bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design and Optimization of Alkaline Flooding Formulations
Authors: French T. R. , Burchfield T. E. 
Published: December 2007

Abstract
The state-of-the-art for alkaline flooding technology is the injection of combinations of alkalis with synthetic surfactants. Surfactant-enhanced alkaline flooding formulations with low-pH alkaline agents have potential for increased oil recovery. They react less with reservoir minerals and facilitate the use of low concentrations of surfactants because surfactant adsorption is reduced in the presence of alkaline agents.
Laboratory experiments and results from field projects have been evaluated and used to establish guidelines for designing optimum alkaline floods. For a reservoir to be a candidate for alkaline flooding, the reservoir should contain little or no gypsum, the divalent ion exchange capacity should be less than 5 meq/kg, and the in situ pH should be greater than 6.5.
Two optimized alkaline systems which exhibit typical interfacial tension (IFT) behavior are described. One system was optimized with a very low acid (acid number = 0.13 mg KOH/g) crude oil from Delawâre-Childers (OK), field. The other system was optimized with an acidic (acid number = 1.59 mg KOH/g) crude oil from Wilmington (CA), oil field. A mixture of synthetic surfactant and low-pH alkali produced lower IFT and sustained low IFT longer than either reactant alone. This effect was observed with the acidic crude and the slightly acidic crude. It was concluded that surfactant-enhanced alkaline flooding with low-pH alkalis shows promise with both acidic and slightly acidic oils.
Synthetic surfactant is an expensive component of low-pH alkaline flooding formulations. Dilute (0.1 – 0.2 %) concentrations of the added synthetic surfactant are being used in some current alkaline flooding field projects. Laboratory results showed that surfactant losses by adsorption are reduced under alkaline conditions. Losses by precipitation should also be reduced due to the lowering of divalent ion concentration by alkaline preflush.
The final section of this paper is an example of how screening criteria, phase behavior tests, and corefloods can be used to design and optimize an alkaline flood for a specific oil field. The example is for the design of a low-pH, surfactant-enhanced alkaline flood in the Ranger Zone of the Wilmington (CA), field, where a high-pH alkaline flood was previously conducted. That project encountered severe problems with alkali consumption and scaling. A low-pH alkali (such as NaHCO3 or NaHCO3 + Na2CO3) in combination with synthetic surfactant should be effective for producing incremental oil in the Ranger Zone of Wilmington field. Problems associated with high pH floods, such as intractable scales and high consumption, will be mitigated.
Evaluation of Unrecovered Mobile Oil in Texas, Oklahoma, and New Mexico
Authors: Becker A. B. , Brashear J. P. , Biglarbigi K. , Ray R. M. 
Published: December 2007

Abstract
This paper summarizes the technical findings of a regional assessment of oil recovery potential through advanced primary and secondary processes for reservoirs in Texas, Oklahoma, and New Mexico. Intensive infill drilling, polymer-augmented waterflooding, permeability profile modification, and selected combinations of these processes show significant promise for increasing recovery and sweep efficiencies in certain geologic reservoir settings. Given the current technical development and costs of these processes, their application could be feasible in a wide range of reservoirs in the region analyzed, even at oil prices below $20/Bbl. These advanced recovery techniques are all directed at producing unrecovered mobile oil (UMO), which is displaceable by waterflooding but remains in the reservoir at the conclusion of conventional production due to reservoir heterogeneity and unfavorable mobility differences between water and oil. The analysis, which was sponsored by the Department of Energy's Bartlesville Project Office and Office of Planning and Environment, evaluates nearly 500 reservoirs described in the data base. The data base, process predictive models, and analytical methodology used in the study are described in this paper. In addition, Important case study results and comparisons to published results for key reservoirs and other detailed analyses are discussed.
The results indicate that UMO extraction has significant future potential to increase oil reserves and maintain domestic production. This potential is large even at low to moderate oil prices and utilizing existing technology. However, the key to maximizing UMO recovery is the development and wide-scale application of advanced techniques resulting from focused research and development (R&D).
Wellbore Stability: The Effect of Strength Criteria on Mud Weight Recommendations
Authors: McLean M. R. , Addis M. A. 
Published: December 2007

ABSTRACT
Hole problems during the drilling phase of operations are often the consequence of mechanical wellbore instability. This leads to higher than necessary drilling costs. A linear-elastic analysis is frequently proposed for the prediction of the onset of failure, and consequently the mud weights required to prevent hole instability. However, there is no clear choice of which compressive failure criterion to use in the analysis. This paper assesses the influence of two commonly proposed failure criteria on mud weight selection. The failure criteria selected is shown to have an extremely significant effect on the computed 'safe’ mud weights. Examples related to field situations are presented which highlight the anomalies and contrary evidence relating to the suitability of failure criteria.
Laboratory Studies on the Stability of Vertical and Deviated Boreholes
Authors: Addis M. A. , Barton N. R. , Bandis S. C. , Henry J. P. 
Published: December 2007

