bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of Offset Mud Weight in Appraisal and Exploratory Well Planning - Practical Approach
Authors: Ugonoh Mohammed , Anifowose Hussein , Ajayi Olajumoke , Sijpesteijn Casper Kaars , Adedotun Wali , Obeta Chukwudi 
Published: August 2012

ABSTRACT
The use of offset mud weight in combination with geologic information and drilling operations report can be very useful in estimating formation pressure in appraisal and exploratory well planning. It has been established that conventional shale pressure modeling is an effective tool for pore pressure prediction William Standifird et al 2005. The model can be updated as new data is acquired to reduce the uncertainty window and optimize drilling. This paper aims to generate shale based pore pressure profiles for the Sahara wells in northern depositional mega structure of the Niger delta using equivalent depth method and compare shale based gradient with predicted gradient from offset mud weight
The offset mud weight was expressed in pressure gradients allowing for computation of hydrostatic head of the mud and subsequently backing out the overbalance. This provided a fair estimate of the formation pressure. The estimated pressure was corrected for hydrocarbon buoyancy. The fracture gradient was derived from the leak off test of the offset well data. The lithostatic gradient is based on the regional gradient for the northern depo belt of Niger delta of Nigeria. In the shale based pore pressure estimate, the overburden gradient was modeled by superimposing the density log of the wells due to the paucity of density log. The Leak off Test of two offset wells was also utilised used to define the fracture gradient. Equivalent depth method was used in the computation of the pore pressure in the three wells
Comparison of the formation pressure profile generated using the offset mud weight from X, Y and Z wells and shale based pore pressure prediction using proprietary software indicated the two methods shows tolerable difference fit for purpose well planning.
Safety Supervision and Leadership
Authors: Samson Igwe Nkwachukwu , Nwaoha Chikezie 
Published: August 2012

Abstract
The supervisor is the one person who can take immediate direct action to make sure that his or her work area is safe and healthful for all employees. Russell DeReamer, author of Modern safety practices, considers the supervisor the only person who can control employees, machines and working conditions on a daily, full time basis. In his text, occupational safety and health management, Thomas Anton relates that the supervisor bears the greatest responsibility and accountability for implementing the safety and health program because it is he or she who works most directly with the employee. It is important that the supervisor understands and apply successful management and leadership principle to safety and health to make sure employee enjoy an injury and illness free work environment. Supervisors can demonstrate leadership by directly providing employees the resources, motivation, priorities and accountability, for ensuring their safety and health. Enlightened supervisors understand the value in creating and fostering a strong safety culture within their department. Integrating safety and health concerns into the everyday supervision allows for a proactive approach to accident prevention and demonstrates the importance of working safely
Application of Experimental Design Techniques to Unravel Sub-Surface Complexity in Gravity Assisted Water Injection Project in the Niger Delta
Authors: Onyeukwu C. A , Peacock A. , Osharode C. O. , Onwuchekwa C. , Adekoya O. 
Published: August 2012

Abstract
A pilot Gravity Assisted Water (Dumpflood) Injection scheme was executed in 1997 in X1 reservoir of a Niger Delta field ‘Alpha’. Post performance analysis showed that the injection has been successful in maintaining good pressure support and in supporting future recovery from the reservoir. However due to X1 reservoir uncertainities and variabilities in Water Dumpfllod injection rates, expected range of future recoveries could not be quantified.
This paper presents a case study of the application of Experimental Design (ED) to understand the historical performance and future predictions of a gravity-assisted water injection in ‘Alpha’ X1 reservoir. A range of static and dynamic models were constructed and experimental design methodology was used to map out the key uncertainties and to develop a range of history matched models which were used to assess the range of future hydrocarbon resource volumes likely to be produced from the reservoir under the existing development concept. In addition to the traditional sub-surface uncertainties, this project also assessed water injection rates as an additional uncertainty that significantly impacted the future recoverable from the reservoir.
Experimental design was used to create a range of history matched dynamic models of a dumpflood development that captures the key uncertainties in the reservoir. Ten history matched models were developed and carried to the prediction phase of the study. A voidage replacement development strategy was applied and all ten models were used to predict the reservoir performance over a range of water injection rates. The outcome of the analysis was used to update recoverable volume estimates and to develop a well and reservoir management strategy for the reservoir.
Evaluating the Impact of Depreciation Methods and Production Decline Patterns on Deepwater Economics: A Case Study of Nigeria
Authors: Onwuka Emmanuel I. , Iledare Omowumi O. , Echendu Joseph C. 
Published: August 2012

