bluuebunny/crossref_metadata_2025_split huggingface dataset:
First Novel Intervention in High Pressure Gas Well to Improve Productivity in SPDC/Nigeria
Authors: Olugbenga Daodu , Michael Osuagwu , Adejoke Adebayo , John Emesi , Olayinka David , Chidi Okoro , Roseline Fasasi 
Published: October 2018

Abstract
The GBN NAG reservoir development project is part of the GBNRC Phase 1-6 project which involves the development of 6 wells with the potential to deliver additional 410MMscf/d to the GBNRC export gas market. The wells were drilled with heavily weighted POBM at 0.68 – 0.72 psi/ft. The lower completion was ran with the heavily weighted mud in hole and isolated with a Formation Isolated Valve (FIV) while the upper completion was completed with brine at 0.48 psi/ft. The wells were completed with 7" 13 Cr tubing, Reslink as sand control with potential of 120 MMscf/d each from each well.
Post clean up and Multi Rate Test activities some of the wells were observed to produce with drawdown higher than the acceptable limit therefore necessitating the reduction of well potential to adhere to the draw down limit and prevent possible well integrity incident.
The team was therefore charged with the responsibility to proffer feasible well intervention options in a High-Pressure environment to restore full wells potential of 410MMscf/d at the most economical way possible without compromising on safety and well integrity.
This paper documents the integrated approach taken by the team to identify the cause of high drawdown in these wells, feasible intervention options and selection criteria leading to restoration of planned potential therefore meeting up company obligations to GBNRC supply and preventing possible well integrity incident in these wells.
Review of Fiscal Incentives on the Development of the Domestic Gas Market in Nigeria
Authors: Adeyinka Temitope , Aron David 
Published: October 2018

Abstract
Over the past two decades Nigeria has made significant progress in the production and utilisation of its gas resources. The development of Nigeria LNG (NLNG) brought about a sharp rise in annual gas production from about 1.5 TCF in 1999 to 2.8 TCF in 2010. The domestic utilisation of gas also got a boost with the approval of the Nigerian Gas Master Plan by government and subsequent issuance of the National Gas Supply and Pricing Regulations in 2008. Over the same period gas flaring has reduced significantly from about 52% of produced gas in the early 2000s to about 10% in 2016. Prior to the development of NLNG, as much 70% to 90% of the gas in Nigeria was flared.
As part of efforts by government to develop gas resources and increase gas utilisation, a series of amendments were made to the Petroleum Act 1969, including different flare-down initiatives as well as new regulations and commercial framework. Fiscal incentives were also provided specifically to increase gas utilisation in the domestic market.
This paper will review the impact of the fiscal incentives on the domestic gas market in Nigeria with a focus on the involvement of the indigenous upstream oil and gas companies. The level of investments in domestic gas utilisation projects by indigenous companies will be analysed. The paper will further explore the level of gas flaring among the different upstream oil and gas companies operating in Nigeria. Comparisons will be made between the different companies under different fiscal arrangements, namely IOCs with JV and PSC arrangements, indigenous companies with sole risk and JV contracts and indigenous marginal field operators. We will review the effectiveness of fiscal incentives in increasing domestic gas utilisation and lessons on areas of improvement for stakeholders.
Success Factors for Marginal Oil Field Development in Niger-Delta Region
Authors: Otombosoba Oruwari Humphrey , Dosunmu Adewale 
Published: October 2018

Abstract
As the hydrocarbon reserves in the fields of Niger Delta region declines, there is the need for improved recovery from existing oil and gas fields reserves especially those classified as marginal oil fields. Despite policy initiatives and considerable potential for the development of marginal fields in Nigeria, marginal oil field development has not been fully successful. It is against this background that this study was undertaken to assess the critical success factors for marginal oil field development in Niger Delta region of Nigeria. An extensive literature review and case study marginal field operators were carried out. The result revealed that the sustainability indicators of marginal oil field development in Nigeria are: Collaboration, partnership/joint ventures, corporate social responsibility, the use of innovative technology, integrated development of oil and gas fields, mergers and acquisition, equipment/facility leasing, clustering and availability of related and support industries are the key factors that enabled the successful operations of marginal field development in Nigeria. The significance of the study is as follows: It serves as a useful guide for investors wishing to participate in the sustainable development of marginal oil fields; it provides new information towards policies that promotes sustainable development of oil and gas resources. The overall significance of the study is to contribute to knowledge on the management of hydrocarbon resource for economic sustainability in Nigeria. It is recommended that the best route for marginal field development is to forge joint action programme by combining global best practice by marginal field operators, government agencies responsible for regulating the oil and gas industry and other stake holders.
Geostatistics – Kriging and Co-Kriging Methods in Reservoir Characterization of Hydrocarbon Rock Deposits
Authors: Ochie Karen Ifeoma , Rotimi Oluwatosin John 
Published: October 2018

