bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scaling Procedures for Capillary Pressure Data at Low Wetting-Phase Saturations
Authors: Melrose J. C. 
Published: December 2007

Summary
New capillary pressure data, applicable to the saturation range below 5%, are reported. The method used to obtain these data involved the determination of low-temperature nitrogen adsorption/desorption isotherms. Three types of samples were studied: Berea sandstone, a producing-reservoir sandstone, and microporous chert extracted from the producing-reservoir sandstone. The data for Berea sandstone, when scaled according to the usual Leverett J-function procedure, did not agree with previously reported data for the air/brine system. Because saturation resulting from wetting films is not expected to scale according to the J-function procedure, one cause of the disagreement could be a significant contribution of wetting films to the total saturation in the low-saturation region. Other contributing causes appear to be a 20% difference in surface area between the two sample sets used in the scaling test and a difference in the clay mineral fabric (pore structure) established under two different test conditions.
Application of Time-Series Analysis to Induced Gamma Ray Spectroscopy Logs From Two Cold Lake Heavy-Oil Observation Wells
Authors: Georgi Daniel T. 
Published: December 2007

Summary
Induced gamma ray spectroscopy (IGRS) logs from two cyclic-steam-stimulation observation wells in Cold Lake were analyzed to determine the vertical resolution and repeatability of data derived from gamma rays of inelastic and capture neutron reac tions. Time-series analysis, a technique that uses the Fourier representation of the log data, was used to quantify the vertical resolution and the signal/noise characteristics of various IGRS log curves and to compute the coherence vs. spatial frequency of data collected on multiple IGRS passes. The coherence function ranges from 1.0 for perfect repeatability to 0.0 for incoherent noise. Because no real variations in the measured data were expected for the 12- to 24-hour data-collection period, any deviation of the coherence function from 1.0 is attributed to incoherent noise. Generally, coherence is high at low frequencies (large vertical scales) and low at high fre quencies (small vertical scales). By noting the frequency at which the coherence level decreases to the expected value of random noise, we can quantify the vertical resolution of a log curve.
Data analysis from these wells indicates that both the vertical resolution and repeatability of individual capture and inelastic curves differ. We found that the H-yield and capture curves have the highest vertical resolution (≈0.3 m) and the best signal/noise ratios (FSN≈30:1). In contrast, the capture Ca and Si yields are of significantly lower quality (FSN≈2:1). Only a small difference exists between the vertical resolution of the inelastic C (1.0 m) and O (1.3 m) yields, but the FSN the O yield is only one-half that of the C yield. Fortunately, the vertical resolution and the repeatability of the C/O ratio, FCO, are determined primarily by the quality of the inelastic C data. Specific to our application of monitoring heavy-oil saturations during cyclic-steam stimulation in a relatively uniform, high-porosity unconsolidated sand, we developed a simplified FCO interpretation that does not rely on the elemental yields from capture data. This linear model permits us to assess the uncertainties in computed saturations from the statistical noise in the inelastic FCO data.
Determination of Reservoir Permeabiiity From Repeated induction Logging
Authors: Tobola D. P. , Holditch S. A. 
Published: December 2007

Summary
When fresh-water mud filtrate invades a gas reservoir containing a saline connate water, a low-resistivity annulus will form and propagate into the formation. Analysis of how readings from an induction log change with time can yield reasonable estimates of formation permeability. This paper describes a method and presents field data that can be used to estimate permeability from time-lapse logging data.
Simulation of Thermal-Well Sucker-Rod Pumping
Authors: Wong Arthur , Sudol Tad A. 
Published: December 2007

Summary
A major problem experienced in pumping thermal wells is low volumetric efficiencies resulting from steam and noncondensable gas interference. This paper examines the results of physical simulations performed on a full-scale sucker-rod pump test facility and numerical simulations that used an equation of state (EOS) to predict theoretical volumetric pump efficiencies.
Experimental Study of Brine Injection and Depressurization Methods for Dissociation of Gas Hydrates
Authors: Kamath V. A. , Mutallk P. N. , Sira J. H. , Patil S. L. 
Published: December 2007

