bluuebunny/crossref_metadata_2025_split huggingface dataset:
HPHT Gas Viscosity Measurements Quantify Error in Existing Models
Authors: Davani Ehsan 
Published: October 2011

Abstract
Measured gas viscosity data at high pressures and high temperatures indicates that the most common gas viscosity correlations return up to 9% relative error in cumulative gas recovery factor at extreme conditions, which translates to significant economic error in current giant natural gas reservoirs.
This error may increase in high-pressure/high-temperature (HPHT) gas reservoirs where no measured data is available above 10,000 psi. Modeling the performance of these unconventional reservoirs requires the understanding of gas behavior at elevated pressure and temperature. Gas viscosity is an important fluid property that dictates the fluid flow through the porous media and production pipeline. Accurate measurements of gas viscosity at HPHT conditions are both extremely difficult and expensive, and the accuracy of the resulting correlations may be doubtful for predicting gas viscosity at HPHT conditions.
An oscillating piston viscometer was used to measure the viscosity of mixture of nitrogen and methane and mixture of CO2 and methane at HPHT conditions. The subsequent measured data, recorded over a wide range of pressure and temperature, was then used to evaluate the reliability of the most commonly used correlations in the petroleum industry.
Estimation of Fluid Transmissibility and Oil Production Allocation in Faulted Multi Layered Reservoirs using Material Balance Analysis
Authors: Ogbodu Ejiro Desmond 
Published: October 2011

Abstract
In the oil rich Niger Delta region of Nigeria, there be existent huge faulted multilayered reservoirs having fluid transmissibilities and pressure communication across the different layers of the stacked reservoir sands. This phenomenon has over time given rise to the problem of incorrect reservoir allocations especially after production has commenced from two or more of these reservoir sands. This thus consequently creates considerable challenges in quoting accurate reserves per reservoir in such fields. This occurrence also has led to great perplexity in understanding/estimating the individual reservoir properties such as the pressures trends of these sands which are, in this case, complex. This complexity is as a result of the separate reservoir sands being in Fluid/pressure communication with each other due to sand juxtaposition. As such similar property behaviour may not be as expected across all the areas within even the same reservoir depending on several geological and petrophysical factors.
The major aim of this work would be to try quantifying the inter-reservoir fluid transmissibility i.e. the Interlayer cross flows neglecting the wellbore conditions and all other production constraints outside the reservoir, and only taking into consideration all the possible geological and petrophysical factors that could influence flow in the reservoir, using models which were built using the MBAL simulation program. Actual production and pressure data of a faulted Multilayered field producing from the Niger Delta region of Nigeria (taking two major reservoir sands D5.0 &D6.0) are used in the modelling, for which a thorough quality check was done on the data. Pressure trend analysis, Production performance analysis, PVT characterization, and Fault seal analysis was done to determine a lot of the conclusions presented. Attempted also was the determination of the reservoir allocation using the horizontal permeability and the transmissibility values.
Laboratory Studies: Analysis of Resin Composition to Handle Sand Problems on Unconsolidated Gas Formation
Authors: Purnama G. W. 
Published: October 2011

Abstract
At the beginning to handle sand production is using mechanical methods (gravel pack, slotted liner, sand screen, and others). This method is successful to hold the sand on consolidated formation in the reservoir, but not success for formation with a poorly consolidated and unconsolidated formation.
The purpose of this research is to produce hydrocarbons (gas) without producing sand. The method is making a strength bonds between sand particles (sand consolidation) using chemicals (resin) without reduce to much the value of porosity and permeability.
This research is using artificial core which made based on unconsolidated formation of reservoir characteristics, such as: (i) matrix grain size in the range of mesh size between 80-120, (ii) Cemented between the matrix is weak, (iii) 25-30% Porosity, (iv) 50-300 mD permeability. Experiment condition conducted at reservoir temperature and pressure, which is 102 ° C and 3145 psi.
Testing of resin effect to the strength of rock stress is done by triaxial stress, which developed and manufactured with the application of high pressure, high temperature, the axial pressure, and radial pressure that using gas and liquid fluid.
The results of this study show that mixing a resin with core can increase rock strength up to 700-800 psi, which can handle sand problems.
In-Situ Combustion Kinetics of a Central European Crude for Thermal EOR
Authors: Glatz G. 
Published: October 2011

