bluuebunny/crossref_metadata_2025_split huggingface dataset:
Laboratory and Theoretical Evaluation of Corrosion-Inhibiting Emulsions
Authors: Civan Faruk , Weers Jerry J. 
Published: December 2007

SummaryMeasurement and correlation of the typical properties of the corrosion-inhibiting emulsions that affect their placement and gradual decomposition in oil wells are presented. The mechanisms of the emulsion breakup and inhibitor release by shearing and heating are determined, formulated, and verified by experimental data. The viscosity, drying and stability processes, surface tension, repetitive film coating on tubing and casing walls, and inhibitor resolution of typical water-external and oil-external emulsions are correlated by relevant theories.
Laboratory and Field Evaluation of an Inelastic Neutron Scattering and Capture Gamma Ray Spectrometry Tool
Authors: Hertzog R. C. 
Published: December 2007

Abstract
An experimental system for gamma ray spectroscopy logging has been developed which uses prompt and capture gamma radiation induced in formations by 14-MeV neutrons from a pulsed-neutron generator to determine relative concentrations of various elements in the formation. The logging system uses computer-processing techniques based on spectral modeling that has been developed to analyze the inelastic and capture gamma ray data obtained with a borehole spectrometer.
The physics of the production of gamma rays from fast-neutron interactions with elemental nuclei in formations is discussed, leading to a simple but realistic interpretation model for the tool's response. This model is confirmed by laboratory and field tests.
The relative spectroscopic contributions from carbon, oxygen, silicon, calcium, iron, chlorine, and hydrogen are used for various cased-hole and openhole logging applications. Particular emphasis is placed on the carbon/oxygen ratio used to obtain oil saturation independent of formation-water salinity. Carbon/oxygen ratio determinations made in the laboratory are compared with values predicted on the basis of known lithologies, porosities, and oil-saturation changes.
In addition, the spectral contributions from iron, silicon, and calcium are used to interpret lithology; hydrogen, silicon, and calcium contributions are used to determine the effects of porosity; and chlorine and hydrogen contributions are used to investigate salinity changes.
Field-test log examples of these elemental determinations are shown.
A Generalized Friction-Factor Correlation To Compute Pressure Drop in Horizontal Wells
Authors: Yalniz M. U. , Ozkan E. 
Published: December 2007

Summary
This work investigates the effect of fluid ingress on flow through perforations in a horizontal wellbore and correlates this effect in the form of an apparent friction factor. The investigation uses theoretical and experimental models. It is shown that when there is no influx, the perforations, or slots, on the well surface cause a reduction in the pressure gradients proportional to their area. The well-bore pressure gradients increase with influx from perforations, but unless the ratio of the influx rate to the wellbore flow rate is sufficiently large, pressure gradients are lower than those of an unperforated well. The results of this study are combined to develop a generalized friction-factor correlation that is a function of the Reynolds number and the ratios of the influx to wellbore flow rate and perforation to wellbore diameters.
Foam Property Requirements for Proper Hole Cleaning While Drilling Horizontal Wells in Underbalanced Conditions
Authors: Martins A. L. , Lourenço A. M. F. , de Sá C. H. M. 
Published: December 2007

Summary
This paper summarizes an extensive experimental program to determine effective foam drilling conditions in horizontal wells. The program included foaming-agent selection (considering optimum concentration and salt/oil contaminants), rheological characterization of foams, development of a flow loop to test the foam-carrying capacity in high-angle wells, definition of the test procedure and matrix, and analysis of the results. After 60 bed tests were performed at a cuttings-transport flow loop, correlations were proposed to predict the cuttings-bed erosion capacity in horizontal wells as functions of the foam quality and the mixture's Reynolds number.
Wettability Effects on Oil-Recovery Mechanisms in Fractured Reservoirs
Authors: Graue A. , Bognø T. , Baldwin B. A. , Spinler E. A. 
Published: December 2007

