bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitrogen Injection Into Water-Driven Natural Gas or Condensate Reservoirs Increases Recovery
Authors: Adler A. B. , Crawford P. B. 
Published: December 2007

SUMMARY
Many natural gas and condensate reservoirs are subject to secondary recovery by either water injection or a natural water drive. If the hydrocarbon is the non-wetting fluid, and water the wetting fluid, the hydrocarbon will be trapped by the water. The volume of trapped hydrocarbons at abandonment may be of the order of 20 to 45 percent depending upon the particular reservoir. It was believed that a tertiary recovery process could be applied which would increase the hydrocarbon recovery. Low cost nitrogen might be injected at the water-hydrocarbon contact. The nitrogen would result in miscible displacement with the hydrocarbon. Water would drive and trap the nitrogen, and such could result in an increase in ultimate hydrocarbon recovery. The cost of nitrogen from an air separation plant can be quite low, and the process might be applicable to both onshore and offshore reservoirs.
Computer simulation studies have been made to estimate the increase in hydrocarbon recovery which might result from injection of nitrogen into natural gas or condensate reservoirs subject to secondary recovery by either a natural water drive or water injection. The effect of dip-angle, porosity, slug size, permeability, gas-water contact and other variables were studied. It would appear that the injection of nitrogen may result in an increase in hydrocarbon recovery by 30 to 50 percent. The projected economics of the process appear to be favorable.
Increasing Oil Recovery From MIS Oil Shale Retorts by Offgas Cooling
Authors: Stevens A. L. , Jacobson C. L. , Purcupile J. C. , Zahradnik R. L. 
Published: December 2007

ABSTRACT
Occidental Oil Shale, Inc., recently completed the demonstration of mining, rubblization, ignition, and simultaneous processing of two commercial-sized modified in situ (MIS) retorts at our Logan Wash Facility near De Beque, Colorado. Two hundred thousand barrels of shale oil were produced from the two retorts, a 70 percent yield of the oil-in-place in the rubbled rock. One of the control measures demonstrated, on this project was the use of water sprays behind the Product Level bulkheads to cool the offgas. When the offgas temperature began to increase as the high temperature region in the retort approached the bottom of the retorts, the water sprays cooled the offgas to acceptable levels and the extended retort life resulted in better oil recovery.
Modeling the Performance of Observation Wells in Underground Storage of Natural Gas
Authors: Tek M. R. , Udegbunam E. O. , Wilkes J. O. 
Published: December 2007

ABSTRACT
Performance of the observation wells related to the monitoring of the presence and extent of gas migration from storage horizons has been investigated using theoretical and laboratory models.
The theoretical model developed for short columns or shallow wells was first evaluated using laboratory data. The results indicated good agreement between theoretical and actual behavior, and the model was extended to field applications where the data from a water observation well going to a full gas column were studied.
It is concluded that the equations derived for both the short and tall columns can be used along with data collected at the wellhead to predict the performance of observation wells being encroached by the nigrating gas.
Through-Tubing Plug-Back Without Depth, Temperature, or Pressure Limitations
Authors: Weeks S. G. 
Published: December 2007

ABSTRACT
Excessive downhole temperatures, as well as some well bore restrictions, may limit the use of wireline bridge plugs. With careful planning, Shell Oil Company has successfully utilized sand-slurries for plugging back through tubing in deep, high-temperature, geopressured, gas tests--without limitations. This has included isolation of water producing zones as well as temporary exclusion of lower intervals that did not warrant additional stimulation expense.
Evolution of Fair Market Value of Natural Gas in the U.S.
Authors: Smith Sol , Baumel J. K. 
Published: December 2007

ABSTRACT
Paper traces the guidelines adopted by the Courts by which fair market value of natural gas can be determined. A history of the Natural Gas Industry is discussed with special emphasis on conditions that caused certain factors to be used in market value calculations. Each new factor on determination used gave greater comparability of natural gas in any particular case. Vela v. Texas Oil & Gas Corporation was the most influential and set factors that should be used in such determination of fair market value. The weighted average approach is the best method to determine the fair market value of natural gas; follows Vela's definition of comparable gas and uses good engineering precepts.
CO2 Flood: Design and Initial Operations, Ford Geraldine (Delaware Sand) Unit
Authors: Phillips L. A. , McPherson J. L. , Leibrecht R. J. 
Published: December 2007

