bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of the Effects of Well Length Tapering on a Horizontal Well Performance in a Laterally Infinite Reservoir
Authors: Ukpong P. O. , Adewole E. S.
Published: July 2023

The amount of oil producible from a horizontal well can easily be reduced if the reservoir has external boundaries which are capable of attenuating further pressure transient propagation through the reservoir. Although several operational measures, such as well stimulation, well re-entry, can be implemented to further boost well production, wellbore length modification by tapering is investigated in this paper. The investigation involves development of a mathematical model for evaluating well performance up to first linear flow period for a tapered horizontal well in an anisotropic reservoir of finite reservoir thickness. Dimensionless radius in the flow model for dimensionless pressure of a horizontal well in a laterally infinite reservoir during linear flow is tapered. The effects of the tapered radius on unsteady state dimensionless wellbore pressure were studied for a hypothetical anisotropic reservoir. Both infinite conductivity and uniform flux cases are considered. The effects of near wellbore problems such as wellbore skin and storage are not considered. Results obtained shows that dimensionless pressure increases as dimensionless time increases and the time at which initial radial flow starts, persists further than completions that are not tapered. Furthermore, tapering delays time at which linear flow starts. Two scenarios were observed for well performance with respect to well length. In the first case, well productivity decreases as the length of the tapered string increases for a particular dimensionless time, while second case shows that performance increases when both dimensionless length and time increases. Reservoir, wellbore, and fluid properties are also found to affect well productivity no matter the number of tapered strings used during well completion. For example, as reservoir pay thickness increases, well productivity also slightly increases. Also, the influence of infinite conductivity and uniform completion is not felt strongly on well productivity whether the lengths are tapered or not. Study shows (1) prolonged infinite acting flow period compared to single tubing completion. This means that time to reach reservoir external boundary is increased with tapered completion than single tubing completion. (2) there is improved production rate compared to single tubing completion. This means that more oil is recovered per unit time for tapered completion. (3) tapered completion requires less frequent stimulation since damage is spread over a larger area instead of concentrating on only a single tubing with same diameter across the pay zone. (4) Mechanical damage is mitigated since larger tubing penetrates the pay zone. Reservoir and well completion engineers are now encouraged to employ tapered completions in horizontal wells for improved well production especially if the reservoir has external boundaries that are inimical to well productivity.
A Quantitative Analysis of the Impact of Well and Reservoir Parameters on Pseudo-Skin Due to Partial Penetration
Authors: Egbe E. P. , Hart A. F. , Omobolanle O. C.
Published: July 2023

Pseudo-skin factor due to partial penetration (Spp) is a crucial parameter when evaluating oilwell deliverability. It creates an additional pressure drop at the near-wellbore region with inimical impact on well productivity. Conventionally, a fraction of the reservoir thickness is targeted for perforation to maximize production and reservoir drive thereby increasing Spp. This paper investigates the impact of changes to pseudo-skin’s intrinsic parameters on its behavior. A software application (SENDI 6.0) was developed to automate the calculation and sensitize on the parameters. The results were subsequently regressed and analyzed to monitor the fractional contribution and impact of each parameter. The results of the investigation revealed that in comparison to other key parameters, penetration ratio is the largest contributor to Spp, accounting for about 37% of the pseudo-skin factor.
Energy Transition in Mono-Economies, the Non-Participatory and Effect Mitigating Approach
Authors: Ekeregbe Merit Prince
Published: July 2023

Energy transitioning has been phenomenal in terms of the energy and commitment to see the implementation of the lofty sway by the big economies and international partnerships like the 2016 Paris Agreement and Sustainable Development Goals (SDGs) initiatives. The same enthusiasm cannot be said of small economies and developing Nations. The paper explores small economies’ approaches to domesticating or internalizing their transitioning and mitigating effects of the global energy transition.

A new definition of energy transition that covers key terms and pillars of any new energy concept is provided. The pillars provide a structured, organized energy transitioning approach to ensure effective participation. The pillars of energy transition underscore corporate and national rhetorics in enhancing or demarketing the transition. Approaches to participate effectively are presented to help mono-economies and small-resource economies domesticate their energy transitioning in light of capability and resource availability.

