bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Integrated Pore-to-Core Image Analysis to Study Fluid Distribution in Reservoir Rocks
Authors: Tomutsa L. , Mahmood S. M. , Brinkmeyer A. , Honarpour M. 
Published: December 2007

ABSTRACT
Effects of small-scale variations in rock properties on fluid distribution was studied in a layered Berea and a glauconite-laminated Shannon sandstone using x-ray computed tomography (CT), thin-section analysis, and rock-slab micromodels.
Dry and partially saturated cores were CT scanned at different stages of imbibition and drainage cycles to determine the spatial variations of rock properties and fluid distributions. Tests with brine-mineral oil (of 6.5 and 20 cP viscosities) and miscible brine-brine systems were conducted.
Based on the CT images, locations of various degrees of oil trapping were identified, from which samples were cut for thin-section analysis. Fluorescent and transmitted light microscopy images from these thin-sections were analyzed using commercial petrographic image analyses (PIA) software. Statistical analyses of pore and throat sizes were used to delineate small-scale spatial distributions of porosity and permeability.
Using a newly developed technique, micromodels containing 2 to 3 millimeter thick rock slabs were constructed. Multiphase displacement tests were performed, and pore-level behavior was observed.
The influence of layering resulting from variation in pore characteristics on front advancement, fluid distribution, and trapping was studied at core and microscopic scales using combination of CT and micromodel techniques. Presence of lower qualitylayers re-duced the effect of instability and inhibited oil intrusion in these layers.
This integrated use of images at different scales, as obtained by various imaging techniques, was found to be useful in providing an improved understanding of the effects of small-scale rock heterogeneities on fluid flow and trapping. Such integration can be helpful in proper interpretation of petrophysical data, such as relative permeability, capillary pressure, and electrical resistivity of core samples.
Feasibility of Reservoir Heating by Electromagnetic Irradiation
Authors: Fanchi J. R. 
Published: December 2007

ABSTRACT
Conventional thermal EOR methods, such as fireflooding and steamflooding, are commercially viable when properly applied. Every conventional method has one or more limitations. Electromagnetic heating (EMH) has the potential for overcoming some of these limitations. The EMH process relies on preferential absorption of electromagnetic energy as the means for increasing the temperature of a material. An algorithm for estimating the temperature increase associated with reservoir irradiation is described. The algorithm accounts for heat loss to confining strata. It is useful for generating a temperature profile of an irradiated reservoir. Applications of the algorithm to hypothetical reservoirs illustrate typical data sources and computational results.
Computation of Drainage and Imbibition Capillary Pressure Curves from Centrifuge Experiments
Authors: Glotin G. , Genet J. , Klein P. 
Published: December 2007

ABSTRACT
In this paper new methods to compute capillary pressure curves from centrifuge are developed for both drainage and imbibition. The methods are applied to experimental data. Results show that accurate determination of drainage capillary pressure curve can be obtained and negative capillary pressure in imbibition and residual oil saturation are also determined.
What is the Market Value of Long-Life Reserves?
Authors: David A. , Hickman T. S. 
Published: December 2007

ABSTRACT
The value of long life reserves is greatly reduced by conventional discounted cash flow approaches due to the present worth effect. However, the prices often paid for such reserves indicate that some buyers use alternate evaluation techniques and/or give considerable weight to nonquantifiable aspects. The impact of various evaluation methods is investigated. While some methods are more representative than others, all fail to express the strategic considerations involved in the business decision to buy reserves. Some buyers are better positioned by virtue of their orientation and capital source to acquire long life reserves.
Capillary Continuity Between Blocks of a Fractured Reservoir
Authors: Labastie A. 
Published: December 2007