Summary
The two most promising techniques for producing natural gas from hydrate reservoirs are depressurization and brine injection. This paper examines the dissociation characteristics of methane hydrates during these processes. A correlation for the rate of hydrate dissociation during brine injection as a function of salinity, brine temperature, brine injection rate, pressure, and hydrate/brine surface area is presented. Depressurization experiments show that hydrate dissociation results in a decrease in the rate of pressure decline and contributes significantly (15% to 70%) to the cumulative gas production.
An Improved Method for Computing Directional Surveys
Authors: Wilson G.J. 
Published: December 2007

Abstract
Difficulties experienced in correlating vertical and lateral locations of subsurface features that are encountered in directional wells prompted critical review of the tangential method of computing directional surveys. Inherent discrepancies were indicated to cause small incremental but significantly large cumulative errors in computed vertical depth and horizontal departure. A radius of curvature method, developed for planning and analyzing directional wells, was studied as a means of more accurately calculating survey data. Errors incurred in the tangential method were not present in the radius of curvature method. Conflicting assumptions in calculating dog-leg severity by the tangential method were resolved by a new procedure that was derived from the radius of curvature method. Results of the investigation showed the radius of curvature method to be an improved method for computing directional surveys.

Introduction
Many improvements in directional drilling tools and techniques have been made in the past 10 years, but the method of computing survey data has remained virtually unchanged. While use of computers greatly aids the process of calculation' and eliminates many human errors, manual and computer calculations are still made with the assumption that the wellbore consists of straight-line segments. This paper points out discrepancies in the method and presents an improved method in which the wellbore is assumed to be curved.
Steam Zone Growth in a Preheated Reservoir
Authors: Closmann P.J. 
Published: December 2007

Abstract
Steam zone growth as a function of time bas been calculated for the case of constant rate steam injection into a preheated reservoir. To simplify the calculation a linear temperature profile has been assumed in the cap and base rock at the start of steam injection. The results indicate that at early times augmentation of steam zone growth due to preheating should be greatest. At longer times the steam zone development becomes close to that calculated with no preheating.

Introduction
With the increasing application of thermal recovery processes to recover viscous oil, cyclic steam injection has become important in many large-scale projects. In this process the cycle of steam injection followed by oi1 production is repeated a number of times. At the beginning of the second and later cycles, steam is injected into a reservoir that has already been heated but that has lost part of its heat both in produced fluids and by conductive heat loss away from the injection zone. In such a case, the temperature level of the injection zone and the temperature distribution of the surrounding rock will affect the growth of the steam zone developed during the subsequent steam injection. Knowledge of the size of steam zone developed is important in determining the amount of oil displaced and the extent of heating in the reservoir. It is also useful to be able to compute the size of the steam zone for cases where thief zones take most of the injected steam. This paper presents a fairly straightforward method of estimating the steam zone developed in a preheated formation, based on certain simplifying assumptions. Some cases of steam injection into a reservoir at its original temperature have already been considered elsewhere.
Because it is difficult or impossible to obtain an accurate representation of the temperature distribution in the reservoir some time after initial heating has taken place, in this work, a linear temperature profile in the cap and base rock is assumed (Figs. 1A and 1B).
SPEJ
P. 313ˆ
Perturbation Analysis of Stress-Sensitive Reservoirs
Authors: Kikani Jitendra , Pedrosa Oswaldo A. 
Published: December 2007