ABSTRACT
A miscible carbon dioxide (CO2) flood was initiated by Conoco Inc. in a 3850-acre area of the Ford Geraldine (Delaware Sand) Unit in Reeves and Culberson Counties, Texas in February, 1981, after a staged waterflood was nearing completion. The CO2 supply is a by-product source obtained from the Lone Star Pikes Peak Gas Plant near Fort Stockton. This previously vented product is compressed to a supercritical state and then transported to the Unit through a 112-mile pipeline which has a capacity of 30 MMCFPD. Compression and transmission system design has minimized start-up and operational problems. Capital costs were reduced by utilizing most of the existing waterflood distribution system. Lack of a sufficient and stable CO2 supply has caused most of the operational problems. New vessels have been installed to better handle production well testing. In addition, a system has been developed and installed to automate all injection and production data so as to provide the surveillance information to properly monitor the flood performance. Response to the limited and unstable CO2 injection supply has been encouraging. Once additional supplies are secured and response is verified, CO2 recycle facilities will be installed. In addition, the flood could later be expanded to the remaining 1430-acre northern area of the Unit, which is still under waterflood.
Drilling Technology: Present Trends and Future Prospects
Authors: Cheatham J. B. 
Published: December 2007

ABSTRACT
This paper addresses the subject of how new technology can be expected to influence future drilling engineering and drilling operations. The work is based upon a review of past developments in drilling technology; a survey of current research and development efforts; personal contacts; and recent workshops, publications and presentations.
The impact of measurements while drilling, Polycrystalline Diamond Compact bits, downhole motors, and utilization of computers is discussed with regard to future developments of computer aided drilling, drilling optimization and hole direction control. Recent work by others on measurements while drilling, drilling simulators, and drilling optimization has been extended to emphasize setting goals for future drilling technology developments.
Transport Efficiency of High-Density Gravel Packing Slurries
Authors: Skaggs B. C. 
Published: December 2007

Abstract
A large-scale wellbore model was used to study gravel transport through the perforations during a simulated, high-density, squeeze gravel-packing operation. The effects of fluid viscosity, gravel concentration, annular velocity and perforation leakoff rate were investigated. Slurry consistency is presented as a means of describing the combined effects of fluid viscosity, gravel concentration and size. Results show that transport efficiency increases with increased fluid viscosity, gravel concentration and annular velocity.
The Effect of Break Mechanism on Gelling Agent Residue and Flow Impairment in 20/40 Mesh Sand
Authors: Almond S. W. , Bland W. E. 
Published: December 2007

Abstract
In hydraulic fracturing, the temperature at which a polymer is to be used determines the break mechanism and the breaker used for its degradation. The polymers most commonly used in fracturing were degraded under a variety of conditions and their resulting flow impairment characteristics were measured in 20/40 mesh sandpacks. Enzyme breaker was used for the low temperature tests (120°F), oxidizing breaker was used for the intermediate temperature tests (180°F) and thermal degradation processes were used for the high temperature tests (275° – 400°F).
The polymers evaluated were derivatized cellulose (0% w/w residue), derivatized guar gum (1-2% w/w residue), intermediate residue guar gum (5-6% w/w residue) and guar gum (8-10% w/w residue). The relative residue volumes for these polymers were determined and compared to their actual flow impairment values. The effect of polymer loading on the relative flow impairment was also determined for these polymers as a function of break temperature.
Formation Damage of Brine Corrosion Inhibitors
Authors: Potter G. F. 
Published: December 2007

Abstract
Brine corrosion inhibitors, varying from highly dispersed organic materials to low-molecular-weight salts, were evaluated for their effect on return oil permeabilities.
Cores used in these tests were 50-to 100-md and 1,0-to 3,000-md sandstone. Temperatures up to 300°F and two different density brines were studied. Results show that emulsion blockage was a problem at low temperatures for inhibitors that yielded low brine/oil interfacial surface tensions. At higher temperatures, emulsion blockage was greatly reduced.
Inhibitors that produce sulfide ions resulted in reduced return permeability with cores containing iron(III).
The Analysis of Filtration Under Dynamic and Static Conditions
Authors: Peden J. M. , Arthur K. G. , Avalos Margarita 
Published: December 2007

Abstract
This paper presents an overview of the work carried out to date on the dynamic and static filtration characteristics of drilling muds. Factors controlling fluid loss to the formation that have been investigated include annular velocity, fluid temperature, hole angle, shear rate and the effect of the filter media. The effect of pressure on static fluid loss and filter cake permeability is also reported. Fluid loss during sequential filtration has also been evaluated. The fluids used comprised a calcium chloride brine with fluid loss additive and two water based muds. The filter media consisted of synthetic core material and a natural sandstone. Conventional photographic techniques have been used to idenify filter cake response to backflushing.
Evaluating Fractured Well Performance Using Type Curves
Authors: Soliman M. Y. , Venditto J. J. , Slusher G. L. 
Published: December 2007

