bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Novel Approach for Predicting Sand Stringers: A Case Study of the Baka Field Offshore Nigeria
Authors: Chudi Obinna , Kanu Magnus , Anaevune Austin , Yamusa Idris , Iwegbu James , Sesan Oloniboko , Musa Joel 
Published: July 2019

Abstract
This paper details the seismic reservoir characterization study, aimed at predicting isolated sand lenses or stringers. Sand stringers or lenses are laterally discontinuous bodies that are encased in a different lithological body, they appear isolated and variable in lateral extent and thickness but mostly occur as thin beds. The thickness of these stringers makes it difficult for pre-drill predictions. One complicating factor of sand stringer is its potential of being isolated overpressured ramps which if unexpectedly encountered during drilling can cause kicks and if severe a blow-out is inevitable.
The Baka field is located some 120km off the coast of Nigeria in water depths of 2600ft (800m) to 3900ft (1200 m) with several wells drilled to date. Two of these wells have encountered unpredicted sand bodies that range in thickness from 15-25ft. These sand bodies were encountered within the Baka reservoir play interval of 5000 to 10000ft and were not predicted from conventional seismic reflectivity data, inverted seismic and offset well correlation. To obtain a better prediction of this stringers, alternative solutions are required. For this reason, a novel methodology - Geo-body constrained inversion approach was developed in 2017 to enable accurate prediction of stringer sands. Using this technique, a high-resolution acoustic impedance volume was built. Result of this study allowed the identification of gas bearing sand stringers encountered in previously drilled wells, thereby calibrating the model. The Geo-body inversion model proved a reliable tool for safe drilling of wells in 2018, ensuring that sand stingers were predicted at pre-drill phase in the Baka field.
Sustainability Assurance and Evaluation for Effective Corporate Social Responsibility Communication
Authors: Uwem E. Ite 
Published: July 2019

Abstract
Over the years, oil and gas companies in Nigeria have adopted several policy approaches to corporate social responsibility (CSR) to complement their stakeholder relations strategy. These include corporate philanthropy, strategic CSR as well as partnership schemes. Some companies have also gone further to demonstrate significant commitment and interest for CSR delivery by increasing their expenditure on CSR. To derive maximum value, companies need to report with certainty, the direct and indirect impact of their contributions to sustainable development. Yet, there are challenges in determining the actual impact and outcomes of CSR initiatives, and reporting same to internal and external stakeholders, without greenwashing. Many CSR projects have been known to fail shortly after completion and handing over to beneficiaries. This is partly due to initial failure to incorporate a robust set of sustainability criteria into the design and implementation process. On the other hand, attempts to measure project impacts after completion sometimes do not yield the desired results for effective CSR communication due to deployment of poorly designed methodology for data collection and analysis. This paper provides guidance on sustainability assurance and evaluation criteria which can assist companies to move beyond the annual reporting on the number of completed projects and amount of money spent (i.e. quantity delivered), to telling the story of the impact of projects on beneficiaries as well as the macroeconomic, social and environmental effects (i.e. quality and value-added). The paper concludes that the knowledge and full understanding of the impacts and effects of completed community development projects are crucial inputs for effective CSR communication as well as lessons for the planning and delivery of subsequent projects.
The Impact of the Proposed Petroleum Industry Fiscal Bill PIFB, 2018 Tax Scheme on the Economics of Oil Production in Nigeria
Authors: Nyoor Bariture , Oyebimpe Adeogun , Iledare Omowumi O. 
Published: July 2019