Summary
Iterative comparison between experimental work and numerical simulations has been used to predict oil-recovery mechanisms in fractured chalk as a function of wettability. Selective and reproducible alteration of wettability by aging in crude oil at an elevated temperature produced chalk blocks that were strongly water-wet and moderately water-wet, but with identical mineralogy and pore geometry. Large scale, nuclear-tracer, 2D-imaging experiments monitored the waterflooding of these blocks of chalk, first whole, then fractured. This data provided in-situ fluid saturations for validating numerical simulations and evaluating capillary pressure-and relative permeability-input data used in the simulations. Capillary pressure and relative permeabilities at each wettability condition were measured experimentally and used as input for the simulations. Optimization of either Pc-data or kr-curves gave indications of the validity of these input data. History matching both the production profile and the in-situ saturation distribution development gave higher confidence in the simulations than matching production profiles only.
Development of an Integrated Reservoir Model for a Naturally Fractured Volcanic Reservoir in China
Authors: Abbaszadeh Maghsood , Corbett Chip , Broetz Rolf , Wang James , Xue Fangjian , Nitka Tom , Zhang Yong , Liu Zhen Yu 
Published: December 2007

Summary
This paper presents the development of an integrated, multidiscipline reservoir model for dynamic flow simulation and performance prediction of a geologically complex, naturally fractured volcanic reservoir in the Shang 741 Block of the Shengli field in China. A static geological model integrates lithological information, petrophysics, fracture analysis, and stochastic fracture network modeling with Formation MicroImage (FMI) log data and advanced 3D seismic interpretations. Effective fracture permeability, fracture-matrix interaction, reservoir compartmentalization, and flow transmissibility of conductive faults are obtained by matching various dynamic data. As a result of synergy and multiple iterations among various disciplines, a history-matched dynamic reservoirsimulation model capable of future performance prediction for optimum asset management is constructed.
Slim Hole Logging and Analysis for Uranium Exploration
Authors: Howell Eddie P. , Gant Orland J. , Crebs Terry J. 
Published: December 2007

Significant improvements have been made in uranium logging equipment and analysis techniques. Logging systems now provide geological, geophysical, and geochemical data from routine measurements. Through computer analysis, these systems also can determine porosity, density, permeability, lithology, formation-water resistivity, and thermal and mechanical properties.

Introduction
Deeper targets for uranium exploration warrant more complete logging systems than those used previously. Such systems can produce adequate data for a geologic understanding of the ore deposition processes with fewer drill holes. As the formation depth increases, data extrapolated from surface outcrops become less reliable and make log-derived data more important. An alternative to a complete logging package is extensive coring of ore-bearing and related formations, but this is expensive and time consuming. We are using reasonably sophisticated logging systems that provide data for geologic models, which are used to understand the sedimentary environment, groundwater, and other physical and chemical properties of uranium deposition. These models, based largely on log-derived data, are important when designing infill drilling for exploration, evaluation, or production.
Uranium log interpretation is simplified somewhat by short drilling times that restrict invasion and by lack of hydrocarbons that complicate fluid properties. However, less-sophisticated small-diameter downhole tools can have the opposite effect.

Logging System
The digital logging systems that we use have been designed for relatively simple operation. Analog records are produced during logging to verify equipment operation and allow operator adjustments if necessary.
For most logging tools, digital data are generated uphole from a depth encoder, two count-rate meters, and four 4.5-digit volt meters. Signals are recorded from all of these devices at operator-selectable digitization intervals. Recordings are made with cassette tape decks using a 1,200-baud transfer rate. With this recording rate, logging speed is limited by the downhole instruments themselves. Up to 2,000 ft (600 m) of multiplexed logs can be recorded on one side of a cassette.
Each truck is designed to run at least 12 separate downhole tools with minimal operator intervention. At present, three sondes are used routinely and several others are used on an experimental basis. These include a gamma-ray log that uses a 0.75×1.25 in. (1.91×3.18 cm) Nal crystal with downhole scaling in areas where count rates are high. This tool also generates 16- and 64-in. (41- and 163-cm) normal calibrated resistivity curves. A single-point resistivity curve can be recorded for correlation with older uranium logs. Also, a spontaneous potential (SP) curve is measured but is difficult to interpret in mineral logging since this potential is the sum of several variable potentials including chemical, membrane, and filtration.
Characterization of Spontaneous Water Imbibition Into Gas-Saturated Rocks
Authors: Li Kewen , Horne Roland N. 
Published: December 2007

