bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimum Application of Environmentally Safe Compound Greases for Casing and Tubing
Authors: Ogasawara Masao , Khoyama Fujimasa 
Published: December 2007

Summary
It is now expected to prevent the contamination of the environment from the use of pipe dope or compound grease in oilfield drilling operations. Recently, some environmentally safe compound greases have been commercially developed and are available, but it is not generally known what effect they will have on the connection performance. This paper will discuss a detailed experimental study of the performance of these greases to investigate the galling tendency and sealing capability of American Petroleum Inst. (API) buttressthread connections (BTC) and metal/metal seal premium connections. It is already known that greases without both lead and zinc can be used for a single makeup of these connections, but some improvements were expected in the antigalling performance for multiple makeups. Greases without lead or without both lead and zinc are not satisfactory for preventing hydrostatic leakage in buttress connections because of the lack of buildup of powders for thread clearance, and the addition of graphite in substituting for these metal powders tends to produce galling. Thus, the ratio of solid/liquid elements and the roughness of the graphite grain will be important in the improvement of existing greases.
Safety of Casing-Shoe Test and Casing-Shoe Integrity After Testing
Authors: Morita Nobuo , Fuh Giin-Fa , Boyd P. A. 
Published: December 2007

Summary
Increased injection volume during a casing-shoe test is needed to gather data, but it increases the possibility of lost circulation or reduced casing-shoe strength after testing. These hazards often encourage drilling engineers to halt casing-shoe tests prematurely just to confirm the casing-shoe strength. This paper addresses drilling-engineering concerns regarding lost circulation during a casing-shoe test, the extent of fracture propagation, the amount of data obtainable as a function of the drilling-fluid volume injected, and the casing-shoe integrity expected after testing. Laboratory data and a numerical model are used to illustrate phenomena that occur during casing-shoe tests. Analysis of the data yields guidelines for safe casing-shoe tests.
Matrix Acidizing: A Novel Approach to Foam Diversion
Authors: Zerhboub Mohammed , Ben-Naceur Kamel , Touboul Eric , Thomas Ron 
Published: December 2007

Summary
This paper investigates the use of the foam diversion technique experimentally to understand the mechanisms governing diversion in sandstones. The effect of the main parameters is presented and discussed, and a process is proposed. Field test results have shown the efficiency of foam as a diverter. Acidizing of water-cut wells is highlighted.
Analysis of Shear-Wave Polarization in VSP Data: A Tool for Reservoir Development
Authors: Winterstein D. F. , Meadows M. A. 
Published: December 2007

Summary
This paper presents results of a new method of using vertical seismic profile (VSP) data to deduce information on certain rock properties that are important for reservoir development. These properties are the direction of maximum horizontal stress or the orientation of aligned fractures and the variation of these quantities with depth. Such information can be important for secondary recovery, horizontal drilling, and infill drilling. The VSP method involves a shear-wave (S-wave) source at the surface and a downhole three-component (3-C) geophone to record first-arrival S waves along predominantly vertical ray paths. The data are analyzed to determine particle motion directions (polarizations) and relative travel time of the two S waves. In simple cases, the polarization of the faster S wave is oriented parallel to the direction of maximum horizontal compressive stress orthe predominantfracture alignment.The travel-time differences between the S waves contain information on the effects of unequal horizontal stresses.
We recorded a number of VSP's for S-wave analysis in California and Texas oil fields. Results from three VSP's are presented here. In nearly every case, we found measurable travel-time differences and also significant variation of the S-wave polarization azimuths with depth. Polarization azimuths, although typically consistent over depth intervals of several hundred feet, tended to change abruptly at various depths. A simple layer-stripping technique made it possible to follow the polarization changes and determine travel-time differences over successive depth intervals. The variations with depth are particularly interesting because they indicate changes of principal stress direction or fracture orientation.
Application of Fluorescence Techniques for Mud-Logging Analysis of Oil Drilled With Oil-Based Muds
Authors: Reyes Marilyn V. 
Published: December 2007

