bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of Depleted Oil Reservoirs for Simultaneous Gas Injection for Underground Natural Gas Storage and Enhanced Oil Recovery in Nigeria
Authors: Anyadiegwu C. I. 
Published: July 2016

Abstract
The development of depleted oil reservoirs for simultaneous gas injection for underground natural gas storage and enhanced oil recovery in Nigeria was evaluated using IZ-2, a depleted oil reservoir located South Eastern Nigeria. The geological information and the production history of the reservoir were applied in estimating the storage capacity at any given pressure. The plot of well flowing pressure (Pwf) against flow rate (Q), shows the deliverability of the reservoir at various pressures. The verification of inventory and assurance of deliverability were evaluated for the reservoir. The results of the estimated properties indicated that IZ-2 is a good candidate for conversion into storage reservoir and enhanced oil recovery. A reservoir engineering simulator (ECLIPSE) was used to forecast oil production from the reservoir without gas storage and with gas storage in the reservoir respectively. The results of the estimated parameters shows that the storage capacity is; 437Tscf and deliverability: 46.4MMscf/d. The production forecast indicated that the cumulative oil production was higher when the reservoir contain gas than when there is no gas. The novelty of this research work is the performance analysis for the determination of the suitability of the reservoir for gas storage and also the recommendation of gas storage in the reservoir based on the analyses conducted for simultaneous gas storage and enhanced oil recovery in Nigeria.
An Integrated Approach to Water Diagnostic Analysis in A Mature Field: SPDC Case Study
Authors: Sukubo Ibianga , Iyowu Olakunle , Balogun Olalekan , Jude-Ofia Ifeyinwa , Esho Muyiwa 
Published: July 2016

Abstract
One of the most popular drive mechanisms in hydrocarbon production is water drive. Depending on the subsurface structural orientation, rock and fluid properties anisotropic distribution and the placement of the well amongst others, it could be edge or bottom water drive. These various patterns of water drive mechanisms have varying degrees of impact on the fluid-water contact, hydrocarbon production and ultimately life cycle recoverable volumes. Whether edge or bottom water, the excessive water production mechanism in a typical well are interrelated; insight to which had been provided by Chan, K.S (1995) in his water diagnostic plot. Though the water-oil ratio (WOR) diagnostic plot has been applied widely in zonal isolation, water shut-off, gas shut-off, gel treatment and its modifications into reserves quantification2, 3, 6, there has not been an integrated approach to the excessive water production analysis; guiding our interpretation of the WOR and its time derivative (WOR’) curves with an integrated understanding of the geological, petrophysical and reservoir properties variation.
The WOR and WOR’ plots for this study were generated using over 20 years of production data from one of our SPDC fields in the Niger Delta with 11 oil wells and spanning 4 oil reservoirs. The reservoirs were modelled stratigraphically to show different flow zones delineated by different facies. The initial water saturation and permeability contrast were mapped against each flow zone including their relative permeability functions. The interpretation was also spot-checked using reservoir production monitoring (RPM) log result.
This paper presents the outcome of an integrated approach to water diagnostic analysis based on the obtained data set with the view to further crystalize the understanding of water production mechanism in the field, proposing fit-for-purpose wells, reservoir & facilities management (WRFM) actions and adding value to global wells and reservoir performance reviews.
The Use of Well Trajectory Design Illustration Tool Version 1.0 in the Design of Directional Well
Authors: Paul Okpozo O. , Samuel Ofesi 
Published: July 2016

Abstract
Directional well trajectory design is an essential part of a drilling plan process, considering various challenging factors from surface and subsurface restrictions/challenges to available technology and equipment and most importantly, economics. Directional well trajectory design requires rigorous mathematics to ensure proper execution of the drill path that would accommodate safety of the tools being used to drill the planned well. Various well trajectory design applications have been developed such as the Halliburton COMPASS which aid in constructing well trajectory designs. Due to the difficulty in affordability and perhaps availability of such an industrial and robust tool, hence as a result of this research a computer application was developed, named WellTIT (Well Trajectory Illustration Tool) version 1.0, which could be used to enlighten students further on the topic, ranging from basic directional well trajectories to complex and multiple well trajectories designs. A survey data ran by COMPASS was used to validate the ability of the WellTIT v. 1.0 application, of which results from both applications fairly matched.
Approximate Method for Estimating Abandonment Reservoir Pressure for A High Pressure Gas Prospectivity Evaluation
Authors: Sukubo Ibianga , Dike Francis 
Published: July 2016