Summary
A method has been developed to characterize the process of spontaneous water imbibition into gas-saturated rocks. Water relative permeability and capillary pressure can be calculated simultaneously from water imbibition data using this method. A linear relationship between imbibition rate and the reciprocal of the gas recovery by spontaneous water imbibition was found and confirmed both theoretically and experimentally, even at different initial water saturations. There was almost no effect of initial water saturation on residual gas saturation by spontaneous water imbibition. The higher the initial water saturation, the lower the imbibition rate and the ultimate gas recovery. It was found that the capillary pressure did not vary with initial water saturation in a certain range. The capillary pressure and the water relative permeability calculated using the new method was consistent with the experimental results measured using other techniques. The method developed in this paper is also of importance for scaling up experimental data.
Quantifying Uncertainty in Production Forecasts: Another Look at the PUNQ-S3 Problem
Authors: Barker John W. , Cuypers Maarten , Holden Lars 
Published: December 2007

Summary
A synthetic reservoir model, known as the PUNQ-S3 case, is used to compare various techniques for quantification of uncertainty in future oil production when historical production data is available. Some results for this case have already been presented in an earlier paper.1
In this paper, we present some additional results for this problem, and also argue an interpretation of the results that is somewhat different from that presented in the earlier paper. The additional results are obtained with the following methods: importance sampling, history matching of multiple models using a pilot-point approach, and Markov Chain Monte Carlo (MCMC).
Efficient Conditioning of 3D Fine-Scale Reservoir Model To Multiphase Production Data Using Streamline-Based Coarse-Scale Inversion and Geostatistical Downscaling
Authors: Tran Thomas T. , Wen Xian-Huan , Behrens Ronald A. 
Published: December 2007

Summary
In addition to seismic and well constraints, production data must be integrated into geostatistical reservoir models for reliable reservoir performance predictions. An iterative inversion algorithm is required for such integration and is usually computationally intensive because forward flow simulation must be performed at each iteration. This paper presents an efficient approach for generating fine-scale 3D reservoir models that are conditioned to multiphase production data by combining a recently developed streamline-based inversion technique with a geostatistical downscaling algorithm.
Production data cannot reveal fine-scale details of reservoir heterogeneity because they respond to the spatial variation of larger-scale effective properties. By solving the streamline pressure solution at a coarse scale consistent with the volume support of production data, we are able to invert numerous geostatistical realizations. Additionally, the streamline method allows fine resolution along the 1D streamlines independent of the coarse-grid pressure solution, so we do not need to explicitly address multiphase scaleup.
Multiple geostatistical fine-scale models are upscaled to a coarse scale used in the inversion process. After inversion, the models are each geostatistically downscaled to multiple fine-scale realizations. These fine-scale models are now preconditioned to the production data and can be upscaled to any scale for final flow simulation.
A 3D extension of the prior 2D sequential self-calibration method (SSC) is developed for the inversion step. This method updates the coarse models to match production data while preserving as much of geostatistical constraint as possible. A new geostatistical algorithm is developed for the downscaling step. We use Sequential Gaussian Simulation (SGS) with either block kriging or Bayesian updating to "downscale" the history-matched coarse scale models to fine-scale models honoring fine-scale spatial statistics. Combining these two developments we are able to efficiently generate multiple fine-scale geostatistical models constrained to well and production data.
History Matching Under Training-Image-Based Geological Model Constraints
Authors: Caers Jef 
Published: December 2007

