bluuebunny/crossref_metadata_2025_split huggingface dataset:
Partial Oxidation Reactions of Methane and Oxygen
Authors: Droege M. W. , Hair L. M. , Pitz W. J. , Westbrook C. K. 
Published: December 2007

Abstract
In considering the typical experimental conditions used for studies of methane oxidation to oxygenates or hydrocarbons in the presence of catalysts, it is clear that a significant potential exists for the appearance of non-catalyzed, thermally activated gas-phase reactions of methane and oxygen. Experimentally, in a quartz reactor at 800 °C with a 3:1 methane-to-oxygen ratio and residence times of the order of 5-10 sec, significant conversion of methane (30%) to light hydrocarbons and COx with appreciable selectivity (25%) to C2+ components is observed due solely to these background reactions. In order to identify and describe the contribution of the gas phase processes during catalyzed reactions, a chemical kinetic model (HCT) developed at this Laboratory has been employed to describe these homogeneous gas phase reactions. Overall, the model predicts very well the trends and steady state results observed when tested against a series of experimental reactions comparing the effects of various reaction parameters such as residence time, temperature, and gas composition. The ability to accurately predict the magnitude of these background reactions should provide a means to begin to dissect the contributions of thermal gas phase chemistry from those of solely catalytic action.
New catalysts materials containing niobium and lanthanum have been synthesized. It is observe that niobium alone at high loading levels is an oxidation catalyst facilitating the production of carbon dioxide. This behavior is modified when lanthanum is incorporated into the catalyst material. In that case, improved selectivity to oxidative coupling products of methane is observed. These results appear to be a consequence of catalyst interaction with the existing background gas phase reactions.
Production and Stimulation Analysis of Multiple Hydraulic Fracturing of a 2,000-ft Horizontal Well
Authors: Yost A. B. , Overbey W. K. 
Published: December 2007

Abstract
The performance of multiple hydraulic fracturing treatments along a 2000-foot horizontal well bore was completed in a gas bearing, naturally-fractured shale gas reservoir in Wayne County, West Virginia. Pre-frac flow and pressure data, hydraulic fracturing treatments, and post-stimulation flow and pressure data form the basis from which a comprehensive analysis was performed. Average field production from 72 wells was used as baseline data for the analysis. Such data was used to show the significance of enhanced production from a horizontal well in a field that was partially depleted.
The post-frac stabilized flow rate was 95,000 cubic feet per day (mcf/d) from 2000 feet of horizontal borehole. Under current reservoir pressure conditions, the horizontal well produced at a rate 7 times greater than the field current average of 13 mcfd for stimulated vertical wells. This increase in gas production suggests that horizontal wells, in strategically placed locations within partially depleted fields, could significantly increase reserves.
Multiple Fracture Height Measurements: A Case History
Authors: Smith M. B. , Reeves T. L. , Miller W. K. 
Published: December 2007

Abstract
Since the inception of hydraulic fracturing, it has been recognized that fracture height is the dominant variable in designing or understanding hydraulic fracture growth. Later, this recognition was formalized with the development of fracture design theories by Perkins $ Kern, Gertsma deKlerk, and others. However, recognition of the importance of height is of little practical aid in the design or post analysis process for a fractured well. More recently, special production logs and open hole logs have been developed to address this problem and aid in fracture height prediction and measurement. These include, in particular, sonic log stress calculations and special spectral gamma ray logs and interpretation techniques. Also, the development of theories and models for analysis of fracturing pressures has been developed as a tool for estimating fracture height and fracture geometry. However, there is little field evidence where these various "tools" have been simultaneously utilized and compared.
This paper discusses a Rocky Mountain gas well case history where extensive testing was conducted to measure hydraulic fracturing characteristics. This included pre-frac lpg predictions of in situ stress and fracture height, in situ stress tests, pressure measurements and model calculations, and post frac temperature/gamma ray logs. The total fracture height (as well as differences in upward and downward growth) as predicted (or measured) with each technique is compared and critiqued as to its reliability and usefulness for this particular application. Of particular interest is the fracture width profile as measured with liquid RA tracer, and the changes in this with time as the fracture apparently closes. The significant differences in RA logs for liquid tracer and post-frac logs for tagged proppant are also significant. Finally, post-frac production and flow/build-up test results are compared to fracture design lengths.
Transient Pressure Analysis and Performance of Gas Wells Producing Under Constant Pressure Conditions
Authors: Berumen-C. S. , Samaniego V. F. , Cinco-Ley H. 
Published: December 2007