Abstract
Revenue from petroleum operations remains the most important contributor to government expenditures in Nigeria. Hence, the onus is on the central government to design fiscal regime that would maximize economic rents to the nation. The Petroleum Industry Fiscal Bill (PIFB) of 2018 seems to be the awaited bill that may satisfy the economic objectives of the Nigerian government. PIFB 2018 proposes the replacement of the default petroleum profit tax with single tax system, petroleum income tax and additional petroleum income tax to cater for windfall profits. This research uses deterministic spreadsheet approach to evaluate the impacts of this new tax scheme on the profitability of oil ventures in Nigerian deep-water production sharing contracts. The deterministic results were subjected to Monte Carlo Simulation using Crystal Ball Risk analysis software to account for risks and uncertainties inherent in the business. The typical project examined under PIFB (2018) generated a positive Net Present Value (NPV) of MM$595.18, an Internal Rate of Return (IRR) of 23.7% which is higher than opportunity cost of capital, Profitability Index (PI) of 1.34, Contractor take of 11.9% and Host Government take of 88.1%. All evaluated indicators gave positive results meaning that investments under this new fiscal regime will be profitable giving the government higher take as compared to the current regime. The results also show that the contractor take can increase to as high as 25% taking advantage of Reserves Replacement Ratio (RRR) tied to additional production allowance. The bill however, does not explicitly state the conditions for cost recovery limit and profit oil sharing, as such could create a lot concerns to investors and may also hamper investment in the industry. Hence, the bill should be reviewed before passage into law.
Data Envelopment Analysis DEA of Natural Gas Utilization in Nigeria
Authors: Ojaraida Lolo , Iledare Omowumi , Idowu Adekunle 
Published: July 2019

Abstract
Nigeria has huge natural gas resources, yet there is a great concern on the availability of natural gas supply for primary energy requirement to power its economy. This paper focuses on evaluating the efficiency of natural gas utilization in Nigeria from 1995 to 2017. Its purpose is to evaluate gas use with respect to industrial development and susceptibility of GDP to a sudden decrease in natural gas production.
Data Envelopment Analysis (DEA), which is a mathematical (optimization) tool for assessing the relative efficiencies of decision making units (DMU), was applied to show that natural gas is not fully utilized in Nigeria and has thus impacted economic growth negatively. The vulnerability indexes for the period under consideration were high, suggesting that Nigeria is not self-sufficient in natural gas. In addition, there is strong evidence from empirical results to suggest that as gas consumption increases GDP rises as well. This implies that a right policy framework and implementation strategies need to be in place to advance Nigeria's economic growth aspiration.
Lessons Learnt from Well Intervention Operations on Well AA, and The Impact of Detailed Recipe Design on Performance of a Niger Delta Well
Authors: Oladunni Oluwatobiloba , Aihevba Leste , Dokubo Richard , Kudayisi Ayopo , Obadaki Muaz , Eze Celestine , Eze Modestus , Ibama Chika 
Published: July 2019

Abstract
Well Intervention operations are carried out to improve production performance of a declining well, restore production to a well that quit, or improve well integrity, among other reasons. Well bore clean out and stimulation are two of the common well intervention operations done on producing oil and gas wells to improve performance. Well AA, a major oil and gas producer started to decline after three years of production, therefore a well bore clean out and stimulation exercise was designed to improve performance of the well. The first Intervention operation was planned after various crude sample and precipitate analysis reports showed organic deposits (wax and asphaltenes) in the well. Slickline drift also indicated a restriction in the tubing. The treatment recipe for the well intervention was designed based on laboratory test carried out on the crude and precipitate sample that showed an 85% dissolution of the organic deposits in Xylene and 55% dissolution in Solution Z (a mixture of Xylene and HCL). The 85% dissolution was considered adequate to ensure a complete wellbore clean out, with Solution Z planned as the contingent treatment recipe for any solid deposits not dissolved by Xylene. Contingent on the successful wellbore clean out, a matrix stimulation was to be done using an Acid preflush and Regular clay acid as the main treatment. But this operation failed because instead of resulting in an increase in production, the well couldn't produce to surface and had to be shut-in. This paper will review the problems encountered from the unsuccessful intervention of well AA because of the lack of a detailed recipe design to find the best treatment to dissolve organic deposits in the well and precipitates, as well as residues formed from the reaction between organic solids and inorganic acids. In addition, this paper will present the detailed work that went into designing the right treatment recipe for well AA that resulted in successfully reviving the well after the initial failed intervention operation to become a prolific producer of over 1500 stock tank barrels of oil per day.
Production Optimization Strategies for Unlocking Resource Potential in A Heavy-Oil Brown Field - The OML26 Success Story
Authors: Ajao Wale , Isiba Ezinwanneakolam , Okoh Eddy , Okoruwa Immaculate , Omenai Stanley , Abu Nicholas , Babalola Olusegun , Oke Oluwatobi 
Published: July 2019

