bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of Effective Concentration of Chemical Treating Agents for Cement Contamination in Drilling Fluids
Authors: Oriji Aleruchi Boniface , Ekpo Bassey. O. , Ubani C. E 
Published: July 2014

Abstract
The drilling fluid contamination is a major problem during oil and gas well cementation, especially when such contamination comes from cement. The treatment is usually done with sodium bicarbonate (NaHCO3) where pH control is not a problem but with sodium carbonate (Na2CO3) to increase the pH of the drilling fluids with low pH. Determining the effective concentrations of these treating agents have always been a challenge as either the drilling fluid is undertreated or over treated which could be detrimental to the entire fluid system and the drilling operations. Therefore, there is a need to determine the effective concentrations of the chemical agents for the treatment of cement contamination. During cementation, the calcium hydroxide[Ca(OH)2] released by the cement decomposes and disperses calcium ions in the drilling fluids which could lead to flocculation of the fluid system and consequently increases the rheological and the filtration properties. When this occurs, the contaminated fluid system may be treated with some chemical agents to precipitate the calcium ions formed depending on the severity. The challenge remained on the determination of the effective concentrations of the chemical agents that will optimally treat the fluid system without causing harm.
This paper investigates the effects of cement contamination on the rheological and filtration properties of a typical KCL/Polymer Water Based Drilling Fluids and also determines the effective concentrations of the treating agents (Sodium Bicarbonate and Sodium Carbonate) in the treatment of the cement contamination. A fresh KCl/Polymer fluid was formulated to serve as a control standard and was then contaminated with certain amount of class-G cement at varying proportions. The contaminated fluids were treated with different amount of Sodium Bicarbonate and Sodium Carbonate respectively to determine the effective concentrations required for the treatment of the different levels of the contamination. The drilling fluids properties such as plastic viscosity, yield point, gel strength, pH and fluid loss were adversely affected when contaminated with the cement. Experimental data were generated and linear correlations were developed to determine the effective concentrations of the sodium bicarbonate and sodium carbonate required for optimal treatment of specific amount of the cement contamination during cementation. This will act as a proactive step during oil and gas well cementation to optimally treat cement contamination, thereby reducing drilling time and minimizing overall well cost.
PVT Fluid Characterization and Consistency Check for Retrograde Condensate Reservoir Modeling
Authors: Akpabio Julius U. , Udofia Emmanuel E. , Ogbu Michael 
Published: July 2014

Abstract
Retrograde gas condensate systems are complex systems as a result of the unique compositional changes that when the reservoir pressure is decreased. Correct selection of Equation of State (EOS) is necessary for proper fluid characterization so that the PVT behavior in the simulation model is a good representation of the reservoir fluid. High quality and accurate PVT data can reduce uncertainty in reservoir fluid properties and set the stage for reservoir engineering modeling whilst improving the technical work on which investment decisions are made.
In order to obtain reliable PVT data for effective reservoir modeling, the following steps are essential:
Acquisition of sufficient volumes of representative reservoir fluid samples. Proper examination and supervision of all field and laboratory experiments to ensure accuracy, consistency and validity of the resulting PVT analysis results. Results from the PVT experiments are imported into PVT software for validation in order to ascertain a good match between the simulated and experimental data.
This process generates the Equation of State model required for material balance and other simulation studies for gas condensate reservoirs.
The mass balance test is one of the methods that can be used to validate laboratory PVT data. It is a rigorous test for the evaluation of compositional consistency between feed composition, separator vapor and liquid compositions. Other laboratory PVT data validation means include Mass balance plot, Hoffman plot CVD/CCE comparison plots and Campbell diagrams. These plots serve as data quality assessment methods prior to their use for EOS characterization. PVT validation checks helps to confirm the true content of the fluid as either a rich or lean gas condensate and also confirm the Gas oil ratio of the system.
Inaccurate PVT data can give misleading information that could cause a wrong evaluation of hydrocarbon in place. However, when these methods are properly applied it could lead to huge savings for the company as accurate results are obtained from reservoir simulation models which could aid optimization efforts and achieve incremental recovery.
Wellbore Stability Management in Weak Bedding Planes and Angle of Attack in Well Planing
Authors: Fekete Paul , Dosunmu Adewale , Anyanwu Chimaroke , Odagme Samuel B. , Evelyn Ekeinde 
Published: July 2014