Summary
The Texaco E&P Technology Div. has developed two fluorescence techniques to enhance the detection of crude oil extracted from formation samples and to improve mud logging as a formation evaluation tool. The quantitative fluorescence technique (QFT) is a portable field method that uses a single excitation wavelength and measures fluorescence at a narrow emission range. When plotted vs. depth, the intensity measurements generate an oil concentration profile of the well. The QFT has successfully located oil-bearing zones that were difficult to identify with conventional mud-logging techniques. The total scanning fluorescence (TSF) technique uses a more sophisticated ultraviolet (UV) spectroscopic instrument and generates a 3D fluorescence spectrum or "fingerprint." This spectrum results from the total fluorescence contribution of the fluorescing species present in the oil. The unique chemical makeups of different crude oils have spectral characteristics that can be used to predict oil composition or type. The TSF method gives more information than conventional fluorescence techniques. This paper discusses the effectiveness of the QFT and the TSF method for identifying crude oil in the presence of fluorescing drilling-mud additives (such as base oils or diesel) and includes a feasibility study that demonstrates the application of these methods in a North Sea well drilled with an oil-based mud. Examples in wells offshore the Mediterranean Sea and Gulf of Mexico are also cited.
On The Efficiency Of Electrical Submersible Pumps Equipped With Variable Frequency Drives: A Field Study
Authors: Patterson M. M. 
Published: December 2007

Summary
A field study was conducted on 18 electrical-submersible-pump-(ESP-) equipped wells operating in the Williston basin. Fifteen of these wells were run with variable frequency drives (VFD's). The purpose of the study was to determine the efficiency and operating characteristics of ESP's operating with VFD's and compare them to those without. Voltage, current, power, and frequency were measured at the drive input, the drive output, and ESP input. Production data were recorded and power and efficiency were calculated at all measurement locations and compared to published data.
Hydrogen-Induced Cracking in Surface Production Systems: Mechanism, Inspection, Repair, and Prevention
Authors: Burk J. D. 
Published: December 2007

Summary
Hydrogen-induced cracking (HIC) is a materials- and corrosion-related problem that occurs in surface production systems. Steels used to construct sour-gas production facilities and flowlines may corrode from wet hydrogen sulfide (H2S) gas in the production stream. The corrosion process generates hydrogen that may damage the steel, resulting in HIC and other forms of damage from hydrogen. HIC control and prevention are an important consideration in operating surface-facility equipment in a safe and efficient manner. By effectively controlling or preventing HIC damage in surface-facility equipment, operating costs are reduced, potential costly downtime from equipment failure is avoided, and a safe work environment is more easily realized.
We developed an overall approach to understand and deal with the HIC problem in sour-surface production facilities. The approach dealt with understanding the mechanism in steel materials used in surface-facility equipment; implementing state-of-the-art inspection techniques; fitness-for-service (FFS) evaluation to assess damage effect on performance; repair procedures on existing equipment; and finally, establishing steel performance and fabrication requirements to eliminate or reduce HIC damage risk for newly fabricated equipment.
This paper presents the results of laboratory examinations of over 40 steels covering both new and existing equipment, leading to the approaches developed for controlling HIC in existing equipment and for controlling or preventing HIC in new construction. We also present the basis for the approaches developed to deal with HIC in surface production facilities.
The Use of Pulsed-Neutron Capture Logs for Reservoir Management in the Midway-Sunset Field
Authors: Guo D. S. , Smith M. E. , Tucker K. E. 
Published: December 2007

