bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drilling into a Charge Shadow Zone of a Prolific Niger Delta Field: Learnings from Well-X
Authors: Ayodeji Ogunlana , Kolawole Akingbade , Oladipo Falade , Olusegun Obilaja , Chikezie Chima , Farran Herve , Timipere Jenakumo , Anita Orakwue 
Published: July 2023

Abstract
Three decades on, a brownfield still springs surprises in the Deepwater Niger Delta. An Exploration well, Well-X was recently drilled targeting an amplitude-supported opportunity within a prolific geological interval in a Deepwater field. The well discovered excellent reservoir of 78 feet thick sand with 100% net-to-gross and 32% porosity, but turned out wet, with no evidence of hydrocarbon. The post well evaluation indicate that the excellent reservoir properties contributed to the false-positive amplitude anomaly that is typically attributed to a direct-hydrocarbon indicator in prospective reservoirs.
A post-mortem was conducted to understand which element of the petroleum system failed resulting in the wet well outcome. Access to hydrocarbon charge and trap integrity were re-assessed as two possible geological failure mechanisms. Results of the investigation and preponderance of available evidence indicated that lack of charge access was the most likely reason for failure as there was no trace of thermogenic hydrocarbons in the entire stratigraphic interval drilled. The post-mortem also revealed that deep-seated faults extending into the charge kitchen act as major hydrocarbon migration conduits into target reservoirs within the field. Unfortunately, Well-X target reservoir was not connected to any of such faults and is located in what is now considered a ‘Charge-shadow’ zone of the field. A Fluid Inclusion Study (FIS) required to validate the charge theory is currently being embarked upon.
A key learning from this well outcome is that access to charge is not ubiquitous, even in prolific fields or basins. A good understanding and clear definition of plausible migration pathways are critical to exploration success.
Otakikpo Offshore Integrity Challenges and Solution
Authors: Akinyemi Johnson , Kala-Otaji Tamunotroko 
Published: July 2023

Abstract
The Otakikpo marginal field was carved out of OML 11 and is situated in the southern part of the license. Green Energy International Limited, the operator, successfully implemented the first phase of the field development between 2015 and 2017. This was followed up with a 2nd phase in 2022. The field currently produces circa 11000 bopd.
Due to its proximity to the shoreline, an amphibious production and evacuation methodology was implemented. This consists of batch production into onshore tanks, a subsequent evacuation into offshore shuttle tanker via an installed 6", 6 Km offshore pipeline and final transportation to a 3rd party FSO facility. The end of the offshore leg is connected to a PLEM (Pipeline End Manifold) which acts as interface between marine pipeline and the submarine hose system. The mooring systems consists of 2 gravity anchors (5tons each ~ port and starboard); 200m steel anchor chains; 40m sling wire; 20m sling wire; and a 100m pick up rope.
However, the offshore environment experiences a significant adverse weather condition between March and December that peaks between June and November every year. Often, it could take professional divers up to 5 days to pick up rope from the seabed depending on weather condition. There were cases of incessant twisting, tension and curling as the hose is exposed to swinging by ocean swell and current leading to loss of operational integrity of the offshore system. Restoring the integrity of the system led to significant operational downtimes as high as 20 days per year; a situation that was not sustainable for a marginal field producer.
The GEIL engineering and operations team developed and implemented several vintages of design modifications over time to mitigate these concerns. The team realized that the most challenging part of resolving the hose swinging issue was finding a way to keep it fixed, in such a way that the hose end does not move under any weather condition(s). To achieve this, the team designed and installed a Crossbar + Buoy system. The Crossbar was installed on the seabed, while ensuring the height is above the water surface. A boat is used to unhook and hook up the cargo hose to the Crossbar before and after every shuttle loading respectively. This allows for a more efficient pick up and transfer of hose to tanker (10 mins) by professional divers while eliminating the challenges with hose twisting which usually results in hose curling around the PLEM and incessant shutdown from the EPF. Luckily for our operations, there was no spill recorded in these scenarios due the effective communication between EPF and the marine team, and timely shutdown of crude flow from the EPF.
This paper aims to highlight the seasonal integrity challenges faced by the Otakikpo offshore evacuation system, its effect on operational excellence and the various stages of the elegant solutions developed and implemented.
Factors Influencing Sustainable Energy Transition and Climate Change in Nigeria.
Authors: Oruwari Humphrey , Ogbuike Onyebuchi 
Published: July 2023