Abstract
Oil Mining Lease 26 (OML 26) is held by NNPC and First Hydrocarbon Nigeria Limited (FHN) in a Joint Venture relationship and operated by an Asset Management Team (AMT). The license consists of several oil and gas discoveries including the Ogini, Isoko, and Ozoro fields on the western part, Ovo in the central area and Aboh to the east.
Oil Production is mainly from the Ogini and Isoko fields with the Ogini field contributing the largest volume. The Ogini oil is relatively heavy, with in-situ oil viscosity ranging from 3 to 59cp, and an oil gravity ranging from 15°API to 19°API. Field development and production from the Ogini field has been very challenging with the characteristic low GOR, low rate and high watercut. Oil production peaked at 8,900 stb/d shortly after field start-up in the 80s and has been declining since then.
In 2018 however, the field witnessed breakthrough performance stemming from production optimization initiatives and strategies which unlocked resource potential of the field. A peak production of ca 17,000 bopd was recorded during Q4 of 2018 without drilling new wells. A number of production enhancement activities carefully designed, planned, and executed coupled with change in operations philosophy released more volumes transforming the production levels and production profile of the field from a mere 3,000bopd to ca 17,000 bopd peak production. This paper highlights the strategies, optimization techniques and the paradigm shift in operational culture that resulted in the significant change and ramp up of production in the field.
Improving the Thermodynamic Properties of Export Gas Through Condensate Spiking
Authors: Oviawele P. E. , Onwukwe S. I , Nwachukwu N. A. , Onyejekwe I. 
Published: July 2019

Abstract
Disposal of condensate produced from stranded gas field have been a major concern to producing companies due to unavailability of nearby oil flow stations to receive the condensate, which have resulted to abandonment of such fields. This work seek to improve the thermodynamic properties (Heat Capacity, Heating Value, Specific Heat capacity, Heat of Vaporization and Enthalpy) of the export gas through condensate spiking. This was carried out by simulating a natural gas plant, consisting of condensate line and spiking mixer. The simulation was done using Aspen HYSYS, to include the point at which the condensate stream was spiked into the high-pressure dry natural gas stream. Phase envelope and hydrate formation curve for the streams (dry natural gas and the mixture after spiking) were obtained. Case study in HYSYS was used to carry out Sensitivity analysis, to determine the effect of temperature, pressure and flow rate of the condensate on the mixture (export gas). Economic analysis of the project was carried out. Results obtained from the thermodynamic analysis shows that the thermodynamic properties of the export gas after spiking improves, such that the heating value and enthalpy of the export gas increases. The phase envelops shows that hydrate will not form in the export gas streams. Through the sensitivity analyses, the effect of variation in the parameters of the condensate shows that the vapour fraction of the export gas increases as the temperature increase and decrease as the pressure increases. The maximum condensate flow rate was obtained to be 12,500 bbl/day, at a dry gas flow rate of 382.2 MMScfd, for a maximum vapour fraction of 0.953, with this operating parameters, flow assurance problem of hydrate formation, liquid holdup and high pressure drops along the pipeline with be eliminated. Hydrocarbon dew point of −13.41°C was obtained showing that liquid hydrocarbon will not condense out of the gas during transportation. Economic analysis shows that the NPV and IRR are $432.778 million and 33%, indicating that the project is viable for investment. Therefore, it is possible to spike condensate into treated export gas without causing flow assurance problems, and helps mitigate against risk associated with environmental pollution.
A Systematic Approach to Resolving Wellbores Stability Issues While Drilling through Depleted Sandstone Reservoirs, Case Study-GAB Field, Niger Delta
Authors: Onyeji J. A. , Mboto J. S. , Stafford T. W. , Ekun O. A. , Adamo G. , Oladimeji O. E. 
Published: July 2019