Summary
The assumption of constant rock properties in pressure-transient analysis of stress-sensitive reservoirs can cause significant error in determination of reservoir transmissibility and storativity. On the other hand, inclusion of pressure-dependent rock properties makes the governing equation for the pressure in the reservoir nonlinear. These nonlinearities can be treated only approximately by numerical means. If a permeability modulus is defined, the nonlinearities associated with the governing equation become weaker and an analytical solution in terms of a regular perturbation series can be obtained for a radial infinite-acting reservoir. Three terms in the perturbation series are derived to show the convergence and accuracy of the solution. The equation obtained for each order (zero, first, and second) in the perturbation series is solved exactly, and hence, the solution is exact to the third order.
The effect of wellbore storage on the pressure behavior is also investigated. First-order approximation for bounded systems is presented to show qualitative effects. A field example is analyzed to determine the permeability modulus and reservoir properties.
Solution of the Immiscible Fluid Flow Simulation Equations
Authors: Breitenbach E.A. , Thurnau D.H. , Van Poolen H.K. 
Published: December 2007

American Institute of Mining, Metallurgical and Petroleum Engineers, Inc.

Abstract
This paper presents the methods used to solve the finite difference equations which we developed in a companion paper (1).
Various possible methods of solution are discussed. Experience has narrowed the numb of suitable numerical methods that are practical to three: Gauss elimination, successive practical to three: Gauss elimination, successive overrelaxation, and the iterative alternating direction implicit process.
The final sections of the paper are devoted to a presentation of computational technique which are vital to actual use of each of the above-mentioned methods.

FINITE DIFFERENCE EQUATIONS, THE MATRIX AND DEFINITIONS
The final finite difference equation for pressure developed in Reference (1) is: pressure developed in Reference (1) is: ..........................................(1)
All the terms are defined in the paper. Here, however, we have dropped the subscript denoting the pressure, p, as an oil pressure. Further breakdown requires definition of the numerical solution to be used. This paper describes the breakdown and solution processes most often used in the MUFFS program. Sufficient detail is given so that computer programming can be done.
Contrary to popular opinion, economic simulation has been found to require the development of several solution methods, rather than relying on a single one. This requires that the computer subprogram for generating coefficients (A's and O's) be written as a distinct, separate entity to supply the coefficients in Equation (1). Furthermore, it is necessary to be able to obtain these coefficients automatically in column-by-column, row-by-raw, or point-by-point form, in any order required by a point-by-point form, in any order required by a numerical solution. Columns, rows, and points refer to the columns, rows, and points of the finite difference grid. A program that can generate coefficients in several forms is a simple but important concept, for it allows the easy insertion and modification of experimental methods. The computing inefficiencies that may be incurred within a general coefficient generator are small in comparison to the computing time saved by using the fastest of several solution techniques.
Reservoir Simulation on Low-Cost, High-Performance Workstations
Authors: Young L. C. , Hemanth-Kumar K. , Bratvold R. B. 
Published: December 2007

Summary
Reservoir simulation with two different computer systems is investigated. A reservoir simulator with demonstrated high performance is used to test these machines. Both systems can perform reservoir simulations at more than 10 times the speed of an Intel 80486 and at a significant fraction of the speed of a supercomputer. With an efficient simulator and enough memory, both processors can solve compositional problems with 40, 000 gridpoints and blackoil problems with 200, 000 gridpoints. With starting prices of less than $15, 000 for a complete machine, these systems provide an attractive alternative to mainframes and supercomputers.
Mud/Gas Separator Sizing and Evaluation
Authors: MacDougall G. R. 
Published: December 2007

SummaryRecent wellsite disasters have led to an increased emphasis on properly sized mud/gas separators. This paper reviews and analyzes existing mud/gas separator technology and recommends separator configuration, components, design considerations, and a sizing procedure. A simple method of evaluating mud/gas separation within the separator vessel has been developed as a basis for the sizing procedure. A mud/gas separator sizing worksheet will assist drilling personnel with the sizing calculations. The worksheet provides a quick and easy evaluation of most mud/gas separators for a specific well application. A brief discussion of other mud/gas separator considerations is provided, including separator components, testing, materials, and oil-based-mud considerations.
Determination of Effective or Relative Permeabilities From Well Tests
Authors: Hatzignatiou Dimitrios G. , Reynolds Albert C. 
Published: December 2007

