bluuebunny/crossref_metadata_2025_split huggingface dataset:
Capturing Reservoir Communication Uncertainty in a Well Proposal Assessment
Authors: Idogun Iroro , Lawal Olumide , Eme Vincent , Oguntona Bayo 
Published: July 2016

Abstract
As Oil fields containing stacked reservoirs are developed, it is not uncommon for these reservoirs to be in pressure communication. The extent of pressure depletion may determine the viability of potential new drills. Possible communication of the X1 reservoir with the Y1 reservoir was initially suspected when a Material Balance study earlier conducted on the X1 reservoir did not yield a reliable historical pressure match using mapped volumes of the X1 thereby suggesting potentially larger Oil in Place number in the X1 reservoir. Also, the structural overlay of the X1 over the Y1 reservoir having compatible hydrocarbon contacts seemed to also indicate possible communication between the X1 and Y1 reservoirs. The conclusion of the Material Balance study recommended a more detailed probe into the X1 reservoir to ascertain the impact of communication on the reservoir development strategy.
A simulation study was conducted primarily to evaluate the impact of communication uncertainty on the new drill recovery. Three scenarios were considered namely: Communication of the Y1 with the X1 through the aquifer; Communication of the Y1 with the X1 through the hydrocarbon and the Y1 completely isolated from the X1. The history match indicates reservoir communication through the aquifer as the most plausible scenario. However, due to active reservoir drive mechanism of gas Cap expansion and strong aquifer support in the X1 reservoir and possibly same in the Y1, all three scenarios did not adversely affect the potential recovery in this instance with recoveries between 50-59%. Hence incorporating surveillance information from offset producers is vital in evaluating production potential of zones which may be unproduced but not virgin.
Cubic Spline and Graphical Techniques for Determining Unsteady State Relative Permeabilities in Field Cores
Authors: Mamudu Abbas , Taiwo Oluwaseun Ayodele , Olafuyi Olalekan 
Published: July 2016

Abstract
Relative permeability is one of the key factors in reservoir engineering calculations to simulate multiphase behavior in porous media. The relative permeabilities calculated from established models do not perfectly characterize the reservoir without a known trend or history. This necessitates the need to use a reliable and globally accepted technique based on Niger Delta field production data for calculating relative permeabilities from the fields so that the models derived from the relative permeability curves could be tamed and domesticated in the region for better reservoir characterization and evaluation. The Johnson, Bossler and Neumann (JBN) method is the industry standard for measuring relative permeabilities from field cores. In order to eliminate the need of using numerical differentiation, and therefore reduce the overall numerical error in this method, a graphical technique was proposed and implemented during late 70s. However, with splines, the numerical differentiations are still done but with improved results.
The current study presents the results from the comparative analysis of two approaches employed to avoid the traditional numerical differentiation required by the JBN method. Production data from field cores in the Niger Delta were used. The graphical method and cubic spline numerical modeling were both used to calculate the individual relative permeabilities from the pressure/production history of the displacements. the results were analyzed and compared. The results of both methods show a very good match over a fairly small saturation range and also differ. However, cubic spline results are closer to the traditional numerical differentiation results because is a modeling approach in which the numerical differentiation is incorporated with improved accuracy.
Managing Fluid Properties Uncertainty in the Evaluation of a Greenfield Gas Development: The Dex Field Case
Authors: Sonde Adenike , Azubike Obi , Ozoemene Uche , Fasasi Roseline 
Published: July 2016

Abstract
In planning the development of a gas field, the gas properties play a critical role in estimating the economic value of the gas development. Chief amongst these gas properties are the Condensate-Gas Ratio (CGR) and the gas formation volume factor (Bg). While the gas volumes to be developed at standard conditions are dependent on the gas formation volume factor (or the expansion factor), the CGR determines the volume of associated condensate that can be produced and sold. A good understanding of these properties is therefore required for the evaluation of any gas field development.
Fluid properties, ideally, are determined from laboratory PVT experiments carried out on fluid samples acquired from the field. These experimental PVT data are vital, especially in green fields where there is no production data that can be used to estimate some of these properties. Where such good quality experimental data are not available, it poses a major uncertainty around the fluid properties, particularly in a green field.
The Dex field, a green field which is predominantly gas-bearing, has been penetrated by six wells, and fluid (PVT) samples were acquired from the last appraisal well drilled in the field. However, besides compositional analyses, extensive laboratory analyses could not be carried out on these samples due to the high level of mud contamination. While the compositional data provided some qualitative data and information on the fluid, the fluid properties essentially remained uncertain. This paper describes how this uncertainty was managed and how a reliable range of fluid properties was generated for use in the Dex gas development evaluation.
Experimental Investigation of the Feasibility of Polymer Flooding in a Shallow Niger Delta Oil Reservoir
Authors: Ogienagbon Adijat , Taiwo Oluwaseun Ayodele , Mamudu Abbas , Olafuyi Olalekan 
Published: July 2016