Abstract
In-Situ combustion is one method of enhanced thermal recovery to access heavy-oil resources. By oxidizing a small fraction of the hydrocarbons in place, thermal energy is released thereby aiding the displacement of the remaining oil. A combination of gas, steam, water drive, and viscosity reduction helps to push the oil towards the producer. Not every oil, however, is a proper candidate for in-situ combustion. Whether or not a crude oil would be a viable candidate is not only governed by the composition of the oil but also by the reservoir matrix. The experimental testing required to determine if in-situ combustion would work in the field is expensive. Therefore, the sooner an oil can be ruled out as as a candidate, the better.
Isoconversional methods have been successfully applied in the past in order to determine effective activation energies of crude-oil oxidation. In addition, the technique can be used as an inexpensive screening tool to determine a priori if a combustion tube experiment, and, therefore, field implementation, would be successful or not. This paper discusses practicability of isoconversional analysis for a heavy oil for which in-situ combustion is economically successful.
Numerical Reservoir Simulation Coupled with Geomechanics State of the Art and Application in Reservoir Characterization
Authors: Rodríguez Hernández Inti Illimani 
Published: October 2011

Abstract
Currently, conventional reservoir simulators are not able to reproduce the changes inferred upon fundamental properties such as porosity and permeability by the action of the stress field and the deformation associated to geomechanics as the reservoir is being depleted. The prediction of the impact of these variables in surface facilities and the integrity of wells is also important. Hence, in many cases it is required to couple the effect of geomechanics in numerical reservoir simulation in order to have a more realistic response on the behavior of the reservoir and more accurate predictions. The coupling between the numerical simulation and reservoir geomechanics can be reached by considering the interaction between the main equations governing fluid flow in porous media, the fundamental equations of rock mechanics and the constitutive laws that describe the deformation of rocks in response to an applied stress in a given time. In this paper the evolution and development of the coupled simulation technology are analyzed through the study of 132 available publications, which include dissertations, reports and articles. This paper also describes the main fields of application of this technology, comprising compaction, subsidence, naturally fractured reservoirs, steam assisted gravity drainage, water injection, steam injection, sanding, hydraulic fracturing, fault recovery and pressure testing, among others. Furthermore, a conceptual numerical simulation example with reservoir features of the Orinoco Oil Belt is presented.
Based on the documented experiences, a generic methodology for the implementation of coupled simulations is presented. A description of the historical evolution of the major mathematical developments in this area is shown and, a ranking of the different coupling techniques in studies of behavior and development of reservoirs focused on solving real problems is performed. The ultimate purpose of this study is to establish a technical base criterion that may be used as a guide to apply this technology in reservoir studies.
Determining the Flow and Erosion Models So Frac Sand Can Be Evenly Distributed into the Formation
Authors: Adams Jeffrey 
Published: October 2011

Abstract
A program was created that successfully models the way frac sand flows through each perf cluster and erodes it away. The models represented in the program successfully match camera photos that were taken of the initial and final perf hole sizes. Our frac jobs were having difficulty evenly distributing the frac sand into the formation. We needed to better understand how the sand was eroding and flowing through the perfs. When these flow and erosion models were determined, the program successfully represented a frac job. Therefore the program can be used to adjust the hole distribution to evenly distribute the sand in to the formation.
Molecular Thermodynamic Modeling of Micellar and Microemulsion Solutions
Authors: Moreira Livia A. 
Published: October 2011

Abstract
Surfactant-based processes are explored in the pledge of using low volumes of amphiphile molecules. In oil and gas production, they can be used to solve problems efficiently in a broad variety of processes, such as water and oil separation, flow assurance, improved oil recovery, oil spills remediation, and drilling and fracturing fluids. In our work, we develop thermodynamic models of micellar and microemulsion systems that can predict phase behavior of these complex systems. We investigate the effect of alcohols and salts in micellar systems and present a thermodynamic model in which the alcohol molecules play two roles: cosurfactant and cosolvent. Our model improves the understanding of the effect of short- and medium-chain alcohols in self-assembly of molecules. For the effect of salts, we present a molecular thermodynamic theory for ionic-surfactant solutions that accounts for the headgroup-counterion specificity and address ion-specific effects. We assume that the charged headgroup and the counterion at the Stern layer form solvent-shared ion pair with different degrees of cosphere overlap. As environmental considerations increasingly shape the development of many industrial products and processes, studies on the physical chemistry of surface-active systems are essential in designing surfactants with minimal environmental impact.
Electrothermal Method of Processing the Near-well Area
Authors: Maria Khusid 
Published: October 2011

Abstract
The report focuses on the results of simulation of the near-well area heating by an electric current and the substantiation of using an electric field as a thermal method of oil production intensification. We give the description of such programs as NKAR (the program of the numerical solution of the direct problem of electrical logging), THERM3C (the program of solving the direct three-dimensional problem of thermometry) which were used in the simulation.
Express-estimation of Effectiveness of System Development Options for Oil Fields with Gas Cap at Conceptual Design Stage
Authors: Prokopyev Mikhail 
Published: October 2011