Abstract
Upstream petroleum industry remains one of the most prolific in terms of technology and risk capital transfer and rewards. Consequently, governments all over the world try to formulate fiscal regimes that could favourably attract investments to petroleum provinces in their jurisdiction. Fiscal systems that are progressive tend to find a common ground for both government and the contractor by optimizing efforts and benefits. Nigeria belongs to a region of low-risk hydrocarbon discovery relative to the world average. Therefore, the government designs fiscal regimes that would seemingly extract more economic rent from the development of its petroleum resources. This paper investigates the impact of some of the technical instruments in the Nigerian PSC on rewards from deepwater investments.
Discounted economic models are developed for two petroleum sharing contracts in Nigeria- the 2005 PSC and the interagency team (IAT) redraft of the 2008 Petroleum Industry Bill (PIB)-with due consideration to the three Arps’ production decline profiles. Different tangible CAPEX depreciation methods are imposed on the models and profitability indicators are estimated. Monte Carlo simulation analysis is applied to resolve the stochastic nature of some model input variables.
Simulation results show that maximum reward is observed when Unit of Production (UOP) depreciation method is applied in the redraft 2008 PIB; while straight line depreciation (SLD) gives better economic metrics for the 2005 PSC keeping all the terms of the contractual arrangements constant. These results could be applied in formulation of petroleum fiscal policies like the PIB by making cost depreciation a form of incentive. It is found that for a specific fiscal contract, cost depreciation method influences economic indices when used in project evaluation. Irrespective of the production decline, UOP depreciation gives earliest contractor-payout while the net present value is negatively impacted by accelerated extraction.
Multiple –Zones Flow Unit Modeling of Ilam and Sarvak Carbonate Formations of Iran through an Integrated Approach
Authors: Shahvar M. B , Kharrat R. 
Published: August 2012

Abstract
Ilam and Sarvak formations are two main Upper Cretaceous oil-bearing carbonate systems that are formed in an unconformity manner in Abadan plain, south-western Iran. Based on comprehensive geological and stratigraphic studies, eight reservoir zones are determined in these formations that four of them are major oil reservoirs, three of them are to some extent poor reservoirs with low amounts of porosity and permeability and the last one is a water zone. Due to the importance of flow unit modeling in appropriate reservoir characterization and simulation, this study has focused on constructing the petrophysical flow unit models for each reservoir interval of the understudy formations. Since rock typing is a challenging task in carbonate rocks and these formations suffer from heterogeneity, relying on the result of one rock typing method would not be wise, therefore it is tried to integrate the results of different flow units characterization techniques that their capability have been confirmed before. For this purpose, Winland R35 model, stratigraphic modified Lorenz plot model, flow zone index model and normalized cumulative rock quality index model are built for each zone. By accurate interpretation of the results, existed discrepancies between the models are removed and the numbers of flow units that are confirmed by all the methods are introduced for each interval that is useful for further field development plans. Difference of this study with respect to prior ones is in integrating the results of four major rock typing techniques because each method has some advantages and disadvantages and cannot be used individually for flow unit characterization especially in heterogeneous carbonate systems.
Vertical-Horizontal Permeability Relationships for Sandstone Reservoirs
Authors: Philip C. Iheanacho , Tiab Djebbar , Alpheus O. Igbokoyi 
Published: August 2012

