bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of the 1987 IADC Roller Bit Classification System
Authors: Winters W. J. , Senger J. , Oliver M. S. 
Published: December 2007

ABSTRACT
The IADC (International Association of Drilling Contractors) roller bit classification system provides a convenient method for categorizing rock, bits according to their design features and intended applications. The system has been used worldwide since 1972. The 1987 version includes improvements which reflect the latest design trends in roller cone bits.
This paper explains the IADC roller bit classification code. Current classification charts are shown for major bit manufacturers. The relationship between IADC code, bit design factors, and operating guidelines is discussed. Examples depict the major design features included in the code.
Diamond Bit Handling and Operation
Authors: Allamon J. P. , McKown T. , Hill D. , Brooks B. A. , Bayoud B. B. , Winters W. J. 
Published: December 2007

Abstract
The predominant experience throughout the drilling industry is with roller cone rock bits. However, diamond bit use has increased substantially in the past five years and continued increases are likely. Diamond bits are different enough in their design and function that they require distinctly different handling and operating procedures. This paper describes such procedures from the point the bit is unboxed, through make-up in the rotary table, tripping into the hole, washing and reaming to bottom (with attention to downhole motors), establishing a new bottomhole pattern, identifying pumpoff effects if present, establishing a satisfactory penetration rate, responding to formation changes, and recognizing and diagnosing indications that may lead to the decision to trip out of the hole. This paper bridges the gap between two other related papers which describe how new diamond bits are classified before they go in the hole23 and how worn diamond bits are graded once they are out of the hole24.
Drilling and Workover Experiences in the Greater Ekofisk Area
Authors: Anvik H. K. , Gibson W. R. 
Published: December 2007

ABSTRACT
Since its discovery in 1969, the Ekofisk Area has developed into one of the most industrious oil centers in the North Sea. The Ekofisk Area presently encompasses twenty-five permanent platforms of which eleven are production/injection platforms with over 125 active wells. To date, 113 workovers have been performed on these wells. Production from the Ekofisk Area peaked on February 8, 1980, when 618,000 BOPD and 1,860 MMSCFD gas were produced. Development drilling activity peaked in late 1979 when there were ten active drilling or workover rigs on nine platforms. Today, there are four drilling and workover crews active in the area.
Reservoir depletion and compaction and the resulting seabed subsidence have altered drilling and workover operations over the past six years. This paper discusses how current drilling and workover practices have evolved in the Ekofisk Area.
Grand Canyon Directional Drilling and Waterline Project
Authors: Lattimore G. M. , Carden R. S. , Shursen Grace , Fischer T. 
Published: December 2007

ABSTRACT
A high inclination directional drill hole was designed as a conduit to carry a fresh water pipeline from an intermediate pump station to the south rim of the Grand Canyon. This use of directional drilling technology was judged superior to an external pipeline for reasons of worker safety, aesthetics, pipeline protection and costs. The hole was designed to meet Park Service criteria: sufficient diameter to contain 8″ water line and exit point accessability.
The hole was drilled to a maximum inclination of 71°. True vertical depth was 2800 ft (855 m) and horizontal displacement was 3800 ft (1160 m). Measured depth along the wellbore was 5075 ft. (1555 m).
A "build-and-hold" pattern was employed from below surface casing, using positive displacement motors, tricone bits and "build" type rotary drilling assemblies. An air and mist circulating system was employed. Modifications of mud drilling equipment were made for air service.
Primary directional measurement was performed with magnetic singleshot instruments. Three confirmation/comparrson gyro runs were made. The visibility and accessability of the exit point afforded an opportunity to compare downhole surveying techniques with surface systems of known and verifiable accuracy.
Drilling problems encountered included: loss of circulation, fractures, solution cavities, severe torque and drag, severe drill string damage, hole cleaning, and sealing and cementing of an open-ended annulus. Solutions considered and implemented are discussed.
Rheological Properties of Foam Fracturing Fluids Under Downhole Conditions
Authors: Cawiezel K. E. , Niles T. D. 
Published: December 2007