ABSTRACT
The oil recovery by a gravity drainage process in a naturally fractured reservoir strongly depends on the total height in capillary continuity. The existence of a capillary continuity between blocks is critical for the computation of this height, but this problem is supported by very few reliable experimental data. We have performed both numerical and experimental investigations to determine under which conditions this continuity actually exists.
The experimental program, designed from a preliminary sensitivity study, includes several series of gravity drainage experiments with a stack of two matrix blocks in contact through bridges made either of:
– porous and permeable media, of various characteristics; – or non porous material, considering that the actual contact zone may be quite tight (stress concentration, recristallization...).
All the experiments have been simulated with a fine-grided model, in order to check the validity of the classical concepts.
The main results of the experiments and their simulation are:
– when the matrix blocks are in contact through porous material, the permeability of the contact area is the most important parameter; Darcy law is satisfactory to represent all the phenomena, as long as all the geometrical and petrophysical characteristics are correctly described; – when the matrix blocks are in contact through tight material, a capillary continuity may be established, depending on the geometry; this continuity cannot be represented by the classical concepts, and allows slow but significant flow rates.
The problem of capillary continuity between the matrix blocks of a fractured reservoir is still quite controversial; we believe this continuity very likely always exists, but flow rates may be small.
Interwell Residual Oil Saturation at Leduc Miscible Pilot
Authors: Wood K. N. , Tang J. S. , Luckasavitch R. J. 
Published: December 2007

ABSTRACT
An interwell test for residual oil saturation to waterflood (Sorw) was successfully conducted at the Leduc miscible pilot during August of 1987. Although the principle of the test was first disclosed by Cooke in 1971, lack of suitable tracers and interpretative techniques would have hindered previous attempts to apply the test in the field. Recent advances in radioisotope tracing technology make it possible to use the test as a cost effective alternative to conventional techniques. The Leduc test appears to be the first successful interwell Sorw test to be reported in the literature. To verify the interwell method, two other independent measurements of Sorw were made at the pilot by well-established conventional methods, namely, single well test and sponge coring. The excellent agreement between the measurements strengthens the credibility of the interwell test for determining residual oil saturation. The paper describes and compares the three techniques, focussing on the design and interpretation of the interwell test.
A New Resistivity Measurement System for Deep Formation Imaging and High-Resolution Formation Evaluation
Authors: Hunka J. F. , Barber T. D. , Rosthal R. A. , Minerbo G. N. , Head E. A. , Howard A. Q. , Hazen G. A. , Chandler R. N. 
Published: December 2007

Abstract
A new induction logging system has been developed that represents a fundamental departure from the technology and application of previous induction-based resistivity tools. The AIT* Array Induction Imager tool abandons the concept of fixed-focused sensors and is constructed of several independent arrays with main coil spacings ranging from a few inches to several feet. The AIT tool is operated simultaneously at several frequencies; in-phase and quadrature signals are acquired from every array at the frequencies suitable for that array length.
The presented log curves range in median depth of investigation from 10 in. to 90 in. Each log uses all the measured channels, combined with a nonlinear processing algorithm, to virtually eliminate environmental effects such as cave effect, shoulder effect, and skin effect. Reliable logs can be obtained even in difficult cases of bad borehole and extreme invasion. These logs are available at resolution widths of 6 ft and 2 ft.
Because of the large number of measurements made by the AIT tool, deep two-dimensional quantitative imaging of formation resistivity is possible. These images expose bedding and invasion features in a clear and quantitative manner. The resistivity in the part of the formation undisturbed by fluid invasion is accurately obtained without making any prior assumptions about the invasion profile. New invasion description parameters conveying more meaningful information about the presence of transition zones and annuli are a result of this imaging capability. Using established interpretation principles, this quantitative information about the invasion can be converted into a two-dimensional image of water saturation.
Deep Saturation in Low Salinity Reservoirs from Dual Laterolog Quadrature Signals
Authors: Saxena Vimal , Sibbit A. M. 
Published: December 2007