Abstract
Borehole instabilities during drilling are more common in shale formations than in most other rock formations. The assessment of in-situ stress and analysis of borehole failure due to instability and weak bedding planes represents one of the most critical factors when evaluating borehole stability that causes borehole failure. Significant amount of research have been done in this area which resulted in various mathematical models about the issue of borehole failure, stability and plane of weakness due to bedding. So far, unified decision about the plane of weakness and failure of borehole on shale is yet to be fully realized by the industry, the most common of these losses are: widening of the well, washouts, stuck pipes, cavings, and deformation of the casing, amongst others. This work highlights the effect of shale bedding plane failure on wellbore stability and the angle of attack for stable drilling conditions in weak bedding planes by developing a robust tool to account for the criterion/conditions for identifying and drilling weak bedding planes, the rock strength for weak bedding planes (Uniaxial Compressive Strength UCS), minimum mud pressure to prevent shear failure & wellbore slip or slip shear failure in weak bedding planes and suitable attack angle to the bedding planes was also developed.
The proposed tool has increased drilling efficiency and has been validated with field data. The advantage of this process is reduction in drilling difficulties and non productive time (NPT) in field operations in the Niger Delta where well construction targeting deeper horizons are proving to be a challenge. The new rock strength for weak bedding planes (UCS) helps to predict the minimum mud pressure to prevent shear failure & wellbore slip or slip shear failure in weak bedding planes having determined the best angle to place the well (angle of attack).
Leveraging the Clean Development Mechanism to Increase the Percentage of Renewable Energy in Nigeria's Energy Mix
Authors: Akpan Morgan Leo 
Published: July 2014

Abstract
It has been asserted that Nigeria's petroleum age will likely expire in a few decades. This makes the need for a renewable energy based post-fossil national energy vision as articulated in the Renewable Energy Masterpan of 2005 very imperative. While the increased utilization of the gas resources provides a bridge to a low carbon energy future, renewable energy looms large in the long-term energy vision for Nigeria. Specifically, the country is endowed with enormous renewable energy resources, with the average solar radiation estimated at about 5.5kWh/m2-day. Based on a 10 percent economic growth rate and the corresponding projected electricity demand profiles of about 16,000, 30,000, and 192,000 MW in the short, medium and long terms in the country, it is envisaged that renewable energy will contribute about 13, 23, and 36 percent in meeting the total electricity demand of the nation in the short, medium and long terms respectively. The Clean Development Mechanism (CDM) of the Kyoto Protocol, a market-based framework which is predicated on the principles of common but differentiated responsibilities provides the catalyst and incentive for meeting Nigeria's renewable energy vision. Renewable energy projects which are categorized under Energy Industries (renewable-/non-renewable sources) is one of the fifteen (15) sectoral scopes of the CDM. Renewable energy projects represent over 70 percent of the projects so far approved and registered by the Executive Board of the CDM. Using relevant case studies as the basis, this paper discusses the CDM as the seemingly neglected opportunity to increase the percentage of renewable energy in Nigeria's energy mix.
The Importance of Geomechanical Analysis for Well Design and Engineering
Authors: Numbere Otokini , Okoli Ugochukwu 
Published: July 2014

Abstract
Wellbore instability presents serious challenges to drilling activities, worldwide. It also has its effect when the wellbore is in production mode. Wellbore instability can be one of the greatest pre-conditions for Non-Productive Time (NPT) during drilling operations, if not anticipated and planned against accordingly.
The principal stresses in the earth's crust are vertical and horizontal in direction. Our wells are not always exactly vertical or horizontal, and it is the stresses parallel to and perpendicular to the well path that we are most interested in. The knowledge of these principal stresses will help plan a stable wellbore.
Some of the factors that affect wellbore stability include, rock strength, mud weight, temperature fluctuations, wellbore geometry, drillstring vibration, stress and strength anisotropy, drilling fluid filtrate invasion, well path orientation and inclination. All these, must be scrutinized and ensured that they in no way affect the safe and efficient delivery of the well. In summary it must be ensured that the total stress redistribution down the subsurface is equal to the summation of the radial stress and hoop stress.
Wellbore instability can result in serious operational problems like borehole collapse, lost circulation, stuck pipe etc, which are undesirable and have dire financial implications. It is therefore extremely important that drilling engineers anticipate this problem during planning and well design and introduce measures to curb it.
This paper discusses the causes of wellbore instability, underscores the importance of geomechanical analysis as a preventive measure, reviews the various wellbore stability models currently applied in the industry, and presents a well design guideline on how to plan against wellbore instability problems.
New Correlation for Oil Formation Volume Factor
Authors: Sulaimon A. A. , Ramli N. , Adeyemi B. J. , Saaid I. M. 
Published: July 2014