Abstract
The aim and objective of this study is to examine the factors influencing sustainable energy transition and climate change in Nigeria and recommend ways to promote sustainable energy transition for policy decisions in Nigeria. There has been a general call for the decarbonization of the global environment. This has necessitated the need for renewable energy and other forms of sustainable energy in developing countries. African governments are passionately disposed to finding a balance between energy transition and energy trilemma. The balance is with respect to energy equity, sustainability, and security However, the African nation of the world are lagging in terms of energy transition and several factors are responsible for the slow speed in energy transition in the Africa. The study adopted qualitative research methodology using literature review. Based on the analysis of literature review in energy transition it has been shown that technically 100 % renewable energy systems have been verified. In order to achieve carbon neutrality, current energy system need to be transformed towards a sustainable energy system or at best quasi sustainable development of petroleum resources. The study findings revealed that there are some barriers to carbon neutrality that presently constrain sustainable energy transition. The study highlighted on the development of an enabling framework that act as counter strategies to overcome the existing barriers and facilitate energy transition to be sustainable. The underlying factors behind sustainable energy transition and de-carbonization are: Financial, technical, energy market and energy policy, support infrastructure, environment/ ecological, legal and regulatory requirements. In conclusion, it is imperative that for a sustainable energy transition and mitigation of climate change in Nigeria, the enabling frame work needed to be reformed.
Project Life Cycle Costing and Sustainability of Natural Gas Pipeline Project in Nigeria
Authors: Oruwari Humphrey , Ogbuike Onyebuchi Michael 
Published: July 2023

Abstract
The World energy council (WEC) of which Nigeria is a member share a common belief that guaranteeing a sustainable supply of affordable energy is one of the best ways to address poverty, inequality and environmental degradation everywhere on the plant. So many natural gas pipeline projects exist at different implementation stages in Nigeria and many of its projects have struggled to achieve sustainability throughout their lifecycle. Specifically, natural gas pipeline construction projects have neglected to consider economic, environmental, and social factors, resulting in inefficiencies and a continued lack of energy access in the country. This research focused on examining the relationship between project life cycle costing and the sustainability of natural gas pipeline construction projects in Nigeria. The study employed literature reviews, document analysis, and case studies, employing both descriptive and explanatory research designs. Nigerian gas pipelines used for power generation, cement production, and other purposes served as the case study. The findings revealed that initial costs significantly influenced the sustainability of natural gas pipeline construction projects. Additionally, maintenance costs and end-life costs were found to impact the sustainability of such projects in the Niger Delta region. Moreover, the research demonstrated that operational costs played a crucial role in explaining natural gas pipeline construction projects in the Niger Delta.
Geological Model of a Near Field Exploration Cluster: Implications on Prospectivity, Reservoir Presence, Reservoir Quality, Formation Pressure Distribution and Prediction
Authors: Adesida A. , Ndulue G. , Ekwealor J. , Omuije J. , Mude O. , Ukeri P. , Alamina P. , Tichelaar B. , Obilaja O. 
Published: July 2023

Abstract
A detailed geological model was built to form the basis for a Near Field Exploration (NFE) project required to secure gas supply shortfall in an area ("cluster") onshore Niger Delta. The key business driver is the proximity (~2-10km) of leads and prospects in the cluster to an existing gas plant in the area. Proximity to the gas plant is expected to facilitate early production hook-up and enhance the Net Present Value of the projects. Moreover, robust exploration success potentially provides lower Unit Development Cost (UDC) options.
The methodology involved seismo-sequence stratigraphic analysis using data from 19 wells penetrating Tortonian 1, Serravallian 2 and Langhian 1 maximum flooding surfaces (MFS). The geological model integrated distinct seismo-sequence stratigraphic analysis, regional isopach maps, sand supply/distribution trend analysis, seismic attribute extractions and geo-feature highlighting volumes.
The combination of the seismic velocity data and geological model show consistent velocity reversals in the outer shelf to shelf margin Gross Depositional Environment in a distinct relationship with the interval net-to-gross (NTG). Drilling kicks occurred in outer shelf to shelf margin sediments with relatively low interval NTG (~15-60%). This work significantly contributes to the understanding of the prospectivity and associated subsurface risks in the cluster area. It has influenced the polarization of the exploration portfolio into low risk, medium to high NTG conventional opportunities and high risk, medium to low NTG deep high-pressure (HP) opportunities. It is the bedrock of the formation pressure prediction in the cluster area.
Microwave Assisted Technique for Oil Recovery from Oily Sludge Shale Drilled Cuttings
Authors: Agi A. , Junin R. , Shakuam M. , Gbadamosi A. , Ridzuan N. , Mahat S. Q. Aini , Gbonhinbor J. , Oseh J. 
Published: July 2023