SummaryHistory matching forms an integral part of the reservoir modeling workflow process. Despite the existence of many history-matching tools, the integration of production data with seismic and geological continuity data remains a challenge. Geostatistical tools now are routinely employed for integrating large-scale seismic and fine-scale well/core data. A general framework for integrating production data with diverse types of geological/structural data is largely lacking. In this paper, we develop a new method for history matching that can account for production data constraint by prior geological data, such as the presence of channels, fractures, or shale lenses. With multiple-point (MP) geostatistics, prior information about geological patterns is carried by training images from which geological structures are borrowed, then anchored to the subsurface data. A simple Markov chain is proposed to iteratively modify the MP geostatistical realizations until history match. The method is simple and general in the sense that the procedure can be applied to a wide variety of geological environments without requiring a modification of the algorithm. The method does not make assumptions on the flow model. Synthetic cases are used to assess the flexibility of the proposed method.
Application and Analysis of Simultaneous Near Bit and Surface Dynamics Measurements
Authors: Macpherson J. D. , Jogi P. N. , Kingman J. E. E. 
Published: December 2007

Summary
Axial, torsional, and bending vibrations are all present in a bottomhole assembly (BHA) while drilling. The dynamic response of the BHA depends on many variables, such as drilling parameters, BHA design, hole condition and inclination, and formation properties. Events, such as bit bounce, forward and backward whirl of the BHA and the bit, and drillstring resonance can occur during drilling. Some of these events are very detrimental and can cause drillstring component failures, twist-offs, etc.
This paper deals with the analysis of measured drilling vibration data from a field test that used both downhole- and surfacevibration measurement devices. Surface sensors included dynamic axial and torsional strain gauges and accelerometers and a singleaxis magnetometer, all mounted in the drillstring above the rotary table. Downhole sensors included an axial accelerometer, two orthogonal bending-moment strain gauges, dynamic weight-on-bit (WOB) and torque strain gauges, and two orthogonal magnetometers, mounted in a measurement while drilling (MWD) sub. The field test involved several drilling runs that included drilling and reaming with polycrystalline diamond compact (PDC) and tricone bits in rotary and motor assemblies.
The analysis described in this paper involves the determination of axial and torsional wave velocities in the drillstring; their use in predicting resonant frequencies; a comparison of predicted and measured resonant frequencies; inference of downhole dynamics with surface measurements (surface noise cancellation), including a comparison of results with measured downhole data; an example of the detection of BHA whirl with downhole data; an example of the detection of bit bounce with downhole axial data; and an examination of precession of the trilobed bottomhole pattern generated by a tricone bit.
The advantages of using either surface or downhole dynamic measurements in identifying different drilling problems are demonstrated as well as the inference of downhole dynamics with surface measurements. Once drilling dynamics problems are identified, remedial action can be taken to reduce tool and bit failures while drilling, thus optimizing the drilling process.
Pressure Transient Analysis for Two-Phase (Water/Steam) Geothermal Reservoirs
Authors: Garg S. K. 
Published: December 2007

AbstractA new diffusivity equation for two-phase (water/steam) flow in geothermal reservoirs is derived. The geothermal reservoir may be initially two-phase or may evolve into a two-phase system during production. Solutions of the diffusivity equation for a continuous line source are presented; the solutions imply that the plot of bottomhole pressure vs. log10t (t = time) should be a straight line. The slope of the straight line is inversely proportional to the total kinematic mobility. Comparison of the theory with a limited number of computer-simulated drawdown histories shows excellent agreement.
Laboratory Studies of Gasification Kinetics for Western Coals Under Conditions Expected During In-Situ Combustion
Authors: Young John E. , Fischer Jack , Wong Samuel H. 
Published: December 2007