Abstract
In slialy sands with low salinity brines, resistivity logs show little contrast between oil and water zones. The phase angle computed from the quadrature signals of the Dual Laterolog, is significantly reduced in front of oil zones, even in very shaly reservoirs.
This phenomenon is used as a basis to estimate deep water saturation.
The Well Response in a Naturally Fractured Reservoir: Arbitrary Fracture Connectivity and Unsteady Fluid Transfer
Authors: Chen Her-Yuan , Poston S. W. , Raghavan R. 
Published: December 2007

ABSTRACT
This work presents the development of a dual-permeability transient interporosity formulation for naturally fractured reservoirs that offers engineers considerable flexibility in analyzing transient pressure data. The chief advantages of our model are: (i) it permits communication of the matrix system with the wellbore, and (ii) it admits transient interporosity flow behavior in the matrix system. Presently available models can be derived as special cases of our formulation. New insights into "pseudosteady behavior" that is often attributed to naturally fractured reservoirs are provided. Alternate interpretations to the fracture skin concept are also discussed.
Workstation-Based Fracture Evaluation Using Borehole Images and Wireline Logs
Authors: Cheung P. S-Y. , Heliot D. 
Published: December 2007

Abstract
Wireline images and logs can be processed effectively to derive quantitative information relating to fracture orientation, density, aperture and porosity. A methodology based on analyses at the levels of individual fractures and fracture sets is presented. A program has been implemented on a workstation allowing a flexible blend of expert-user input and machine processing power.
Experimental Pulsed Neutron Porosity for Gas-Filled Boreholes in the Gulf Coast
Authors: Butsch R. J. , Vacca H. L. 
Published: December 2007

ABSTRACT
Determination of formation porosities in cased holes becomes necessary when no other porosity information is available, such as openhole logs or core data.
Within the pulsed neutron generations of logging tools, there have been various hybrids of "neutron" porosity computations made. The porosity has primarily been derived from a ratio of the count rate data obtained from selected gating and or detector combinations. Success has varied, depending on tool type and the composition of the formation encountered.
A technique has been developed for the Gulf Coast which has much less sensitivity to the environmental effects of gas in the borehole. Over the period of a year, numerous tests were made with data from wells with various borehole conditions.
The results to date indicate that this new technique will have application in eliminating or minimizing wellbore environmental effects due to gas in the wellbore. Gulf Coast and other examples are included which illustrate comparisons of this new technique with other porosity measurements.
3-D Acoustic Scanner
Authors: Aas M. , Bacri J-C. , Frenois C. , Salin D. , Woumeni R. 
Published: December 2007

ABSTRACT
The sound velocity in a porous medium varies with the concentrations of, liquids, miscible or immiscible, that saturate the medium. The sensitivity of acoustic measurements lead to accuracies in fluid concentration better than 1 %. This technique is used to design a 3D acoustic scanner. Compared to X-ray or NMR computerized tomography, the acoustic scanner has poorer spatial resolution (3×3×3 mm3) but it is less expensive, faster and do not require any dopant. Most liquids and solids being transparent to acoustic waves, this technique is well suited for a wide range of sample coating, for example for studies under pressure.
Laboratory Characterization of Anisotropic Rocks
Authors: Auzerais F. M. , Ellis D. V. , Luthi S. M. , Dussan V E. B. , Pinoteau B. J. 
Published: December 2007