This paper approach provides guidelines for National and corporate organization self-appraisal of efforts towards ensuring effective energy transition. The self-appraisal is necessary to ensure that efforts are in the right perspective to create room for improvement and that areas that need further action in the energy transition are engendered. The right approach for energy transitioning investment is advocated considering capacity, resource availability, and the benefits to humanity. The mono-economies and small-resource economics approach must focus on domesticating the energy transition regarding local resource availability and garnering the people-process-policy trios to prepare for the forward-looking global energy transition. Monoeconomies and small economies must domesticate the availability of energy resources locally, given the global energy transition.

The review of the energy transition equips mono-and-small scale economies to harness available resources and domesticate their energy transition. The energy transition analysis reveals ineffective and aloof tendencies. It strengthens the role clarity of all Nations and how best to transition into the new energy or mitigate the global effect.
Polymeric Gel Treatment for Water Shutoff – A Case Study
Authors: Stephen Babagbemi Adetoye , Mofunlewi Samuel , Kayode Sote Olujimi , Onobrakpor Ochuko
Published: July 2023

Production from several matured oil and gas fields is impacted by high water cut. Common causes of excess water production in wells are coning, inflow through fractures and poor cement quality behind casing. Operators always aim at increasing the recovery of oil and gas and prolong well life in the absence of or negligible water cut. Polymeric gel system is a clear fluid formulated with low-molecular-weight polymer which allows penetration into matrix pore spaces for complete shut-off. Its low viscosity prior to crosslinking aids its injectivity; after placement in small openings such as pore throats and channels in cement behind casing, the final product is a rubber-like ring gel which penetrates formation matrix to reduce permeability and eventual shut-off flow. This paper focuses on the application of polymeric gel solution designed to shut off water production in two wells in Niger Delta. The candidate wells were carefully selected following a comprehensive review of the well schematic, petrophysical information and the reservoir performance monitoring logs. Based on the results of the data analyzed, polymer gel system was recommended. The required laboratory tests were conducted to confirm gelation time prior to field deployment. Coiled tubing and thru tubing inflatable packer were the preferred deployment method for precise treatment placement. The wells were shut-in for five days and surface samples were collected and kept in the water bath under downhole temperature conditions to allow curing of the treatment. The wells were opened after the curing time, and pressure tested against cured treatment system downhole and held for 10mins. The positive results from the pressure tests in both wells showed that total shut-off of the existing perforations were successful. The wells were thereafter re-perforated at shallower depths and production sustained on both wells.
Dimensionless Pressures and their Derivatives for a Vertical Well Completed within a Pair of Inclined Constant-Pressure Boundaries
Authors: Ojukwu I. N. , Adewole E. S. , Taiwo O. A.
Published: July 2023

Dimensionless pressure and their derivatives assist tremendously in understanding the reservoir boundary types, efficient well design, completion and production scheduling for optimum recovery from the reservoir. For a reservoir boundary as inimical as constant-pressure to oil or gas production, the need to adequately anticipate its presence and approach pattern towards the wellbore cannot be overemphasized. In this paper, dimensionless pressures and their derivatives are provided for a vertical well completed within a pair of inclined constant-pressure boundary (CPB) support. The angle of inclination of the constant-pressure boundaries is varied between 0 and 360 degrees. Hence, a generalized dimensionless pressure and derivatives expressions are derived by superposition of dimensionless pressures of all image wells on one object well. Therefore, distances of every individual well from the object well and the sign of every image, taken through a counterclockwise direction from the object well, are major inputs into the dimensionless pressures and dimensionless pressure derivatives derived. Only the object wellbore skin but not its storage is considered. The solutions are plotted as type curves.

Results show dependence of both dimensionless pressure and dimensionless derivatives on angle of inclination of the constant-pressure boundaries. The dimensionless pressures exhibit a unique gradient at late dimensionless times. There is a collapse of the derivatives to zero at late dimensionless times. The rapidity of the collapse depends on object well distance from the boundaries and the angle of inclination of the boundaries. Wells completed farther away from the CPBs exhibit unperturbed production for longer periods than nearer wells.
Machine Learning Techniques for Real-Time Prediction of Essential Rock Properties Whilst Drilling
Authors: Amadi K. W. , Alsaba M. T , Iyalla I. , Prabhu R. , Elgaddafi R. M.
Published: July 2023