Abstract
Oily sludge, obtained during drilling processes, is considered a hazardous waste due to its composition. Conventional techniques of treating oily sludge indicates that desorption of the oily sludge is inhibited by asphaltenes. Herein, the effect of microwave power on oil recovery from contaminated drill cutting was investigated. Also, the effect of drilled cutting sizes on oil recovery was evaluated. Besides, the impact of microwave exposure time (10-60 minutes) on oil recovery was determined. Based on this, the mechanisms of microwave disintegration of the oily sludge were analyzed. Experimental result depicts that higher microwave power was more effective in the desorption of oil from the drilled cuttings. Moreover, more oil was recovered from smaller sizes of the drilled cuttings at a longer exposure time. The mechanisms of dipolar interaction and ionic conduction broke the hydrogen bond between the asphaltene and solid particles by this means enabling oil recovery of 59-99% from the contaminated drilled cuttings.
Exergy, Exergy–Economics and Pinch Analyses of Butadiene Production Process from Sweet Sorghum
Authors: Omofoyewa M. G. , Adeniyi A. T. , Giwa A. 
Published: July 2023

Abstract
The utilization of biomass to generate energy, chemicals and materials is one of the essential elements of sustainable development. It would be beneficial if substitutes for these petrochemicals are developed with an eye to the future. Currently, research is being done to discover ways to produce petrochemicals in an eco-friendlier way, e.g., converting biomass towards bulk chemicals like butadiene. Butadiene is an essential element in the petrochemical sector, and demand for it has increased along with the expansion of the petrochemical market. Furthermore, rubber products have a wide range of applications in the automotive, oil and gas, medical and plastic industries. When oil prices are stable, the rubber market becomes steady and prices become reasonable. In contributing to this development, an energy efficient plant has been designed in this work. The plant uses sweet sorghum as the main raw material stream and produced 30,000 kg/hr of 1, 3-butadiene. The process consisted of four distinct stages: juice extraction, fermentation, ethanol dehydration and butadiene separation. The thermodynamic method used in the simulation was Non-Random Two-Liquid (NRTL) model. The results from the work provided a design and an economic analysis for a complete butadiene production plant. Mass and energy balances were also provided, and the utility requirements were determined by exergy, exergy-economics and pinch studies using Aspen Plus software.
Modelling and Simulation of Natural Gas Condensate Production Using Artificial Neural Network
Authors: Ashinze A. S. , Adeniyi A. T. , Giwa A. 
Published: July 2023

Abstract
Natural gas condensates are hydrocarbon liquid streams separated from natural gas when it is cooled to temperatures within the upper and lower limits of the hydrocarbon dewpoint curve at a definite pressure in a cryogenic gas plant. They find useful applications in the petroleum and petrochemical industry for production of high octane-petrol, jet, diesel and boiler fuels as well as in production of aromatics, olefins and other monomers used in the production of plastics, synthetic rubbers, resins and fibers. This research paper focused on modelling the process involved in obtaining natural gas condensates from raw natural gas in a cryogenic plant. Stationary-state process data were obtained from a natural gas processing facility in southern Nigeria. The data were pre-processed, five inputs and three output variables were then carefully chosen and arranged in cell arrays in Microsoft Excel before being incorporated into a written MATLAB m-file script, which was ran to generate time-series input-output datasets in Microsoft Excel via a developed Simulink transfer function model. The generated chaotic time series dataset was then fed into the neural network graphical user interface of MATLAB R2021a software and optimized using Levenberg Marquardt, Bayelsian regularization and conjugate gradient algorithms respectively to develop neural network models that represented the production process. Two key indices, namely the mean squared error (MSE) and regression value were used to evaluate the level of accuracy of the developed neural network models. The results obtained revealed that the neural network models developed could effectively capture the underlying trend in the time-series dataset with the Levenberg-Marguardt optimized-neural network having a faster convergence time of 10 seconds, higher regression value of 0.999 and lower MSE value of 0.0489.
Agile Adoption Enhances Cross-Functional Assessment of Idle Wellbore Restoration Project
Authors: Adegboye Phillip , Onyekwena Ekene , Kuku Tolu 
Published: July 2023