Abstract
This work shows the results of a systematic study of transient pressure analysis of gas flow under either constant bottom-hole pressure conditions or the constant wellhead ‘Pressure conditions. The effects of formation damage, wellbore storage and highvelocity ‘flow are included in the model. The analysis of simulated well tests showed that the interpretation methods used for liquid flow are generally accurate when the m(p) is used. For these conditions, a graph of 1/qD vs log tD presents gradually lower values than the exact conventional value of liquid flow of 1.1513 as the value of pwf decreases; for pressure buildup conditions a graph of mD(1,ΔtaD)/qD(ΔtaD=0) vs (taD+ΔtaD)/ΔtaD shows values of this siope witnin 1% of tfte 1.1513 vaTue. The maximum error was in the rate performance simulated cases that included high-velocity flow, being less than 13%. This upper limit occurs when the formation has a relatively "high" permeability (around lmd) and the rate performance test is affected by high-velocity flow. It was found that pressure buildup tests are superior to rate performance tests because high-velocity flow does not affect the slope of the straight line portion of the buildup curve.
Effects of Phase Segregation on Buildup Test Data from Gas Wells
Authors: Olarewaju J. S. , Lee W. J. 
Published: December 2007

Abstract
This paper considers the influence of wellbore phase segregation effects on pressure buildup test data. Wellbore phase segregation is a phenomenon that occurs in a well that is shut in with gas and liquid in the wellbore leading to an anomalous increase in wellbore pressure. This paper presents the use of pressure derivatives to identify phase segregation distortion and to differentiate this distortion from behavior of dual porosity reservoirs. Practical analysis techniques are presented for such tests. Using an automatic history matching technique, four field examples of buildup tests distorted by wellbore storage and phase segregation are analyzed.
The Effects of Operating Conditions, Reservoir Characteristics and Control Methods on Gas Kicks in Oil Based Drilling Muds
Authors: Rommetveit R. , Blyberg A. , Olsen T. Lie 
Published: December 2007

Abstract
A number of parameters influence the development of gas kicks in oil based drilling muds. The dynamic effects of operating conditions (drilling rate, pump flowrate, well depth and casing depth), reservoir characteristics (permeability and formation pressure) and control methods (drillers and wait and weight methods) have been studied with a dynamic simulator for gas kicks in oil based muds. The model accounts for the effect of pressure, temperature and gas solubility on the mud density, and the mass and momentum balance equations are solved to give the detailed pressure and flowrate distribution in the well as a function of time.
The control phase is studied in two kick cases; a distributed kick and a concentrated kick. A perfect control is performed using wait and weight and drillers methods, and the corresponding surface and casing shoe pressures are analyzed.
The study also identifies the most sensitive parameters for kick development, and gives guidelines on how to optimize the drilling operations related to well control.
The simulations are also analyzed with relation to early surface detection of kicks, and the most sensitive detection parameters are identified.
Restart Protection for Pipelines Transporting Paraffinic Crude Oil
Authors: Wheeler Gale , Gouhie Hugo , Laskowski Frank 
Published: December 2007

