bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Formation Absorption on the Thermal Neutron Porosity Measurement
Authors: Ellis D. V. , Flaum C. , Galford J. E. , Scott H. D. 
Published: December 2007

Abstract
Compensated thermal neutron porosity devices provide reliable estimates of formation porosity in standard borehole conditions. Departure from these conditions perturb the measurement and it is necessary to apply corrections to determine the true porosity. One common perturbation is due to the salinity of the formation water.
As the salinity of the formation water increases, its hydrogen density (or index) decreases. By itself, this would cause the apparent porosity reading to decrease, reflecting a lower hydrogen content. The additional chlorine, however, causes an increase in the thermal neutron capture cross section (Σ) that depresses the thermal neutron flux in the formation. This, in turn, tends to increase the apparent porosity. Empirical correction charts have been established for these two competing trends. They are sufficient for correcting porosity readings for salinity effects. However, the presence of additional thermal neutron absorbers associated with either the rock matrix or the pore fluid can result in a residual error on the porosity estimate even after salinity correction. This arises because the correlation between Σ and porosity, used to derive the salinity correction, is no longer valid.
An analysis of the response of a compensated thermal neutron device has been made in terms of the slowing-down length, and diffusion length. It provides a simple method of describing salinity, absorption and lithological effects, and results in a predictive model of the tool response that separates neutron absorption effects from changes in hydrogen index. The model is shown to conform to established salinity corrections as well as to measurements made in laboratory formations with large values of Σ. It provides a means of correcting apparent neutron porosity values for variations in formation Σ not associated with salinity.
Quantitative Flood Monitoring Utilizing a New Pulsed Neutron Tool Modeling Concept
Authors: Smith M. P. , Wyatt D. F. 
Published: December 2007

ABSTRACT
A new flood monitoring technique is presented that models both the capture cross section (sigma) and ratio/porosity responses of a pulsed neutron logging tool using known reservoir, hydrocarbon and flood agent properties. Open hole logs and pulsed neutron logs acquired before, during and after flooding are combined to determine individual hydrocarbon, saltwater and flood agent saturations. This new model uses total neutron migration length and direct ratio computations1 to compute the flood agent volume fraction. Improved accuracy of the computed fluid saturations and the ability to handle specific flood agents are two enhancements to flood monitoring provided by this new approach. Accuracy is especially important because often the results from a limited number of monitor wells are used to project the sweep efficiency and economics of the flood process for an entire reservoir.
This new method is applied to a CO2 flood and the resulting fluid saturations for oil, saltwater and CO2 are analyzed and discussed. These results are compared with those based on the older excavation effect method.2,3,4
A New Flowmeter for Production Logging and Well Testing
Authors: Piers G. E. , Perkins J. , Escott D. 
Published: December 2007

ABSTRACTThere are two primary reasons to utilize a flowmeter. One reason is to measure total flow rate at different depths in a well. Total flow is then used for a single phase flow profile or used in conjunction with other sensors to produce a multiphase flow profile. Measurement of transient rate in conjunction with pressure transient testing is another use of the flowmeter. The analysis of these transients then yields reservoir parameters such as permeability, skin, and reservoir pressure. In either case, flow rates must be accurately measured or gross errors in the final interpretation will result.Multiphase flow, especially in deviated wells, often results in an unpredictable flowmeter response. Most wells are multiphase downhole with a high percent of water present even though little or no water is being produced at the surface. This downhole condition makes it difficult to derive an accurate flow rate from a measured spinner speed. Petal basket flowmeters attempt to force fluids into a flow regime that can be measured but fail because all of the flow is not diverted through the metering section.A new flowmeter is described that has a linear, predictable response in single and multiphase flow and results in a much better measurement of downhole flow rates. Flow loop data are presented, comparisons are made of the new flowmeter response with other flowmeter responses and the results of field tests are discussed.
Design, Execution, and Analysis of a Stimulation to Produce Gas from Thin Multiple Coal Seams
Authors: Hanson M. E. , Nielsen P. E. , Sorrells G. G. , Boyer C. M. , Schraufnagel R. A. 
Published: December 2007