ABSTRACT
Foams are complex mixtures of gas and liquid whose rheological properties are largely influenced by foam quality, temperature, pressure and shear rates. A comprehensive study of the effects of these variables on the rheological properties of foams was conducted as a first step to understanding, defining and predicting the rheological properties of foam fracturing fluids.
Rheological properties of nitrogen/water/surfactant foams and gelled foam fluids were evaluated using a recently developed foam rheology simulator. The simulator is capable of exposing foam fluids to temperatures of 400°F (204°C), pressures to 10,000 psi (68.9 pKa) and shear rates to 100,000 sec−1. Results indicate that the rheological behavior of foam fluid is primarily that of a yield-pseudoplastic fluid and can best be described by a Herschel-Bulkley model. As foam quality increases so does its apparent viscosity and it becomes increasingly more pseudoplastic. Foams exhibit yield points whose dependency on quality is very similar to that of apparent viscosity. Temperature has little affect on the foam flow behavior but significantly affects its viscosity. The apparent viscosity of the foam decreases as the temperature of the foam increases. Pressure increases cause an increase in the apparent viscosity of foam systems, while an increased shear rate reduces the apparent viscosity. Effects of foam quality, temperature, pressure and shear rate on gelled foam fluids follow the same trends as those found for simple nitrogen foam fluids. Differences in bubble size and bubble size distribution effect changes in foam quality, etc., and give physical explanations for the observed changes in the rheological behavior of foam fluids.
The complexity of foam systems and their sensitivity to external conditions require that foam system properties be closely controlled and monitored in field use to optimize the frictional pressure required to utilize foam fracturing fluids.
Production Improvement Through Identification of Conductive Natural Fractures Utilizing Multiple Radioactive Isotope Technology
Authors: Lopus T. A. , Seifert D. J. , Schein G. W. 
Published: December 2007

ABSTRACT
Recently developed technology with a high-rate, high-volume stimulation technique has been utilized to identify naturally conductive fractures in the Austin Chalk. Past completion theories suggested that conventional two wing vertical hydraulic fractures could be achieved. However, the fracture gradient of the Austin Chalk matrix is approximately 1.0 psi per foot. Experience has shown that treatment pressures equate to a conventional fracture – gradient of .50 to .68 psi per foot. The use of gamma ray spectroscopy devices and multiple radioactive isotopes has helped verify that hydraulic fracturing treatments are limited to the naturally existing fractures.
A recompletion program has been developed utilizing the following procedure:
A base Compensated Spectral Natural Gamma Ray (CSNG)* log is run. The well is perforated utilizing original open hole logs and the CSNG to identify natural fractures and previously produced intervals. A high-rate, high-volume stimulation treatment intended to remove by dissolution or abrasion secondary mineral deposits in the natural fracture system is performed. Within the stimulation treatment, diverters are incorporated which are traced using multiple radioactive isotopes. A post treatment CSNG Log is run and the TracerScan* technique, which resolves the different isotopes, is used to identify zones of fluid entry and subsequent diversion.
An increase in production has been observed using this technique. A description of the stimulation process, multiple isotope placement and TracerScan technique along with log examples and production history are presented.
A Method for Predicting Horizontal Well Performance in SolutionGas-Drive Reservoirs
Authors: Plahn S. V. , Startzman R. A. , Wattenbarger R. A. 
Published: December 2007

ABSTRACT
A new set of type curves are presented which can be used to forecast oil production from horizontal wells producing at their maximum rate (with constant hottomhole pressure) from homogeneous, isotropic, solution-gas drive reservoirs.
The type curves were developed by correlating the results of 48 reservoir simulation runs. The input i data used in the simulation runs was chosen so it would encompass a wide range of PVT properties, relative permeability characteristics, rock properties, and well dimensions.
A new dimensionless variable is proposed which normalizes the reservoir simulation results. It appears, therefore, that production forecasts can be made without the use of a reservoir simulator. The type curves should be used primarily to screen can didate reservoirs for horizontal drilling possibilities.
Coupling and Attenuation: A New Measurement Pair in Cement Bond Logging
Authors: Leslie H. D. , de Selliers J. , Pittman D. J. 
Published: December 2007