ABSTRACT
The use of pour point depressants to provide pipeline restart protection in systems transporting paraffinic crude оil is dramatically illustrated by the successful restart of the Kotter system after an unplanned three week shutdown. This unfortunate event created an infrequent opportunity to compare predictive laboratory generated data with actual field restart data.
Field Experience in Down Hole Annulus Safety Valve
Authors: Geyelin J. L. 
Published: December 2007

ABSTRACT
It is now a standard practice to equip production strings of offshore wells with SC-SSV's. Although there are no rules concerning the use of Down Hole Safety Valves in an annulus submitted to gas injection for gas lift purpose, concerns have been raised about the availability and implementation of such equipment.
This paper reviews the experience of T.CFP in Down Hole Annular Safety Valves that started 8 years ago. It covers the field experience of Annular Safety Valves in single and dual completion.
New Method for Determining Downhole Properties That Affect Gas Migration and Annular Sealing
Authors: Sutton D. L. , Ravi K. M. 
Published: December 2007

Abstract
Cement sealing of the casing-borehole annulus and gas migration control following primary cementing are closely related to real-time downhole fluid loss rates during the cement transition period.1
A series of cement fluid loss tests on washed mud filter cake clearly illustrate that downhole fluid loss rates are strongly dependent on fluid loss rates of drilling fluid. Unless altered by reactive washes, the initial fluid loss rate of the cement is equal to the rate established by the drilling fluid filter cake, but after 60 minutes cement filtration time control contributed by cement fluid loss additive is readily apparent.
Using technology similar to hydraulic fracturing fluid loss rate theory,2 a method of predicting the real time fluid loss rate for cement on drilling fluid filter cake has been developed. This method uses data derived from (1) standard high pressure-high temperature (HP-HT) tests on the cement slurry, (2) standard HP-HT tests on the drilling fluid, (3) laboratory drilling fluid filter cake thickness, and (4) estimated downhole drilling fluid cake thickness.
A method was derived combining static gel strength development rate, downhole fluid loss rate, and well geometry to give a dimensionless evaluation number. This evaluation number, defined as the slurry response number (SRN), is a relative prediction of cement slurry performance for controlling gas migration. Its practical use is illustrated with a case history. A field survey shows a firm correlation between this new evaluation number and successful gas migration control.
The results of HP-HT fluid loss tests on drilling fluid filter cake are given and compared to standard fluid loss tests and to simultaneously measured static gel strength. The influence of pressure on fluid loss rates and static gel strength rates is illustrated. Mechanisms by which fluid loss affects cement bonding and gas migration are discussed.
A method for determining slurry permeability during the transition period is given and results relating fluid loss to slurry permeability and specific static gel strength levels are shown.
A New Approach to the Interpretation of Wellbore Images
Authors: Wong S. A. , Startzman R. A. , Kuo T-B. 
Published: December 2007

ABSTRACT
This paper presents a new approach for identifying features from wellbore images. We have developed a prototype system which finds geometric primitives related to geologic events in wellbore images. Rules are used to mimic the reasoning process used by image interpreters in identifying features related to geologic or natural events.
In this approach, the system takes digital data and converts it to symbolic forms. The symbolic forms proceed through a network of blackboards representing different levels of abstraction. Additional information from relevant sources such as previous geological interpretations, well logs, or well data can be used to constrain interpretations or limit searches.
Knowledge based systems with a large visualization component require both high and low level vision expertise. Using a multiple blackboard approach allows us to create knowledge bases which are specialized in particular aspects of the simulated visual process. A master control knowledge base controls the direction of inference. The multiple blackboard approach to the visual problem allows us to modularize the solution process. As more robust pattern matching algorithms are developed, they can be inserted into the system to improve system performance.
The system is implemented on a microcomputer and consists of four parts: interactive wellbore analysis modules, inference engines, specialized knowledge bases, and pattern matching algorithms. The paper explains the structure of the system and shows a field example.
Effects of Crossbedding on Well Performance
Authors: Lord M. E. , Collins R. E. 
Published: December 2007