ABSTRACT
Polyaxial or true triaxial tests have been performed on weak and strong sandstones in order to investigate the stability of model boreholes. Both vertical and deviated boreholes in anisotropic stress systems have been studied. The results indicate the decrease in stability of the deviated boreholes with increasing inclination. Boreholes oriented parallel to the maximum horizontal stress direction also produces less stable boreholes compared to those drilled parallel to the minimum horizontal stress. Comparisons of the laboratory test results with simple predictions using linear elasticity, and a Mohr Coulomb failure criterion, show that the boreholes in the strong sandstones are approximately 4 times stronger than predicted; while the weak sandstones are approximately 8 times stronger than predicted.
Applications and Limitations of Composite Cutter Drill Bits in the Gulf Coast Region
Authors: Vrooman D. , Munger R. , Rawicki A. , Smith L. 
Published: December 2007

ABSTRACT
First introduced to the Gulf Coast region in 1987, the composite cutter bit is the result of research involving two design enhancements that combine polycrystalline (PDC) and thermally stable (TSP) cutters on one bit.1 Each cutter type provides complete bottom hole coverage alone, and, when combined in a 60% PDC/40% TSP mixture, greatly increases the range of applications for both.2-3
The composite cutter bit is able to drill relatively hard, abrasive formations that contain large quantities of shale or shale stringers, achieving maximum penetration rates with extended bit life. Until now, neither traditional PDC nor TSP bits could successfully drill this relatively common Gulf Coast sequence of formation types unless the individual formations were relatively thick and their occurrence was predictable.4-5 Thus, composite cutter bits increase the already-proven benefits that PDC and TSP bits offer versus traditional rock bits or natural diamonds, and provide a viable drilling alternative to conventional bit selection.
Implementation of composite bits -- from the initial onshore Gulf Coast application into proven offshore applications - is described in several key case histories. Field data documents their introduction in the onshore Lac Blanc/North Freshwater Bayou fields, then details offshore successes in the Mississippi Sound, South Timbalier and Mustang Island areas. The case histories illustrate the broad range of well programs and drilling conditions in which these bits have performed. Successful application of composite bits now has spanned extreme variations in bit sizes, hydraulics, depths and lithologies.
Operating recommendations resulting from analysis of these case histories and more than 100 composite bit runs are outlined. Analysis of this information has helped more clearly define the limitations and applications of composite bits in this region.
Improved Channel Repairs with Small-Phased Circumferential Perforating Guns
Authors: Hart P. E. , Wilson L. C. 
Published: December 2007

ABSTRACT
Behind-pipe communication (channeling) may lead to environmental concerns, lost hydrocarbon reserves, and additional workover costs to detect and attempt channel repairs. This case study of channel repairs compared (a) perforation phasing and placement, (b) cementing procedures, and (c) production data in 37 wells over the past eleven years in the Texas Gulf Coast and East Texas areas. An improved repair technique, which focuses on the phasing and placement of perforations and cementing procedures was implemented, resulting in an increase in the success rate of channel repairs from 37 to 89 percent.
Channeling was repaired in wells with undesired gas or water flow past shale intervals from 2 to 29 feet thick. The improved repair success rate was obtained by adding and then squeezing perforations with 15-degree phasing and at least 24 shots across an impermeable zone, where possible. The channel repair success rate of the other wells which typically had 90- or 120-degree phased perforations was only 37 percent. This significant change in success rates was largely due to the increased percentage of the cement's circumference that was perforated. Further improvement is anticipated due to a newly developed perforator with 100 percent circumferential coverage over a 6-inch length which has been tested in two wells.
Drilling Waste Disposal in the Arctic Using Below-Grade Freezeback
Authors: Maunder T. E. , Le K. M. , Miller D. L. 
Published: December 2007

ABSTRACT
The disposal of waste muds and cuttings has become increasingly difficult for operators worldwide. Disposal tasks are complicated by the great variety of operating environments as well as the multitude of local, state and national regulations governing any waste disposal.
This paper describes the successful disposal method used by ARCO Alaska, Inc. (AAI), on two exploratory wells drilled on the North Slope of Alaska in early 1988. The disposal method, below-grade freezeback, involves burying waste muds and cuttings in the permanently frozen ground known as permafrost. When buried, the waste freezes, becoming part of the permafrost. This disposal method utilizes the ability of the natural Arctic environment to isolate and permanently contain the waste muds and cuttings.
A Two-Dimensional Simulator to Predict Circulating Temperatures During Cementing Operations
Authors: Bittleston S. H. 
Published: December 2007