ABSTRACT
Acoustical coupling is proposed as a new measurement to complement the attenuation rate measurement now available with multispacing cement bond logging tools. Coupling responds principally to the mechanical impedance and distribution of material outside the casing, but is largely insensitive to bonding. Estimates of cement strength may be obtained even in the presence of microannulus.
Viscoelasticity of Crosslinked Fracturing Fluids and Proppant Transport
Authors: Acharya A. 
Published: December 2007

ABSTRACT
In hydraulic fracturing treatments, the success of the treatment strongly depends on the proper placement of the proppant particles in the fracture. By proper placement, one means the packing of the fracture to achieve maximum conductivity of gas/oil through the fracture into the wellbore. The placement of the proppants along the fracture is based on design equations where sand transport velocity is related to the rheological parameters of the fracturing fluid and characteristics of the proppant particle such as size and density. The current design equations consider viscous parameters such as K' and n' of power-law model. In practice, however, there are numerous cross-linked fracturing fluids which are not just viscous, but visco-elastic in nature. At present, there are no design equations for proppant transport that can be incorporated into a hydraulic fracturing program which takes into account linear and non-linear viscoelasticity of cross-linked fluids.
The purpose of this paper is three fold. The first part of the paper describes the theoretical transport equations that take into account the elasticity of the fluid in predicting proppant settling rate in the fracture. The second part of the paper presents the experimental data of commonly used fracturing fluids (titanate and borate cross-linked). The rheology data includes both viscous and elastic parameter measurements using Rheometrics Pressure Rheometer and Rheometrics Mechanical Spectrometer. This data shows some important differences between borate cross-linked gels and titanate cross-linked gels. The third part of the paper presents experimental data of proppant settling rates in various fracturing fluids and how these can be correlated with rheological parameters that were obtained in this work. The difference in rheology between borate and titanate gels was correlated with the difference in settling rates of proppants in these two gels. Based on the theoretical and experimental work presented in this paper, it is concluded that the model for proppant placement in a hydraulic fracture should include: (i) proppant characteristics, (ii) viscous rheological parameters (K' and n'), (iii) elastic parameters (complex dynamic viscosity) from linear viscoelastic constitutive equation, and (iv) normal stress difference from non-linear viscoelastic constitutive equation. The influence of cross-linked polymer gel network structure on proppant transport is also discussed.
Understanding Formation Damage Processes: An Essential Ingredient for Improved Measurement and Interpretation of Relative Permeability Data
Authors: Amaefule Jude O. , Ajufo A. , Peterson E. , Durst K. 
Published: December 2007

ABSTRACT
Anomalous trends have been observed in laboratory-derived relative permeability data especially in rock samples that contain mobile (siliceous/micaceous/ kaolinitic) fines and/or water sensitive clays. Water-oil relative permeability data determined for such rocks by the unsteady-state technique have at times exhibited the following characteristics:Non-monotonic trends with saturationSlightly S-shaped relative water permeability with a ‘bend-over’ at high water saturationsRebound in relative water permeability at residual oil saturation with reversal in flow direction
These characteristics are indicative of adverse physicochemical interactions between the flowing phases and the rock, which invalidate the relative permeability concept.
This paper presents the results of laboratory studies conducted to elucidate the role of formation damage processes in the determination of relative permeability data. Experimental data generated on rocks with fine particulates, indicate that mechanically induced damage can occur if the displacing fluid velocity, increased to overcome capillary end effect, exceeds the critical velocity for mobilization of resident mineral fines. Chemically induced damage was found to accompany the mechanical damage if the injected brine was not in ionic equilibrium with the rock.
Most friable samples containing micas, feldspars and illite/kaolinite, which have potassium ions in their interlayer sites, were damaged by the flow of sodium and/or calcium chloride brines during brine permeability tests. Critical velocities for entrainment of fines were determined to be higher for KCl brines than for NaCl/CaCl2 brines in water-wet Berea samples.
Laboratory protocols which eliminate formation damage processes during relative permeability measurement have been developed and are presented in this paper. These include: (a) use of velocities less than critical for floods on butted cores with lengths sufficient to reduce capillary end effects, (b) addition of trace ions such as K+ ions in simulated formation brines, (c) equilibration of the fluids with the rock and the use of aged fluids for dynamic displacement. Unsteady-state imbibition tests performed on short core plugs at flowrates greater than critical for fines mobilization, are discouraged. Rather, low rate floods should be conducted and the data analyzed by numerical techniques which include the capillary pressure term in deriving relative permeability curves.
Legal Duty to Market Natural Gas in a Declining Market
Authors: Dancy J. R. , Dancy V. A. , Taylor L. S. 
Published: December 2007