Wellbore instability is the most significant incident during the drilling of production sections of most wells. Common problems such as wellbore collapse, tight hole, mechanical sticking, cause major delays in drilling time due to extended reaming and sidetracking in worst-case scenario. Geomechanical property of rock such as Unconfined Compressive Strength (UCS) affects wellbore stability, drilling performance and formation in-situ stresses estimation. Conventional methods used to estimate UCS requires either laboratory experiments or derived from sonic logs and the main drawbacks of these methods are the data and samples availability, high costs and time This paper presents an alternative technique of utilizing real-time drilling parameters and machine learning (ML) algorithm in the prediction of UCS thereby enabling timely drilling decisions. ML algorithm enables a system to learn complex pattern from the dataset during the training (learning) phase without any specified mathematical model and afterwards the trained model can predict through a model input. In this work, five ML models were used to predict UCS using offset well data from an already drilled wells. The models include; artificial neural network (ANN), CatBoost (CB), Extra Tree (ET), Random Forest (RF) and Support Vector Machine (SVM). The ML models were first trained with 1150 data points using a 70:30 percentage ratio for training and testing the model respectively. After that, 560 datapoints from a different well were used to validate the developed model. The real-time drilling parameters required included weight on bit, penetration rate, rotary speed, and torque. The analysis result revealed good match between the actual and predicted (UCS) with correlation coefficients for training and testing dataset; 0.970 and 0.70 and 0.85 and 0.77 for CatBoost and ANN respectively. The main added value of this approach is that these drilling parameters are readily available in real-time and timely drilling decisions can be modified to improve the drilling performance.
Decarbonization: Economic Analysis of Powering a Filling Station with Solar Panel System in Nigeria
Authors: Ayodele Emmanuel , Okoli Kingsley , Ibrahim Bilal , Ebere Emmanuella , Akinyemi Oluwaferanmi , Wosu Nwonodi
Published: July 2023

From the refineries to the filling stations to the vehicles themselves, the transportation industry is responsible for one of the highest levels of emissions in the contemporary era. These emissions come from vehicles that run on diesel, gasoline oil, and premium motor spirit. This study is centred on the reduction of carbon emissions at filling stations for petroleum products as a means of lowering a facility's overall carbon footprint. Throughout the study, data on the overall energy output of the filling station was collected and the costs associated with solar energy systems were analysed. The cost of installation of a solar energy system, as well as the cost of maintenance and the life cycle of the alternative source of energy, in this case, solar energy, are factored into the study. During an investigation into the economic viability of substituting a solar system for diesel power generators, a total of one hundred (100) refuelling stations in Nigeria's Niger Delta region (Port Harcourt) were considered. The paper shows a breakeven period of 1-4 years for different filling station designs investigated when power is supplied with a solar system. The cost-failure theory was also evaluated and found to be 441 Naira for the cost of diesel if the system were termed inefficient. This paper presents a feasibility study that demonstrates an efficient method for lowering the carbon emissions footprint caused by diesel powered filling stations.
A Digitized Tool for Well Candidate Selection for Matrix Acidizing in Sandstone Reservoir
Authors: Okologumw W. C. , Onyeoru J. O.
Published: July 2023

Matrix acidizing is a well-stimulation that has evolved and is still used to increase productivity when the productivity index drastically decreases and the production rate declines. A candidate well-stimulation selection method and software are suggested in this work. The process is based on technical, workover complexity, production decline curve analysis (for future forecasting), and economics since candidate selection must be rigorous. Production data from four onshore Niger Delta stimulation candidate wells were used to validate the software developed. R-factor, productivity index, and flow efficiency were the technical parameters used, and eleven (11) indicators were used for workover complexity evaluation. The future forecast was done using the production decline curve analysis and different economic indicators such as the Internal Rate of Return (IRR), the Net present value (NPV), and the Payback time. Profitability Index (PI) was used for analysis and make decisions. All wells analyzed in this study met the technical parameter criteria, making each well a potential candidate; hence, further studies can be conducted. From further reviews based on the author selection criteria carried out with regard to production trend (decline curve analysis) and economics, it was seen that WELL XX-01 was ranked first due to its shortest payback time of 2.0899 months and highest NPV of $23,636,983, WELL XX-03 was ranked next, having a payback of 2.2472 months and an NPV of $9,627,221, WELL XX-02 was ranked following having NPV of $7,260,917 and a payback of 2.2560 months and lastly, WELL XX-04 having a payback time of 2.3615 months and NPV of $6,777,548.
Evaluation Studies of KCl and Amino Acid Mixtures for Clay Stabilization and Rheological Enhancement of Water-Based Fracturing Fluids
Authors: Duartey K. O. , Quainoo A. K. , Darko C. K.
Published: July 2023