ABSTRACTA single hydraulic fracture stimulation was designed to contact several thin coal seams in a broad vertical interval overlying a narrow open hole section. The design was based on a large water prepad to create the required height growth. Analyses of extensive fracture diagnostics confirm that significant height growth occurred through the interval.
Evaluation of Initial Reservoir Data to Estimate Devonian Shale Gas Reserves
Authors: Vanorsdale C. R. , Boring P. A. 
Published: December 2007

ABSTRACT
This study analyzes the Devonian shale gas reservoirs of the Appalachian Basin and the applicability of using initial test data to assign reserves in this reservoir system. Data has been collected on over 500 such wells and recovery has been related to initial test data to assess the reliability of reserve estimation. This study concludes that there is no true linear relationship between recovery and initial test data.
Oil Production from the Troll Field: A Comparison of Horizontal and Vertical Wells
Authors: Kossack C. A. , Kleppe J. , Aasen T. 
Published: December 2007

ABSTRACTOil production from thin oil columns in deep water environments, such as one finds in the Troll Field in the North Sea, presents difficult coning problems at economical production rates. A pattern of oil production wells must effectively drain a designated area at a high oil production rate. If too few vertical wells are drilled, the wells will be shut in due to high gas-oil ratio before the oil recovery is satisfactory. If two many wells are drilled they interfere with each other and may cone gas even earlier. The drilling of horizontal wells has been proposed as a possible solution to this problem.This paper investigates numerically the performance of various patterns of vertical wells and compares the results with the performance of a pattern of horizontal wells. The effect of the length of the horizontal wells, their location relative to the fluid contacts, the change in performance with production rate, and the effect of an oil saturation in the rock below the water-oil contact are all investigated. The most significant results found were that a 1500 foot horizontal well would produce the same amount of oil as two vertical wells in a typical sector pattern when the sector is produced at a constant oil production rate, and a 2000 foot horizontal well would perform much better than three vertical wells. Also, specially designed production schedules were determined that would increase the life of the horizontal wells significantly, and yield oil recoveries of up to 30%.
Designing Gyp Scale Removal Treatments Based on Chemical Characteristics to Optimize Field Performance
Authors: Schutte R. W. 
Published: December 2007

ABSTRACT
In recent years, gyp (calcium sulfate) scale removal techniques have become increasingly complex and the number of fluids and additives have continually grown. The purpose of this paper is to provide the field engineer with the fundamental understanding of the calcium sulfate removal procedures and the roles different fluids and additives play in this process so that a more cost effective treatment can be planned.
Cost effectiveness can be achieved by minimizing the number of treatment phases necessary to complete a chemical calcium sulfate scale removal treatment. Also, the success of the treatment can be enhanced by minimizing residual chemical compounds left in the formation.
Turbulent Flow of Stimulation Fluids: An Evaluation of Friction Loss Scale-Up Methods
Authors: Lord D. L. 
Published: December 2007

