bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spontaneous Ignition in Oil Reservoirs
Authors: Burger Jacques G. 
Published: December 2007

Abstract
Typical experimental data on low-temperature oil oxidation in porous media are presented. Using these kinetic data, numerical models in radial and longitudinal flow are proposed for computing the spontaneous ignition conditions when air is injected into oil reservoirs. The models account for heat transport by conduction and convection in the formation.
The computed ignition times are compared with the values obtained by an analytical approach. The distance from the well to the injection zone is also discussed.

Introduction
Ignition is the first step of the in-situ combustion process. It may be obtained by heating the formation around the ignition well with a burner or an electrical heater.
The heat required to initiate a combustion front also may be provided by an exothermic reaction between air and an appropriate chemical compound. This compound may be an easily oxidizable organic liquid injected into the formation in the vicinity of the ignition well before air injection. But if the formation crude oil itself has sufficient reactivity with oxygen under reservoir conditions, the formation may ignite spontaneously when air is injected for a prolonged period. As a matter of fact, spontaneous prolonged period. As a matter of fact, spontaneous ignition has been obtained in some reservoirs in a reasonably short time.
The ignition delay may vary from a few days to an indefinite period if the rate of heat dissipation to the surroundings of the reacting volume prematurely becomes as high as the rate of heat prematurely becomes as high as the rate of heat release.
In the approximate analytical approach of Tadema and Weijdema, heat dissipation by conduction and convection was neglected. Hence, ignition would occur for all reservoir conditions eventually after an ignition delay of several years. However, if Tadema and Weijdema's approach gives a good approximation of the ignition delay when the oxidation rate is high under reservoir conditions, this delay is likely to be significantly underestimated when crude oil reactivity is low.
A numerical model was built for computing the ignition conditions (ignition delay and position of the ignition zone) as a function of reservoir, oil, and gas flow characteristics. The kinetic parameters of oil oxidation were determined experimentally.

DESCRIPTION OF THE NUMERICAL MODEL
Gas flow is assumed to be one dimensional and linear in x or radial in r. Longitudinal conduction and convection are accounted for. Transversal conduction is neglected since, during the ignition delay, the vertical temperature gradient is very low, especially if the central part of the oil layer is considered. Fluid and solid temperatures are supposed to be equal.
Air is injected into the ignition well. Pressure and gas flow rate are assumed to be approximately constant in the investigated zone around the well. Water and oil flow or vaporization are neglected in the heat balance. Diffusion-dispersion of oxygen is not considered.
SPEJ
P. 73
High Penetration Rates and Extended Bit Life Through Revolutionary Hydraulic and Mechanical Design in PDC Drill Bit Development
Authors: Taylor M. R. , Murdock A. D. , Evans S. M. 
Published: December 2007

SummaryPDC drill bit developments have been made to achieve higher penetration rates and longer life, involving a compromise between open, light set, bits for speed, and heavy set ones for durability. Developments are described which provided the benefits of both in a revolutionary hydraulic and mechanical design. The hydraulic design causes mud to flow first towards the bit center and then outwards. It was extensively flow tested using high-speed photography to ensure that bit balling was prevented. It includes features to address bit whirl which were demonstrated in full scale laboratory testing to reduce the bit's vibration level. The mechanical design maximizes open-face volume, known to benefit penetration rate, by using very high blades. However, the heights attainable can be limited by the bit body's mechanical strength. Steel was chosen to maximize blade strength and was coated with a newly developed hardfacing to improve erosion resistance. A program of fatigue testing assured adequate strength.
How to Improve Rate of Penetration in Field Operations
Authors: Fear M. J. 
Published: December 2007