Abstract
The study area is characterized by sequences of sandstone and shale formations. Hydrocarbon production depletes the pore pressures within the sandstone reservoirs while the shale formations retain their original pressures. This leads to the narrowing of the safe mud weight window while drilling and increases the probability of the occurrence of wellbore stability issues such as loss circulation, tight spots, stuck pipe and hole collapse during drilling and casing run activities. Depleted reservoirs were traversed while drilling through the intermediate (12-1/4") hole section in GAB-7H. It was drilled with 9.0ppg equivalent mud weight (EMW) and an equivalent circulating density (ECD) of 9.6ppg EMW to the target depth. While running the 9 5/8" casing, it was observed that the wellbore had collapsed, thereby preventing the casing from getting to bottom of the hole which led to the abandonment of the hole section and a consequent side-track. This paper presents the lesson learnt and best practice that were adopted for GAB-7Hst and subsequent wells in the GAB field.
Prior to the drilling of the sidetrack, a one-dimensional mechanical earth model (MEM) was constructed using petrophysical logs and formation tests of GAB-7H and other offset wells. Shale pore pressure was derived from gamma-ray, resistivity and sonic logs using the Eaton's and Bower's methods while sand pressures were measured/ estimated from modular dynamic testers (MDTs) and depletion models. The fracture gradient was derived using Matthew's and Kelly equation. Shear failure gradient was calculated using Modified Lade equations and log derived mechanical rock properties. The post-drill analysis of the offset wells was then calibrated with the drilling events and mud weights used. This revealed that the mud weight used to drill the 12-1/4" in GAB-7H was inadequate. An optimum mud weight program coupled with close monitoring of ECD is a key requirement to successful well construction in the GAB field, where several reservoirs at various states of depletion, sandwiched by shale formations are traversed. These has led to several successful drilling operations in the field.
Application of the Combined Analytical Methods & Time Lapse Seismic 4D as a Veritable Tool for Water Shut Off WSO Operations – Deepwater Akpo Field
Authors: Usman Musa , Biu Victor , Oukmal Jed , Adeyemi Adeoye 
Published: July 2019

Abstract
The prohibitive costs & risks associated with performing PLT and potentially the isolation of the water producing zone through WSO in deepwater fields such as Akpo renders these operations economically unattractive.
This paper addresses the application of analytical method including the use of 4D monitor results to replace conventional PLT to identify, screen and select viable successful water shut off candidates.
Prior to executing water shut-off treatment programs, a combination of 4D seismic interpretation, production history review as well as the collection of completion and reservoir information were thoroughly performed to ensure that the wells are properly selected.
Well's diagnostic plot (WOR and WOR′) must be consistent with the type of water coning or channeling problem identified from the 4D time lapse seismic and also the depth of possible mechanical plug must be around or above estimated current oil-water contact (COWC).
Two candidate wells having 6-5/8″ SAS Slot 10 in 8.5″ open hole, at approximately 4,000 meter TD, and 82 deg C reservoir temperature were selected. The water cut values were 55% in one well and 60% in the other.
This paper presents below the significant upside for WSO attributed to the use of analytical method and integration of 4D seismic data by eliminating the need to run a traditional PLT. The operation was technically & economically successful on one well with a decrease of watercut from 55% to 16% resulting in the well incremental oil production of ~3kbopd. Operation is planned mid 2019 for the second well
Formulation and Evaluation of Slow-Release Fertilizer from Agricultural and Industrial Wastes for Remediation of Crude Oil-Polluted Soils
Authors: Obieze Chinedu Christopher , Chikere Chioma Blaise , Adeleke Rasheed , Akaranta Onyewuchi 
Published: July 2019