Abstract
The global oil price as well as Nigeria’s current reserve is on a continuous alarming decline. With the increasing finding cost of new wells and demand for energy, improving oil recovery from existing wells becomes highly pertinent. Generally, waterflooding leaves approximately two thirds of the OIIP as un-swept or residual oil resulting to a low recovery factor. The improvement of recovery factor is one of the identified five Research & Development (R&D) grand challenges or upstream business needs highlighted by the SPE R & D committee. Enhanced Oil recovery (EOR) methods provide an avenue to Petroleum engineers to unravel this challenge. In lieu of this, we investigated the feasibility of improving recovery with polymer flooding technique in the Niger Delta region of the Sub-Sahara Africa. A sequence of brine saturation, oil saturation, water flooding and polymer flooding was carried out on four different cores (core A, B, T & R). Core A & B are ROBU cores (specially manufactured synthetic cores), T is Bentheimer core and while R is a reservoir rock core sample from a shallow central Onshore Niger Delta reservoir.
The results show comparative responsiveness of oil recovery to polymer flooding by the various core samples. Core samples T & R are good candidates for polymer flooding having produced 21.28% & 13.33% after polymer flooding. Model Bentheimer rock sample (T) which has close petro-physical properties to that of the case studied reservoir has the highest displacement efficiency of 52.63%. The core flood analysis demonstrated that polymer flooding could improve oil recovery within the Central Onshore reservoir of the Niger Delta.
Impact of Data Quality on Well Operations: Case Study of Workover Operations
Authors: Enyekwe Alfred , Urubusi Osahon , Yekini Raufu , Azoom Iorkam 
Published: July 2016

Abstract
Significant emphasis on data quality is placed on real-time drilling data for the optimisation of drilling operations and on logging data for quality lithological and petro-physical description of a field. This is evidenced by huge sums spent on real time MWD/LWD tools, broadband services, wireline logging tools, etc.
However, a lot more needs to be done to harness quality data for future work-over and or abandonment operations where data being relied on is data that must have been entered decades ago and costs and time spent are critically linked to already known and certified information.
In some cases, data relied on has been migrated across different data management platforms, during which relevant data might have been lost, mis-interpreted or mis-placed. Another common cause of wrong data is improperly documented well intervention operations which have been done in such a short time, that there is no pressure to document the operation properly. This leads to confusion over simple issues such as what depth a plug was set, or what junk was left in hole.
The relative lack of emphasis on this type of data quality has led to high costs of work-over and abandonment operations. In some cases, process safety incidents have arisen.
This paper looks at some work-over operations carried out in a span of 10 years. Data management system is generally analysed and a categorisation of issues experienced during the work-over operations is outlined. Time lost due to data error was seen to average 1.54% but with a unit peak of 19%. An analysis is done on the wells' activity history to check for correlations. Bottlenecks in data management are defined and solutions currently being implemented to manage these problems are listed as recommended good practices.
Project Finance for Indigenous Oil and Gas Companies in Nigeria: An incentive for Energy security and Stability
Authors: Essien Oluwadamilola Ayomide 
Published: July 2016

Abstract
The energy industry is highly capital intensive, hence the reason for a very few but powerful players in the industry. The disadvantage of this to a developing country like Nigeria is that new, ambitious upcoming indigenous companies, may not be able to make significant achievements in this industry because of the amount of capital required to operate in this industry.
One method of financing capital intensive projects is through project finance. In the financing of a project, the lenders would be satisfied to look to the project being financed as the source of repayment for the loan. The project sponsors are only liable to the lenders in the event of a breach in the equity contributed to the project and no more. As good as project financing may sound in the ears of a project sponsor particularly, it comes with loads of obligations and responsibilities. Every participant in the project is made to be economically interested in order to ensure that all parties are working towards the success of a common goal. The obligations are taken higher and thus lenders confidence boosted when they are able to secure a sovereign guarantee from the host government. However, these guarantees may be given depending on the importance of such projects to the economic development of the country, the debt ceiling of the government and also the current financial state of the government. (Duke 2016) Because of the uncertainties that may surround soverign guarantees, project lenders are more satisfied to obtain guarantees and political insurance from multilateral organizations as well as private insurance companies on a given project. (Duke 2016) At the heart of project finance is risk identification and allocation. Given that it is impossible to identify and allocate all anticipated risks, where a large chunk of the risks can be identified and allocated, the lenders would be satisfied to finance oil and gas projects in Nigeria which in turn promotes energy security and sustainability in Nigeria.
Zoning Steam-Heated Reservoirs by Heat-Transfer Mechanisms
Authors: Lawal Kazeem A. 
Published: July 2016

