bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Approach to Water Saturation Modeling and Distribution in Dynamic Models Using Log Derived Saturation Height Function (SHF) (A Case Study of Niger Delta Province)
Authors: Omeke James E. , Ugwoke Marcel , Aihumekeokhai Basil O. 
Published: July 2014

Abstract
Complex variations in pore geometrical attributes, which in turn, defines the existence of distinct zones or hydraulic unit within a mappable geological facie or “rock type (RRT)' which have similar dynamic behavior is “masked” when “rock types (RRT's)” in reservoir simulators are assumed to be different geological facies of similar dynamic behavior. To effectively and accurately distribute water saturation (Swi) in the cells of dynamic model, capillary pressure (Pc) vs.Swi and relative permeability curves must be assigned such that they honor the pore system structure as well as the saturation from well logs. Therefore it might not be enough to assign one SHF for a given geological RRT. These poses a challenge, for example, in Niger Delta sandstone reservoir comprisingmainly alternating deltaic sandstone with shale suggesting two or three consistent RRT's with wide variability in Swi.
The proposed approach tends to develop a correlation that will consistently replicate the behavioral relationship between reservoir quality index ((RQI=0.0314K/∅ϵ)), effective water saturation S* = (Sw − Swirr)/(1 − Swirr) and Height above free water level(HAFWL) of both routine core and log data. This correlation is used to develop drainage log derived Pc and relative permeability curves for each class of RRT. Rock classification employed in this work was based mainly on irreducible water saturation(Swirr) classes. The SATNUM keyword in ECLIPSE was used to assign each SHF and relative permeability curve to the grid cells of the dynamic model based on the rock classification.
The developed SHF yielded an excellent match, both vertically and laterally, with log derived Swi and within 1% difference between static and dynamic hydrocarbon-in- place for some Niger-delta reservoirs studied. Also, a plot of Swi generated from the newly developed SHF at well points on the Y-axis and those from well logs on the X-axis yielded a 45° straight line through the origin with an R-square of 0.9935. The dynamic model stability and running performance was greatly improved using the developed SHF.
A Strategic Cost Saving Initiative for Dual-Zone Completions in Marginal Fields
Authors: Ogbunuju E. , Ekeigwe A. , Pepple B. , Ogaji D. , Yahaya I. 
Published: July 2014

Abstract
Dual zone gravel pack completions, mostly the preferred sand control mechanism of choice in unconsolidated stacked reservoirs, can be quite expensive in marginal field environment, particularly in the Niger Delta region due to high logistics and security costs associated with rig costs. This cost escalation (Rig spread, logistics, security and associated costs) progresses from land to swamp and ultimately offshore locations. Conventional techniques for such completions involve multiple trips in and out of the hole with gravel pack and isolation tools, with pumping stages and a wireline trip to set the sump packer. This process typically takes between 12-14 days and has often resulted in border line economics, when this technique is applied in a marginal field.
In this paper, we present a different sand control technique for carrying out a cost-effective completion for a two zone well in a marginal field, situated in the Niger Delta. This technique involves the use of Multi Mesh Screen (MMS) and can eliminate the use of gravel pack pumping treatments for several applications. It has specific design criteria for enhancing sand control and has found great application as standalone screen in cased hole.
The proposed system involves the combination of a special MMS with engineered electric-line deployed perforating technique. The entire deployment of a two zone completion required only about four days of rig time. Post completion, the deeper interval has been producing at an average oil rate of 220 bopd and associated gas production of 0.35 MMscf/d while the shallow interval has average production of ca. 500 bopd with associated gas production of 0.35 MMscf/d. Both intervals have performed at an order of magnitude higher than the predicted sand-free production rate without any or other conventional sand control methods. Overall, the use of this adaptive completion technique resulted in some 50% cost savings to the operator compared to the conventional gravel packing of both zones. This has greatly enhanced the economics of the well. The details of the installation design, field procedures along with an analysis of the production data and an economic comparison to the alternatives are presented herein.
Using Robust Torque and Drag Modelling Software For Efficient Well Planning and Operations Monitoring. Paradigm Sysdrill for OML 126 Wells – A Case Study
Authors: Ugochukwu Okoli , Verity Simon 
Published: July 2014