ABSTRACT
Uncertainty exists in our industry over selection of the most appropriate means to satisfy the simplest of scale-up requirements. The requirement in question being conversion of isothermal pressure loss measurements made with "simple" fluids in smooth laboratory pipes to appropriate values for field-size tubing and casing. These fluids are classified as "simple" because they comprise the time-independent, homogeneous, linear polymer-in-water solutions that form the nucleus of most stimulation fluid formulations. It is only after determination of an appropriate scale-up method that our industry can make real progress toward solution of more difficult problems dealing with the effects of non-isothermal conditions, pipe roughness, non-homogeneity, and time and/or energy dependency. Addressing these more difficult problems will permit development of more reliable correlations to be used in making bottomhole treating pressure estimates for real-time analysis.
The current uncertainty associated with scale-up is fostered by availability of a wide variety of methods, each of which appears to be unique in its formulation. In this paper, we provide comparisons among various scale-up procedures in use and/or available to industry. These comparisons are made using laboratory data collected from turbulent flow experiments conducted in nominal 3/4 to 2-in. [1.905 to 5.08-cm] Schedule 40 pipe using 0.36 to 0.95 weight percent hydroxypropyl guar in water solution. Complicating this analysis is the fact that a non-trivial scale-up method does not exist, i.e., it is necessary to determine unique, method-dependent parameters for each fluid formulation using turbulent flow pressure loss measurements obtained with the fluid in question. Each scale-up procedure evaluated is shown to produce a diameter invariant correlation of the type necessary to facilitate scale-up. Using these various diameter invariant correlations (all developed from the same data base), conflicting predictions for large diameter friction loss are produced. At a fixed fluid velocity and with increasing pipe diameter, percent friction reduction below that of water was predicted by the various methods to either increase, decrease, or remain the same. The significance of these variations in terms of their impact on stimulation operations is discussed.
Gravel Pack Studies in a Full-Scale, High-Pressure Wellbore Model
Authors: Schroeder D. E. 
Published: December 2007

ABSTRACT
The low perforation efficiency in many gravel pack completions suggests that current technology used in these completions could be improved. A full-scale, high-pressure visual wellbore model has been built to study the gravel packing process. This 100 ft long model is capable of operating at pressures up to 1,000 psi. It has 280 perforations over a 35 ft zone to accurately simulate a typical 500 md Gulf Coast well.
Excellent reproducibility has been obtained with the model. Model experiments show that the circulating/squeeze pack method performs better than the squeeze method, and that standard HEC carrier fluid is superior to crosslinked CMHEC. As reported by other investigators, highly deviated wells are more difficult to pack than vertical wells. End effects observed in this model show that conclusions drawn from shorter models could be highly erroneous.
An Investigation of Analytical and Numerical Sucker Rod Pumping Mathematical Models
Authors: Schafer D. J. , Jennings J. W. 
Published: December 2007

ABSTRACT
This paper details a study made of the analytical (diagnostic) and numerical (predictive) models commonly used today in the analysis and design of sucker rod pumping systems. The results should help the user of this technology in selecting appropriate values for the several parameters used in applying the models.
Analysis of Flow of Gas and Water in a Fractured and Non-Fractured Low-Permeability Reservoir Under Production
Authors: Arastoopour H. , Chen S. T. , Hariri M. H. 
Published: December 2007

ABSTRACT
We modified Black Oil Applied Simulation Tool (BOAST) Program for gas Reservoirs, and successfully applied it to simulate production of gas from fractured and non fractured low permeability reservoirs. Our modification results in significant decrease in computational time and storage requirements, and allows us to reduce the designated grid blocks to the size of the fractures. Thus the fractures were only distinguished from the matrix By their physical properties. Pressure and saturation of gas and water were calculated at different locations in the reservoir during the production. Our calculation shows that the coproduction of gas and water and presence of the induced fractures significantly enhance the economical production of gas from low permeability reservoirs.
Sweep Efficiency in Multilayered Porous Media: Contrast Between Stable and Unstable Flow
Authors: Soucemarianadin A. , Touboul E. , Bourlion M. , Nittmann J. , Lenormand R. 
Published: December 2007

ABSTRACT
In this paper, we study fluid displacements in layered porous media and focus particularly on the effects of viscous instability and of capillarity. We first present several series of experiments of miscible and immiscible displacements in a three-layer cell with two different permeabilities. We cover a large range of viscosity ratios in the two cases of unstable and stable miscible displacements. The fluid boundaries are followed by visualizations and quantitative saturation data obtained by ultrasonic mapping. The second part of the paper is devoted to the description of a pore network simulator and a stochastic model which are suitable for describing viscous instability. Both models not only reproduce the experimental patterns very closely but are also in good quantitative agreement with experimental data for the ratio of the volumes of fluid injected in the two different layers.
Early Performance and Planning of One-Well Upstructure Drainage Projects in Solution-Gas-Drive Reservoirs at Mississippi Canyon 281
Authors: Lewis L. R. 
Published: December 2007