Summary
A method has been developed to identify which factors are controlling rate of penetration (ROP) in a particular group of bit runs. The method uses foot-based mud logging data, geological information, and drill bit characteristics, to produce numerical correlations between ROP and applied drilling parameters or other attributes of drilling conditions. These correlations are then used to generate recommendations for maximizing ROP in drilling operations.
New Formulations of Potassium Acetate and Potassium Formate Polymer Muds Greatly Improved Drilling and Waste Disposal Operations in South Italy
Authors: Gallino G. , Guarneri A. , Maglione R. , Nunzi P. , Xiao L. 
Published: December 2007

Summary
This paper discusses the field results of innovative K-Acetate or K-Formate mud formulations that have been used by ENI S.p.A./Agip Division to drill several wells through very plastic shales in South Italy. Field muds have been carefully designed and evaluated as far as drilling and waste disposal activities are concerned. While drilling, the integration between field observations, standard laboratory tests, and nonconventional rheological approaches provided the assessment of useful correlations between rheological properties, performance, and formulations of field muds. These findings permitted a gradual improvement of the mud effectiveness with a large reduction in dilution rates, bit balling, and hole cleaning problems. At the rig, the strict cooperation between all the people involved in field operations represented a key factor for the successful application of the know-how acquired. With respect to the previous wells drilled in the field with traditional dispersed muds, the optimization and careful management of the new muds contributed, in spite of the increased ROP, to a considerable reduction both in time spent to remove bit balling or reaming and in tons of wastes produced per hole volume. These improvements led to great savings in drilling and disposal costs that largely compensated the 8.4% increase in the mud mixing costs per hole volume due to the presence of potassium salts.
A Material for Tubing and Casing Applications in Deep, Sour Gas Wells
Authors: Heacox Richard A. , Stroup James P. 
Published: December 2007

Introduction
Multiphase MP35N is a nickel-cobalt-base alloy containing 35-percent nickel, 35-percent cobalt, 20-percent chromium, and 10-percent molybdenum that is produced by double vacuum melting. MP35N exhibits a produced by double vacuum melting. MP35N exhibits a unique combination of ultrahigh strengths, good ductility, and excellent corrosion resistance.
Multiphase MP35N develops yield strengths of 150 to 250 ksi with 10- to 25-percent elongation by cold working and aging. Mechanical property data for large bars and tubing are presented. Corrosion test results show excellent resistance to cracking in H2S environments. Testing by a number of oil companies has resulted in very high interest in this alloy for such applications as down-hole tubing and casing in deep, sour well environments and for valve cores exposed to H2S. Presently, this alloy is being used successfully for Presently, this alloy is being used successfully for cables to suspend instrument packages in sour wells.

Metallurgy
At high temperatures MP35N has an austenitic face-centered cubic (FCC) structure. Although a hexagonal close-packed (HCP) structure is stable below about 800 deg. F, this transformation is so sluggish that the FCC structure remains after cooling to room temperature. Subsequent cold working results in the formation of thin, coherent HCP platelets in the metastable FCC matrix. The coherency of the platelets strains the lattice and results in strengthening. The amount of strengthening (transformation) depends on the amount and, to a lesser degree, the temperature of deformation. Further strengthening can be achieved by aging, which results in precipitation of a Co3Mo compound at the interfaces between the FCC matrix and the HCP platelets.
In the annealed condition (Table 1) MP35N exhibits moderate strengths and very high ductilities. The effect of cold reduction (by drawing) and aging on the room-temperature tensile properties of MP35N is shown in Fig. 1. For fastener applications (bar sizes of 0.2 to 1.3 in.), cold reduction is designed to provide an ultimate minimum tensile strength of 260 ksi, a 0.2-percent minimum yield strength of 240 ksi, and ductility minimums of 8-percent elongation and 35-percent reduction of area after aging at 1,100 deg. F. Note also that the properties of MP35N can be controlled over a wide range by adjusting the amount of cold reduction.
Properties obtained from large-diameter bars are shown in Table 2. The two larger bars were produced by cold Pilgering rather than by cold drawing. Note that, after equivalent amounts of cold work, the material reduced by drawing exhibits higher strengths than the Pilgered material.
TABLE 1 -- TYPICAL ANNEALED PROPERTIES OF MP35N
Tensile strength, ksi 135 0.2-percent yield strength, ksi 60 Elongation in four dimensions, percent 70 Reduction of area, percent 70 Hardness 90 to 100 Rb Charpy V-notch impact, ft lb 2,001
JPT
P. 705
New Apparatus for Studying Pressure Induced Fracturing in Reference to Lost Circulation
Authors: Teplitz A.J. , Pohoriles E.M. , Rodgers J.K. 
Published: December 2007