SummaryThis work presents a procedure for estimating effective or relative permeability curves directly from well-test pressure data obtained from a well producing a solution-gas-drive reservoir. The method requires accurate drawdown data. The basic procedure developed and discussed in this study combines computed effective permeability versus pressure values with nonlinear regression analysis techniques to determine the parameters involved in Standing's and Corey's relative permeability correlations. Once these parameters are determined, effective or relative permeability curves as a function of saturation can be generated.
A Comparison of Mixed-Gas Foams with N2 and CO2 Foam Fracturing Fluids on a Flow-Loop Viscometer
Authors: Harris P. C. 
Published: December 2007

Summary
A study of the rheological properties of mixed-gas foams was conducted on a flow-loop viscometer. The variables studied included different ratios of N2 and CO2 in 70%-quality foams, base gel concentration, crosslinking agent, and temperature.
The rheological properties of mixed-gas foams are very similar to the rheologies of N2 and CO2 foams. This finding was anticipated, because the rheologies of N2 and CO2 foams are similar. The exact static stability behavior of these foams was not anticipated. Pure CO2 70%-quality foams have four to five times the static half-life as pure N2 70%-quality foams. Replacement of CO2 by N2 in a 70%-quality foam decreases the half-life of the foam. The inclusion of only 20%-quality N2 in a 70%-quality mixed-gas foam decreases the foam stability to equal a pure N2 70%-quality foam. We saw no evidence that addition of N2 to a CO2 foam improved its stability.
Previously published foam-rheology equations for N2 and CO2 foams were found to be valid, and only minor adjustment to a few coefficients were needed to include the effects of mixed gases. A BASIC program is included which allows foam viscosity to be calculated as a function of quality, gas type and concentration, external liquid-phase power-law parameters n′ and K′, shear rate, and temperature.
Fluid loss characteristics of mixed-gas foams were found to be the same as for N2 or CO2 foams.
Groundwater Issues Relating to an Alaskan Methanol Spill
Authors: Robertson S.B. 
Published: December 2007

Summary
A Dec. 1989 methanol spill resulted from sabotage to three railroad tank cars. Samples taken from nearby drinking-water wells and groundwater-monitoring wells were below the analytical detection limit. Monitoring well data demonstrated that groundwater flow was not toward local residential wells. Dilution by snow and subsequent freezing in the soil limited the downward spread of the methanol, an advantage not found in milder, more temperate conditions. Contaminated material was removed and processed to reclaim the methanol. Volatilization and biodegradation should remove any remaining methanol. Cleanup options were limited by the possible hazardous waste classification of the contaminated soil. The regulatory status of spilled methanol waste should be re-evaluated, especially if use of methanol as a motor fuel increases.

Introduction
Methanol is used in the oil fields of the North Slope of Alaska for freeze protection. Air temperature, ground temperature (wells are drilled through 2,000 ft [610 m] of permafrost), and gas expansion are sources of cooling that may result in its use. For example, methanol is used to protect pipelines and shut-in water injection wells, to reduce the freezing point of water vapor and hydrates in natural gas handling, and as a component in water-based hydraulic fracturing for well stimulation. Before 1990, Arco Alaska Inc.'s standard practice was to transport the material by railroad tank car to its North Star Pipeyard, a material storage and transfer facility in Fairbanks, AK. There it was transferred to tank trucks and driven up the Dalton Highway (the Trans Alaska Pipeline Haul Road) to Prudhoe Bay.
On Dec. 4, 1989, at approximately 2:30 a.m., while moving tank cars on a siding in the pipeyard, the railroad switching crew noticed methanol leaking from three 30,000-gal [114-m3] -capacity cars. The crew closed the valves on the bottom of the tank cars, which had been opened by saboteurs. Special tools are required to open the valves and seals had to be broken. Graffiti written on all three cars, also indicated that sabotage was involved. The Fire Dept. and other emergency personnel were quickly called to the scene. Because of the potential fire and health risks, nearby residents inhabiting homes southwest of the pipeyard were evacuated. After organic vapor analysis demonstrated little or no atmospheric contamination and no danger of explosion, the residents were allowed to return home. Because vents on top of the cars had not been opened, a partial vacuum developed upon drainage. This prevented release of the entire contents of the cars. Subsequent measurement of the remaining contents revealed that only about 9,300 gal [35 m3] of methanol had spilled, rather than the 67,000 gal [254 m3] originally feared.
Time Series Analysis for Reservoir Zonation
Authors: Bennion D.W. 
Published: December 2007