Abstract
The quest to appraise un-stacked reservoir sands and other surface location constraints has given rise to complex wellbore profiles due to the requirement of building angles and azimuth changes through these targets. This has increased the length and inclination of the wells drilled in the past decades. There are also larger departures and more tortuous wellbore. These trajectories can give rise to excessive torque and drag during the well delivery.
Excessive drill string torque and drag is one of the major limitations of horizontal and extended reach wells, and when unplanned is a primary limiter. Because of the increased costs and risks in these wells, torque and drag analyses is recognized as an important part of the risk management process.
Torque and drag models have proven to be very useful in the planning, drilling and post analysis of these difficult wells. During the planning stage they are used to optimize the trajectory design to minimize the torque, drag and contact forces between the drill string and the borehole wall. They are used during operations to monitor the hole conditions while drilling, diagnosing hole cleaning problems, watching out for impending differential sticking, and monitoring for high torque in planned highly tortuous trajectories. In post analysis the models help to determine the true causes of the hole problems, which will further be highlighted, documented and used to optimize operations.
Accurate torque and drag analysis gives an opportunity to build reliable well trajectories, as it will take into account the capabilities of the rig and the geological complexity of the formation to be traversed. Ideally the model must be able to predict with minimal error the forces and along the wellbore. Generally the discrepancy between torque and drag prediction and actual measurements in conventional wells is within 20% depending on the variables used. This percentage error might increase or decrease depending on the variables used for these models.
In this paper, a general overview of the torque and drag model is presented. It is then discussed how the Paradigm Sysdrill software has been able to accurately predict the torque and drag values of a planned wellbore. The error margin between the predicted and actual values was very minimal. This software has been able to effectively aid in the planning, monitoring and helped to give a reasonable and concise post mortem of the subject well that will be used as the case study in this paper.
Spreadsheet Modeling and Simulation Analysis of Production Sharing Contract Terms and Instruments in Nigeria
Authors: Echendu Joseph C. , Onwuka Emmanuel I. , Iledare Omowumi 
Published: July 2014

Abstract
This paper evaluates the economics of petroleum exploration and production (E&P) projects within the context of the expected economic value of a portfolio of blocks/fields owned and developed under the existing petroleum production sharing contracts (PSC), the jettisioned Inter Agency Team (IAT) memorandum on PIB 2008, and the Petroleum Industry Bill (PIB) 2012. The study incorporates important key variables in the determination of the expected or realized economic values from E&P projects including but not limited to location, technical cost & price, and field size. The model framework adopted for this paper is the Discounted Cash Flow (DCF) Model. The model framework is estimated by coding each segment of the DCF model equations in Microsoft Excel Spreadsheet to calculate deterministic economic and sytem performance measures, Government Take (GT), Discounted Government Take (DGT), and Front-end Loading Index (FLI). Two popular economic measures, the net present value (NPV) and internal rate of return (IRR), are derived and adopted to evaluate investment performance; and to account for uncertainties inherent in the data assumptions. A spreadsheet simulation tool is applied to quantify the impact of selected variables on relevant performance indicators using Monte Carlo simulation approach. Sensitivity analysis of decision variables and stochastic variables in the model is applied. The paper reports the P50 value of selected economic and system performance indicators. Simulation results show that for a viable deepwater project the unit technical cost (UTC) has to be within global average range of $27 and $35 per bbl; and contractor domiciling much of its cost at home. This enables the contractor to have a better IRR and helps to impact positively on local content. The result from this study shows that the PIB is less regressive than the earlier PSCs keeping in perspective our study assumptions.
The Effects of Natural Gas Flaring on Climate Change in Nigeria
Authors: Bisong Anthony Oso 
Published: July 2014

Abstract
Nigeria is a major producer and exporter of oil and gas in the world. Most oil and gas exploration activities takes place in the Niger Delta region of the country where there is high rate of gas flaring from oil and gas production. Although the federal Government of Nigeria had directed all oil and gas producing companies to reduce gas flare to a minimum by 2008 and stop total gas flaring by 2010 due to its effects on the environment and climate. Oil and gas companies are yet to implement these directives, making the country suffer intensive climate change, environmental degradation, revenue losses, chronic energy shortage, e.t.c. Despite the directive passed by the Nigerian Government declaring gas flaring technically, economically, environmentally and totally unacceptable, the oil and gas companies still flares billions of cubic meters of gas yearly. A huge amount of suffering, repression, depression, degradation, pollution and climate change have accompanied this long practice of gas flaring. Natural gas flaring emanating from hydrocarbon exploration has been internationally and locally acknowledged as a significant source of greenhouse gas emission and a major contributor to climate change. During combustion process, gaseous hydrocarbons react with atmospheric oxygen to form carbon monoxide (CO) – Incomplete combustion and carbon dioxide (CO2) – Complete combustion. Gas flaring also causes acid rain, produces air pollution and causes severe impact on the environment. This paper will extensively highlight the negative effects and impact of gas flaring, how greenhouse gases emission from gas flaring affects climate change, the environment and human lives and also proffer pragmatic and strategic measures to combat this unsafe, unhealthy and unfriendly practice in Nigeria.
Innovative Compact Sand Removal Technology: Developments, Qualifications and Successful applications
Authors: Opawale Adekunle , Abdalla Tarig 
Published: July 2014