ABSTRACT
Marked changes in the natural gas industry have occurred over the last few years. Much natural gas has been freed of comprehensive price controls under the Natural Gas Policy Act, and direct or spot sales have become commonplace. The price of "old gas" has been devintaged under FERC Order 451, and FERC Order 436 has encouraged pipelines to transport natural gas on an open access basis to end users or local distribution companies.
In addition to these marked regulatory changes, the overdeliverability surplus and the decline in crude oil prices has severely depressed the market price of natural gas. Wellhead values in producer states have fallen by as much as one-third over the last two years. The following chart of natural gas wellhead values in Oklahoma illustrates the severity of the price decline.1/
Even with the price decline it should be noted that in many producing states gas production is at or near all-time record levels. Early exploration and development efforts focused on oil production because of the limited markets and low prices for natural gas, and only recently has gas production become a highly valued commodity. For example in Oklahoma oil production peaked in 1927, however natural gas production in Oklahoma peaked in 1984, and has doubled since 1960. The total value of natural gas production has also recently peaked in most producing states.
Rate Acceleration and the Untimely Depletion of Petroleum Assets
Authors: Campbell J. M. , Campbell R. A. 
Published: December 2007

Abstract
The oil industry suffered hard times recently and faces the prospect of equally difficult times in the near future. Some of the problems arise from conditions beyond the control of an individual company, but others arise from the methods employed in the analysis and management of petroleum investments. Faced with pessimistic price forecasts at present and, given the limitations of the methodologies used to evaluate such projects, current investment decisions may be hastening the uneconomical waste of companies and nations resources. The cause of the inefficient, unprofitable production of such resources and ways to avoid the untimely depletion of our scarce resources are outlined in this paper. The problem is introduced first, limitations identified, and several correcting methods presented. Each is illustrated with one or more examples.
Operation of the Central Basin CO2 Pipeline System
Authors: McCollough D. E. , Stiles R. L. 
Published: December 2007

ABSTRACT
The Central Basin Pipeline (CBPL) is a 178 mile carbon dioxide (CO2) pipeline system located in the Permian Basin area of West Texas, see Figure 1. It is a private contract carrier system which was commissioned in November, 1985 to provide CO2 transportation service for enhanced oil recovery (EOR) projects. The CBPL transports CO2 in dense phase. Accurate custody transfer of CO2 is accomplished through standard orifice meters in conjunction with state of the are mass measurement and computer equipment. Measurement and computer data, and control signals are transmitted to a control headquarters located in Odessa, Texas and Omaha, Nebraska via standard telephone lines. The coupling of traditional and high technology elements have been very successful in the CBPL System operation.
Oil Hedging Strategies Using Futures and Options: Applications for the State of Alaska
Authors: Lindahl M. , Venkatesh E. S. 
Published: December 2007