ABSTRACT
A number of layered rock samples with large permeability contrasts has been collected mostly from the western United States. The collection provides samples from a variety of depositional geological environments with bedding thicknesses ranging from millimeters to decimeters. The objective of this study was to investigate the origin of the large permeability anisotropy.
To characterize these rocks, conventional laboratory methods have been used such as macroscopic petrographic description, mineralogical analysis using Fourier transform infrared spectroscopy, as well as permeability, porosity, conductivity and acoustic velocity measurements on Hassler cores orthogonal and parallel to the bedding surfaces. Additionally, novel techniques consisting of permeability scans on the rock surfaces with an experimental minipermeameter setup, petrographic image analysis from thin sections, and density profiles obtained from a computerized tomographic (CT) scanner were used. These provided detailed maps of vertical density, porosity and permeability changes within these rocks. Results of CT scanning at two different energies allowed us to simultaneously determine densities and estimate photoelectric factors.
All of these rocks are layered and exhibit large porosity changes over very short vertical distances of sometimes as little as one millimeter. Some sandstone samples as well as an interlayered sand/shale sample were found to exhibit permeability anisotropies of more than one-hundred and vertical porosity variations of up to a factor of three. Conductivity anisotropies of these samples, however, were generally less than 1.6, and acoustic anisotropies less than 1.2.
The sedimentological origin of these anisotropic rocks is attributed to an interaction of two or more depositional processes during lateral acceration or vertical aggradation, producing vertical variations in mineralogy, grain size and other petrographic characteristics.
Calcite Cementation: Description and Production Consequences
Authors: Omre H. , Sølna K. , Tjelmeland H. , Claesson L. , Holter C. 
Published: December 2007

ABSTRACT
Stochastic modeling in reservoir description should be classified with respect to the type of variables involved in the study: continuous, mosaic or event spatial variables. The calcite cemented units in a sand stone reservoir is considered as a mosaic variable, and the stochastic model is based on Markov random field theory. The model and parameter values, constrained by the well observations, provide the base for generating several realizations of the reservoir description. These realizations are homogenized and the production potential is evaluated by a preliminary numerical production simulation. The set of production profiles corresponding to the reservoir realizations will reflect the uncertainty due to lack of exact geological knowledge about the reservoir. The importance of establishing an automatic line of production for uncertainty evaluation is emphasized.
Acidization of Analcime-Cemented Sandstone, Gulf of Mexico
Authors: Underdown D. R. , Hickey J. J. , Kalra S. K. 
Published: December 2007

ABSTRACT
In a number of offshore Louisiana oil wells a white powdery, finely granular siliceous material was swabbed from wells and found on screens after acidizing with mud acid. The white material was analyzed as silica gel or aluminosilicate gels. Analysis of the formation sands which produced the white material after acidization shows the sands to be extensively cemented with analcime.
Analcime is a hydrated sodium aluminosilicate related to zeolites. Analcime is a low density (2.3 gm/cc) mineral which is highly soluble in HF and will form hydrated gels with concentrated HC1. Analcime is associated with volcanic ashes, altered volcanic sandstones and salt domes. There are many salt dome related oil fields in the central Gulf where volcanic ash beds are locally common. Therefore, the occurrence of analcime cemented sandstones may be more widespread in the Gulf than previously suspected.
A significant production decline was noted in a number of wells in the South Pass Blk. 61 field, a complex salt dome related structure, after acidization with HF or concentrated HC1. In many cases, production decline is attributed to damage by mineral precipitation or gel formation from acid spent on analcime-cemented sands.
This paper describes the petrographic and fluid/rock studies done to optimize pre and/or post gravel pack acid stimulation system for analcime- cemented sandstones from South Pass Blk. 61. SEM photos show the effect of various acid systems on analcime and an effective acid system for these types of formations is discussed.
A Comprehensive Mechanistic Model for Two-Phase Flow in Pipelines
Authors: Xiao J. J. , Shonham O. , Brill J. P. 
Published: December 2007

ABSTRACT
A comprehensive mechanistic model has been developed for gas-liquid two-phase flow in horizontal and near horizontal pipelines. The model is able first to detect the existing flow pattern, and then to predict the flow characteristics, primarily liquid holdup and pressure drop, for the stratified, intermittent, annular, or dispersed bubble flow patterns.
A pipeline data bank has been established. The data bank includes large diameter field data culled from the A. G. A. database, and laboratory data published in the literature. Data include both black oil and compositional fluid systems.
The comprehensive mechanistic model has been evaluated against the data bank and also compared with the performance of some of the most commonly used correlations for two-phase flow in pipelines. The evaluation, based on the comparison between the predicted and the measured pressure drops, demonstrated that the overall performance of the proposed model is better than that of any of the correlations, with the least absolute average percent error and the least standard deviation.
The Measurement of Crude Oil/Natural Gas/Water Flow Rates by Using Microwave Technique
Authors: Lin Feng , Chen Xuejun , Zhou Fangde 
Published: December 2007