Abstract
The Joint Venture ("JV") Offshore Asset of company X in Nigeria hosts a portfolio of more than 600 wellbores. The asset is over 55 years old and as such, has a sizable number of idle wellbores. The Asset Team has been actively intervening in these idle wellbores using non-rig workover ("NRWO") units over the years. However, due to the age of these wells and the severity of some of the downhole conditions, an increasing number of these wells have become mechanically challenging to execute using NRWO barges. A higher capacity but cost-effective workover unit is therefore required.
A cross functional team comprising Asset Team, Wells and Facilities Engineering, was set up to evaluate this cost-efficient restoration project at a unit development cost ("UDC") less than $7/BOE, being the Unit Operating Expenses target for the Business Unit (BU). The early challenge faced by the cross-functional team was the determination of a jointly agreed set of criteria to adopt in assessing the candidates for viability. A candidate considered robust by the Asset Team, based on subsurface estimated ultimate recovery ("EUR") might not necessarily be viable from the Wells and Facilities Engineering ("FE") standpoints. The challenge resulted in delays in making appreciable progress at the early stage of the project. An Agile framework was adopted by the team to aid cross functional engagements. This is an iterative decision-making process which provides frequent feedback on work-in-progress thereby resulting in an early project value delivery.
The team collaboratively developed a cross plot which integrates the subsurface, Wells and FE assessment considerations and criteria. It is a plot of Ease of Execution ("EoE") versus EUR which displays the spread of all the candidates assessed against the backdrop of jointly agreed set of criteria. Utilizing the Agile framework principles, every new candidate was screened through the cross-functional plot with little or no recycling. Within 3-4 months, the team assessed 52 wells through this process, a feat which could have otherwise been achieved in 8-12 months. The quadrants of the cross plot enabled a simple visualization of the candidates across four distinct categories namely: High EUR & High EoE, High EUR & Low EoE, Low EUR & High EoE, and Low EUR & Low EoE.
The adoption of Agile principles by the experienced multifunctional team accelerated the workover assessment process. A sound understanding of the asset was also pivotal to achieving a successful assessment.
Driving Profitability in Brownfield Field Cluster Production Through Focused Back-To-Basics WRFM Optimization & Restoration: Habic Field Cluster Experience
Authors: Uyiosa Osazuwa B. , Ovokerhoyi Esharegharan , Onajite Taro , Suka Baranu , Gbolade Ibikunle , Aniekan Obot 
Published: July 2023

Abstract
Most brown fields have inherent issues ranging from, but not limited to increasing water production, reservoir pressure decline, increasing sand production and wells/facility integrity challenges due to Asset aging. For the Habic Assets, frequent incidents of insecurity and vandalization of facilities has added non-engineering challenges to the effective management of Assets. Well production uptime is highly impacted by this new challenge, and this has necessitated continuous optimization and innovation to ensure that the Asset remains profitable.
This paper presents the simple and cost-effective approach used by the integrated Petroleum Engineering & Asset Production teams to deliver business promise for the Asset. The integrated team reviewed various strategies to harness the benefits of the age long "fix-the-basics" tools to arrest the dwindling fortunes of the Assets. Two key approaches were employed: firstly, surveillance data was incorporated in integrated production system models (IPSM) and using the Chan diagnostic tool, well operating envelopes were defined and used for optimization of producers. Based on the outcome of the reviews, the team proposed several production system optimizations with combined estimated gain of ca. 7800 bopd within allowable rate. Secondly, long closed-in well stock meant for temporary securing in line with standard well integrity recommended practice were flow tested using surveillance data gathered as a guide. The team prioritized strings in terms of historical closed-in tubing head pressure (CITHP), held risk assessments sessions and secured mitigations to perform the flow trial. This led to the identification of 7 conduits with combined potential of 4200 bopd.
Both restoration and optimization efforts from integrated review of producing and closed-in well stock has added a combined potential of 6200 bopd with a further ca.5800 bopd expected once the outstanding optimization opportunities and open-up of 3 other closed-in wells are implemented and tested.
Sensitivity Analysis of Choke Size Selections on Reservoir Pressure Drawdown Using Prosper Modelling for Reservoir Management
Authors: Gidado A. O. , Adeniyi A. T. , Olusola B. , Giwa A. 
Published: July 2023

Abstract
It is important to know that analysis and selection of choke sizes for oil wells is imperative for production optimizations in reservoir management. Chokes are necessary in every wellhead completion for regulating flow from the reservoir. Random selection of choke sizes has been a bad practice. For the case study of this work, productions from 3 gas condensate wells have declined with pressure over three years. The initial reservoir pressures of 5870 psi, 4373 psi and 2248 psi, initial production rates ranging from 82.3 BOPD to 242.57 BOPD and 3.018 MMSCFD to 5.001 MMSCFD respectively, with choke sizes ranging from 22/64" to 24/64". However, these reservoir pressures have depleted over 3 years by about 100 psi to 3800 psi for each well with early water breakthrough ranging from 10% to 25% basic sediment and water (BS&W). No analysis of choke sizes selection to flow the wells at the initial stage. This research work has been carried out on pressure depletion control corresponding with its drawdown. This was achieved by modelling and simulating PVT data, completion data, IPR and VLP data and well-test data as well as sensitivity analysis with the aid of PROSPER. Results obtained indicated the need to reduce choke sizes, thereby reducing the drawdown. The reduction of choke size gave a decrease in production volume ranging from 15 to 59% for both oil and gas. However, the reduction in choke sizes also gave decrease in water production of about 92%, 100% and 22% for the respective wells. The choke size sensitivity analysis showed that continuation of the initial choke sizes on 24/64" gave a higher drawdown value above 100 psi, which increased the pull of water conning. Recommendation of the new choke sizes within 18/64" to 20/64" showed the drawdown of 79 psi, 71.5 psi and 80.5 psi. New choke size selection was recommended for the reservoir management of each well.