Introduction
This note is presented in order to call attention to a newly developed laboratory apparatus that appears to have interesting possibilities for the study of lost circulation of the pressure-parting type, for a more realistic evaluation of sealing materials for this type of loss, and for investigation of other aspects of hydraulic fracturing.
A study of lost circulation, conducted jointly by operating divisions of the Gulf Oil Corp. and the Gulf Research & Development Co., has been in progress for the past few years. Earlier phases of the study dealt with mechanical factors contributing to loss of returns in laminar type sediments.
One aspect of this type of loss which has been widely discussed in the literature and elsewhere concerns the geometry of the fractures into which such losses occur. This subject is not merely a philosophical one, but has an important bearing on procedures for combating lost circulation difficulties and on other well operations.
The further course of the collaborative studies previously mentioned has produced some information on this subject which, though limited in amount, is believed to be significant. In several typical cases of lost circulation in laminated shale and sand formations, the wells have been surveyed with instruments capable of detecting the points of loss with considerable accuracy. These wells were located in the Gulf Coast of Texas and Louisiana, in the Texas Panhandle, and in the Rocky Mountain area. In each of these instances the loss was shown to be occurring at some distance removed from the bottom of the hole and sharply confined to a very narrow interval, less than 1 ft in thickness.
It is rather difficult to imagine that fractures of a vertical nature would be of the limited extent indicated by the surveys in these wells. Furthermore, the high rates of loss at relatively low pressure differentials observed in some of these instances together with the narrow intervals involved would appear to require the radial flow pattern which would be associated with a more or less horizontal fracture plane.
The Energy Yield of Micellar Flooding
Authors: Carpenter Dan H. , Davies John B. 
Published: December 2007

JPT Forum articles are limited to 1,500 words including 250 words for each table and figure, or a maximum of two pages in JPT. A Forum article may present preliminary results or conclusions of an investigation that the present preliminary results or conclusions of an investigation that the author wishes to publish before completing a full study; it may impart general technical information that does not warrant publication as a full-length paper. All Forum articles are subject to approval by an editorial committee.
Letters to the editor are published under Dialogue, and may cover technical or nontechnical topics. SPE-AIME reserves the right to edit letters for style and content.

Introduction
The higher price of crude oil and the dependence on crude imports are providing a great incentive to accelerate commercialization of enhanced oil recovery procedures. Recovery of known oil in place is becoming an procedures. Recovery of known oil in place is becoming an increasingly urgent matter for the petroleum industry because, for enhanced recovery to be economically attractive, it must be initiated before producing fields are shut down and existing wells are plugged. Unfortunately, however, the present political uncertainty about future oil prices causes companies to be reluctant to make the large front-end investments in chemicals and chemical manufacturing plants that are necessary to demonstrate enhanced recovery technology on a large scale.
The U.S. crude oil "barrel" (Fig. 11) shows a target of about 60 billion bbl of additional oil physically recoverable with enhanced recovery methods now being developed. In addition, some 60 billion bbl may be recovered with future enhanced recovery methods. There are four principal enhanced oil recovery techniques now considered feasible for the production of crude oil: thermal recovery methods, hydrocarbon miscible floods, carbon dioxide floods, and water-miscible micellar floods.
All methods require introducing energy into oil-bearing formations by gas, water, or solvents under pressure, but each technique has its own advantages and pressure, but each technique has its own advantages and limitations.
Thermal recovery methods are perhaps uniquely suited to recovering viscous crudes, but they also may be used to recover many conventional crudes. This is not, however, a broadly applicable technique because of the required formation porosity and the lack of sweep control. Hydrocarbon miscible flooding probably can be discounted as a widespread commercial recovery method because of the general unavailability of low-cost ethane and propane. Limitations on control for the flood bank and pressure requirements to achieve miscibility create practical problems that will limit commercialization of this technique. Carbon dioxide miscible floods suffer from a lack of cheap carbon dioxide in areas near many potential project sites, and from the same general limitations and problems of hydrocarbon miscible systems.
JPT
P. 103
Improved Model for Collapse Pressure of Oval Coiled Tubing
Authors: Zheng A. S. 
Published: December 2007