ABSTRACT
The individual flowrates of crude oil, natural gas and water three-phase mixture are measured separately by using a single phase flowmeter. The microwave technique is used to measure the water to oil and gas ratio. It can measure 0-100% water concentration in water/oil two-phase and oil/gas/water three-phase mixtures. This instrument is not temperature or salinity sensitive - a shortcoming of the capacitance and conductivity probes. The capacitance cross-correlation method is used to measure the overall flowrate of a three-phase fluid. A new cross-correlator is developed, cheaper than others. Its calculating time is much shorter than before. A bypass is used to separate the liquid from the three-phase mixture, and to measure the oil fraction in the remaining oil/water mixture. The natural gas fraction in three-phase fluid is measured from the main flow. The experiments have been done in the laboratory and field. The flowrate range measured is more extended than that of single phase flowmeters, such as a turbo-meter or orifice plate. The flowrate measuring error is less than 5%.
This kind of three-phase flowmeter is suitableto many kinds of oil wells to measure the flowrates of crude oil, natural gas and water, including flows with high water to oil ratios or high gas and oil ratios. The flowmeter is compact and non-invasive. It keeps high accuracy during measuring, despite the presence of paraffins, tar and sand. Its low cost makes it possible to install a flowmeter in each oil-well .
Fracture Height Growth and Production From Multiple Reservoirs
Authors: Saulsberry J. L. , Schraufnagel R. A. , Jones A. H. 
Published: December 2007

ABSTRACT
The objective of two separate fracture treatment experiments performed in the Oak Grove Field, Alabama, was to estimate fracture geometry and effectiveness. In the first treatment an innovative design to connect a number of thin seams with one stimulation was tested. In the second treatment the goal was to determine the height growth and fracture length that might be achieved in a typical conventional water/sand stimulation design. Fracture diagnostics and modeling were used to estimate fracture geometry. Post-fracture production analysis indicates that the treatment using a crosslinked gel created a more effective propped fracture than the treatment using fresh water.
Gas-Lift Troubleshooting Engineering: An Improved Approach
Authors: Ortiz J. L. 
Published: December 2007

ABSTRACT
The present paper describes the basis and applications of some gas lift troubleshooting techniques being used in the production operations of Lake Maracaibo field, Venezuela.
By integrating simple physical models and analytical procedures, engineers are able to diagnose a broad range of gas lift wells.
The presented techniques have been applied successfully on a large amount of gas lift wells, making them an alternative to some methodologies that appear in the literature.
Representative field cases have been included to illustrate the explanations.
The Role of Asphaltene in Wettability Reversal
Authors: Kim S. T. , Boudh-Hir M- E. , Mansoori G. A. 
Published: December 2007

Abstract
Wettability is an important factor in a number of petroleum production processes. Asphaltene deposition can have a strong role in wettability reversal. Among many factors, the high molecular weight, polar fraction of crude oils, including the asphaltenes, are considered to be the primary wettability altering agents.
Understanding the role of asphaltene in wettability of reservoir fluids on solid surfaces and its reversal will help us plan for more efficient oil recovery processes. It will also establish the role of asphaltene deposition in the production operation of asphaltic crudes including heavy petroleum crudes. In this paper the groundwork for the study of the complex role of asphaltene and its deposition in altering the wettability of reservoir fluids on solid surfaces is presented. A number of experimental observations in support of the strong role of asphaltene in altering the interfacial tensions and wettability is reported. A new molecular theory for prediction of wettability and its reversal is also introduced.