bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interpretation of Production Data from Cyclic Steam Stimulation at Cold Lake
Authors: Vittoratos E. 
Published: December 2007

ABSTRACT
A conceptual model of the flow regimes during Cyclic Steam Stimulation indicates that the traditional reservoir flow conceptualization of bitumen and water slipping past each other according to the relative permeability curves is to a large extent inapplicable. Emulsification of water into the bitumen swells the bitumen to occupy the whole pore space resulting in single phase flow during early cycles; thus the bitumen need not compete with free water for movement to the wellbore by the reservoir pressure gradients. Pure emulsion flow is characterized by rates changing smoothly with time. In a mature CSS well, however, free water accumulates in the flow streams, resulting in erratic production rates; this also occurs during displacement and during CSS production from vertical fractures.
As a first approximation, the wellbore production during single phase emulsion flow can be viewed as the mixture of two streams, one initially heated by convection (emulsified water content about 50%) and the other by conduction (water content about 15%). Conductive heating is dominant in early cycles in high bitumen saturation zones, implying low leak-off near the wellbore.
Scaled Model Studies and Numerical Simulation of Inert Gas Injection With Horizontal Wells
Authors: Meszaros G. , Chakma A. , Jha K. N. , Islam M. R. 
Published: December 2007

ABSTRACT
Gas injection is one of the oldest enhanced oil recovery techniques used for recovering light oils. Recently, there has been renewed interest of gas injection in both light and heavy oil reservoirs. It has been pointed out that in order to apply gas injection, gravity stabilization is required to avoid early gas breakthrough. In absence of natural dip, such gravity stabilization may be achieved through horizontal wells placed on top of the reservoir while producing through another horizontal well placed at the bottom of the reservoir. The possibility of such recovery technique is investigated in this paper.
A series of partially scaled 2-dimensional model studies indicated that close to 70% oil in place may be recovered by using gas injection from the top of a heavy oil reservoir of oil viscosities of 1000 and 4000 mPa.s. Due to scaling requirements, the porous medium was replaced by glass beads of much higher absolute permeabilities. Two additional runs were also conducted with 750 mPa.s and 7500 mPa.s oils using high-pressure geometrically scaled physical models. These results indicated that it is much harder to maintain a stable gas front in a geometrically scaled high pressure 3-dimensional model than in a partially scaled 2-dimensional model. In order to maintain a stable gas front, one has to operate the injection/production wells at a very low rate. While this process is found to be rather slow, oil recovery was still found to be much higher than primary recovery if a stable gas front is maintained. If the frontal stability is lost, gas injection does not increase oil production beyond that of a primary depletion case. Several tests with variable gas composition were conducted. The presence of CO2 as opposed to nitrogen improved recovery to some extent.
Finally, numerical simulation of field cases is presented. The danger of invoking an unstable displacement front is demonstrated through numerical simulation.
Impact of Reservoir Heterogeneity on Initial Distributions of Hydrocarbons
Authors: Kocberber S. , Collins R. E. 
Published: December 2007

Abstract
The objective of this study was to demonstrate the effects of heterogeneity on the initial distributions of oil, water and gas in sandstone reservoirs and to provide a preliminary assessment of the effects of this structure on primary recovery. This is achieved by generating realistic capillary pressure and relative permeability relations parameterized by absolute permeability. These were then employed to compute initial fluid saturation distributions in composite blocks based on capillary-gravity equilibrium. The method is also illustrated in a real geological setting by employing the spatial distribution of permeability measured in an outcrop of Page Eolian sandstone. Severe discontinuities in saturation and effective permeability are demonstrated. These effects are most dramatic in water-wet systems; the higher capillary pressures in the low permeability laminae of a cross-bedded system cause high water retention, with correspondingly low hydrocarbon permeabilities, over the entire range of average saturations. Thus such "tight streaks" literally become permeability barriers to hydrocarbon flow and create very non-uniform reservoir drainage patterns; extensive pockets of trapped hydrocarbons result.
Pressure Desuperposition Technique for Improved Late-Time Transient Diagnosis
Authors: Ehlig-Economides C. A. , Ambrose R. W. , Joseph J. A. 
Published: December 2007