Abstract
Fertilizers are used to enhance the degradation and sequestration of oil-polluted environments, but a decrease in fertilizer efficiency can lead to severe environmental consequences. The aim of this study was, therefore, to formulate a slow release fertilizer using nutrient-rich, ecofriendly and readily available agricultural and industrial wastes. The formulated fertilizer was coated with a renewable, nontoxic and biodegradable material which was then tested against commercial NPK fertilizer for its effect on hydrocarbon degradation rate. Crude oil polluted soil from an artisanal refining site was used to evaluate the efficiency of the fertilizers. Next-generation sequencing technique was used to determine the microbiome of the oil-polluted soil. Metabolic fingerprints were also determined as remediation progressed. Other parameters monitored were pH, extractable total petroleum hydrocarbons (ETPH), NO3- -N, total phosphate and total potassium. Initial ETPH of the polluted soil was 16,388 mg/kg which reduced to 2,250.21 mg/kg after 56 days of remediation. The formulated fertilizer gradually led to an increase in soil pH from being slightly acidic (5.6) to near neutral (6.9), while the commercial NPK fertilizer led to a further decrease in soil pH. Both fertilizers enhanced degradation without significant differences, however, the formulated fertilizer greatly improved microbial diversity. Proteobacteria, Chloroflexi and Acidobacteria dominated the soil microbiome with Acidocella being the leading bacterial genus. Signature metabolites identified included benzenamine, cyclobutanone, octadecane and hexadecane which were all related to hydrocarbon biodegradation. The study revealed that the formulated fertilizer effectively enhanced the restoration of oil-polluted soils as well as microbial diversity and soil fertility. It also shows that acid-loving bacteria are important in the bioremediation of acidic oil-polluted soils.
3D Numerical Modeling of Linear Flow of Non-Newtonian Fluid in Porous Media: Application to Non-Newtonian Draw-Down Pressure Transient Analysis
Authors: Adenuga Kazeem , Achumba Gabriel , Ezenworo Ebuka 
Published: July 2019

Abstract
In this study, a 3-Dimensional non-linear partial differential equation (PDE) describing flow of non-Newtonian fluid in porous media was developed for a no-flow boundary reservoir. Non-Newtonian fluid flow in porous media has direct applications in polymer flooding for secondary oil recovery operations and flow of heavy crude in the reservoir. This novel work presents the pressure behavior of horizontal wells with non-Newtonian fluid flow in porous media as well as the methodology for analyzing pressure transient data from non-Newtonian reservoirs.
The main assumptions in the mathematical modeling of the differential equation are; permeability anisotropy with directional permeabilities kx, ky and kz horizontal well is in the y-direction perpendicular to direction of maximum permeability kx effects of gravity, skin and wellbore storage were neglected and the reservoir fluid was considered to be a non-Newtonian pseudo plastic fluid that obeys power law model in an isothermal condition.
The derived equation was discretized using finite difference approach; A 3D numerical simulator was developed with the aid of MATLAB to solve the system of linear equations obtained from the discretization of a 15 X15 × 15 grid system to obtain pressure transient data. Type curves in terms of PwD and tD were generated for different power law flow index n ranging from 0.1 to 1 for horizontal well length of 600ft, 1000ft and 1200ft.
The developed type curves in this study were validated with a Newtonian case using Tiab Direct synthesis (TDS) technique to analyze the radial flow regime for the determination of average permeability as well as the early linear flow for determining kx The results obtained from the Newtonian fluid case were very close to the actual property been determined.
Integrated Static/Dynamic Modeling of Reservoir Stack Helps to Resolve History Match Challenge and Identify New Drill Opportunities
Authors: Yusuf Nurudeen Oluwatosin , Bovet Paul , Silpngarmlers Lynn 
Published: July 2019

Abstract
Simulation studies are often conducted on single-reservoir levels even though hydrocarbon accumulations hardly occur in isolation. However, it is sometimes beneficial to conduct studies on multiple reservoirs to evaluate opportunities in the sequence simultaneously. This can help to optimize the development plan by enabling the combination of opportunities with multiple strings and providing an avenue to evaluate interactions among reservoirs. Where these interactions exist, they can be critical parameters in the simulation history matching process1.
This approach was used in the simulation studies of five reservoirs across two fields (Field_A & Field_B). Collaboration among an interdisciplinary team helped to overcome challenges in the history matching process, especially regarding a recent observation that one reservoir was exhibiting an increasing reservoir pressure while on production with no water injection. The learnings/insights from the study were used to improve field management of reservoirs with water injection, optimize base production, and identify five development opportunities with a proposed incremental recovery of 15 MMBO.