Abstract
This paper describes an advanced numerical simulator for the prediction of down-hole temperatures during cementing. The novel two dimensional approach used in the simulator is detailed together with a method for calculating the dynamic heat transfer boundary conditions on the casing surfaces and the fluid formation interface. The time-dependent numerical scheme is discussed together with the implementation of the pressure and temperature-dependent fluid rheology. The paper also covers the heat diffusion calculations in the formation and the importance of considering the effects of drilling history on the temperature distribution at the beginning of cementing.
The results of the numerical simulator show that the fluid temperatures can be predicted throughout the well and as a function of time e.g. the hottest fluid temperature is not found to be at the casing shoe but some distance up the annulus and so measurements made at the casing shoe cannot be used directly as the design temperature for cementing. The two-dimensional implementation also allows the heat transfer coefficients (Nusselt numbers) for each fluid-solid interface to be examined as a function of time and position. It is shown that the heat transfer coefficients differ significantly from the analytical pipe flow constant heat flux and constant wall temperature solutions. Moreover, the values are seen to vary with time, particularly widely in the annulus. The implication derived from these results is that one-dimensional approximations, often applied for modelling circulating temperatures, may be in significant error because of the necessity to assume values for the heat transfer coefficients in such models.
Simulation to Support Interpretation of the Loudon Surfactant Pilot Tests
Authors: Huh C. , Landis L. H. , Maer N. K. , McKinney P. H. , Dougherty N. A. 
Published: December 2007

ABSTRACT
A surfactant process simulator was used to evaluate the performance of a series of surfactant flood tests carried out at the Loudon field in Illinois. The process model, developed and calibrated with laboratory data, accounts for the detailed phase behavior of the injected and resident fluid mixtures, relative permeabilities and rheology of the resulting phases, the oil displacement mechanism by low interfacial tension, and the retention of surfactant and polymer on reservoir rock. When the surfactant retention is adjusted from laboratory to field levels, the process model does a reasonable job of describing the field performance. The pilot tests matched by simulation included a 0.7-ac inverted fivespot, a 40-ac pattern comprising nine 2.5-ac normal fivespots, and an 80-ac pattern with nine 5.0-ac normal fivespots.
The validity of the process model under field conditions was first tested using a simplified reservoir model — an octant of a confined fivespot pattern. Effects of various process parameters and reservoir stratification on process performance were examined. For full-pilot simulations, reservoir models were prepared from detailed reservoir description data for each pilot, including analyses of cores from 43 pilot wells, induction logs, pressure falloff tests, and pulse tests. For the small pilot, only minor corrections to the sand thickness and permeability outside of the pattern area are needed to match the production of oil, surfactant, polymer, and nine different tracers. The tracers included one overall and four quadrant tracers for the microemulsion bank and four quadrant tracers for the polymer drivewater bank. For the two multi-pattern pilots with larger pattern sizes, reasonable matches are also obtained but require more substantial permeability adjustments overall.
An important task of this effort is to understand why the oil recovery performance of the tests with larger pattern sizes was not as good as that of the earlier smaller tests. Based on the interpretation of the history matches, it is believed that the major reason for the poorer-than-expected performance of the larger tests is the failure of the polymer bank to propagate as designed. Reasons for poor polymer transport are discussed.
Pore-Level Modelling of Gas-Condensate Flow through Horizontal Porous Media
Authors: Mohammadi S. , Sorbie K. S. , Danesh A. , Peden J. M. 
Published: December 2007

ABSTRACT
In order to evaluate recovery strategies from gas condensate reservoirs, it is necessary to have some knowledge of the behaviour of the gas and liquid relative permeabilities. Very little experimental work is available on this subject and the approach taken in this paper is to consider gas-condensate relative permeability from a theoretical viewpoint. The process of retrograde condensation and revaparisation by pressure depletion has been modelled in a horizontal network of pores using microscopic rules developed from micromodel observations. These rules relate both to the pore occupancy pattern of the condensate liquid and to the effect of condensate accumulation in the tight comers of the pore elements. Concepts from percolation theory have been used along with observations of condensate formation and growth in etched physical micromodels, to determine the distribution of each phase in the pores. The relative permeabilities of gas and condensate in the presence of immobile connate water are then calculated using percolation theory. Resulting relative permeabilities are compared with those that are predicted for conventional drainage/imbibition (oil/water) processes in strongly water wet porous media. A Monte-Carlo model is also developed for comparison with the analytical model. A wide range of sensitivities of the relative permeabilities to a number of governing factors is presented.
Improved Calculation of Oil Production Response to Electrical Resistance Heating (ERH)
Authors: Baylor B. A. , Maggard J. B. , Wattenbarger R. A. 
Published: December 2007