Summary
Systematic time-lapse pulsed-neutron capture (PNC) logging was conducted during a 2-year steam-foam mechanistic field trial in the steamflooded Monarch reservoir, which is composed of interbedded sandstones, conglomerates, siltstones, and diatomaceous mudstones. Observation wells were drilled with one continuously cored through the reservoir interval and two emptied to facilitate better temperature logging. Uncalibrated PNC log responses in the air-filled wells were normalized to water-filled conditions and were used to generate a series of steam/gas saturation profiles that indicate clearly the dynamics of the fluid and foam in the reservoir during the experiment.
Correlations between neutron capture cross sections (sigma), mineralogy, and rock chemistry from core samples were examined for additional use of the PNC logs for steamflood reservoir characterization. Sigma was found to increase with increasing clay/mica content and diatomite content. This finding may result in improved stratigraphic correlations of the more laterally continuous diatomaceous mudstones based on PNC logs.
The PNC log data from the field trial, when used in conjunction with core, temperature, and pressure data, were critical in developing a better understanding of foam generation and propagation in the reservoir. Furthermore, they minimized the time and cost required to complete the field trial successfully. They also led to opportunities for vertical expansion of steamflooding in the area.
Evaluation of Fracture Treatments Using a Layered-Reservoir Description: Field Examples
Authors: Rahim Zillur , Holditch S. A. , Zuber M. D. , Buehring D. R. 
Published: December 2007

Summary
This paper presents a practical analysis technique to determine actual fracture geometry and proppant profile using a three-dimensional (3D) hydraulic-fracturing simulator. The hydraulic-fracturing model used in this study considers the variation of in-situ stress, Young's modulus, Poisson's ratio, and net pay thickness in the productive interval.1–4 When our method is applied, the results from the fracture propagation model conform well with the results we obtain from pressure-buildup and production-data analyses.
This study analyzed hydraulic-fracturing treatments from several wells in the Vicksburg formation of the McAllen Ranch area in south Texas.5,6 We have provided guidelines to properly describe the treatment interval, how to use this information in the analysis of such fracture treatments, and how to confirm the results using pressure-transient tests and production-data analyses. This paper presents examples illustrating that a detailed description of the reservoir layers is essential to properly evaluate hydraulic-fracture treatments.
For the example wells presented in this paper, post-fracture-production and pressure-transient data were available. We have analyzed production and pressure-transient data to estimate permeability and fracture half-length. The values of fracture half-length used to analyze the production data matched closely with those predicted by the fracture model.
Problem Detection During Tripping Operations in Horizontal and Directional Wells
Authors: Cordoso J. Venâncio , Maidla Eric E. , Idagawa L. S. 
Published: December 2007

Abstract
Most directional well drilling problems detected in Brazil, and also verbally reported by service companies abroad, occur during tripping operations. A comprehensive research program was undertaken to study this problem. The work is summarized in this paper, and shows the development of a field analysis procedure that proved to be reliable and thus translates into significant cost savings.
The field data was obtained using an in-house mud logging offshore unit and service companies' drilling sensors. The analysis was performed using the new developed method—Two Stage Type Curve Matching: an alert hook load expert system, followed by a pseudo friction factor "signature" analysis.
Field results showed this to be useful for early borehole detection.
An Assessment of the Mechanical Stability of Wells Offshore Nigeria
Authors: Lowrey John P. , Ottesen Steinar 
Published: December 2007

AbstractIn 1991 lost time due to stuck pipe related drilling problems accounted for approximately 18% of total drilling time in Mobil Producing Nigeria Ultd.'s (MPN) offshore operations. The primary cause of stuck pipe was identified as mechanical wellbore instability. This paper presents an assessment of the mechanical stability of MPN's wells offshore Nigeria. The objectives of the study were to: 1) determine the magnitude of the in-situ principal stresses and material properties of the troublesome Intra-Biafra and Qua Iboe shale sequences; 2) quantify the drilling fluid densities required to drill mechanically stable wells through these formations; 3) review and recommend well planning and operational parameters which aid in minimizing wellbore stability-related drilling problems. The wellbore stability assessment was carried out with the aid of a 3-dimensional wellbore stability model using field derived data from the study area to corroborate the results. The collection and analysis of drilling data (borehole geometry and density logs, pore pressure, leak-off tests, local geology and other relevant well records) to determine the magnitude of the in-situ principal stresses, together with compressive strength tests on formation cores are discussed. Minimum safe drilling fluid densities to promote wellbore stability as a function of well geometry and depth are presented for the most troublesome shales drilled in the study area. Implementation of the results reduced wellbore stability related problems and associated trouble time to less than 5% in 1992.
Average Reservoir Pressure Estimates in a Commingled Reservoir
Authors: Chen H. Y. , Raghavan R. , Poston S. W. 
Published: December 2007