Abstract
Diagnosing the reservoir model from a field data set is one of the main challenges in well test analysis. The loglog pressure and pressure derivative plot is now firmly established as a primary diagnostic tool. This paper provides a new derivative formulation that enhances model diagnosis and addresses techniques for reducing noise in the derivative response.
Transients initiated by a sufficiently large increase in the surface rate closely represent the ideal reservoir response. However, when a transient is initiated by a decrease in surface rate, distortions due to superposition effects from previous surface flow rate changes are frequently present in the late-time derivative and can lead to incorrect characterization of reservoir boundaries.
To improve the late-time response, the pressure data are corrected for effects of a variable surface rate history before differentiation. The resultant desuperposition derivative avoids assuming a model for the reservoir behavior by using the late-time character of a representative transient. The desuperposition derivative appears as an equivalent drawdown (injection) response regardless of the nature of the perturbation that was actually used to induce the particular transient. This technique is particularly useful in reservoir and limits tests designed to delineate heterogeneities or boundaries; it also applies to multirate and multilayer tests.
Noise in the derivative can either mask or give a false impression of the true reservoir behavior. Overly smoothing noisy data may obscure the response and lead to erroneous model diagnosis. This study addresses logarithmic filtering and sampling techniques for reducing noise in the data.
New Solutions for Two-Well Systems with Applications to Interference Slug and Constant Rate Tests and Linear Boundary Detection
Authors: Grader A. S. 
Published: December 2007

Abstract
This paper presents new analytical solutions for two-well systems with storage and skin in both wells. The solutions are generated by the application of the addition theorem and the Laplace transformation. Previously presented research in this area is limited to one-dimensional radial flow. In contrast, the new solutions presented in this paper are true two-dimensional, and do not make use of the superposition principle for solving the basic cases. Hence, limitations stemming from the incorrect application of the superposition principle in the presence of finite sources are overcome. The paper describes the mathematical formulation for sixteen different configurations and some calculations showing the pressure transient response of both the active well and the interference well. The results of this study show that under certain conditions, storage in the observation well may have a significant effect on the analysis procedure. The presented solutions show that an impermeable linear boundary has a significant effect on the pressure response of a slug test. In addition, the traditional constant rate test with storage and skin can also be used for linear boundary detection. However, current techniques are limited in that the boundary effects must occur after the storage effects have ended. The new solutions presented here show the combined effects of an impermeable boundary and wellbore storage and skin.
Analysis of Well Tests Affected by a Pressure Trend
Authors: Cinco-Ley H. , Macias-Chapa L. , Samaniego-V F. , Morales-Gil C. 
Published: December 2007

Abstract
A new methodology is presented for the analysis of pressure data measured under the influence of a reservoir pressure trend. This technique allows interpretation of information from wells in developed reservoirs, because production or injection from wells adjacent to the test well generate pressure trends that affect the reservoir behavior. Such effect becomes dominant in reservoirs with high permeability, and in some cases, is of the same order of magnitude than the pressure changes originated in a well test.
The method presented in this work consists in the utilization of type curves that eliminate the effect of the pressure trend. For the cases of interference or pulse tests the type curve is based in a function defined as: pmdp(t)=abs ((pj-p(t))-tdp(t)/dt) and the match is performed in a Log pmdp(t) vs Log t graph. For the pressure build-up case the match function is defined as pmdp(∆t)=t{ pj-pws -tp'ws }/24Q, where Q is the cumulative production for the test. The application of the above procedures is illustrated through field examples of Abkatun and Midale reservoirs.
A Complete Set of Laplace Transforms for Finite-Conductivity Vertical Fractures Under Bilinear and Trilinear Flows
Authors: Azari M. , Wooden W. O. , Coble L. E 
Published: December 2007