Abstract
One of the important petrophysical parameter in reservoir description is the permeability distribution in a given reservoir. It is well known that most reservoir are heterogeneous in nature and homogeneous ones being the few exceptions. Therefore, most reservoirs exist with different degree of permeability anisotropy and reservoir heterogeneity.
This work investigates the relationship between vertical and horizontal permeability in sandstone reservoirs. Various petrophysical properties were estimated from core and log data obtained from a Niger-Delta sandstone reservoir. New and improved correlations between vertical permeability, horizontal permeability, effective porosity and shale fraction were developed for the zones that were analyzed.
These correlations show that there is a strong relationship between vertical permeability, horizontal permeability, effective porosity, and shale fraction for the different zones that were analyzed and that these correlations are affected by the number of flow units in each zone.
Improving the Efficiency of the Fischer-Tropsch Synthesis Using the CO2 Reduction Alternative
Authors: Habib Bello , Ogbonna Joel , Ikiensikimama Sunday Sunday 
Published: August 2012

Abstract
Gas-to-liquids technologyy (GTL) involves the chemical conversion of methane (usually in the form of natural gas) into easily transportable liquids like gasoline, diesel and heavy oils. GTL technology involves three basic steps: syngas production, Fischer-Tropsch (FT) synthesis and product upgrade. The FT synthesis (or Fischer-Tropsch process) is a set of chemical reactions which converts synthetic gas or "syngas" into liquid hydrocarbons.
This work show the benefits of a new GTL process (called the CO2 reduction process) over the conventional GTL process. ASPEN Hysys® Version 2004 (Build 13.1.2) Process Simulator was used to compare the product yield, power recovery and effluent water outlet of the conventional GTL and the CO2 reduction alternative.
The simulation shows that successful elimination of the O2 generator, the CO2 removal unit and the H2 conditioning unit in the CO2 reduction GTL plant decreases the total power consumption of the GTL plant by about 21%, lesser effluent water production and increases yield of the most desired FT fuel, diesel by 33.5%.
Economic Analysis of Subsea Oil and Gas Production Pipe-In-Pipe Technology for Offshore Gas Development in Nigeria
Authors: Osokogwu U , Joseph A , Ajienka J. A , Ogiri Rex. O. 
Published: August 2012

Abstract
Pipe-in-Pipe technology is a pipeline system consisting of two coaxial pipes. The inner pipe carries the fluid and is encased within a larger diameter outer pipe which seals the annulus between the two pipes. The annulus can be filled with a wide range of thermal insulating materials such as fiberglass, glasswool, microporous materials, aerogel, polyurethane foam, ceramics etc. This is seen as a solution to the effective management of the long problem of flow assurance in subsea fields. The pipe-in-pipe technology is thought to be extensively ideal for the transportation of well bore fluids from a subsea field, as it is capable of withstanding the difficult conditions of the ocean with its low overall heat transfer coefficient (OHTC) of less than 1 W/m2K, but this it does achieve at added cost. The aim of this paper is to economically analyze the pipe-in-pipe technology using a case study of Rosa field, an offshore field off the coast of Angola relative to offshore Gas Development in Nigeria. The following profitability indices; Net present value (NPV), internal rate of return (IRR), Profitability index and Payout or payback period were used to compare the cost of a pipe-in-pipe technology and that of a conventional pipeline system for an oil and gas field. For the pipe-in-pipe technology, a real NPV of $5.5 billion, IRR of 65.7%, PI of 3.22and payback period of 1.46 years and a money of the day NPV of $10 billion, IRR of 82.1%, PI of 5.0 and payback period of 1.19 years were achieved while for a conventional pipeline, a real NPV of $5.6 billion, IRR of 66.5%, PI of 3.28 and payback period of 1.49 years and money of the day NPV of $10.1 billion, IRR of 83%, PI of 5.1 and payback period of 1.16 years were achieved.
Transient Analysis in Partially Completed Wells
Authors: Otiede D. O , Onyekonwu M. O , Olafuyi O. A , Laka Z. L 
Published: August 2012