Summary
This paper presents a new modeling technique to predict collapse pressure of oval coiled tubing. Through finite element analysis, a failure mechanism for tubing collapse is identified and a collapse model proposed. This model relates the tubing collapse pressure with its yield strength, ovality and its D/t ratio. Collapse pressures predicted by this model correlates well with finite element method prediction. Collapse experiments were also performed to generate test data for collapse pressure under various ovality. To better simulate the actual material behavior in a typical tubing operation, the ovality in the collapse experiments was generated through a fatigue machine. Predictions from this model are compared against the experimental data as well as other published test data and good agreement is achieved. This new model predicts very well the effect of the ovality and axial force on the collapse pressure. The paper concludes with an introduction to an enhanced software that incorporates this new modeling technique for collapse prediction.
Improved Prediction of Reservoir Behavior Through Integration of Quantitative Geological and Petrophysical Data
Authors: Davies D. K. , Vessell R. K. , Auman J. B. 
Published: December 2007

Summary
This paper presents a cost effective, quantitative methodology for reservoir characterization that results in improved prediction of permeability, production and injection behavior during primary and enhanced recovery operations. The method is based fundamentally on the identification of rock types (intervals of rock with unique pore geometry). This approach uses image analysis of core material to quantitatively identify various pore geometries. When combined with more traditional petrophysical measurements, such as porosity, permeability and capillary pressure, intervals of rock with various pore geometries (rock types) can be recognized from conventional wireline logs in noncored wells or intervals. This allows for calculation of rock type and improved estimation of permeability and saturation. Based on geological input, the reservoirs can then be divided into flow units (hydrodynamically continuous layers) and grid blocks for simulation. Results are presented of detailed studies in two, distinctly different, complex reservoirs: a low porosity carbonate reservoir and a high porosity sandstone reservoir. When combined with production data, the improved characterization and predictability of performance obtained using this unique technique have provided a means of targeting the highest quality development drilling locations, improving pattern design, rapidly recognizing conformance and formation damage problems, identifying bypassed pay intervals, and improving assessments of present and future value.
Determination of Producible Hydrocarbon Type and Oil Quality in Wells Drilled With Synthetic Oil-Based Muds
Authors: Hashem M. N. , Thomas E. C. , McNeil R. I. , Mullins Oliver 
Published: December 2007