Abstract
Laboratory measurements are the most reliable methods for PVT analysis of reservoir fluid properties. Faster and cheaper methods are important for real time decision making and mathematical correlations are used to predict the properties. Most of the existing correlations do not give accurate estimations due to either simplifying assumptions or inappropriate technique. In this work, a new correlation for estimating oil formation volume factor (βo) using a Group Method of Data Handling (GMDH) technique was developed. It is a family of inductive algorithms which executes computer-based mathematical modeling of multi-parametric data sets. In developing the correlation, 93 PVT data sets from Malaysian crude oil analyses were used. The data consist of solution gas-oil ratio (Rs), βo, oil viscosity (µo), oil gravity (γo), gas gravity (γg) and temperature (T). Some of these parameters were set as inputs while the properties to be predicted were set as output. The correlation was developed using the estimated outcome from the technique. Subsequently, 39 data points from different reservoir fluids were used to validate the correlation. Analyses of results show that the GMDH correlation is more accurate than the existing correlations with the Average Absolute Relative Error (AARE) of 0.976%, and with maximum and minimum average relative errors (max. ARE and min. ARE) of 3.989% and 0.001% respectively.
Interpretation of Laboratory PVT Analysis Result a Case Study of a Niger Delta Field
Authors: Nnabuo Nnaemeka Nnamdi , Okafor Ikechukwu Stanley , Ubani Chikwendu Ebenezer 
Published: July 2014

Abstract
Laboratory PVT Analysis involves the study of reservoir fluid samples by simulating the fluid flow of oil and gas from the reservoir to the surface, in a laboratory, under various conditions of pressures, volumes and temperatures. The correct interpretation of laboratory PVT analysis results is essential for effective and efficient reservoir engineering studies. The interpretation can be used to classify the reservoir fluid and to assess the quality of PVT data obtained. High quality PVT data will reduce uncertainty in reservoir fluid properties, provide a sound foundation for reservoir engineering studies/judgement, and improve investment efficiency. Poor quality data will however result in lost time due to rework and additional studies, poor development plans, and inefficient investment. This paper presents the classification and quality assessment of the results obtained from the laboratory analysis of a reservoir fluid from a Niger Delta oil field. The classification was done on the basis of the field and laboratory analysis of the PVT results obtained. Quality assessment of the non-compositional and compositional data, were carried out through graphical techniques, material balance tests and Hoffman plots. From the study, it was discovered through the analysis of the obtained PVT results that the reservoir fluid is light black oil.
Determination of Average Reservoir Pressure from Constant-Rate Drawdown Tests
Authors: Mohammed S. , Enty G. S. , Amarfio E. M. 
Published: July 2014

Abstract
This paper presents a method that can be used to analyze constant-rate drawdown tests to determine average reservoir pressure as a function of flowing time. The proposed method couples the pseudosteady state equation with its integral function to yield a unique plotting function that results in a zero slope (i.e., a constant value on the ordinate), which, based on the definition of stabilized flow equation, is equivalent to the difference between the average reservoir pressure and the bottom-hole flowing pressure. The average reservoir pressure history is, thus, obtained since the bottom-hole flowing pressure profile is known.
As opposed to derivatives, the proposed approach yields smooth data; and is very diagnostic on the cartesian plot. Extension to gas wells is also considered.
The significant contribution of this paper is that average reservoir pressure profile can directly be estimated using constant-rate drawdown test. Also, our proposed approach is based on a sound theoretical background. We demonstrate the validity of the proposed method with simulated and field data that are already published in the literature.
Environmental and Health Impacts of Nanoparticles Application in Our Oil Industry
Authors: Amarfio Eric Mensah , Mohammed Shaibu 
Published: July 2014

Abstract
This study seeks to bring to the forefront among many other publications, the pernicious and inconspicuous hazards that the unguarded application of nanoparticles or nanotechnology may pose to the environment, as well as, the health of both humans and animals. The environmental and health implications of this new transcending technology differs not in many field where this technology is applied, but this work narrows down most of these identified risks in our oil and gas fields as an area of major concentration for this work. As part of the major work of resolving the emulsion problems in the oil and gas field using engineered nanoparticles, this paper analyses the risk and the reliable safety measures that must be followed from production to the application of the nanoparticles in the oil field as well as the disposal of the spent nanoparticles. This work is not only to increase the awareness of the health and environmental risks associated with the production and application of nanoparticles, but more also we showed in this work, the great benefits and the future impact of this technology as we produce and apply the nanoparticle under the proposed safe measures that we have described in this paper.
Application of the Yield Energy Approach to Prediction of Sand Debris Production in Reservoir Sandstones
Authors: Lamorde Mustapha , Somerville Jim M. , Hamilton Sally A. 
Published: July 2014