ABSTRACT
This paper will review the early performance, model predictions, and planned expansion of one-well upstructure drainage projects for improved recovery in solution-gas-drive reservoirs in the Mississippi Canyon 281 Field. This is an innovative secondary recovery process in which significant incremental oil volumes are obtained from relatively small one-well reservoirs at low incremental costs.
Methodology Used in Estimating the Raman Reservoir Fracture System Data for Simulation
Authors: Sener I. 
Published: December 2007

ABSTRACT
Reservoir modelling of a fractured reservoir with any dual porosity/permeability simulator requires three basic fracture properties – fracture porosity, permeability, and average fracture spacing – to be provided as part of the reservoir description. Theoretically, any two of these are sufficient to determine the remaining third. In many instances, however, direct measurements on these properties or good pressure test data are missing or unreliable, making it virtually impossible to infer the fracture properties.
In a recently completed study on the Raman reservoir in Turkey, the spatial variations of the fracture system properties were estimated using a method developed for this purpose. The technique utilizes reservoir structure and layer net thickness data, production information, and some qualitative geological input on the nature of the fractures. The generated fracture system description was later used in successfully history matching close to 40 years of reservoir performance with a fractured reservoir simulator.
This paper presents the principles involved and the methodology that was developed to estimate the required fracture description.
Fracture data before and after the history match are compared to show the extent of the modifications that were needed.
The proposed technique is suitable for the Raman reservoir and others like it. Its application to another situation may require appropriate modifications.
Recent Advances in Polycrystalline Diamond (PCD) Technology Open New Frontiers in Drilling
Authors: Sneddon M. V. , Hall D. R. 
Published: December 2007

Abstract
Recent developments in polycrystalline diamond (PCD) technology have led to breakthroughs in PCD bearing designs and PCD insert cutting structures. The authors suggest that the next major step in bit technology will be to combine these two innovations in a new generation roller cone bit, capable of sustained operation with a PDM or turbine.
Other potential areas of innovation are now made possible with this new technology. One of the first areas will be an integrated high-speed downhole drilling system consisting of the next generation roller cone bit, turbine, and MWD. Another area for development will be a downhole mudhammer for percussion drilling of petroleum wells. A more distant potential development is called the Robotic Advanced Drilling System (RAD), which uses a flexible drillstem and a downhole thrusting mechanism to give WOB and real-time drilling control.
Use Of Log-Derived Parameters For Completion Design Enhancement In The Medina Formation
Authors: Davis R. J. 
Published: December 2007

ABSTRACT
Production in the Appalachian Basin comes primarily from "tight" gas and oil sands of the Devonian and Silurian period. The primary target in Northwestern Pennsylvania and Southwestern New York is the Lower Silurian Medina Formation. Nearly all of these wells are stimulated by hydraulic fracture treatment. Proper treatment of these wells is critical for economic results; therefore, knowledge of reservoir rock properties to enhance the completion design becomes increasingly important.
For improved completion design, measurements of rock mechanical properties need to be obtained. This can be accomplished either with a mini-frac or the use of log values. The optimized completion treatment design would use these properties to accurately determine many important variables including perforation selection, transport fluid type and viscosity, treatment volume and pumping rate, and proppant type and amount (all of which can be related to closure stress). These factors can be determined using the FracHite* Log output of gross fracture height, closure stress gradient, and treatment pressures.
This paper will deal with the application of log-derived parameters in modifying completion design strategy in the Medina formation. These modified completions will be compared with the "cookbook" completions as well as the production results of several wells treated with and without these vital parameters.
Measurement and Analysis of the Pressure Drop in a Vertical Annulus in a Simulated Air Drilling Operation
Authors: Supon S. B. , Adewumi M. A. , Fairchild N. 
Published: December 2007

