recorded a 122% cumulative annual growth (CAGR) for reserve base increase, a 43% CAGR in production rate increase without drilling new wells, and a 38% CAGR in total production offtake. The direct unit operating cost also improved significantly averaging 31% year on year improvement. From Q4 of 2018, the Asset witnessed breakthrough performance attaining a peak production of ca 18,000 bopd in 2019 from existing drainage points. The rate is the highest rate ever recorded in the long history of the Asset. This is an excellent achievement for a mid-sized E&P company.
This paper aims to share the techniques deployed to attain such a sterling production boost in a 45-year-old field.
Techno-Economic Assessment of the Hydrates Mitigation Potential of LDHI and MEG in Deepwater Scenario
Authors: Okereke Ndubuisi , Edet Pius , Afolabi Funsho , Baba Yahaya , Izuwa Nkemakolam , Kanshio Sunday , Nwogu Ngozi , Nwanwe Onyebuchi , Odo Jude 
Published: August 2020

Abstract
Previous studies in literature and field experience indicates that hydrates mitigation can increase production cost by 15%. Hence, the need for optimum hydrates inhibitor selection. In this study, a deepwater oil field; currently producing at over 100,000 bbl/d had experienced hydrates and an integrated production modelling approach was utilized to model this scenario via MAXIMUS 6.20. The key input data to model were reservoir pressure at 2650 psia; Oil API Gravity at 35.4 °API; GOR at 1324 scf/stb and the produced water rate at an average of 3138 STB/d. Key results indicates that the injection of LDHI into the hydrate lattice within the hydrocarbon stream dispersed the hydrates particles in an unsteady manner and subsequently prevented the formation of hydrates at 40 gal/day. The cost of using LDHI was lower by over $520/day, from simulation results. This study also assessed technical benefits and challenges of using LDHI and MEG in deepwater scenario.
Rethinking Well Integrity for Sustainability: Adopting a Risk Based Approach
Authors: Adeyinka Adeboye , Tsakporhore Abraham , Arije Oluwaseun , Adegoke Oluwagbemiga , Aliyev Shahin , Iwueze Cosmas , Hulett Robert 
Published: August 2020

Abstract
Loss of containment (LOC) issues are every oil and gas operator's nightmare. These low frequency, high consequence spill-events have the potential to adversely affect the environment, an operator's financial health and public perception. For operators with mature aging assets and a sizeable well count, the probability of a LOC event is more likely.
As the industry moves towards increased efficiency, there is a growing need to get more well integrity projects completed despite competition from oil-generating projects in the company-portfolio. This has necessitated re-thinking our response to the fundamental question of "how can we work within the existing constraints to ensure a robust well integrity program that protects people, the assets and the environment from a LOC event?"
We show in this paper, a risk-based approach to solving this challenge. With over 1000 well strings, the starting point was having a comprehensive well integrity management system underpinned by a robust database that contained the test records of all well-related safety devices. A swiss-cheese model was then applied to analyze each device (Downhole safety valve, Wellhead valves and Casing valves) as a layer of protection considering possible hydrocarbon flow-paths.
With this new methodology, each safety device was assigned a risk-factor denoting its relative importance in preventing the occurrence of a LOC event. Multiple safety device failures (e.g. combined failure of downhole and wellhead valves) had extra penalty assigned since holes lining up in the swiss-cheese would allow a catastrophic event pass through undetected. The risk factors were then summed up for each well to generate a risk-index that was used to compare wells and prioritize barge intervention activities accordingly.
The key message is that catastrophic events typically require multiple safeguard failures and we can significantly reduce the chances of its occurrence by applying a risk-ranked approach to well integrity.
Enhancing NAG Well Surveillance by Realtime Measurement of Condensate-Gas Ratio CGR Using Coriolis Meter
Authors: Ihe Chimdike , Udobata Uchenna , Ogbokuma Ekine , Maheshwari Rahul , Arash Aref , Aja-Onu Uchenna 
Published: August 2020

Abstract
Reliable gas well tests provide valuable data for production optimization and maximizing ultimate recovery of gas reserves. Poor data quality, heightened process safety risks and elevated OPEX are inherent limitations in the methods undertaken by operators to measure Condensate Gas Ratio (CGR) during Multi-Rate Tests (MRT) and routine production.
This paper describes the steps undertaken by the team in BERA to overcome this challenge by utilizing the density-measuring capability of the Coriolis meter. A density-based algorithm was setup using a designed decantation procedure and encoded in the control system for real-time measurements and made available in the office domain.
This technique provides improved data quality, ease of well surveillance and a long-term cost avoiding option while simultaneously increasing the flexibility and ease of executing MRTs. It eliminates the need for manual sampling with its associated process safety concerns.
Effect of Riser Base and Flowline Gas Injection on the Characteristics of Gas-Liquid Two-Phase Flow in a Vertical Riser System
Authors: Brini Ahmed Salem Kalifa , Aliyu Aliyu M. , Ehinmowo Adegboyega , Yeung Hoi 
Published: August 2020

Abstract
We report an experimental study has been conducted on a 52 mm internal diameter vertical riser of which is met at the riser base by a 10.5 m long. The effect of two different gas inlet configurations were tested: riser base gas injection and horizontal inline injection 40 meters upstream of the riser base. A 16×16 wire-mesh sensor was used to measure the void fraction at the riser top and we present a detailed analysis of the characteristics of flow because of the injection scheme. These include regimes and cross-sectional void fraction distributions of the time series data. Among our findings are wall-peaking gas fraction profiles at lower gas injection rates through the flowline, while core-peaking profiles were established at the same flow conditions for riser base injection. This provides valuable information that can feed into the design of downstream facilities such as slug catchers and separators.