Abstract
In-situ oil recovery by thermal methods entails introducing heat into the reservoir to enhance productivity and ultimate recovery. Clearly, proper design and management of thermal floods require adequate insights into the temperature distribution in the reservoir. This paper interrogates the robustness of the traditional approach of describing steam-flooded reservoirs with two isothermal zones. Employing a rigorous one-dimensional reservoir-heating model, the spatial distribution of the heat-transfer mechanisms during each of conduction, convection (non-condensing) and multiple-contact condensation processes has been investigated. After a sufficient period of heating, the prevailing temperature profiles are analysed and the reservoir delineated into zones according to the temperature responses. From the simulation results, the thermal front is mapped, and the dominant heat-transport mechanisms at its leading and trailing edges are analysed, both in space and time. It is found that a maximum of four zones vis-à-vis condensation, convection, conduction and quiescent, can be identified at any instant of a thermal flood. However, the presence and relative thickness of the zones are controlled by the maturity of the thermal flood and the dominant process (conduction or convection) at the time of interest. In practice, these findings should find applications in the design and management of thermal floods, on both laboratory and field scales.
Seismic Constrained 3D Static Modelling: Conceptual Model Replication by Integrating Analogues and Seismic Facies
Authors: Kehinde Oyeleke Zaid , Olatunbosun Afolayan 
Published: July 2016

Abstract
Subsurface risks involved in a field development activity are best mitigated by establishing a narrow uncertainty band from all available subsurface data. Horizontal wells, based on their profile usually presents a set of ‘point’ data for a number of spatial location along the bore, however these information are usually not accurately captured in the development of a conceptual model.
This field study attempts to show the integration of data from horizontal wells, analogue and seismic in order to accurately predict facies/reservoir properties distribution and also look into the production potential of a newly drilled offshore production and injector wells.
The study area is situated in the deepwater South west of Niger Delta, Nigeria. An integrated approach which incorporates statistical and neural network seismic attribute analysis, horizontal well point properties, and analogue data to generate a robust depositional facies distribution was adopted in the static modelling. The facies model being an underlining step in distribution of reservoir petrophysical properties was then utilized to generate descriptive reservoir properties model that captures the subsurface heterogeneity of the "Zat" field. The correctness of this methodology is being substantiated by result culminated from other similar projects.
The depo-facies accurately captures the stratigraphic geometry and distribution of facies as seen by wells and seismic thereby leading to improved lateral and vertical facies predictions. So what you see is what you get! The interplay of along well-bore and three-dimensional prediction of sand intervals enables a better QC workflow for assigning petrophysical properties (e.g. porosity, permeability and water saturation) to the static model. The trend and connectivity of amalgamated channel bodies mimic to a greater extent the observed seismic and wellbore facies.
The resultant net-to-gross estimation of this approach compares better to the seismic data set prediction from inversion.
PVT Analysis: Validity Checks and EOS Tuning Techniques for Retrograde Gas Condensate Reservoirs
Authors: Ibeh S. U. , Chubueze S. E. 
Published: July 2016

Abstract
PVT analysis is pertinent to field-wide development and optimization. This is because we need to know the over-all behavior of the fluid from reservoir through production and process facilities, down to the refinery. Its emergence as a separate discipline has been supported by the development of modern computer software that utilize EOS models for simulating experiments and representing fluid phase behaviours. PVT simulations are carried out to determine operating conditions that will maximize the surface liquid content and extend the production plateau duration at the lowest possible cost. In such simulations, Laboratory derived data are used to tune the EOS models and the results incorporated for reservoir simulation and studies. Obtaining a good match between EOS and laboratory data depends on data quality and for retrograde gas condensates, this can be very challenging due to their complicated phase behavior. Inadequate match results in computational errors and unrepresentative results when used in reservoir simulations and thus, jeopardize reservoir management decisions which are based on it.
The major contributions of this paper are-first,a review of critical issues and success factors in PVT analysis and its associated challenges. Second, methods for quality checking PVT data. Third, techniques for improving Lab – EOS match and their influence in PVT results.
Assessment of Factors Influencing Inflow Performance Relationships of Horizontal Oil Wells: A New Approach
Authors: Ogali O. I. , Ikiensikimama S. S. , Ajienka J. A. 
Published: July 2016