SummaryLate-transient buildup responses at a well that produces a two-layer reservoir with no-crossflow are studied. The well is located at the center of a circle and the outer boundaries are assumed to be impermeable. The initial pressure is identical in each layer. Our emphasis is on the determination of average reservoir pressure. This study provides (i) a complete description of the buildup trace following the initial-transient period (or the semilog straight line should it exist) by obtaining analytical expressions that highlight the influence of the variables that affect the trace, (ii) a physical interpretation for the value of pressure that corresponds to the level portion of the buildup curve, (iii) an interpretation of average pressure estimate obtained by using the Matthews-Brons-Hazebroek functions for single-layer systems (in this regard a number of insights are provided), (iv) a theoretical justification for the application of the Muskat and the Arps-Smith methods to estimate average reservoir pressure, and (v) a direct method to compute average reservoir pressure. Results are extended to multilayer systems.
The Effect of Crude-Oil Aging Time and Temperature on the Rate of Water Imbibition and Long-Term Recovery by Imbibition
Authors: Zhou Xian-min , Torsæter Ole , Xie Xina , Morrow N. R. 
Published: December 2007

Summary
We investigated short-term rates of imbibition of water and long-term recovery by spontaneous imbibition for crude oil/brine/rock systems. Increasing the aging time and aging temperature decreased the early time rate of imbibition of water. Moderately water-wet plugs gave the highest recovery by long-term imbibition. We present photographic records of oil production at core surfaces, which are indicative of connectivity and capillary-pressure driving forces for imbibition.
Use of Flow Units as a Tool for Reservoir Description: A Case Study
Authors: Ti Guangming , Ogbe D. O. , Munly Walt , Hatzignatiou D. G. 
Published: December 2007

Summary
This paper presents a method where fluid flow units are used in reservoir description. We developed the proposed method using core and well-log data from the Endicott field on the North Slope of Alaska. Sedimentary intervals of the cored wells are divided into major zones on the basis of core description information. The major zones are further subdivided into subzones to allow less variation in geologic and petrophysical properties within each subzone and more variation between the subzones. On the basis of the transmissibility, storativity, and net- to- gross-thickness data, the subzones are classified into four distinct fluid flow units by use of the statistical method of cluster analysis.
We use a regression relationship established between the core and well-log data in the cored wells to estimate the permeability of the uncored wells, allowing for extension of flow units to these wells. We present stratigraphic cross sections to illustrate areal variations of the petrophysical properties in the Endicott field.
Why Do Gels Reduce Water Permeability More Than Oil Permeability?
Authors: Liang Jenn-Tai , Sun Haiwang , Seright R. S. 
Published: December 2007

Summary
A capacity to reduce water permeability much more than oil permeability is critical to the success of gel treatments in production wells if zones cannot be isolated during gel placement. Although several researchers have reported polymers and gels that provide this disproportionate permeability reduction, the explanation for the phenomenon was unclear. In this paper, we examine several possible explanations for why some gels reduce water permeability more than oil permeability. Our experimental results indicate the disproportionate permeability reduction is not caused by gravity or lubrication effects. Results also indicate that gel shrinking and swelling are unlikely to be responsible for the phenomenon. Although wettability may play a role in the disproportionate permeability reduction, it does not appear to be the root cause for water permeability being reduced more than oil permeability. Results from an experiment with an oil-based gel suggest that segregation of oil and water pathways through a porous medium (on a microscopic scale) may play the dominant role in the disproportionate permeability reduction. However, additional work will be required to verify this concept.
Estimation of Horizontal Stresses at Depth in Faulted Regions and Their Relationship to Pore Pressure Variations
Authors: Addis M. A. , Last N. C. , Yassir N. A. 
Published: December 2007