Abstract
A novel methodology of predicting sand debris production based on the yield zone and fracture energy dissipation of experimentally produced shear fractures, created under various triaxial stress states, is presented. This technique involves determination of the lateral extent of the failed rock around a wellbore, quantifying the energy available for fracturing and applying experimentally determined comminution constants to estimate the volume and mass of debris created. In more brittle and competent rocks, grains are deformed elastically with increasing stress, storing strain energy in the process. During failure, the stored strain energy is released as heat energy, seismic energy and also in the context of sand production as comminution of grains into debris.
The proportion of energy which accounts for the generated debris is estimated from the ratio of the energy dissipated in the creation of debris (EA) to the fracture surface energy (GIIC) required for the extension of the failure surface. The fracture surface energy (GIIC) is determined from the shear stress on the failure surface and the slip along it (slip weakening curve) generated during triaxial tests. The debris will be accumulated between the failure surfaces and may be available for sand production. This technique is used to determine the propensity of sand production of several reservoir sandstones.
Probabilistic Material Balance: Application in Green Field Development Planning
Authors: Shittu Hammed , Kemelayefa Ejeru , Emeka Ejika 
Published: July 2014

Abstract
The authors have used this paper to demonstrate how material balance was applied in field development planning for a green gas field. In this work, we have used one of the reservoirs as case study.
Deterministic tank model was initially built for the reservoir using MBAL™. Petrophysical properties, aquifer parameters and relative permeability data were all added into the model. Well flow models were generated using PROSPER™ and then imported into MBAL™. Facility constraints were imposed, and deterministic prediction run was performed.
Key impacting parameters on the recovery factor were assessed, and corresponding ranges were estimated for each. A probabilistic prediction workflow was developed and applied to the deterministic model. This uses experimental design to generate multiple runs with the aid of OpenServer™. Response/proxy function for gas recovery was then generated and tested for consistency with "observed" data.
Multiple Monte Carlo runs were then done using Crystal ball, and the 10th, 50th and 90th percentiles were extracted. The corresponding parameters for these respective percentiles were then tested in MBAL™ to check for reliability. Finally, all reservoirs were rolled-up using GAP™, and the recovery factors were checked for consistency with MBAL™.
The recovery factors (P10, P50 and P90) from the probabilistic material balance work were then compared with results from grid-based simulation work done on the reservoir. The figures were further compared with estimates from local and global analogues, as well as analysis done by a third-party.
Results from the MBAL™ work compared reasonably with recovery factors from the other methods.
Probabilistic material balance approach helps to remove bias/anchoring while estimating a range of outcomes for recovery factor. It also gives reasonable estimates, as demonstrated by the closeness of results with other methods. However, it is not a replacement especially for the grid-based simulation, but should rather be a complement.
The methodology has been successfully applied to other gas fields and reliable results were also obtained. The work was equally adapted to more complex systems as multi-tank models.
Production Profile Analysis: A Case Study of Well-Y in Niger Delta
Authors: Animashaun M. B. , Abrakasa Selegha 
Published: July 2014

Abstract
Nigeria has abundant hydrocarbon reserves. This work is aimed at reviewing the production profile of an existing Well-Y in Niger-Delta and simulating the process using Petroleum Experts IPM 7.0 software (precisely MBAL) with Microsoft office excel 2007. For the case study, the pressure, PVT and production data at Niger-Delta are used. From the production history table, the reservoir pressure is continuously above the bubble point pressure, 2200 psig. The producing Gas-Oil Ratio (GOR) is estimated to be the solution GOR, 500 SCF/STB. Hence, the data is consistent with the PVT, since there is no free gas. Based on the response of the Campbell plot, the presence of an aquifer as a source of energy is very likely. Therefore Hurst-van Everdingen-Modified model is used as the aquifer model. The energy plot shows that the dominant drive mechanism is the water drive. From the decline curve analysis, it is observed that the decline curve type is hyperbolic with the smallest standard deviation of 0.0200079 STB/day and exponent of 1.24149. The results demonstrate that the approach is suitable for decline curve fitting and offers a new insight in decline curve analysis in the presence of unusual observations. This study is useful for the unconventional fields. It is deduced that the thickness of the reservoir is high enough and the point of perforation is far from the Oil-water Contact (OWC) to the extent that the water produced is negligible compare to the oil production. Hence, water encroachment is not considered for the economic limit. The economic limit is estimated to be 191.60bbl/day theoretically but in practical sense, no company in Nigeria would produce at that rate. Based on the prediction plot, it is recommended that the production should continue till at least 01/01/2015 because the reservoir pressure is still sufficiently high.