Abstract
The effects of cross-bedding on transient pressure well tests have been investigated using a combination of numerical and analytical mathematical methods. It has been shown that for systems in which cross-bed laminae are thin, and closely spaced, relative to formation thickness, wells exhibit a negative skin factor and an effective permeability that are dependent on the dip angle of the cross-bed laminae.
Determining Optimum Estimation Methods for Interpolation and Extrapolation of Reservoir Properties: A Case Study
Authors: Brummert A. C. , Pool S. E. , Portman M. E. , Hancock J. S. , Ammer J. R. 
Published: December 2007

ABSTRACT
The accuracy of four-point estimation methods (simple averaging, fifth-degree bicubic spline, inverse weighted distance squared, and kriging) were compared in five reservoir layers using data sets consisting of five different reservoir properties (horizontal permeability, vertical-horizontal permeability ratio, thickness, porosity, and top of structure). This study had four objectives: (1) to determine if kriging could be applied to petroleum-related data sets; (2) to determine the optimum estimation method by layer for each reservoir property and to use that optimum method to assign values to grid blocks for use in a reservoir simulation study; (3) to determine if a correlation could be established between the optimum estimation method and a reservoir property; and (4) to determine if criteria could be established for choosing the optimum estimation method through initial evaluation of data set size, distribution, and spatial correlation.
Kriging was found to be the optimum estimation method in 10 out of 12 cases for data sets having a normal or lognormal histogram distribution and a stable overall semivariogram. Simple averaging and inverse weighted distance squared were optimum in the other two cases. Fifth-degree bicubic spline proved to be the optimum estimation method for data sets that did not have a normal or lognormal histogram distribution. Simple averaging was found to be the optimum method for data sets that did not have stable overall semivariograms because of limited data set size. These results show that kriging can be applied to petroleum-related problems with a relatively small number of data points as compared to kriging's usual application in the ore industry with much larger data sets.
Borehole Directional Radar System for Subsurface Scanning
Authors: Chang H-T. 
Published: December 2007

Abstract
This paper summarizes the progress in the development of the Borehole Directional Radar (BDR). The theory for using radar for geological mapping is shown, and the design and characteristics of the antenna are discussed. The results of field tests in rock formations under both dry and wet conditions are presented. Finally, possible applications of the BDR system are outlined.
Computer Emulation of Human Mental Processes: Application of Neural Network Simulators to Problems in Well Log Interpretation
Authors: Baldwin J. L. , Otte D. N. , Wheatley C. L. 
Published: December 2007

Abstract
The skill of experienced log analysts is emulated by a new computer technology called Simulated Neural Networks (SNNs). Two SNNs are applied to problems in log interpretation. The first SNN is applied to a trivial and conceptually familiar interpretation problem: learning to compute total porosity (PHIT) and apparent grain density (RHOMA) from log data and lithology inputs. The second SNN learned to identify lithofacies patterns as a response to input log data. Interesting and human-like results were obtained when these SNNs interpreted log data in a well which has been full bore cored from top to bottom. Both SNNs performed as well as experienced humans and at least as well or better than conventional sequential computer program interpretations of the same two analysis problems.
Gravity-Stable Nitrogen Displacement of Oil
Authors: Naylor P. , Frørup M. 
Published: December 2007

Abstract
A series of experiments to investigate secondary and tertiary, gravity stable, immiscible, nitrogen displacement of oil in the presence of connate water is presented. Both high and low pressure experiments have been conducted using water wet sandstone cores and dead oils. Effluent production was recorded and the spatial distribution of oil along the core was determined using a radioactive tracer technique.
Experimental results are presented for secondary nitrogen injection at different flow rates, connate water saturations and core orientations. In-situ saturation measurements in a low pressure experiment have revealed a residual oil saturation to gas of 0.15 after 68 days of drainage.
The results of a tertiary nitrogen injection experiment at low pressure are presented. The residual oil saturation to water flooding was 0.47. During the tertiary gas flood, an oil bank was observed to develop and the oil saturation decreased to 0.08 after 86 days of gas flooding. This experiment demonstrates that tertiary gas injection can result in significant oil production, even at low pressures where the process is expected to be least efficient.
Oil relative permeability data have been derived from the in-situ saturation measurements and permeabilities down to 10-5 observed.
An Analysis of Water Shielding in Water-Wet Porous Media
Authors: Walsh M. P. , Negahban S. , Gupta S. P. 
Published: December 2007