Abstract
Good understanding of the flow regimes is necessary for accurate interpretation of well test results. Partially completed or penetrating wells develop flow geometries which are different from the radial flow model on which conventional well test analysis is based and so the radial flow equation will not be adequate for analysing the transient behaviours resulting from such wells. A threefold, approach, namely, Model Preparation, Numerical Reservoir Simulation, and Well Test Analysis was used in this work to study the effects of partial penetration on the transient pressure response of partially penetrating wells. The effects of anisotropy, wellbore storage, position of partial completion and penetration were all considered. Spherical flow approximation was used for the description of wells with partial completion and partial penetration.
In the analysis, three flow regimes were found to appear on the transient pressure response. Pressure drop was greatest in wells with very low penetration ratio. The position of partial completion had no effect on pressure transient response.
Vertical permeability is very important in predicting gas or water coning or performance of horizontal wells. This is very useful in for completion engineering optimisation and as well provides a good rationale for drilling horizontal wells. Also Knowledge of the vertical anisotropy will aid reservoir development and the planning of future secondary recovery.
Economic Comparison of Liquefied Natural Gas Floating Production Storage and Offloading Plant (LNG FPSO) with the Proposed Brass LNG
Authors: Lazson Nchekwube Edwin , Ikiensikimama Sunday Sunday 
Published: August 2012

Abstract
With the ongoing gas revolution in Nigeria, it will be appropriate that our government invest wisely by going for the best economical venture. The objective of this study is to provide a perspective on portfolio diversification, investment and resource development. The economic analysis was carried out deterministically using economic indices like Net Present Value, Internal Rate of Return, Present Value Rate and others. Probabilistic model was also incorporated to assess the impact of the uncertainties in the input parameters using Monte Carlo Simulation through the use of Crystal ball software. The key uncertainties parameters were the same for both projects though their level of impacts differs. The deterministic model results obtained was Net Present Value of $2.3 billion at a discount value of 15% and Internal Rate of Return at 32.68% for LNG FPSO while Brass LNG has NPV of $607,640,260.85, at a discount value of 15% and internal Rate of Return at 16.28%. These clearly showed that LNG FPSO is profitable for offshore environment within the range of 25 nautical miles with water depth of 20 meters and above.
Vision 20:2020 Initiative and the Nigerian Oil and Gas Industry: An Empirical Analysis of the Environmental Dimension
Authors: Leo Morgan 
Published: August 2012

Abstract
Presently, crude oil generates about 90% of Nigeria's foreign exchange and 82 percent of the Government revenue. Together with natural gas, the industry contributes about 79 percent of commercially traded energy in the country. Meanwhile, Nigeria Vision 20:2020 Economic Transformation Blueprint being implemented by the present administration is envisioned to place the country among the Top 20 economies in the world, with minimum Gross Domestic Product (GDP) of USD900 billion and a per capita income of no less than USD4000 per annum by the year 2020. Judging from the critical role the oil and gas industry plays in the Nigerian economy, and the confidence derived from the projection from the International Energy Agency (IEA) that through 2030, fossil fuels will continue to satisfy the vast majority of the global energy demand, it is readily inferred that the bulk of the financial resources required to bankroll the development agenda will be mobilized from the oil and gas sub sector. Evidently, the successful implementation of the programme depends largely on the stability of the oil and gas industry, especially in the context of the natural environment. This paper gives an overview of the environmental dynamics necessary for sustainable exploitation of fossil energy sources in Nigeria. Leveraging tested case studies and best practices, it also diagnosis the linkages between environmental sustainability and national development programmes.
A New Model for Determining the Radius of Mud Loss During Drilling Operation in a Radial Fractured Network
Authors: Shahri M. Pordel , Zabihi S. H. 
Published: August 2012