ABSTRACT
This paper consists of three parts. The first part presents new type curves for a well intercepting a vertical fracture with finite conductivity. The type curves are for a well located in a limited reservoir and producing under constant flowing pressure. The second part describes how the type curves can be used in predicting and matching reservoir performance. Description of automated history match is also included. The match procedure considers the effect of turbulent flow inside the fracture as well as the change in fracture conductivity due to change in flowing pressure (crushing of sand).
The third part of the paper presents application of the first two parts to actual field cases. The discussed procedure is applied to two gas wells in South Texas. The paper presents the following for each well: A pre-fracturing build-up test analysis.Fracturing treatment design.History match of production data calculating the fracture length and conductivity.
Viscometric Measurement of Chromium(III)-Polyacrylamide Gels by Weissenberg Rheogoniometer
Authors: Aslam Sohail , Vossoughi Shapour , Willhite G. P. 
Published: December 2007

ABSTRACT
Gelled polymers are being used increasingly to modify the movement of injected fluids in secondary and enhanced oil recovery processes. A common gelation process involves the reduction of Cr(VI) to Cr(III) in the presence of polyacrylamide. The Cr(III) reacts or interacts with the polymer to form a gel network. Although correlations of gelation time with principal process variables have been obtained, viscometric data have not been reported during or after gelation. These data are needed for fluid flow calculations in surface equipment and estimation of flow behavior in reservoir rocks.
A Weissenberg Rheogoniometer, with cone and plate geometry, was used to obtain viscometric data for the gelation of polyacrylamide and chromium (III). Solutions consisting of polyacrylamide polymer, sodium dichromate-dihydrate and sodium bisulfite were gelled under a steady shear field at constant temperature. The shear stress vs. time profile for the gelation process was interpreted to define a gelation time and to determine the apparent viscosity of the gelled fluid. The gelation time decreased as the applied shear rate increased up to about 14.25 sec−1 and was affected by shear rate history. Viscometric properties of the gelled solutions were determined. Apparent viscosity of the gelled solutions decreased as the shear rate under which they were formed increased.
Post gelation studies indicated that gels exhibited a residual or yield stress at zero shear rate and behaved as Bingham plastics under steady shear. Gels formed at low shear rates were more viscous than gels formed at high shear rates. However, the structure of these gels was susceptible to shear degradation.
Kinetics of Polymer/Metal-Ion Gelation
Authors: Prud'homme R. K. , Uhl J. T. 
Published: December 2007

ABSTRACT
Polyacrylamide and partially hydrolyzed polyacrylamide solutions can be crosslinked by tri-valent chromium ions to form stable gels. In this study the kinetics of the gelation reaction are determined from the time dependence of dynamic mechanical measurements using classical network elasticity theory to relate the storage modulus of the gel to the number density of crosslinks. The reaction is second order in chromium ion concentration corroborating previous reports of a bi-molecular chromium ion complex. Gelation studies with anionic and nonionic polyacrylamides in NaCl, KI, and Na2SO4 solutions show that electrostatic interactions between chain segments alter the rate of reaction. The effects are successfully modeled using electrostatic theories of Odijk and Fixman.
A New Multicomponent Surface Tension Correlation Based on Scaling Theory
Authors: Lee Sheng-Tai , Chien M. C. H. 
Published: December 2007

Abstract
This paper presents a multicomponent surface tension correlation based on scaling theory. In addition to particular exponents employed, the correlation contains two new features: (1) A corresponding-states equation is derived for a correlation coefficient, commonly referred to as a parachor. As a result, the hydrocarbon pseudocomponent parachors can be calculated through this equation, once their pseudocritical properties are estimated. (2) An approach is proposed to calculate the parachors of mixtures. In contrast to the conventional approach, which calculates the mixture parachor via molar mixing of component parachors, this approach first obtains the pseudocrtical properties of the mixture and then employs the corresponding-states equation to calculate the mixture parachor.
For various reservoir-fluid related pure components, the corresponding-states equation predicts parachor values to within 1% of those listed in the literature. The surface-tension correlation developed was tested against 45 sets of measured binary surface tension data and four sets of multi-component CO2-reservoir oil surface tension data. Other existing surface tension correlations, i.e. Weinaug-Katz's and Stegmeier-Hough's correlations, are also tested and compared. For the 45 sets of binary data, the average deviation of the new surface tension correlation is 3.71%, which is about 50% smaller than the deviations of the other two correlation cited. In addition, for the CO2-reservoir fluid data, the average deviation is about 7.3%, which is also a significant improvement over the existing correlations. It is worth noting that the surface tension correlation developed does not involve any adjusted parameter and it is also completely compatible with existing compositional numerical simulators.
Evaluation of a-Olefin Sulfonates for Steam Diversion
Authors: Hu P. C. , Tuvell M. E. , Bonner G. A. 
Published: December 2007