Conventional stabilizers such as inorganic salts in water-based fluids are restricted for use in gas and oil shales drilling and hydraulic fracturing for drilling due to environmental, economic and performance concerns. For example, 2% use of KCl, a commonly used inorganic salt, contains an excess of 9500ppm chloride. This is considered high and toxic. Apart from environmental problems, KCl inhibiting solutions tend to negatively affect the rheology of the water-based fluids, posing a dilemma for industry operators. The clay and rheological stabilizing effects of KCl and amino acid mixes for hydraulic fracturing operations were investigated in this study. The stabilizing and rheological potentials of mixes of KCl and organic compounds have proven to be superior to the separate compounds in studies. The KCl was used in the study at safe quantities (1%) to prevent toxicity concerns. In this study, the inhibition potentials of KCl+ Arginine and KCl + Alanine solutions, mixed approximately at ecologically safe quantities, were tested at different bentonite wafers using M4600 Linear swell at 25°C and 1000psi in the work. Furthermore, rheological studies on bentonite-based suspensions were carried out using a high-precision Discovery Hybrid Rheometer (DHR-1). This was done to monitor the flow parameters of the inhibiting suspensions and their anti-swelling effects on the bentonite component of the prepared fracturing fluid. The effects of the mixtures were also compared to that of KCl, Arginine and Alanine inhibition solutions. Herschel-Bulkley's model was also used to determine the flow characteristics. After 24 hours of testing, the swelling findings reveal that KCl+ Arginine/KCl + Alanine treated fracturing fluids significantly affect the clay stabilization and rheological properties of the fracturing fluid. The study provides basic information on the inhibition potentials of KCl and natural amino acid mixtures in water-based fracturing fluids for clean clay stabilization.
Determination of Non-Darcy Flow Coefficient and Completion Skin from Multi-Rate Test Data with a Decreasing Effective Skin
Authors: Ekeregbe Merit Prince
Published: July 2023

Non-Darcy skin is always present in the gas, gas-condensate, and high Gas Oil Ratio (GOR) oil wells, increasing as the rate increases. However, the reverse is true in a well with a loading skin. This paper outlines the interpretation procedure and unmasking of the non-Darcy skin in a loading well with a new calculation approach.

A rate test for a gas or gas-condensate well with a pressure transient test (PTT) is required for well-test interpretation, and the diagnostic and the matched well production history plot provide the nominal or rate-dependent skin. The effective skin comprises completion, non-Darcy, and loading skins in a well with decreasing effective and loading skins. This approach focuses on matching the production history plot to provide the rate-dependent skins to determine the loading and completion skins.

It becomes impossible to determine reservoir parameters with a masked radial flow regime. When compounded with serious liquid-loading skin, non-Darcy skin determination becomes another challenge. In this scenario, Ramey's method and Spivey's for determining non-Darcy skin become insufficient because the former deals with an increasing non-Darcy skin only; in this case, we have a decreasing skin, and the latter does not account for a loading skin. This study resolves the limitation of both methods by accounting for the loading skin and unmasking the non-Darcy skin. With the new formulation for effective skin, the reservoir parameters can be determined from the general flow regime equations. The loading-skin rate-mitigation strategy proves successful in well recovery.

This approach is utilized with a loading-skin mitigating rate to recover well that would have quit on production. The non-Darcy skin effect and the loading-skin curves reveal a minimum loading-skin mitigating rate for improved productivity and overcoming Ramey and Spivey methods’ limitations.
Influence of Surface Modification on the Interfacial Tension Reduction and Wettability Alteration of Iron Oxide Nanoparticles Under Reservoir Conditions
Authors: Yakassai F. , Jaafar M. Z. , Sidek M. A. , Agi A. , Gbonhinbor J. , Ridzuan N. , Mahat S. Q. A. , Ngouangna E. , Oseh J. , Al_Ani M.
Published: July 2023