Abstract
Resource volume assessment is an integral part of prospect evaluation. A prospect, in its simplest form, is an unpenetrated reservoir block with seismic data sometimes as the only available data. Hence, a prediction of the most likely hydrocarbon accumulation is required. Recovery factor evaluation for a prospect that has been prognosed via basin modelling to most likely contain non-associated gas (NAG) under high pressure will require an assessment of the abandonment reservoir pressure primarily from analogues or comparable reservoir.
The current practice assumes pressure gradient ranges which are then used to estimate the abandonment pressure for the high pressure gas prospectivity evaluation hence it does not take into account the impact of the dynamics of flow (and flow regime). Besides, the assumed pressure gradient ranges may not be robust enough for the evaluation.
This paper discusses an approximate methodology to evaluate abandonment reservoir pressure for a high pressure NAG prospect where suitable analogues are not readily available. Two methods were proposedand modelled accordingly using the available seismic data: pressure gradient and pressure sensitivity. The result showed that the pressure gradient modelling approach gave a wider range of recovery factor, wide enough for the resource class maturity.
Non-Technical Risks Management: A Framework for Sustainable Energy Security and Stability
Authors: Ite Uwem E. 
Published: July 2016

Abstract
The concept of sustainability implies concern for the present and future generations. In its true form, sustainability requires striking a good balance in the decision-making process by considering the economic, environmental and social aspects of any development, including the development and maturation of oil and gas projects. Based on current projections of global population growth, there is no doubt that future demand for energy will increase significantly from current levels. On the other hand, the envisaged population growth and increased demand for energy will present opportunities and responsibilities for oil and gas companies. This will be compounded by the fact that the additional oil and gas volumes are more likely to be derived from locations with very complex economic, environmental and social characteristics. As such, the ability of oil and gas companies to sustainably mature the opportunities, and effectively manage the responsibilities, will have significant implications for energy security and stability at various levels. This paper discusses the role and significance of non-technical risks (NTR) management as a sustainable development framework, and the need for proactive NTR integration and management in oil and gas project maturation and development process. Efficient and effective management of NTRs has the potential to contribute to greater transparency in the oil and gas business, better returns on investments, and sustainable energy security and stability.
Compressibility Factor Correlation for the Niger Delta Gas
Authors: Muonagor C. M. , Ikiensikimama S. S. , Anyadiegwu C. I. 
Published: July 2016

Abstract
Gas compressibility factor (z) is very essential in gas engineering. Apart from PVT Lab measurements and its subsequent calculations, correlations exist for the estimation of Niger Delta gas z-factor but the correlations were developed with data of gas samples from regions different from the Niger Delta so they do not always predict Niger Delta gas z-factor with good accuracy hence the need for a new correlation that would predict Niger Delta gas z-factor with high accuracy. Correlation for estimating the z-factor of Niger Delta gas was developed in this work using Microsoft Excel Data Analysis Tool and SPSS Statistics Software. 300 data points from PVT analyses of 14 fluid samples from Niger Delta were obtained for this study. The existing correlations were evaluated for Niger Delta gas z-factor to determine the best performing correlation using statistical parameters like percent mean relative error, %MRE, percent mean absolute relative error, %MAE, standard deviation, SD, correlation coefficient, R and performance plots. The developed correlation was compared with the best performing correlation selected using the same parameters. The new correlation was found to perform better than the best performing existing correlation selected, the new correlation had lower %MRE, %MAE and SD; higher R and better performance plot than the best existing correlation. The developed correlation found to outperform the existing correlations is for the Niger Delta gas but can be used for all types of gas with properties falling within the range of data used for its development.
Seismic-Consistent Reservoir Facies Modelling; A Brown Field Example from Deep Water Niger Delta
Authors: Amoyedo Sunday , Atoyebi Haraya , Bally Joakim , Usman Musa , Nateganov Arthur , Bergamo Laurent , Berthet Philippe 
Published: July 2016

Abstract
Reservoir models often tend to be simple and do not always represent typical reservoir property variations and sometimes complex communication patterns typically encountered in deepwater turbiditic systems (amalgamated, laterally-offset stacked channel complexes and lobate systems). Consequently, such models prove unreliable for development planning and long term production forecast. To address this, seismic facies, which are derived from 3D inversion and subsequent classification studies, are often used either as a background trend or direct quantities in static model building process to guide both lateral and vertical reservoir grid population away from well control points.
In this paper, we discuss a methodology for the integration of well data (reference data) and seismic reservoir facies probabilities (auxiliary data) to build a seismic-consistent static reservoir model in a deep-water field, deep offshore Niger Delta. The methodology captures both vertical and lateral variations in reservoir quality seen on well logs (after up-scaling) and seismic-derived reservoir properties inferred from 3D and 4D seismic. Furthermore, we discuss the challenges (fault shallow effect, amplitude degradation across fluid contacts, etc.) and pitfalls (inversion uncertainties, clustering/classification uncertainties etc.) of seismic-driven reservoir facies modeling and their impacts on the reservoir history matching process. Additionally, we discuss potential corrective measures to address some of these challenges, thereby enhancing the consistency of seismically-derived reservoir facies.
The paper concludes with the validation of the geologic model with the use of 3D seismic loop-back process.
Portfolio Optimisation and Screening in Low Funding Era
Authors: Nwaokorie Chukwuemeka , Abia Godwin , Johnsen Esben 
Published: July 2016