Abstract
This paper presents simulation results for water shielding in strongly water-wet Berea rock. The analysis of experimental data indicates three oil phase fractions; flowing, trapped and dendritic (refers to isolated oil fraction which is in contact with flowing oil phase), which are different for different Berea core samples. Model calculations demonstrate that the noted differences are significant and that data measured from one sample cannot be used to predict displacement performance in other samples. Berea rock exhibits relatively small amounts of dentritic oil; therefore, formulating a dendritic oil fraction in model calculations is not as critical as correctly estimating the trapped fraction. The trapped oil saturation can be estimated from the oil primary drainage and imbibition relative permeability data.
Model validation using only an oil trapping function is supported by good agreement between model and experimental oil recoveries over a wide range of water/solvent injection ratios for tertiary CO2 displacements of a West Texas oil from water-wet Berea rock. Also presented are the results of a parametric study to identify key variables and their effect on water shielding phenomena.
Mobility Control Using CO2 Forms
Authors: Yang S. H. , Reed R. L. 
Published: December 2007

Abstract
Mobility reduction caused by CO2 foams that are "stable" or "unstable" in the bulk phase was studied in Berea sandstone and San Andres carbonate outcrop cores at l00°F and 2000 psi. Depending on hydrophilicity, some surfactants led to foams having a favorable dependence on permeability and oil saturation whereas another did not. Foam mobility was found "shear thinning" at high flow rates and "shear thickening" at low rates. Bubble coalescence was investigated in relation to snap-off, transport and trapping.
Interfacial Phenomena in Miscible Gas Processes
Authors: Rao D. N. , Girard M. , Sayegh S. G. 
Published: December 2007

Abstract
The interfacial phenomena of wettability, adhesion, mass transfer, and phase behavior due to miscible hydrocarbon gas injection have been studied by the use of the sessile drop contact angle technique, qualitative adhesion tests, and visual phase behavior observations under reservoir conditions. This experimental study has been conducted using crude oils from three Canadian reservoirs, pure mineral crystals of quartz, calcite and dolomite to represent the reservoir rock, and ethane for the hydrocarbon solvent.
While one of the three reservoir crude oils, namely that of Beaverhill Lake, showed significant changes in contact angles upon miscible gas addition, the others did not. The changes observed in the Beaverhill Lake system constituted a shift from water-wet to intermediately-wet behavior. However, phase behavior effects such as solids separation and settling within the crude oil drop due to solvent injection were common to all three reservoir systems studied. This indicated that the observed phase behavior changes were not reflected by the contact angle measurements.
Qualitative tests for adhesion at the crude oil/mineral crystal interface were also conducted under reservoir conditions. In contrast to the response of contact angles, the adhesion behavior was affected both by the aging time of the interface and by the injection of a miscible gas. These experiments demonstrated the insensitivity of the contact angles to the phenomenon of adhesion at the oil/crystal interface. The adhesion tests further demonstrated that an oil drop could adhere to the crystal surface even after the heavy ends (like asphaltenes) had precipitated within the oil drop away from the interface. This indicated that the heavy ends may not be solely responsible for the interfacial adhesion effects. Furthermore, it was observed that the solvent-mixed oil drop, when moved to a new spot on the crystal surface, could redevelop the adhesive bond with the solid surface.
This study brings forth the importance of including interfacial phenomena, which affect the reservoir flow characteristics, as an integral part of designing miscible gas floods.