Abstract
Understanding the spatial distribution of the physical and chemical properties of rocks and the fluids they contain is very essential in determining hydrocarbon deposits, source, seals and aquifers. Population of petrophysical data for reservoir analysis has always been challenging in hydrocarbon exploration with little or no knowledge about the reservoir or with few pilot wells. Several basic interpolation methods, and geostatistical interpolation methods such as kriging and co-kriging have been used to populate the petrophysical parameters for better analysis but without much consideration for removal of inherent data error. The need then arises for the data to be populated to be error free because an abnormal or anomalous data set would not be representative, irrespective of the accuracy of the model. In this study, the Gamma test (GT) which is a non-parametric technique is used to assess the quality of the data since it is independent on the geostatistical model. Five workflow that took cognizance of GT filtered and unfiltered data assemblage were used. The data is then populated in the models by using geostatistical methods of kriging and co-kriging to interpolate the petrophysical data for further analysis thereby reducing the uncertainties faced during reservoir characterization and reserves estimation of in-place hydrocarbon and understanding of intrinsic reservoir heterogeneities. Results were compared to the results obtained when using both a basic interpolation method: inverse distance method, and geostatistical methods without proper data assessment. Compared to the other interpolation methods, this technique achieved a lower estimation variance error hence can be said to create a better representation of the reservoir petrophysical parameters.
Nano Augumented Biosurfactant Formulation for Oil Recovery in Medium Oil Reservoirs
Authors: Temiouwa Ojo , Oluwaanmi Olabode , Ifeanyi Seteyeobot , Tomiwa Oguntade 
Published: October 2018

Abstract
Production from most oil field using waterflooding has proven not to produce residual oil due to numerous factors. Several recovery mechanisms have been applied which to an extent has its own influence both on the environment, percentage recovery and also the cost of purchase.
In this blending process the bio-surfactant derived from jatropha oil at different concentrations were augmented with nanoparticles for core flooding experiment. A blend of Bio-surfactant and nanoparticles (B-NPs) is a dual purpose recovery mechanism which alters surface wettability, improves fluid mobility, solubility improvement and stabilizes the foam and emulsions formed. At the surface of the nanoparticle, a single layer is formed by the bio-surfactant which is an electrostatic based interaction given rise to particles that are oil loving. Encouraged greatly by electrostatic interactions, the surfactant will then become a monolayer on the nanoparticle surface, resulting in more hydrophobic particles. The impact of the various particle sizes will be considered to analyze to stability of each BNPs concentration for residual oil recovery.
During the laboratory core flooding experiment on Berea cores, the results shows that the nanoparticle-stabilized emulsions increased the oil recovery rate by 8% after water flooding and reduction in the interfacial tension was at the minimum approximately 25 to 1 mN/m.
Effects of Direct Injection DI on Knocking Combustion in Spark Ignition SI Engine Operated on 75-RON and Ethanol Fuels
Authors: Nwovu Sampson Ojon , Cairns Alasdair , Vafamehr Hassan 
Published: October 2018

Abstract
The study compares the effect of simultaneous Port Fuel Injection (PFI) and Direct Injection (DI) on heavy knock in Optical Spark Ignition (SI) engine operated on gasoline (75-RON) and ethanol. It involved evaluation of the Knocking Intensities (KI), In-cylinder Pressure, and Mass Fraction Burned (MFB) of the fuels. The engine has full bore and operated at typical stoichiometric part-load condition with fixed spark timing. We used high-speed natural light (or chemiluminescence) imaging and the engine operating thermodynamics properties to analyze the influence of a particular combustion cycle on the preceding cycle. We observed the combustion process until multiple centred auto-ignition occurred with varied knocking intensities of up to ~50bar. During heavy knock, we adopted fast over-fueling approach and injected varied amounts of fuel into the end-gas region. We found the fast over-fueling to consistently suppressed auto-ignition and eliminated knock for both fuels, especially ethanol. We attributed the effect to reduced auto-ignition delay time and charge cooling effect associated with DI. We compared the cyclic variations of both fuels using the in-cylinder pressures. The result showed that ethanol had higher pressure than RON-75 at both PFI and DI approaches. We attributed the higher pressure of ethanol to its higher affinity to pre-ignition. In terms of MFB, 75-RON demonstrated fastest burning rate than the ethanol at both PFI and DI. We attributed the lower burning rate of ethanol to the increased air mixture dilution effect associated with alcohol fuels. We also attributed it to the higher latent heat of vaporization of the ethanol. Between 50 to 90% mass of the mixture burned, Ethanol proved a higher MFB than RON-75. We likened the improved combustion of ethanol to the presence of oxygen or hydroxyl ion (OH-) in its molecular structure.
Examining the Legal and Regulatory Framework on Marginal Oil Field Development in Nigeria
Authors: Otombosoba Oruwari Humphrey , Dosunmu Adewale 
Published: October 2018