Abstract
Analytic solutions for finite-conductive vertical fractured reservoirs are developed based on bilinear1,2 and trilinear3 fracture flow models for constant-pressure and constant-rate cases with and without boundaries. These solutions include effects of linear skin on the fracture, fracture conductivity, fracture to formation height ratio, wellbore and fracture storage, fracture to formation hydraulic diffusivity ratio, and wellbore phase segregation.
A simple method for solving these calculations is used to extend the transient fracture solutions to pseudoradial flow regime for various fracture parameters. Characteristic curves relating the effective wellbore radius for different fracture conductivities, skin and wellbore storage values are presented to facilitate the transition to the pseudoradial solutions.
The provided type curves identify fracture linear, storage linear, bilinear, formation linear, and pseudoradial flow regimes. Example problems are analyzed using type curve methods, and parameters are optimized with a Levenberg-Marquardt4 regression technique.
Acquisition and Analysis of Sonic Waveforms From a Borehole Monopole and Dipole Source for the Determination of Compressional and Shear Speeds and Their Relation to Rock Mechanical Properties and Surface Seismic Data
Authors: Harrison A. R. , Randall C. J. , Aron J. B. , Morris C. F. , Wignall A. H. , Dworak R. A. , Rutledge L. L. , Perkins J. L. 
Published: December 2007

Abstract
Classical sonic logging employs the acquisition and analysis of data with a simple monopole source. For this type of source, physics limits shear speed determination to speeds faster than the acoustic velocity of the borehole fluid. A dipole source excites the borehole flexural mode, providing a means to determine shear speed without this limitation. Propagation models and waveforms from computer simulations of hard and soft formations with both monopole and dipole sources are presented. These simulations are then compared to laboratory scale model data. Real-world borehole data acquired with both monopole and dipole sources, along with the instrumentation employed to acquire the data, are described. In particular, a combined monopole and dipole logging instrument with a high fidelity monopole and dipole receiver array is discussed. A processing algorithm for extracting compressional, shear and Stoneley speeds from monopole and dipole full waveform data is presented. Log examples are presented for hard, soft and extremely soft formations from both monopole and dipole sources. Application of log data to evaluation of rock mechanical properties, such as Poisson's ratio, fracture evaluation, and correlation to compressional and shear seismic data, is also discussed.
A New and Innovative Technology for Cement Evaluation
Authors: Bigelow E. L. , Domangue E. J. , Lester R. A. 
Published: December 2007

ABSTRACT
The Segmented Bond Tool is a new, innovative acoustic logging device that utilizes six pads and twelve high-frequency, steered transducers to accurately evaluate cement integrity both longitudinally and radially around the entire casing periphery. Two comprehensive presentations are available, both of which are easily interpreted. Several examples from commercial and test wells emphasize the versatility of this new high-tech tool design.
The Effect of Bimodal Pore Size Distribution on Electrical Properties of Some Middle Eastern Limestones
Authors: Dixon J. R. , Marek B. F. 
Published: December 2007

ABSTRACT
Laboratory investigations into the causes of anomalously low electrical resistivity of drill core Samples from two Middle Eastern carbonate reservoirs revealed bimodal pore size distributions. The rocks contain abundant interparticle porosity, but saturation exponents (Archie relation) are low (median=1.45). Scanning electron microscopy and high-pressure mercury porosimetry indicate that a network of interconnected micropores is the most likely explanation of the low resistivity behavior.
Heterogeneity in a Complex Turbiditic Reservoir: Stochastic Modelling of Facies and Petrophysical Variability
Authors: Alabert F. G. , Massonnat G. J. 
Published: December 2007

ABSTRACT
The paper presents an application of recently developped geostatistical conditional simulation techniques to the modelling of heterogeneity in a complex turbiditic reservoir. Heterogeneity is mainly controlled by the distribution of sandstones embedded in laminated facies. Channels and lobes account for most of the production. Their frequencies and geometries are critical factors that affect reservoir connectivity, hence oil recovery. The combined used of flexible stochastic techniques allows generating realistic 3D models of this complex architecture. The modelling strategy is multi-steps, with first a geologically constrained generation of facies distributions, and second, simulations of permeability variations within the previously generated facies distributions.
Pressure Transient Analysis of the JX-2 Horizontal Well, Prudhoe Bay, Alaska
Authors: Rosenzweig J. J. , Korpics D. C. , Crawford G. E. 
Published: December 2007