Abstract
Sand particles are usually produced with oil, gas and water from the reservoir, constituting several operational challenges. Presence of sand in the production stream can cause erosion of upstream facilities and – even more commonly – clogging of flowlines and accumulation in production vessels; reducing residence time and thereby performance of separator internals. Operators have experienced expensive plant shut downs due to excessive sand production and hence demand for highly efficient, robust and compact solution for upstream sand removal from production streams.
This paper presents a recent advancement in the design of compact sand removal equipments, for applications in subsea separation systems, offshore topsides and onshore process plants. The FMC Technologies' inline desander technology is based on an innovative cyclonic separation principle, utilizing a smart stationary swirl element to develop an enhanced separation force.
The desander design is governed by mechanistic models which describe the dynamics of sand particles dispersed in a radial flow field. Produced sand particles are separated from process stream by virtue of their inertia, and radial acceleration developed within the motion field. They are extracted as concentrated slurry through the reject outlet of the desander. The unique geometry of the desander and its internal design enables development of a low pressure core inside it, which initiates a reversed flow of the clean separated fluid into an underflow outlet. As part of the development process of the inline desander, CFD simulation studies were also carried out to study the flow patterns developed in the desander and model the trajectory of the sand particles inside it.
Extensive technical information about the technology development process of the compact desander is discussed in this paper; with reference to qualification tests and R&D reports. Some of its successful applications in challenging situations and advanced production facilities are also discussed.
Chemical Compromise: A Thermodynamic and Ionic Solution for Hydrate Control
Authors: Olabisi Odutola Toyin , Sunday Ikiensikimama , Appah Dulu 
Published: July 2014

Abstract
In recent times, polymers and surfactants have been used to influence the kinetics of hydrate growth and coagulation. However, these Low Dosage Hydrate Inhibitors are limited in terms of water-cut and sub-cooling. This work considers using a blend of Thermodynamic Hydrate Inhibitor and Ionic Inhibitor for hydrate inhibition. A comparative study was carried out to evaluate the combined effect of Ionic and Thermodynamic Hydrate Inhibitors in preventing hydrate formation by combining their temperature depression using Hammerschdmidt and Østergaard equation. This work finds application in hydrate inhibition by reducing the dosage of inhibitors. This will be useful for deepwater reservoirs and flowlines having large subcooling temperature and (or) high water-cut. The Thermodynamic Hydrate Inhibitors used are Methanol, Monoethylene Glycol and Diethylene Glycol while the Ionic Inhibitors used are Calcium Chloride, Sodium Chloride and Potassium Chloride salts. It was observed that the dosage of Thermodynamic Hydrate Inhibitors reduced by over 14% when it was combined with Ionic Inhibitors. The best blend was the hybrid of Methanol and Sodium Chloride salt which saved about 34% of methanol. This simple approach to hydrate inhibition will enable the Engineer reduce the use of methanol or glycols based on the salinity of the formation water. The operator can also save a lot by using the hybrid instead of methanol or glycol alone.
New Techniques for Estimating Solution-Gas Drive Reservoir Properties Using Production Data
Authors: Mosobalaje Olatunde O. , Tiab Djebbar 
Published: July 2014

Abstract
A number of attempts have been made to establish the theories of rate decline in solution-gas drive reservoirs with multiphase flow, and to formulate techniques for reservoir properties estimation using production data. Until recently, none of the attempts have established a consistent functional link between the empirical and the theoretical domains of decline analysis for such reservoirs. The absence of such link has inhibited the formulation of simple techniques for reservoir properties estimation.
This work presents a new, simple technique for estimating reservoir permeability in solution-gas drive reservoirs, using production data. The technique is based on a recently-established relationship between the empirical and the theoretical domains of decline curve analysis for solution-gas drive reservoirs. The technique has been applied to a number of cases and found to yield excellent estimates of reservoir permeability, even for heterogeneous reservoirs. In addition, this work presents a new technique for estimating a well's drainage area, using production data in solution-gas drive reservoirs. This is based on a 2-phase material balance equation. Analyses have been performed on the sensitivity of the techniques to some key parameters.
A Simple Approach to Determining Original Gas-in-Place Using Production Data
Authors: Mohammed S. 
Published: July 2014