Abstract
The legal and regulatory frame work is critical for marginal field development in Nigeria. The petroleum amendment decree No 23 of 1996 is the basis of marginal field development. The Petroleum Act of 1969 with its amendments prior to Decree 23 of August 1996, prevented access by non-discoverers/owners to undeveloped or marginal fields. Indigenous companies are mostly non-discoverers/owners and this concern about the low level of participation of Nigerian nationals in the petroleum industry was addressed in the Petroleum (Amendment) Decree No 23 of 1996, which had the effect of giving the government absolute discretion in making guidelines for the farm-out of marginal fields. Before August 1996, the potentials of significant contributions by small and/or third-party operators (the so-called independents) to national production capacity had remained negated, unlike many oil basins of the world where the emplaced laws for acreage lease, farm-in/farm-out, the permissible limits of production, and interest acquisition/assignment, all serve to facilitate the transfer of rights to reserves. The overriding reason for the initiation of marginal field development program is to bring about economic development through revenue generation, promotion of indigenous participation in oil and gas sector and discouraging the abandonment of depleting oil fields considered marginal in Nigeria, in additional to technology acquisition and diffusion in the oil and gas industry. However no meaningful oil and gas development can take place without adequate legal and regulatory frame work. This paper assesses the effectiveness of legal and regulatory frame work for marginal field development program in Nigeria. The outcome of the study showed that the decree only guaranteed a 40% foreign equity holding. The provision preventing foreign equity holders of 40% from acting as operators will also act as a disincentive to investment as the lack of competencies on the part of local Oil Companies LOCs (as operators) will discourage many investors It also identifies lack of compensation clause for the original owners of the marginal oilfields in the legal frame work setting up marginal oil field program. The study offers useful suggestion for improvement. It is recommended that the passage of the Petroleum Industry Bill should make the laws governing the marginal field operations in Nigeria to be robust and comprehensive.
Design and Evaluation of Cement Slurries to Prevent Gas Migration – Well XRT Abandonment a Case Study
Authors: Okoli Ugochukwu 
Published: October 2018

Abstract
Well Cementing design is a critical component of Well engineering, as efficient cement design ensures the protection of the casing assemblies from fluid corrosion, and ensures the mechanical support of the well. It also ensures that hydraulic communication between different zones is prevented.
Well abandonment is also critical as the design of the slurry required needs to be designed to efficiently keep hydrocarbons in the wellbore and prevent any immediate, short term or long term migration of hydrocarbons to surface.
There are numerous studies and publications discussing the causes of gas migration after primary cement jobs and well abandonment, some of the causes of gas migration have been linked to poor fluid loss control, poor drilling fluid displacement (reduces seal efficiency at the interfaces), and long cement setting times which allows time for gas to percolate through the partially set cement slurry.
This paper highlights the engineering methods, and how they can be used to properly evaluate the cement slurry design to ensure that gas flow through the cement lattice is completely prevented. It assumes that all other issues which involving poor execution (mud displacement, poor slurry mixing, use of low quality materials and chemicals, human errors), are annulled.
The correlations/equations discussed and used for the evaluation of the abandoned case study well (Well XRT) are the Gas Flow Potential, Slurry Performance Number, Hydrostatic Number and Pressure Decay Limit Parameter. Results from critical evaluation with these equations confirmed that the Well XRT was efficiently abandoned.
The paper further recommends that these equations should be used by Well Engineers be used to evaluate slurry designs for casing cementing and abandonment operations, as they will help ensure that the mechanical and hydraulic isolation is efficiently designed for and achieved.
Using a Land Rig in an Offshore Location: Some Lessons from a Niger-Delta Experience
Authors: Eyitayo Mumuney , Eyitayo Stella , Lawanson Sulaimon 
Published: October 2018

Abstract
In line with national aspiration to increase hydrocarbon reserves and production rate, the last 18 years have witnessed the award of licenses for the development of about 30 marginal fields in the Niger Delta. However, only nine of these green fields have come on-stream to date, while others are at different stages of development, including inactivity. Among multiple reasons, this disappointing performance has been attributed to the combination of high development costs and paucity of funds. With rig rate as the main culprit, drilling/completion typically accounts for 60-70% of development costs. One strategy to lower the commerciality barrier of marginal fields is to address rig costs, without compromising safety and other performance indicators.
This paper presents a case study on the unusual, but successful, deployment of a land rig in a swamp-located marginal field (5-ft water depth) in the Niger Delta. To save about 70% on rig rate, a land rig was evaluated and used in preference to a swamp rig to develop this oil field, which was hitherto stranded.
Employing rigorous multidisciplinary technical evaluations, this feat was accomplished by constructing a fit-for-purpose platform using a reinforced 18-5/8″ casing, thick metallic sheets and 20mm H-beams. The design and execution entailed several considerations, including rig positioning, corrosion risks, and drilling dynamics to total depth (9400ft MD). To enable this first successful use of a land rig in a Niger-Delta swamp, subsequent hydrocarbon production, evacuation and storage were considered.
The planning and execution of the drilling and completions aspect of this project are described, focusing on the success, challenges, and lessons learnt. Among other lessons, the engineering and operational tactics behind the rig placement are highlighted. These insights should be of significant value to other operators of marginal fields in the Niger Delta, and elsewhere.
Making JV Gas Available to the Domestic Market with Minimum Additional Oil Recovery AOR Impact
Authors: Mkpasi Ernest 
Published: October 2018