Abstract
Portfolio optimisation is the process of choosing the proportions of various assets to be held in a portfolio, in such a way as to make the best use of the opportunities in that portfolio in any prevailing circumstance. This is a component of full-wide portfolio management which is an ill-defined and often over-used term. Whether or not a company's portfolio solution entails consolidating data into a spreadsheet or employing modern portfolio theory to develop an efficient frontier, the goal is to ensure long-term business success by optimising value returns at the minimum risk.
Since June 2014, international oil and gas prices have been declining and currently (Dec 2015) below 40 USD per barrel and 2.5 USD per million Btu respectively (Fig 1). This has brought much pressure on funding availability both on the sides of national and international oil companies.
To fully manage the SPDC's gas portfolio, innovative and sound processes were initiated to optimise and screen a very significant part of our portfolio to ensure that the company still meets and sustains her gas supply obligations with optimal value returns. Prioritisation and ranking of different projects using known parameters and also generating portfolio sensitives using PetroVR tool provided us the foundation for robust decisions on the way forward.
Problem Statement: Evaluate different portfolio options to meet supply agreements and obligations.Prioritise all projects in the portfolio and rank them considering technical, commercial and other non-technical indicators.
The methodologies applied in resolving the above problems were along two work streams namely: Build an integrated gas portfolio model using the PetroVR tool. This was built consistent with latestcompany's operating plan and creating multiple scenarios. The model has production forecasting and economics evaluation/screening capabilities. Therefore, it was possible to check each portfolio scenario in terms of ability to meet gas supply and their economics value.Project prioritisation tool. This is an in-house tool with analytical abilities. Key input data are ultimate recovery, gas Production rate, CAPEX, UDC, NPV, strategic considerations, etc.
The results of these evaluations have helped the company make appropriate decisions on its gas supply strategy and ensuring projects with capacity to meet obligations are matured in priority order.
Experimental Approach to CEOR Optimization in Niger Delta
Authors: Taiwo Oluwaseun Ayodele , Mamudu Abbas , Adijat Ogienagbon , Olafuyi Olalekan , Joshua Dala 
Published: July 2016

Abstract
As important as Chemical Enhanced Oil Recovery (CEOR) methods are to generating additional oil, the effectiveness of the CEOR method used is dependent on its design, rock-fluid and fluid-fluid interaction. Therefore this paper presents the outcome of experimental works to formulate an optimum surfactant Polymer slug for tertiary oil recovery (TOR) of the Niger Delta oil.
Firstly, the displacement efficiency of Hengfloc 63020, a polymer was tested four flood experiments for Niger delta oil. Also the rheological properties for a wide range of concentrations were measured. Secondly, Teepol was screened in the pack flood test at different concentrations. Thirdly, the optimum surfactant concentration and optimum surfactant injection rate were investigated. The fourth set of experiments investigated the effect of flood process design in a three beads pack flood tests to select an appropriate scheme. Using the best flood scheme, the formulated SP slug was then used to recover oils of viscosity range from 3.5cp to 140cp. Advanced mathematical methods were used to analyze and model the experimental results.
The experimental results show that better displacement efficiency can be achieved within a range of polymer concentration for oil. Also the performance of SP flood program is dependent on the right slug formulation, the injection rate and the overall project design. From the analysis of the cores used in the experiment, a fair idea of the efficiency of surfactant –polymer flooding in reservoirs with similar properties of the cores used in the experiment can be inferred.
Grain Size Effects on Residual Oil Saturation
Authors: Taiwo Oluwaseun Ayodele , Mamudu Abbas , Dagogo-Jack Cyrusba , Joshua Dala , Olafuyi Olalekan 
Published: July 2016