Abstract
Electrical resistance heating (ERH) is a thermal stimulation technique in which electrical current passes through the formation. Field testing of this process is continuing. The current work uses results generated with reservoir simulation. Two models were used to describe ERH power dissipation (heating patterns): (1) a radial power model, and (2) an r-z power model.
Wattenbarger and McDougal1 developed a hand method for estimating the heated oil production rate under ERH stimulation. The first objective of the current paper is to present improvements to that hand method. The new hand method has the following advantages: (1) downhole electrical power is estimated, (2) well damage is accounted for, and (3) accuracy of heated production rates is improved. This new hand method can be quickly and easily used for screening potential ERH projects.
The second objective of this paper is to present results from the r-z power model. The r-z power model provides a more detailed description of in situ heating patterns, including areas of intense heating (hoc spots) which occur near the ends of the electrode. These hot spots may limit the amount of power that can be used in field installations.
The Fractal Nature of Viscous Fingering in Porous Media
Authors: Peters E. J. , Cavalero S. R. 
Published: December 2007

ABSTRACT
An experimental study was undertaken to investigate the fractal nature of viscous fingering. Unstable first-contact miscible displacements were performed in a two-dimensional areal model. Images of the fingering patterns were captured and analyzed with a microcomputer-based imaging workstation. Results show that the areal sweep efficiency of the unstable displacements follows a fractal scaling law with a fractal dimension between 1.9 and 2.0. These results have potential application in the mathematical modelling of unstable EOR displacements and in the scaling of laboratory displacements to field conditions.
Managerial Goals and the Strategic Planning Process
Authors: Hailey W. A. , Barnes C. W. , Ryan E. J. 
Published: December 2007

ABSTRACT
The authors examine the major decision process goals and constraints that impact the investment decisions within the oil and gas industry. The goals and constraints, reported by 124 executives during a mail survey of the 1987 Oil & Gas Journal 400, were arranged in hierarchies that vary in importance from high to low. The results can serve as planning factors for goal setting and as a basis for managing by objectives.
Scaled Miscible Floods in Layered Beadpacks Investigating Viscous Crossflow, the Effects of Gravity, and the Dynamics of Viscous Slug Breakdown
Authors: Sorbie K. S. , Sheb M. , Hosseini A. , Wat R. M. S. 
Published: December 2007

ABSTRACT
In this paper, certain fluid recovery mechanisms that occur in stratified systems are analysed using experimental floods in layered beadpacks. In particular, the roles of viscous and gravitational crossflow are studied in viscous stable and viscous slug type displacement processes. The results from these floods are then scaled to field processes using a combination of scaling theory and numerical simulation. The effects of smaller sub-layer heterogeneity (within the larger scale layering) on the fluid recovery mechanisms are also examined in some detail. It is found that, although the levels of smaller scale heterogeneity studied in this work does not largely affect the total recovery profiles, they do have some impact on the detailed levels of fluid crossflow in the system. However, it is stressed that the level of heterogeneity description required for a given system must depend both on the type of system, the details of the fluid recovery mechanism operating in that reservoir and also actual balance of forces (viscous/gravity etc.) that exists in that participle situation.
Steam Injection in a Low-Permeability Reservoir Through a Horizontal Well in Lacq Superieur Field
Authors: Sahuquet B. C. , Spreux A. M. , Corre B. , Guittard M. P. 
Published: December 2007

ABSTRACT
After several steamdrive patterns realized in the fractured zones of the Lacq Superieur field, a high rate steam injection in a very low permeability zone through a 350 m horizontal well is presently performed in this field.
Several tests showed that steam injection through a vertical well was not efficient due to the low permeability. The use of a horizontal steam injection well was, therefore, considered. The combination of steam and horizontal wells is in fact already a reality, in tar sands in Canada for example. The particularities of the Lacq Superieur operation are that the horizontal well is used to have a high steam injectivity in a low permeability carbonated facies and that the drain location is optimized to sweep a large area delimited by existing producing wells.
In this paper, reservoir engineering studies and the drilling of the well are presented.
Numerical simulations enabled us:
– to demonstrate the advantages of a horizontal injection well with high steam injection rate, – to show the efficiency of the dynamic and thermal mechanisms involved in such a configuration, – to optimize the location of the drain between two lines of existing vertical producers with respect to both energy savings and economical aspects.
From the drilling point of view, the geometrical data restricted the drilling domain inside a parallelepiped 9 meters wide by 5 meters high. In addition, a special type of completion was needed to be designed to allow injection in the 350 meters horizontal section only.
The horizontal well was drilled at the end of 1988 and steam injection started in April 1989. In accordance to the guidelines arrived at by numerical simulation, 600 tones per day of steam were injected, without problems.
After some changes in the initial conditions of operations, due to a too sharp increase of the flowing temperatures in some wells, the results up to date show clear and promising increases of the oil production in the neighbouring wells. This increase is somewhat earlier than what was predicted by computer simulations.