ABSTRACT
It is important to immediately clear cuttings from the face of the bit and to efficiently carry them to the surface in any drilling operation. Cuttings removal is especially critical in air drilling operations because of the relatively low viscosity of the gas compared to drilling mud. Air can effectively clear and remove cuttings, however, if the proper volumetric flow rate and injection pressure are used.
One important feature of pneumatic conveying of solid particles in vertical pipes is that pressure drop initially decreases as the air velocity decreases, reaches a minimum, and then increases with further drops in air velocity. Eventually, the air flow can attain such a low velocity that the result is a sharp increase in pressure drop often accompanied by flow instabilities and vibration.
The purpose of this study was to experimentally verify the presence of this minimum pressure drop in a simulated air drilling operation and to accurately determine it. The eventual goal is to develop a predictive capability for the velocity that yields this minimum pressure drop since this is an important parameter in optimizing the power requirements.
A plexiglass wellbore model was constructed with air and sand feed lines at the bottom. The air-sand mixture flowed through a cyclone at the top to separate the two components and then recycled back into the feed line at the bottom. The pressure drop across the wellbore model was measured at various sand feed rates and air velocities.
One of the findings of this study is that a minimum pressure drop does indeed occur at all sand feed rates as the air velocity decreases. We also found that there is a velocity at which the air moves too slow to lift any of the particles. No more pressure readings are possible when air is moving at the choking velocity.
This study is the first in a series of studies designed to foster a better understanding of the air drilling process. Our goal is to better understand the mechanics of air drilling and, ultimately, to be able to select the proper surface equipment for an optimized operation.
Suitcase-Size Data Recording System Improves Fracturing Operations
Authors: Weightman G. H. , Roberts T. H. 
Published: December 2007

ABSTRACT
The quality and economy of fracturing operations can be enhanced by using a portable, computerized data acquisition system to monitor and record treatment data on an on-site and real-time basis. Improvements can be realized in equipment and operator performance, job documentation, and post-job analysis on nearly every stimulation job.
Improved Fracturing Technique Yields Increased Production Potential
Authors: Church D. C. , Peters B. A. 
Published: December 2007

ABSTRACT
A new technique is presented for proppant apportionment during hydraulic fracturing which has the potential to increase production through improved placement of conductivity in the fracture. A "ramped" proppant schedule versus a "stair step" design is discussed to show the advantage of ramping the proppant stages. Additionally, case histories are presented which reflect increased hydrocarbon production where this technique has been applied when compared with the conventional "stair step" design.
This paper is limited to hydraulically induced fractures that are in the vertical plane. Further, that deeply penetrating fractures with a constant confined height are desired.
Non-Graphical Solutions for Average Reservoir Pressure from Production or Buildup Data
Authors: Azari M. 
Published: December 2007

ABSTRACT
Simple equations were developed for determination of the distance from wellbore at which the reservoir pressure is the same as average formation pressure. This volumetric averaging method was derived for both constant boundary pressure and no-flow across boundary type of reservoirs. The technique was then extended to transient flow equations to obtain mathematical relationships for determination of average reservoir pressure during either production or buildup periods without the need of a Horner plot or any other published graphs. These equations were then reduced to much simpler forms, by which approximate values of average reservoir pressure could be assertained within 0.01%, provided that rinv/re ratio were greater than seven. Two example problems at the end of this paper compare the results of the proposed equations with the ones obtained by using Miller-Dyes-Hutchinson1, Matthews-Brons-Hazebroek2, Dietz3, and Ramey-Cobb4 methods. Furthermore, the examples show that the approximate equations are still providing very accurate results (within 0.1%) inspite of the rinv/re ratio being much less than seven.