ABSTRACT
Buildup analyses of the JX-2 horizontal well, Prudhoe Bay, Alaska, were carried out to determine the skin factor, vertical, and horizontal permeabilities. The analysis approach, was to attempt to match analytical and numerical simulations to the data on the Log-Log Derivative plot. Analytical simulations failed to match the data while numerical simulations incorporating the gas cap were able to match the data well. More than one numerical match was found possible even for widely different formation parameters. The non-uniqueness of match is believed to be a result of insufficient buildup duration.
Analytical and numerical parametric simulations were carried out to improve the understanding of the range of possible pressure transient responses from JX-2. Conditions under which non-unique interpretations can occur were identified. A comparison of the pressure transient response with and without the gas cap showed that gas cap effects exert a major influence during the Pseudo-Radial flow period. Additionally, gas cap influence cannot be properly modelled by a constant pressure boundary. Thus, multiphase numerical simulations are necessary for an accurate interpretation.
Advances in Slug Flow Characterization for Horizontal and Slightly Inclined Pipelines
Authors: Scott S. L. , Kouba G. E. 
Published: December 2007

ABSTRACT
Current methods for characterizing slug flow behavior are examined in light of experience with their use in multiphase pipeline design. Isograms of slug flow properties, displayed on a flow pattern map, are used to examine slug flow characteristics and identify conditions under which current prediction methods perform well. Using this technique, the equilibrium film simplification is shown to not be justified for a large portion of the slug flow region. Slug length isograms on a flow pattern map are shown to be particularly useful for visualizing slug length behavior. New methods are developed for predicting the existence of slug flow, modeling slug length behavior in inclined flowlines, and for predicting pigged slug length under slug flow conditions. Methodology is developed to determine slug flow characteristics and is applied to an example pipeline connecting the Eldfisk and Ekofisk fields in the Norwegian North Sea.
Safe Perforating Unaffected by Radio and Electric Power
Authors: Huber K. B. , Pease J. M. 
Published: December 2007

ABSTRACT
Radio transmission, radar, electric welding, cathodic protection, and electric generators, motors and their connections can create an unsafe environment for certain operations using explosives. Transporting and arming electrically initiated explosive perforating devices in this environment can be hazardous. A premature detonation can occur if correct procedures are not followed. The procedures required to prevent premature detonation often include the interruption of radio and microwave transmission, welding operations and cathodic protection systems. These shutdowns are costly and cause operational and logistical difficulties and may pose new safety problems. This problem is especially acute when operating offshore or in highly congested urban areas.
The paper briefly reviews perforating equipment and operations and identifies the potential hazards of transporting and arming explosive devices in the previously described environment. The present safety procedures and equipment are discussed, along with a detailed analysis of the problems and the procedures used to allow limited radio silence. A new method of initiating perforating guns is described that is based on the principle of a foil, subjected to a large electric power burst, slapping a secondary explosive and a safe and arm system that totally eliminates the need for radio silence. Electric welding, cathodic protection and other electric equipment can also be operated without interruption.
SECTION 1 - RADIO AND ELECTRIC POWER INSTALLATIONS AFFECTING PERFORATING
The Nonhomogeneous Flow Character of a Delayed Crosslinked Gel
Authors: Cameron J. R. , Joha R. J. , Veatch R. W. 
Published: December 2007