Abstract
In this paper it is suggested to consider known but narrowly distributed approach to simulation flowsheet development of field. The main principles of computational models hierarchy is the theoretical base of approach considered. Mathematical tools, which are the base of high-level model developed, are considered in the paper along with correlation analysis in various media of simulation. Besides in this paper it is developed the optimization algorithm, which allows to limit significantly the number of economically justified field development options at the stage of conceptual design.
Water Coning Management in Gas Reservoir via Downhole Water Dump Flood
Authors: Buranatavonsom Napat 
Published: October 2011

Abstract
Water coning, the upward encroachment of water into a perforation zone of a well, is one of the main problems in many petroleum fields especially in strong bottom water-drive reservoirs. It results in high water cut and low oil rate that lead to early shut-in of a well without adequate recovery of hydrocarbons in place.
Over many years, many authors or reservoir engineers have attempted to find the efficient ways to handle with water coning. For a long time ago, conventional method to control or delay water influx is to produce hydrocarbon less than critical flow rate; but, the critical flow rate is proven not commercially economical. In recent years ago, Downhole Water Sink (DWS) is the new method to control water coning effectively which is proven by both theoretical calculation and field examples; however, this method needs to produce a large amount of water at another well and then requires to be handled in water treatment system on the surface.
From the reason mentioned above, the new method called "Downhole Water Dump Flood (DWDF)" is proposed. This method can reduce water coning by the same principle of DWS method but it is not required to produce water into surface and also to drill a well for water production. Therefore, it can minimize cost of drilling and water treatment system.
Analytical and Numerical Solution for Large Plastic Deformation of Solid Expandable Tubular
Authors: Al-Abri Omar S. 
Published: October 2011

Abstract
This paper presents analytical and numerical solutions developed to investigate the structural response of thick circular cylindrical shells subjected to large plastic deformation due to expanding them using rigid mandrel of conical shape. The work is especially focused on the petroleum drilling application known as Solid Expandable Tubular (SET) technology. Equilibrium equations, incompressibility conditions and Levy-Mises flow rule were used to develop analytical model which relates the expansion ratio and the mandrel-tubular system configuration to the force required for expansion and the tubular length and thickness variations. In addition, Tresca's yield criterion was used to represent the plastic behavior of the tubular material. The developed analytical model is capable of predicting the force required for expansion and the length and thickness variations induced in the tubular due to the expansion process. A numerical solution of the tubular expansion process was also developed using the commercial finite element software ABAQUS. Experiments have been conducted for tubular expansion on a full-scale test-rig in the Engineering Research Laboratory at Sultan Qaboos University to validate the analytical and numerical solutions. A standard tubular of 7⅝ inch (193.68 mm) outer diameter and ⅜ inch (9.525 mm) wall thickness was expanded using expansion ratios of 16%, 20%, and 24%, the mandrel semi-cone angle being 10°. The parameters like thickness variation, length shortening and expansion force were measured experimentally and calculated through analytical and numerical models. Analytical and numerical results were in good agreement with the experimental values. Expansion ratios of 16%, 20%, and 24% resulted in tubular thickness reduction of approximately 6.67%, 10.3%, and 13.16%, respectively. Also, the required expansion force for the same expansion ratios was around 940 kN, 1092 kN, and 1213 kN.
Improved Estimation of Bubble Point Pressure of Crude Oils: Modelling by Regression Analysis
Authors: Bandyopadhyay Parag 
Published: October 2011

Abstract
The Bubble Point Pressure of crude oil is a critically important property for the description of reservoir fluid behaviour. Accurate estimation of such properties is required for important reservoir and production engineering calculations such as reserve estimation, production forecasting and design of Enhanced Oil Recovery (EOR) projects. A comprehensive literature review was carried out to understand and analyze the limitations of currently available methods for estimation of bubble point pressure. A large database consisting of the compositional analysis, temperature and measured bubble point pressure of more than 140 crude oil samples of varying geographical origins was compiled. The parametric form of the model was constructed based on the analysis of trends from collected experimental data and theoretical inputs. The model was then calibrated, using non-linear regression techniques, to a major portion of the data set. The remaining data was used to validate the calibrated model and verify its conformity to physical processes. The performance of the model was then compared and found to be more accurate than existing methods such as Equations of State (EOS). The various applications of this new model to the simulation of Liquid-Vapour phase boundary were explored. Laboratory experiments such as the swelling test were simulated using this model and the predictive performance was found to be better than that of an EOS. These laboratory tests, especially swelling tests, are integral for the design of miscible flooding EOR projects. Other applications and modifications of this model were also such explored in the latter portion of this work. It is concluded that the performance of this new model is better than other current methods when operating in a purely predictive mode and that the model could be manipulated as a powerful tool for applications which require identification and simulation of the Liquid-Vapour phase boundary.
Study of the Horizontal Wellbore and Reservoir Coupling
Authors: Oliveira Rodolfo 
Published: October 2011