Abstract
In continuation of her drive to energize the Nigerian economy, the Federal Government of Nigeria (FGN) recently introduced policy reforms in the oil and gas sector to ensure adequate gas supply to the power, gas-based industries and commercial sub-sectors of the domestic gas market.
Mobil Producing Nigeria (MPN) and her Joint Venture (JV) partner, the Nigeria National Petroleum Corporation (NNPC), through the National Petroleum Investment Management Services (NAPIMS) are progressing the 20", 400 million scf/d, 53km Oso – QIT Gas Pipeline Project (OQPP), a key enabler for making the JV's gas available to the domestic market.
The NNPC/MPN JV currently holds about 14 Tcf of gas resources, with the Associated Gas (AG) accounting for 74% while the Non Associated Gas (NAG) account for the balance. The AG are located in the JV's producing fields while the NAG are located in mostly undeveloped fields.
The NNPC / MPN JV currently produces over 1 Bscf/d of gas from mostly the AG fields/reservoirs. Some 67% of this produced gas is utilized for gas injection for Additional Oil Recovery (AOR) in 7 fields. Making the JV's gas available to the domestic market will entail diverting some of the gas currently being re-injected for AOR to the domestic market.
This paper describes the workflow undertaken to optimize oil recovery (in the gas injection reservoirs) within the boundaries of making some 100 – 400 million scf/d of the JV's gas available to the domestic market.
Visualization of Heavy Oil Recovery Processes Using Hele-Shaw Cell
Authors: Izuchukwu Ojukwu , Ayodele Taiwo Oluwaseun , Abdullahi Gimba S. , Joshua Dala , Olalekan Olafuyi 
Published: October 2018

Abstract
The linear core flood (physical model) has been used severally in the past to conduct laboratory researches and experiments on Tertiary Oil Recovery. A potential pitfall of the 1D nature of the linear core flood arises during waterflooding; water channels would be blocked due to limited pathways, hence producing the additional oil before chemical consequently breaks through. In real reservoirs, there are more water pathways present; hence the relative impact of these chemical additives on incremental oil recovery is potentially overly emphasized in the laboratory.
This paper presents a study on heavy oil production using chemicals in a locally fabricated 2D Hele-Shaw cell system. The 2D nature of the cell also aids the visualization of non-linear flow pathways. The experiments are run for a constant pore volume (5PV) flooding of Brine, Surfactant slug and Surfactant-Polymer (SP) slug. Recovery and digital images are taken at a minute interval each, thereby making it easier to study growth and distribution of fingers before and after water or chemical breakthrough.
It was observed that after the 5PV of waterflooding, the recovery of oil from the cell reduced gradually till there was no more recovery. The Surfactant slug increased recovery by additional 21%. The more viscous Surfactant-Polymer slug gave an even improved and better recovery. This can be attributed to a clear interaction between the Surfactant and Polymer chemicals in the SP slug. The distribution of fingers between the different phases of flooding were visually observed and compared.
Finite Element Analysis of Induced Stresses on Casings in High Pressure High Temperature HPHT Wells
Authors: Ikponmwosa U. B. , Bello K. O. , Olafuyi A. O. , Dala J. 
Published: October 2018

Abstract
High temperature variation in wells used in thermal oil recovery processes, deep gas wells, offshore wells with significant riser lengths and wells completed in abnormally hot reservoirs cause compaction of formations and this induces local compression and tensile stresses in the various casing strings cemented and landed in the well. Cemented wells are under various stresses and strains in various directions which can result in significant deformations and fracture. Therefore, casing failure or damage is inevitable largely due to thermally generated strains and stresses in the casing and the surrounding formation. This research studied the effect of the non-uniform loading (poroelastic effect) on stresses and failure of casing and cement by developing a Finite Element (FE) method for the analysis of temperature-stress interaction in three dimensions (3-D) for casing, cement and formation with all its complexities using ABAQUS simulation tool.
The tool was used to develop temperature distribution and thermal stresses in the casing and near wellbore formation. This enabled possible casing failure predictions and provided theoretical basis for casing thermal stress failure by coupled temperature field and thermal stress field of casing.