Abstract
Kinetics for the reaction of steam with western U.S. sub-bituminous chars are described for operating conditions characteristic of those expected during underground coal gasification (UCG). The mineral matter present in these coals has been found to have significant catalytic activity for the water/gas shift reaction. Also, the inorganic constituents of brackish waters occurring naturally in western aquifers have been found to have little effect on the gasification rates.
An Experimental and Analytical Study of Steam/Water Capillary Pressure
Authors: Li Kewen , Horne Roland N. 
Published: December 2007

Summary
Significant mass transfer between the steam and water phases makes it difficult to measure steam/water capillary pressure using routine methods. Because of the difficulties, few experimental data are available. A formula was derived on the basis of the Kelvin equation to calculate steam/water capillary pressure. The waterphase temperatures and pressures measured with a steady-state flow method were used to perform the calculations. The preliminary results of both drainage and imbibition steam/water capillary pressure were obtained. It was confirmed that the lowering of vapor pressure was small, but the capillary pressure was significant for the system studied. This experimental observation is consistent with thermodynamic analysis.
The Nominal Sand-Control Screen: A Critical Evaluation of Screen Performance
Authors: Underdown D. R. , Dickerson R. C. , Vaughan W. 
Published: December 2007

Summary
Over the past few years, several premium sand-control screens have been introduced into the market. The proliferation of new screens has raised questions about how to choose the proper sand-control screen for a particular formation. To address this concern, a project was initiated at ChevronTexaco Exploration Production Technology Co. (EPTC) to devise a method to evaluate sand-control screens.
As a result of this program, a method has been standardized for the evaluation of sand-control screens. The method, known as the screen efficiency (SE) test, shows the relationship between normalized sand-control characteristics (i.e., sand-control factor) of the screens and the normalized length of time it takes a screen to plug under a certain set of conditions (i.e., the performance factor). The results of SE tests to evaluate several sand-control screens for a North Sea and a west Africa field are discussed in the paper.
The data in this paper also document that the numerical ratings given by the manufacturers are generally not very useful in understanding the sand-control rating of the particular screen or in comparing screens from different manufacturers. In addition, the effect of particle size distribution and sand concentration on the relative performance of sand-control screens was demonstrated by a comparison of SE plots of sands from the North Sea and west Africa fields.
A Unique Cost-Effective Technique for One-Trip Selective Gravel Packing Over Multiple Zones: Dacion Field Case Study
Authors: Marshall John , Obianwu Chike , Tibbles Raymond , Vargas William 
Published: December 2007

Summary
Selective gravel-pack completions of multiple zones present the oil industry with major challenges and expenses. Current practices have two key problems associated with them: they are limited to zones separated by 30 to 50 ft (depending on the treatment type) because of the length of the assemblies, and they have proven to have a higher risk of installation failure.
This paper describes equipment and procedures for gravel packing multiple zones in a single completion with total zonal isolation for spacing as small as 5 ft. Zones can be produced separately or comingled. Risk of execution failure is significantly lower than with conventional stacked packs. Production data is presented that verifies complete zonal isolation, improved productivity, and reduced costs from this technique.
Wellbore Position Errors Caused by Drilling-Fluid Contamination
Authors: Wilson Harry , Brooks Andrew G. 
Published: December 2007

Summary
Recent improvements in magnetic-survey quality control have revealed the presence of systematic azimuth anomalies that affect the calculated trajectories of a significant number of wells. Although these anomalies display some features commonly associated with drillstring magnetic interference, they cannot be removed by traditional magnetic correction techniques. New magnetic-survey quality-control procedures have identified the problem as an attenuation of the transverse component of the Earth's field, similar to that caused by magnetically permeable material surrounding the magnetometers. The drill collars housing the sensors were inspected but showed no magnetic susceptibility, which led to the suspicion that the problems were caused by magnetic particles suspended in the drilling fluids. Laboratory testing has confirmed the magnetic properties of these fluids, and chemical analysis has verified the presence of iron in significant quantities. Field examples demonstrate the use of a multiple-survey qualitycontrol and correction method for identification and removal of these survey anomalies.