Iron oxide nanoparticles (IONPs) are at the forefront of advanced materials considered for enhanced oil recovery (EOR), due to their unique physicochemical properties. However, the major drawback is that IONPs quickly agglomerate to diminish their high surface energy, particularly in reservoir brine. Hence, losing their stability and beneficial characteristics which have a negative impact on oil recovery. In this study, these challenges have been circumvented by the functionalization of IONPs with 3-aminopropyltriethyloxysilane (APTES) and tetraethyl orthosilicate (TEOS). Herein, co-precipitation synthesis of bare IONPs and post-synthesis grafting of APTES (AIONPs) and TEOS (SIONPs) were carried out in the laboratory. Synthesis and functionalization were confirmed by examining the physical and chemical properties of the nanomaterials (NMs) using high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray analysis (EDX), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR) analysis. The stability of the nanofluids (NFs) was examined using zetapotential and sedimentation analysis in the presence of reservoir brine (25,000ppm NaCl). The ability of the NFs to decrease interfacial tension (IFT) and alter the wettability of rock/fluid at reservoir conditions was examined using a K20 Easy Dyne Kruss tensiometer and Kruss drop shape analyzer, respectively. Based on the results, it was found that reservoir brine, decreased the electrostatic stability of IONFs, AIONFs, and SIONFs by 75.9%, 41.3%, and 68% respectively. The IFT reduction and wettability changes relative to the reference values of 25.53 ± 1.51 mN/m and 128 ± 3.4° at reservoir conditions were 11.6mN/m and 26° for IONFs, 7.7mN/m & 22.2° for AIONFs and 8.2mN/m& 15.5° for SIONFs. These findings contribute towards understanding the influence of functionalization on the oil recovery mechanism of IONPs under reservoir conditions.
The Effect of Low Salinity Flooding of Silica Nanoparticles Functionalized with (3 Aminopropyl) Triethoxysilane on Enhanced Oil Recovery
Authors: Ngouangna E. , Jaafar M. Z. , Anam M. N. , Agi A. , Gbonhinbor J. , Ridzuan N. , Mahat S. Q. A. , Yakassai F. , Oseh J. , Al_Ani M.
Published: July 2023

Silica nanoparticles (SNPs) have been widely employed in the oil and gas industry for drilling, well cementing, workover procedures, wastewater cleanup, and oil production. Due to their 1 to 100 nm particle sizes, large specific surface area, high dispersibility, and variable physico-chemical properties, they can change the wettability of reservoir rock and reduce interfacial tension between crude oil and low salinity brine phases. Functionalized SNPs has not been well-studied in amine-based oil recovery. This work functionalized the surface of SNPs with (3-aminopropyl) triethoxysilane (APTES) to improve dispersion stability, change the wettability of sandstone, lower the IFT between oil and water, displace oil in a sand pack flooding setup at low salinity and ambient temperature conditions. FTIR identified functional groups, which validated functionalization by changing surface morphology. EDX validated the elemental composition with added nitrogen and carbon. Zeta potential confirmed stability. Analysis increased from -16 mV to +36.4 mV, and contact angle changed from 46.4° to 115.5°. the critical micelle concentration (CMC) of 1.0 %wt was achieved at IFT of 8.5mN/m and 76% of the oil was recovered after flooding with APTES-SNF. APTES deposited its molecules on the negatively charged hydroxyl (-OH) groups of SNPs, causing electrostatic attraction forces. This increases oil recovery by stabilizing dispersion.
Mega Project with High Shaping Complexity During Front End Loading: A Niger Delta Case Study
Authors: Obidike Peter , Ezekiel-Hart Elisha , Oluwafemi Akinwumi
Published: July 2023

The three dimensions of complexity of Mega projects according to Edward and Nandurdikar are about Scope, Organizational and Shaping. According to Edward and Nandurdikar in "Leading Complex Projects", there are instances where a Mega project with a regular scope can result to extra-ordinary scope and organizational complexity. The experience we intend to share in this paper demonstrates that a project with a simple scope can have a complex shaping process. In projects maturation, the shaping process is where the value is created, while in the execution and operation phases we realize the value. In the Niger Delta case study that we share in this paper, a simple upstream project that initially required drilling of 5 non-associated gas (NAG) wells (in a first phase of development), flowlines, and hookup to a manifold 100 meters away from the wells, manifested high shaping complexity. This was due to different reasons stemming from involvement of large number of stakeholders (internal and external), technical (subsurface and surface) and non-technical risks including commercials. This paper will discuss the early wins in the subsurface development strategy, changes in regulatory environment from introduction of Petroleum Industry Act (PIA). The PIA impacts on regulator availability, required different interfaces for upstream and downstream and risks to resource ownership within the projects contract period and the impact on the shaping process are discussed. The objective is to share these learnings on the key shaping issues and perspectives on things that could have been done differently for a more desirable shaping outcome. Some of these issues include subsurface uncertainties, risks, and the robustness of the development strategy to support the gas supply obligation, the phased development and confidence of external stakeholders to the operators planned development strategy and commercial aspects of a required update to the gas supply agreement.
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

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

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

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

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

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

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

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

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

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

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.