ABSTRACT
Experiments were done using modified Model 50C Fann viscometry and tubular flow tests to study the nonhomogeneous flow character of a delayed cross- linked fracturing fluid. Previous testing showed that a delayed crosslinked fracturing fluid can exhibit two distinct forms of nonhomogeneous flow when tested on the Model 50C Fann viscometer. At low shear stresses, the fluid exhibited apparent slip flow with low viscosities, but when the stress was increased to a critical value, the gel broke up forming a dispersed fluid with a much higher viscosity. However, in the dispersed form, nonhomogeneous flow was still evident. Testing described in this work found that when this fluid is crosslinked at very low shear energies on the Fann viscometer, the resulting gel still exhibits apparent slip flow, but with very high viscosities. In this case, high stresses are required to break up the gel. Flow visualization tests indicate that the stress buildup during gel breakup results from a flocculation process and secondary flows as well as destruction of the low-viscosity slip layer. When tested in a tubular-flow loop, this gel did not exhibit comparable stress buildup behavior. However, retesting of flow-loop generated gels on the Fann viscometer showed that flow-loop data corresponded most closely to the low viscosities observed on the Fann viscome-ter when the gel was in apparent slip-flow. Thus, this gel may slip when tested in tubular flow and perhaps when flowing in fractures.
Remote Gas Measurement for Production Allocation: Douglas Creek Arch Region, Colorado
Authors: McConnell J. D. 
Published: December 2007

ABSTRACT
A Supervisory Control and Data Acquisition system has been installed as a part of natural gas production operations in Northwestern Colorado.
The system was installed in conjunction with a large production acceleration project and assists in monitoring gas production from the individual well, through a gas gathering system and into a company owned processing facility.
Advantages offered by the system include a comprehensive overview of gas production and gathering operations from a central location and improved efficiency by allowing production operators to target their daily activities toward problem areas.
Implementation of a Mainframe-Supported Handheld Data Terminal Collection System
Authors: Lopez M. A. , Merritt R. J. 
Published: December 2007

ABSTRACT
In 1989, Oryx Energy Company implemented a handheld data collection system throughout all its U. S. field locations. Its purpose was to replace various paper reporting processes and provide real time data. This system is uniquely characterized by the maintenance of all data describing a particular lease operator job on a mainframe system. The job file is updated and automatically downloaded to the handheld terminal. Data collected daily by the lease operator is uploaded to a main-frame based collection file. The system is multitasking, incorporates electronic mail messages, and provides other features not normally found in handheld terminal systems.
Real-Time 3-D Hydraulic Fracturing Simulation: Theory and Field Case Studies
Authors: Meyer B. R. , Cooper G. D. , Nelson S. G. 
Published: December 2007

ABSTRACT
This paper presents a foundation and methodology for real time three-dimensional hydraulic fracturing simulation and analysis. The equations governing fracture propagation are summarized for both rate and net pressure boundary conditions. A new dimensionless pressure slope parameter is introduced which prevents using chaotic measured or calculated pressures. This parameter also helps identify near wellbore restrictions.
The real time fracturing simulator utilizes the same numerical modules and routines as the design program. This will insure design, real time and post-design simulation compatibility. Simulated results for the rate and net pressure driven models can be displayed concurrently during the hydraulic stimulation.
Comparative studies of the rate and net pressure driven numerical results are included. A post-treatment analysis of a real time field case study is presented to illustrate the application of this real time fracturing system. The importance of using a dimensionless pressure slope is also discussed.
Improved Rod String Taper Design
Authors: Gault R. H. , Takacs G. 
Published: December 2007

ABSTRACT
This study presents an improved method for designing sucker rod taper percentages.
The API RP11L is the usual source for sucker rod taper percentages. When it was last revised, in 1976, it was necessary to make several simplifying assumptions because the complete calculations were too laborious for hand calculation.
Correlation of Scale Inhibitor Structure With Adsorption Thermodynamics and Performance in Inhibition of Barium Sulfate in Low-pH Environments
Authors: Breen P. J. , Diel B. N. , Downs H. H. 
Published: December 2007

ABSTRACT
In order to develop improved barium sulfate inhibitors for acidic (pH 4) environments, adsorption thermodynamics have been measured for several homologous series of inhibitors wherein the molecular structures have been varied systematically.
Correlations between thermodynamic, structural and performance data will be discussed.