Abstract
Over the last two decades, directional and horizontal wells have become the most usual design in Brazilian offshore scenarios. The increasing use of these types of wells relies upon new drilling and completion techniques being developed at the same time so as to achieve the full benefits of this practice. The main usages of horizontal wells are: to increase the drainage area; to improve the ability to exploit thin reservoirs; for exploration of natural fractured formations; for water/gas conning reduction; and to increase the efficiency of Enhanced Oil Recovery (EOR) methods. The aim of this work is to present case studies involving horizontal wells simulations using computational fluid dynamics techniques. In order to predict the total flow rate and flow distribution along the extended reach horizontal wells, the three-dimensional CFD model was built comprising of the well geometry and its drainage radius over the reservoir. This methodology makes it possible for well engineers to determine, for specific scenario, the optimum configuration for a horizontal well design. The predicted flow fields obtained from the CFD simulations were in agreement not only with results found in literature (Troll Field - Ozkan et al. 1999), that were used to validate the model, but also with production data from some Petrobras oilfields (Sansoni et al. 2007). Using this CFD tool, it was possible to identify situations where the infinite conductivity approach is valid, and the cases where this assumption results in great errors in the production forecast.
The Effect of Oil on Foam Flow in Pipes for Underbalanced Drilling Processes
Authors: Panchadhara Sneha 
Published: October 2011

Abstract
Recent experimental studies on foams in pipes show that there exist two foam flow regimes: a "high-quality regime" in which unstable pressure response prevails due to slug flow pattern; and a "low quality regime" in which the pressure response is stable and dominated by segregated or plug flow. These two flow regimes are shown to be separated by fg* which is a function of many experimental conditions. Lousiana
In line with these previous accomplishments, this study for the first time focuses on the effect of N-decane, as the oil phase in this study, on two foam-flow regimes by conducting a series of flow experiments in a wide range of conditions. More specifically, the experiments were conducted within the foam-quality range of 80 – 95%, by using two different surfactants at varying concentrations and two different oil rates. The pipe dimensions were 0.36 inch inner and 0.5 inch outer diameters and 12 ft in length, with 8 pressure taps installed along its side.
The results showed that the presence of oil impacted foam stability significantly reducing the steady-state pressure drops and fg* values. This implies that foam modeling and simulation during foam drilling processes should take the presence of oil into account for reliable hydraulics calculations.
Upscaling for Field-scale In-situ Combustion Simulation
Authors: Zhu Zhouyuan 
Published: October 2011

Abstract
In traditional thermal reactive reservoir simulation, mass and energy balance equations are solved numerically on discretized reservoir grid blocks. The reaction terms are calculated through Arrhenius kinetics using cell-averaged properties, such as averaged temperature and reactant concentrations. The chemical reaction front is physically very narrow, typically a few inches thick. To capture accurately this front, centimeter-sized grids are required that are orders of magnitude smaller than the affordable grid block sizes for full field reservoir models. We propose a new method based on a non-Arrhenius kinetic upscaling approach. We do not resolve the combustion front on the grid, but instead use a subgrid-scale model that captures the overall effects of the combustion reactions on flow and transport, i.e. the amount of heat released, the amount of oil burned and the reaction products generated. The subgrid-scale model is calibrated using fine-scale highly accurate numerical simulation and laboratory experiments. This approach significantly improves the computational speed of in-situ combustion simulation as compared to traditional methods. We are currently developing a field-scale simulator using the above ideas. Test cases illustrate the solution consistency when scaling up the grid sizes in multidimensional heterogeneous problems. The methodology is also applicable to other subsurface reactive flow modeling problems with fast chemical reactions and sharp fronts.
Reliability and Validity of the Multidimensional Scale of Perceived Social Support (MSPSS): Thai Version
Authors: Wongpakaran Tinakon , Wongpakaran Nahathai , Ruktrakul Ruk 
Published: November 2011

This study examines the Thai version of the Multidimensional Scale of Perceived Social Support (MSPSS) for its psychometric properties.

Methods:
In total 462 participants were recruited - 310 medical students from Chiang Mai University and 152 psychiatric patients, and they completed the Thai version of the MSPSS, the State Trait Anxiety Inventory (STAI), the Rosenberg Self-Esteem Scale (RSES) and the Thai Depression Inventory (TDI). Test-retest reliability was conducted over a four week period.

Results:
Factor analysis produced three-factor solutions for both patient (PG) and student groups (SG), and overall the model demonstrated adequate fit indices. The mean total score and the sub-scale score for the SG were statistically higher than those in the PG, except for ‘Significant Others’. The internal consistency of the scale was good, with a Cronbach’s alpha of 0.91 for the SG and 0.87 for the PG. After a four week retest for reliability exercise, the intra-class correlation coefficient (ICC) was found to be 0.84. The Thai-MSPSS was found to have a negative correlation with the STAI and the TDI, but was positively correlated with the RSES.

Conclusion:
The Thai MSPSS is a reliable and valid instrument to use.