Abstract
A simple approach is presented that utilizes production data to determine original gas-in-place (OGIP). In particular, we propose a "modified" Agarwal-Gardner rate/cumulative decline type curves that yield an anchor point of unity, instead of 1/2π. The advantage of this unit anchor point is that, the normalized pseudopressure drop ratio, which is a plotting function on the abscissa, need not be modified; hence, providing a simpler approach than the traditional methods.
The computation of pseudopressure drop ratio (or pseudocumulative function) requires a prior knowledge of average reservoir pressure history, or indirectly, OGIP. Consequently, various methods have been proposed in the literature to solve OGIP. This paper utilizes an approximate gas flowing material balance equation, which was previously presented by this author, to make an initial estimate or provide a "true window" for OGIP. This approximate plot yields two negative slopes during boundary-dominated flow regime – early-time pseudosteady state and late-time pseudosteady state lines. The early-time pseudosteady state line is shown to yield a reasonable initial estimate of OGIP while the late-time pseudosteady state line yields an optimistic result.
The proposed approach is applicable to general variable pressure and/or variable rate case for single- and multi-well systems during boundary-dominated flow regime. The method is validated with two simulated data; and then, applied to two field data – one from a single-well system and the other from a multi-well system.
Fast Algorithm for Calculating Present Values and Rate of Return on Investment
Authors: Adeniji A. , Idigbe K. I 
Published: July 2014

Abstract
The popular yardsticks for ranking ventures in order of their profitability, among others, are rate of return on investment and present value. This paper describes applications of polynomial algorithms for fast and efficient determination of present-day value of total profit for a fixed interest rate and internal rate of return. Thus, establishing the value of the cash flow backs compared to the expenditures and the time value of money become trivially algebraic formulated using a discount rate compatible with the average rate of return on equity.
Average rate of return on investment based on predicted cash flow backs compared to force value of investment to balance value of cash-flow-back at some common reference time, the time of investment. This leads to another definition; the internal rate of return is the rate of interest that makes the present-day value of the total income equal to the capital investment. Emphasis is placed on the proper utilization of the results in development of realistic mathematical model and proper consideration of profitability in economic evaluation. Application of digital electronic computer simplifies the extremely cumbersome calculation in 3-step algorithm.
Improved Method of Predicting and Monitoring Flow Assurance Problems in the Niger Delta Using PROSYS
Authors: Osokogwu U. , Emuchay D. , Ottah D. G. , Aliu S. , Ajienka J. A. 
Published: July 2014

Abstract
Flow Assurance – a term used to evaluate the effects of fluid hydrocarbon solids (i.e. asphaltene, hydrate and wax) and their potential to disrupt flow of hydrocarbon fluids in the flow lines due to deposition in the flow system. This study presents a quick and easy tool – PROSYS - that helps in the preliminary screening of asphaltene to determine if the operator will experience severe or mild problems arising from deposition of asphaltene and also estimates the dissociation temperature of hydrate in a pipeline during depressurization and the thickness of the melted ice in the pipeline. The models used in the development of PROSYS was validated with several experimental results from literature. PROSYS predicted the severity of asphaltene deposition in an analysis carried out on a field having asphaltene issues. Furthermore, PROSYS estimated the thickness of ice melted of a hydrate plug using Osokogwu and Ajienka model as well as the dissociation temperature of a hydrate plug which compared very well with Peter (1999) and Bollavaram (2003) experimental results with less than 5% error.
Developing A New Analytical Tool for the Quantification of Oil Slick on Waters
Authors: Ogwo O. U. 
Published: July 2014

Abstract
Offshore spillage is an attendant problem to offshore oil operations. As offshore oil operations continue to expand, the search for a more precise and cost-effective method for offshore oil spillage quantification becomes more imperative. Effective monitoring and control of polluted waters requires the knowledge of the extent of the area polluted and the quantity of the pollutants (which includes produced and/or transported crude oil, refinery/petrochemical plant disposals, industrial machinery waste oil, and automobile crank case oil disposal). A number of methods have been proposed for use in the determination of the quantity of oil spilled on waters. Unfortunately these methods would not be cost-effective when the volume of oil spilled is not on the high side. There is therefore the need for a tool that would be suitable for use in the petroleum industry under all conditions of hydrocarbon quantity, quality and economics. A new analytical tool has been developed for the quantification of oil slick on waters. The new tool (a relationship between the volume of crude oil floating on the water surface and its surface area, termed the Spread Equation) is the result of extensive research on the minimum thickness of oil on the water surface. From the research, oil-on-water colour spectrum has been developed that has proved reliable in the determination of the quantity of oil slick on waters, given the area covered by the slick. This work presents the analytical tool – the functional form, the experimental data and result of the investigations.