Abstract
In order to improve the efficiency of the enhanced oil recovery process, researchers have come up with different methods such as mobility control, chemical, miscible, thermal and other processes such as microbial. In chemical flooding for example, alkaline, polymer, surfactant, surfactant polymer (SP) and alkaline surfactant polymer (ASP) have all been employed in the quest for better efficiency. However, grain size effect on the recovery system during these tertiary recovery techniques has received less attention over the years.
This paper presents evaluation of the effects of grain size on residual oil saturation (ROS) from experimental studies of oil recovery potentials of a formulated ASP slug in synthetic porous media. 1% weight of sodium hydroxide (NaOH), 0.15% weight of shell enordet 0242 supplied by shell research centre and 0.02% weight of hengfloc 63020 were used as alkali, surfactant and polymer respectively. Ranges of core grain sizes of 0.063 to 0.090, 0.106 to 0.150, 0.150 to 0.212, 0.212 0.300 and 0.425 to 0.600 micron were considered in five different experiments performed. Each of the experiment was accomplished by a procedural sequence of brine saturation, oil saturation, water flooding and ASP flooding.
The results show that the porosity of the synthesized core increases with decreasing grain size from 37.2% to 43.74% for a range of 0.600 micron to 0.063 micron of sizes. The permeability of the synthetic core decreases from 2309 millidarcy to 669 millidarcy as the grain size decreases from 0.600 micron to 0.063 micron. Pressure drop across the beads pack increases from 0.294 psi to 1.015 psi as the grain size reduces. The oil recovery by an immiscible fluid through the beads pack increases as the pore throat get smaller or the grain size reduces. The volume of ROS after flooding reduces as grain size reduces.
Fractional Wettability Effects on Surfactant Flooding for Recovering Light Oil Using Teepol
Authors: Taiwo Oluwaseun Ayodele , Uzezi Orivri , Mamudu Abbas , Onuoha Sean , Adijat Ogienagbon , Olafuyi Olalekan 
Published: July 2016

Abstract
The fractional or mixed wettability of porous media has been recognized as ubiquitous condition in the petroleum literatures. Fractional wettability refers to the fraction of the total pore surface area which is preferentially water or oil-wet. And this wetting condition of a reservoir rock plays a significant role in determining the oil recovery
This paper presents laboratory analysis of the effect of wettability alteration on recovery mechanism and the effects of Teepol at different wettability conditions using a glass beads-pack. Oil wet condition was established by the use of kerosene and other fractional wettability conditions were also established. Six experiments were performed. In all the experiments, imbibition, drainage, water flooding, surfactant flooding and polymer flooding were carried out on the porous medium. 0.7PV surfactant solution (teepol) at a concentration of 0.9%wt and 1.1PV polymer solution (gum Arabic) at 5%wt concentration were used. In experiment A, B, C, D, E and Z (control), the porous medium was 100% water wet, 25% water wet and 75% oil wet, 50% water wet and 50% oil wet, 75% water wet and 25% oil wet, 100% oil wet, 100% water wet respectively.
The results show that equal percent wettability of both water and oil and complete wettability of either oil or water yield more incremental oil when compared with those of 25% water wet and 75% oil wet condition and 75% water wet and 25% oil wet fractional wettability. Teepol is effective in lowering the oil-water IFT in all porous media with recovery ranging from about 75.5 to 90% of the residual oil saturation (ROS). Experiment C (50-50 fractional wettability) has the highest incremental oil recovery due to grain-to-grain interactive forces while experiment Z has the lowest recovery (about 41% of ROS). This strongly suggests mixed or fractional wettability reservoirs are good candidate of chemical EOR technique. However, even fractions contributions to the mixed wettability by both phases are required for optimum process performance.
Enhanced Integrated Characterization of a Complex Naturally Fractured Reservoir using Mud Logs, 3D Seismic and Performance Data
Authors: Ershaghi Iraj , Ojukwu Chima , Mayerson Drew , Rozek Stephanie 
Published: July 2016

Abstract
This paper presents the results of a study for estimation of reserves in a highly complex naturally fractured reservoir off the Coast of California. The fractured reservoir at the Point Arguello Field, consisting of the siliceous rocks of the Monterey Formation, has produced more than 187 million barrels of oil during the last three decades primarily from fractures intersecting the extended reach and directionally drilled wells. This study was conducted to assess the economic viability of continuing production of the field and economic incentives for maintaining operations at the three existing offshore production platforms. In our study we examined the remaining reserves from the fracture controlled production and scrutinized the potential contribution of the tight matrix to primary recovery and for EOR processes. In this integrated and comprehensive study, we used a new interpretation of 3D seismic data, re-visited extensive mud log data, prepared diagnostic plots of performance data and incorporated conventional logs, DST and core data to characterize the production system.
From the analysis of GOR, WOR, and 3D seismic we identified 10 separate compartments and related the vast differences observed in well productivities to the compartment size, degree of fracturing and behavior of water influx. We also developed common sense reservoir forecasting solutions to examine the potential application of CO2 injection for extracting oil from the tight matrix. The economic forecasting indicates substantial opportunities by managing water influx, exploiting bypassed intervals by new perforations, and drilling infill wells in blocks using volumetric curvature analysis data.
Lessons learned show the definitive significance of integrated reservoir characterization, importance of mud logs and 3D seismic, and fault characterization for defining compartments, and potential applications to other similarly fractured reservoirs.