A time series is a set of data of which each element is associated with a moment of time. In this report the elements of the set are denoted by x(t). If two time series are used, the second will be denoted by y(t). Well logs can be considered to be time series and can be analyzed using time series techniques. Methods for analyzing time series have been discussed by Weiner and Bendat and Piersol, and have been employed in geophysical studies. The cross-correlation function is used for two time series whose elements are x(t) and y(t). It is used to determine the dependence of the two series on each other. The cross-correlation function is given by the following equation:
(1)
(2)
where
Rsy = cross-correlation function for time series x(t) lagging y(t) by lag number r Ryx = cross-correlation function for times series y(t) lagging x(t) by lag number r N = number of data points in each time series r = lag number r = 0, 1, 2, . . . . m m = maximum lag number, usually 10 to 15 percent of N.
If each time series is normalized so that it has a mean of zero and a variance of one, the cross-correlation function will range from minus one to plus one. A perfect correlation between two time series yields the value plus one. Filtering is used to remove noise from time series and thus helps to increase the cross-correlation function. Many techniques to filter out noise have been proposed. For this report a simple smoothing method proposed by Healy and Bogert was used.
(3)
where
Si = smoothing data, i = I to F Xk = unsmoothed time series Wj = weighting series G = a given selection interger; for example, G=3 applies weight to every third item of the time series N = number of sample points in time series M = number of weights, must be odd k = j . G - G + r r = i - I + 1
I =
F = N - .
P. 913
Extended-Reach Drilling From Platform Irene
Authors: Mueller M. D. , Quintana J. M. , Bunyak M. J. 
Published: December 2007

Summary
Two wells extending more than 2 miles were drilled from Platform Irene in the Pt. Pedernales field, offshore California. These wells are the two longest extended-reach wells on the U.S. west coast. Although several wells around the world have been drilled beyond two miles, none extend at such shallow true vertical depths (TVD's) as the two from Platform Irene. The average angles from rotary table to total depth (TD) for Platform Irene Wells A-16 and A-17 are 70.9° and 68.2°, respectively. This paper presents the concepts of a "negative-weight well" and "drag-risk analysis, " focusing on the innovative technology used to drill and complete a high-drag well. The successful drilling and completion of these wells will allow recovery of millions of barrels of oil originally expected to be produced from a second platform.
Gravel-Pack Field Examples of a New Pulsed-Neutron-Activatlon Logging Technique
Authors: Watson J. T. , Carpenter W. W. , Carroll James F. , Smith B. C. 
Published: December 2007

Summary
Gravel packs traditionally have been evaluated with gamma/gamma density and neutron logging tools, but some environments adversely affect the measurement resolution of these tools. These environments include high-density completion fluids, matched-density gravel-pack systems, and changes in fluid density and hardware. This paper presents an alternative measurement of gravel-pack quality.
A Coupled Analysis Approach to the Assessment of Marine Drilling Systems
Authors: King G. W. , Burton Kevin , Hodgson Trevor 
Published: December 2007

SummaryThis paper describes the development of a new approach to marine-drilling-system analysis. From studies with traditional analysis techniques where components were treated independently, a decision was made to develop a new model. This new model was based on a requirement to analyze the system as a complete entity by "coupling" the system components. This new approach was used to analyze the behavior of a drilling riser and conductor. It has demonstrated the influence of conductor parameters on riser response and the factors that influence conductor design.