Abstract
A new solution for determining the amount of mud loss during drilling operation in a fractured reservoir having a regular two- or three-dimensional radial fractured network with the novel inclusion of a convective transport of filtrate in the matrix is presented. Convective-dispersive filtrate transport along the network is modeled in which drilling mud can be filtered in existing matrix. The filter cake effect at the fracture-matrix interface in the network is simulated by means of an empirically decaying filter rate equation. The numerical solution is used in this study. The consistency of numerical solution is checked and the best situation is considered. The sensitivity analysis on all parameters in the model has been done and the effect of each parameters such as wellbore loss rate, reservoir thickness, fracture opening size, matrix porosity, matrix permeability and dispersivity, on the amount of filtration are inversitaged. By means of developed model, the amount of mud filtration can be plotted against position in different fractured network configurations for different wellbore conditions, reservoir properties and reservoir geometries at different times. The position in the fracture network at which the curve of concentration reaches zero can be considered to represent skin radius caused by drilling operation. This radius can be used for determining the acid volume which is needed for acidizing operation and accurate well-log interpretation.
Role of Innovation and Policy Development for a Sustainable Environment
Authors: Oyekunle A. A 
Published: August 2012

Abstract
The global demand for energy has been on the rise. Most of this demand has been satisfied through hydrocarbons. The exploration, exploitation and growing consumption of hydrocarbon have had great impact on the environment. At the rate energy demand is rising and the disappearance of cheap hydrocarbon, other sources of energy would have to come into the energy mix to meet this growing demand.
Despite ready availability of energy being desirable and a key to economic progress, energy development has to be done in a way that ensures our environment can continue to exist and support life. As energy development is putting stress on the environment and the need to sustain the environment is putting constraints on conventional energy development, policy development and technological innovation especially towards the development of renewable energy have come to play a big role.
This paper uses quantitative and qualitative approaches to show the roles of technological innovation and policy development in achieving a balance between the sustainability of the environment and meeting energy demands.
Effects of Partial Completion on Productivity Index
Authors: Dankwa O. K , Igbokoyi A. O 
Published: August 2012

Abstract
A new method for analyzing productivity index (PI) on vertical wells is presented. Well performance is often measured in terms of the well's productivity which is dependent on a number of factors such as the reservoir's configuration, the type of completion, petrophysical and fluid properties, formation damage, etc. The effect of partial completion is the main focus of this study since almost all vertical wells are partially completed due to the reasons of water coning or gas cap issue, etc.
Productivity of a well is usually evaluated on the long time performance behavior, thus the pseudo-steady state (late time) approach has been employed for the calculation of the productivity index. Closed system (no-flow boundary) and constant pressure boundary (mixed boundaries) cases are investigated.
Several key factors have been tested on productivity index such as pseudo skin, shape factors, penetration ratio, reservoir drainage area and etc. The effects of these factors have been analyzed on productivity index.
Shape factors of various well positions in bounded reservoirs were computed and compared with the results obtained by Dietz.
Natural Gas as an Alternative Fossil Fuel; The Prospect and The Market In 2020
Authors: Osokogwu U , Ajienka J. A 
Published: August 2012

ABSTRACT
Natural gas within the mix of energy sources is likely to take the lead in the world's energy needs. The decisive trend in its utilization relative to other fossil fuels is as a result of; the growing energy demand from an expanding world economy, environmental pressure for the use of a fossil fuel free from environmental degradations, market development and improved technologies for its production, processing, transportation, storage and more importantly its abundance in nature. Presently, the world has a proven reserve of about 156 trillion cubic meters (5500 Trillion cubic feet) of natural gas. Out of this, approximately 31% is discovered in Russia, 36% in the Middle East and 8% in the Asia-Pacific region with overall consumption of about 2.5trillion cubic meters per year. The overall demand will continue to increase especially in Asia-Pacific region where most countries are pressing ahead with energy– intensive industrialization projects. Natural gas prospect is high with the market improving appreciatively since the advent of LNG and CNG technologies where over 4,660 refuelling stations with approximately 2.7million vehicles are running on CNG globally. More so, we envisage more growth in natural gas market in 2020 with the recent projects on GTL from countries like Qatar which is currently constructing her GTL plants up to 15 trains.