Abstract
Enhanced oil recovery studies have consistently demonstrated the need to mitigate gas channeling in processes involving use of gaseous substances (such as steam, carbon dioxide, nitrogen and air) to stimulate oil production. The use of foam to control the mobility of the gas was suggested thirty years ago, and earlier field tests2,3 indicated that significant benefit in oil production could be achieved using this concept.
The use of foam to improve mobility control is based on the observation that most foams have great flow impeding characteristics and provide greater flow impedence in high permeability porous media than in low permeability media.
Sibree4 was probably the first to report that froth has an apparent viscosity much higher than either of its constituents. He compared the rheological behavior of a froth to that of a coarse emulsion and attempted to relate apparent viscosity to the volume fraction of gas in the liquid.
Relative Permeabilities of Surfactant/Steam/Water Systems
Authors: Monsalve Armando , Schechter R. S. , Wade W. H. 
Published: December 2007

Abstract
Surfactants are now being used in field application to help reduce the flow of steam into more permeable zones during steamflooding operations. Despite the increasing interest, little is known about how surfactants function to reduce the permeability to steam nor how surfactants are transported from the wellbore into the formation. An important aspect in helping resolve these issues is the relative permeabilities to both steam and water.
In this paper the relative permeabilities to both steam and water in the presence of two surfactants are reported. One important finding is that the steam saturation at residual increases with increasing surfactant concentration for the systems studied and the relative permeabilities to steam are shifted but the general shape of the curves is not changed.
Unlike previous findings for gas-liquid systems, the relative permeability to water has been found to increase with increasing surfactant concentration rather than remain constant. While the mechanism responsible for this unexpected finding is not understood, the experimental trends are well defined.
Considerable attention has been devoted to the design of the experimental apparatus. Calculations are presented which show that heat exchange with the environment can, in the absence of surfactants, give rise to both flow dependent relative permeabilities and abnormally low residual steam saturations. These same calculations also indicated that more reliable results may be obtained if the core is well insulated even though it is in a well controlled thermal environment.
In the absence of surfactant the relative permeabilities to both steam and water in Berea sandstone were found to be similar, although not identical, to oil-water relative permeabilities.
An Experimental Study of Water Imbibition in Chalk from the Ekofisk Field
Authors: Torsaeter Ole 
Published: December 2007

ABSTRACT
The Ekofisk Field in the North Sea produces from two lithologically similar, low permeability fractured chalk formations. The Ekofisk Formation of Danian age is separated from the lower Tor Formation of Maastrichtian age by a tight zone of about 15 m thickness. With a projected primary recovery factor of only 18%, the secondary recovery target is substantial. A pilot waterflood has been conducted in the Tor Formation and expansion of waterflooding to a large area of the Tor is planned. For waterflooding to recover substantial oil in a highly fractured rock large saturation changes in the matrix rock must be achieved through water imbibition.
Water imbibition in Tor samples is high and variable and the imbibition in Ekofisk samples is low and also variable. The first objective of the laboratory investigation reported here was to establish correlations between imbibition and rock parameters in the highly water wet Tor samples. The second objective was to determine the reasons for differences in Ekofisk and Tor water imbibition.
The volume of water imbibed and the initial water saturation in Tor samples correlated very well with porosity for the two wells examined. The water saturation after imbibition was constant at about 60 percent of pore volume, independent of porosity. Imbibition in the Ekofisk samples from the one well examined varied widely and did not correlate with any of the rock parameters examined. Pore structure studies and extraction experiments with strong solvents indicate that the difference between Tor and Ekofisk samples is due to rock surface chemistry differences.
The correlation developed here with the Tor samples provides a sound basis for comparing data from different wells, for examining the effect of various handling and laboratory procedures, and for data input in models. The indication of rock surface chemistry differences provides direction for further research aimed at explaining in greater detail differences between the Ekofisk and Tor rocks with respect to imbibition.
Comparison of Simulation and Experiments for Compositionally Well-Defined Corefloods
Authors: Giordano R. M. , Salter S. J. 
Published: December 2007

ABSTRACT
The mechanisms which affect the efficiency of chemical flooding processes have been the focus of considerable research and speculation in recent years. One method to identify these mechanisms is the comparison of carefully conducted experiments with results generated using a mathematical model (simulator). In this paper we report both experimental and simulation results for II−, II+, and three-phase systems run so that the entire flood remains on a single phase diagram. In order to do this rigorously, we have used simple systems in which the complexities of non-pseudoternary behavior are absent. We simulated experimental core floods using a modified version of INTERCOMP's Chemical Flooding Simulator CFTE and tested the sensitivity of the results to a variety of process mechanisms. We also employed a method-of-characteristics solution to independently check the simulator. In doing so we extended the method-of-characteristics to three-phase, multicomponent flow in porous media. Our major objective is to show the interactions among the phase behavior, fluid flow, mixing, and mobility mechanisms which are present in chemical flooding processes.