Summary
Determination of the type and quality of hydrocarbon fluid that can be produced from a formation prior to construction of production facilities is of equal economic importance to predicting the fluid rate and flowing pressure. We have become adept at making such estimates for formations drilled with water-based muds, using open-hole formation evaluation procedures. However, these standard open-hole methods are somewhat handicapped in wells drilled with synthetic oil-based mud because of the chemical and physical similarity between the synthetic oil-based filtrate and any producible oil that may be present. Also complicating the prediction is that in situ hydrocarbons will be miscibly displaced away from the wellbore by the invading oil-based mud filtrate, leaving little or no trace of the original hydrocarbon in the invaded zone. Thus, normal methods that sample fluids in the invaded zone will be of little use in predicting the in situ type and quality of hydrocarbons deeper in the formation. Only when we can pump significant volume of filtrate from the invaded zone to reconnect and sample the virgin fluids are we successful. However, since the in situ oil and filtrate are miscible, diffusion mixes the materials and blurs the interface; as mud filtrate is pumped from the formation into the borehole, the degree of contamination is greater than one might expect, and it is difficult to know when to stop pumping and start sampling. What level of filtrate contamination in the in situ fluid is tolerable?
We propose a procedure for enhancing the value of the data derived from a particular open-hole wireline formation tester by quantitatively evaluating in real time the quality of the fluid being collected. The approach focuses on expanding the display of the spectroscopic data as a function of time on a more sensitive scale than has been used previously. This enhanced sensitivity allows one to confidently decide when in the pumping cycle to begin the sampling procedure. The study also utilizes laboratory determined PVT information on collected samples to form a data set that we use to correlate to the wireline derived spectroscopic data. The accuracy of these correlations has been verified with subsequent predictions and corroborated with laboratory measurements. Lastly, we provide a guideline for predicting the pump-out time needed to obtain a fluid sample of a predetermined level of contamination when sampling conditions fall within our range of empirical data.
Foam Flow in Heterogeneous Porous Media: Effect of Cross Flow
Authors: Bertin H. J. , Apaydin O. G. , Castanier L. M. , Kovscek A. R. 
Published: December 2007

Summary
Previous experimental studies of foam generation and transport were conducted, mainly, in one-dimensional and homogeneous porous media. However, the field situation is primarily heterogeneous and multidimensional. To begin to bridge this gap, we have studied foam formation and propagation in an annularly heterogeneous porous medium. The experimental system was constructed by centering a 0.050 m diam cylindrical Fontainebleau sandstone core inside an 0.089 m acrylic tube and packing clean Ottawa sand in the annular region. The sandstone permeability is roughly 0.1 μm2 while the unconsolidated sand permeability is 6.7 μm2. Experiments with and without cross flow between the two porous media were conducted. To prevent cross flow, the cylindrical face of the sandstone was encased in a heat-shrink Teflon sleeve and the annular region packed with sand as before. Nitrogen is the gas phase and an alpha olefin sulfonate (AOS 1416) in brine is the foamer. The aqueous phase saturation distribution is garnered using X-ray computed tomography (CT).
Results from this study are striking. When the heterogeneous layers are in capillary communication and cross flow is allowed, foam fronts move at identical rates in each porous medium as quantified by the CT-scan images. Desaturation by foam is efficient and typically complete in about 1 PV of gas injection. When cross flow is prohibited, foam partially plugs the high permeability sand and diverts flow into the low permeability sandstone. The foam front moves through the low permeability region faster than in the high permeability region.
Advances in Homopolar Welding of API Line Pipe for Deepwater Applications
Authors: Hudson R. S. , Carnes R. W. , Nichols S. P. 
Published: December 2007

Summary
The University of Texas at Austin Center for Electromechanics is conducting a research program, funded by six oil companies, two industrial contractors, and two government agencies, to study homopolar welding of line pipe for J-Lay applications. In 1995, the third year of the five year research program, the set of weld parameters, those input variables used to control weld performance and quality, was expanded to include joint geometry, with dramatic improvement in the mechanical properties of two HSLA nominal 3-in. line pipe materials: X60 and X65. These improvements increased the Charpy V-Notch impact toughness properties to near parent metal values, while maintaining acceptable strength. After demonstrating repeatable performance with the new parameters, new research focused on real world effects including tolerancing the parameters and evaluating the effect of poor fit up resulting from misalignment and rough and wavy interfaces. During the final year of the research program, the pipe welding program has scaled up to 12-in. nominal line pipe, a seven-fold increase in the cross-sectional area. The paper will cover the basics of homopolar welding (HPW), weld parameters and modifications, the effects of these changes on real time process data, mechanical properties, weld upset profile, HPW metallurgy, and the studies of real world effects. Results from HPW of 12-in. pipe will also be presented.