Summary
This paper focuses on the relationships used for estimating the magnitudes of horizontal stresses acting in faulted sedimentary basins. Relationships are derived here based on the assumptions of a faulted but essentially elastic rock and take into account the tectonic stress component associated with active normal and thrust faults, as well as the pore pressure. The equations presented predict that the orientation of the minimum stress can change once a normal or thrust fault has formed. They further predict that an increase in pore pressure gradient will result in a more isotropic stress state. Field data are used to assess the predictions and include stress-depletion measurements from normally faulted basins and stress measurements performed "at depth" in compressive tectonic "thrust" regions.
Pressure-Transient Testing of Gas Reservoirs With Edge-Waterdrive
Authors: Chen Chih-Cheng , Chu Wei-Chun , Sadighi Soleiman 
Published: December 2007

Summary
A pattern to recognize the presence of water encroachment and a reliable method for estimation of reserves in single-well gas reservoirs with edge-waterdrive have been developed from analysis of simulated pressure data. An alternative to the traditional interpretation of boundary effects has emerged as a result. This paper discusses the development of this new methodology and presents field examples of buildup data to demonstrate the applicability of the signature.
Parametric Study of Gas Entry Into Cemented Wellbores
Authors: Sabins Fred , Wiggins M. L. 
Published: December 2007

Summary
A cement slurry is placed in a wellbore to harden into an impermeable mass that seals the annulus from fluid flow and protects the casing from corrosion for the life of the well. If fluid flow does occur in the form of gas migration, expensive remedial squeeze-cementing techniques are generally required.
The objective of the work covered in this paper was to study the parameters that affect entry of gas into a cemented annulus. This research incorporated a detailed study of the factors that contribute to gas influx from the time of initial placement of the slurry, through the gelation or transition state of the slurry, to the set condition. On the basis of the understanding of the processes involved in gas entry, a simulator was developed that predicts the amount of gas that enters a cemented wellbore, and identifies the critical parameters that affect the gas entry.
This study concerns itself with a portion of the gas flow problem: the entry of gas into a cemented annulus — and not with the flow of the gas up through the cement and the formation of a gas channel.
This study will provide insight to the following questions.
What cement properties are important to minimize gas entry? What role does fluid loss play in minimizing gas influx? What well parameters affect gas entry?
Application of Short-Radius Horizontal Boreholes in the Naturally Fractured Yates Field
Authors: Gilman J. R. , Bowzer J. L. , Rothkopf B. W. 
Published: December 2007

Summary
This paper discusses the performance and simulation of short-radius horizontal boreholes being used in the Marathon-operated Yates Field Unit in west Texas to minimize drawdown and therefore to reduce gas and water coning in a thin oil column. Yates is a very prolific field with extensive fracturing and high-quality reservoir rock. Superimposed on a high-density orthogonal fracture network are widely spaced regional joints with a strong directional tendency. Major questions are how these directional joints affect the horizontal-well performance and whether wells should be drilled parallel or perpendicular to the joints. Dual-permeability reservoir simulation studies were performed to study optimum orientation of the borehole with respect to the natural fracture network. Additionally, optimum well-completion elevation was studied. Forty-six vertical wells have been recompleted as short-radius horizontal boreholes since 1986. The large productivity increase of the horizontal boreholes compared with the previous vertical completions indicates that the wells are intersecting the regional joints.