ABSTRACT
The continued decline in the price of oil and increased uncertainty about future revenues have caused severe budgetary constraints for oil companies and for states dependent on oil revenue. Using the futures market to hedge against adverse price changes is becoming an important tool in the oil industry to establish future dollar income figures. An additional hedging tool, options on crude oil futures, began trading on an organized exchange in November, 1986. Like other options, they offer a means of buying insurance against a potential price decrease.
This paper describes the possibilities of risk reduction that are available through crude oil futures contracts and the new options on crude oil futures contracts, and examines the case for the state of Alaska. Basis risk, the key variable based cn the relationship between cash and futures prices, is calculated for Alaska North Slope oil and the results are interpreted to judge hedging strategies for Alaska. A variation of traditional hedging, called Exchange of Futures for Physicals (EFP), is also presented as an alternative hedging plan.
Heber Geothermal Field: Reservoir and Production Characteristics
Authors: Hoang V. T. , James E. D. , Epperson J. I. 
Published: December 2007

ABSTRACT
Heber reservoir has a dual permeability structure which controls the movement of the thermal fluids in the geothermal system. The three key permeability elements of the Heber reservoir are: "capping" clays above 1800', a matrix permeability dominated region from 1800'–5500' in deltaic sandstones, and a fractured "feeder" zone in indurated sediments below 5500'. The fractures are created by NW trending strike slip faults and NE trending normal faults. The permeability structure of the reservoir was defined by logs, core analyses, temperature, transmissivity and lost circulation data. Initial production creates a sharp pressure decline in the center of the producing area that rapidly stabilizes. Long-term pressure decline is predicted to be low (less than 5%). Pressure is the main factor which limits the development of Heber reservoir. Temperature data and reservoir modeling indicate that additional production can be developed in the fault zones south of the current development.
Pressure Transient Analysis of Heterogeneous Naturally Fractured Reservoirs
Authors: Jalali Y. , Ershaghi I. 
Published: December 2007

Abstract
In naturally fractured reservoirs, the transition zone observed on semi-log plots of pressure data versus time exhibits slope characteristics that are often ignored by the analyst. This study shows that analysis of this segment can lead to the quantification of matrix heterogeneity and fracture intensity. A pressure transient model is developed to substantiate this concept. It is found that the transition zone slope characteristics cover a spectrum embracing, as special cases, double porosity and triple porosity response corresponding to both pseudo-steady state and unsteady state inter-porosity flow.
Frontal Advance Theory for Flow in Heterogeneous Porous Media
Authors: Pande K. K. , Ramey H. J. , Brigham W. E. , Orr F. M. 
Published: December 2007

ABSTRACT
This paper concerns the application of frontal advance theory to displacement processes in heterogeneous porous media. The assumptions under which a generalized frontal advance equation can be used to describe a flow process in a heterogeneous porous medium are examined. Material balance equations are derived based on these assumptions, and the theory is illustrated by application to the Dykstra-Parsons model of flow in noncommunicating layers. We show that the resulting formulation can be used to forecast performance and to solve the inverse problem: the determination of a permeability distribution from displacement data. This approach can also be used to determine pseudorelative permeability curves appropriate to a one-dimensional description of a layered system. We also consider the use of pseudorelative permeabilities in simulation studies to represent the effects of reservoir heterogeneities with length scales smaller than a grid block. The dependence of process performance and pseudorelative permeabilities on scale is described.
Results show that frontal advance theory may be applied to flow in heterogeneous porous media for processes that exhibit linear characteristics. In such a process, a given saturation travels at a constant velocity through the porous medium. Displacement performance for the two-dimensional Dykstra-Parsons model is exactly duplicated using one-dimensional frontal advance theory for unit mobility ratio displacements. One-dimensional theory reproduces the qualitative performance of the two-dimensional model for nonunit mobility ratios, but exact quantitative agreement is not obtained, because the characteristics are nonlinear.
Pseudorelative permeabilities determined for a system of noncommunicating layers apply to any scale as long as the layer structure does not change with system length. However, for processes that are not purely convective, process performance varies with the scale of the displacement Thus, pseudorelative permeabilities obtained from flow processes that are not purely convective are only applicable to the scale at which the displacement data was measured.