Abstract
Inflow Performance Relationships are used in evaluating the deliverability of a well in an oil and/or gas reservoir. Several factors influence the deliverability of a horizontal oil well; such as reservoir fluid properties, near wellbore conditions and reservoir relative permeabilities. Using dimensionless inflow performance relationships, the impacts of some reservoir rock, fluid and well properties on horizontal oil well performance were assessed. In this study, the concept of Concavity Index was used in assessing the impact of these factors. The Concavity Index is obtained from modelling the dIPR curves to capture the degree of curvature. In assessing the impact of these factors, the Change in Concavity Index is used. A factor is considered to have an insignificant impact if, for the range of values of the factor being assessed, the change in Concavity Index is less than. Absolute permeability had insignificant impact, for all the recovery factors assessed; whereas, wellbore skin had significant impact. For other factors assessed in this study, the impacts varied with the recovery factors. Therefore, the magnitude of the impact of these factors on horizontal oil well performance depends on the recovery factor at which the assessment is carried out. This new approach will improve horizontal well planning and management, and consequently economics.
Developing Renewable and Unconventional Energies as a Panacea to Falling Oil Price. How Possible in the Nigerian Case?
Authors: Osuagwu David 
Published: July 2016

Abstract
As a developing or underdeveloped country, a Nation backward in scientific and technological innovations, how can renewable and unconventional energies bridge the gap or ameliorate losses from oil and Gas energy derivatives? Globally, can renewable and unconventional sources of energy fittingly serve as an alternative or bridge the shortfall from conventional sources like coal, oil and gas? Though clean, green alternative energy is teeming all around the world – Solar, wind, Biomass, Hydroelectric, tidal, wave power to mention a few. This paper evaluates the potentials of renewable and unconventional energies as an alternative source to oil and gas in Nigeria. It further examines the preparedness and capabilities of Nigeria to develop these energies in the face of her scientific and technological state. Granted that Nigeria is backward in science and technology, with concerted efforts and enabling government policies, technological breakthrough is achievable. It is incontrovertible that Nigeria has abundant human and natural resources. Her diverse people and huge population have produced talented professionals, excelling in other parts of the world. What the nation requires as a lunch-pad are sound management and government policies that are pragmatic, motivating, invigorating, strong in purpose and discipline. The natural resources are visible all over the place in Nigeria. The non-renewable and conventional energies which have been the main stay of Nigeria's economy are in crisis. What other choice does the nation have? The renewable and unconventional energies like Solar, Wind, Hydroelectric, Piezoelectric, Helioculture, Salt water power, ocean thermal energy conversion, Human sewage, Hot rock power, Evaporative energy, vortex induced vibrations, Mining the moon and even space-based solar power are begging to be harnessed. How prepared are we as a Nation to develop these renewable energies? The level of preparedness for scientific and technological development is still very low. Research and production are still at minimal level. Budgets for scientific research over the years have been an aberration. The will and zeal to innovate appears to be absent. The paper concludes that there is real energy crisis in Nigeria and the world generally and there is a wakeup call to this militating economic cancer. The paper recommended that renewable and unconventional energy sources should be explored and assiduously exploited as a panacea for the declining conventional energy sources.
Optimizing Well Design and Delivery for Wellbore Stability Management by Minimizing Subsurface Uncertainties
Authors: Odagme Baridor S. , Dosunmu Adewale , Oriji Boniface A. , Fekete Paul 
Published: July 2016

Abstract
Modeling instability in shales is pertinent to managing risk and uncertainty associated with drilling troublesome formations. Design parameter such as Unconfined Compressive Stress (UCS) is usually estimated from sonic or other porosity logs and calibrated with results of triaxial test from core samples. However, sonic logs may not be available for some wells, making UCS estimation difficult thereby increasing uncertainty. In this work, a compositional approach was used to evaluate UCS and the Volume of Shale (Vsh) of the rock was modelled from the spectral gamma ray (SGR) or gamma spectrometry as a measure of shaliness instead of the gamma ray. This is because the sandstone sequences as obtained in Niger Delta fields contain some non radiactive clay which gamma ray log may not delinate clearly. Subsurface geological issues like bedding plane and faults were also modelled and the estimated UCS at various intervals and lithologies were calibrated with offset well data. Field results showed consistent and reliable estimates of UCS in the absence of Sonic logs with a percentage error of ± 0.0208. The predicted safe drilling mud weights must be accompanied by good drilling practice and proper hole cleaning. ECD and fracture gradient issues were captured to prevent excessive loss circulation. Instability risk were minimized and the case study well presented showed consistent result.