bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interpretation of a CO2/N2 Injection Field Test in a Moderately Fractured Carbonate Reservoir
Authors: Denoyelle L. , Bardon C. , Couve de Murville E. 
Published: December 2007

Summary
The Coulommes-Vaucourtois field operated by Petrorep and located in the Paris basin is near abandonment. During the 25-year production span, one-fourth of the original oil in place (OOIP) has been produced by a strong bottomwater drive. Reservoir engineering studies and laboratory measurements have shown that the reservoir characteristics were favorable for CO2 injection.
In 1983, an injection well was drilled between four existing production wells. During the spring and summer of 1984, 49 × 106 scf [1.4 × 106 std m3] of CO2 followed by 54 × 106 scf [1.5 × 106 std m3] of N2 were injected. After 2½ months of CO2 injection, gas broke through into a well located far outside the pattern area. Shortly afterward, a producing well of the pattern showed a four-fold oil production increase as gas broke through. The three other wells exhibited smoother responses, with production of minute quantities of gas. Significant WOR decreases and oil production increases were observed. Gas analyses showed that the areal extent of the gas "bubble" was 15 to 20 times larger than the pattern area and that CO2 and N2 did not spread in the same directions.
This paper tries to match the test results with the geologic description, which shows the presence of fissures, and the production history of the reservoir, which exhibits a single-porosity behavior. It also stresses the difference between the incremental oil recovery resulting from the formation of an oil bank and that resulting from the gas-lift effect.
Size-Exclusion Chromatography in the Measurement of Concentration and Molecular Weight of Some EOR Polymers
Authors: Hunt James A. , Young T. S. , Green D. W. , Wlllhlte G. Paul 
Published: December 2007

Summary
Procedures that involve the use of size exclusion chromatography (SEC) for the measurement of concentration and weight-averaged molecular weight, M¯w, of some EOR polymers were developed and found to give improved detectability, accuracy, and/or efficiency. The separation of polymer from low-molecular-weight impurities by size allows unambiguous detection of polymer properties such as concentration and M¯w. A combination of an SEC column of a pore size small enough to exclude the polymer totally and a mobile phase of ionic strength of 1.5 was found suitable for the separation of Polyacrylamide, partially hydrolyzed Polyacrylamide, cationic Polyacrylamide derivative, and xanthan polysaccharide from impurities.
Concentration detection of the separated polymer sample with a variable-wavelength ultraviolet (UV) detector was found to give superior detectability over detection by refractive index difference. A wavelength of 214 nm [2,140 Å] was used for the detection of these polymers on the basis of the spectra of samples purified by dialysis. With the active polymer assay determined by reprecipitation into a nonsolvent, the detection limit by UV was determined to be &lt;0.1 μg/cm3 for Polyacrylamide and a cationic Polyacrylamide derivative, &lt;0.2 μg/cm3 for partially hydrolyzed Polyacrylamide, and &lt;0.7 μg/cm3 for a xanthan polysaccharide. The linear calibration range was up to 500 μg/cm3. The precision of the concentration measurement was better than 4% for Polyacrylamide and its derivative and 5% for polysaccharide at a 95% confidence level.
On-line measurement of M¯w of four different types of EOR polymers was made by connecting a low-angle laser-light-scattering (LALLS) detector to the SEC system and interfacing the detectors to a computer. The polymer sample was dispersed in the SEC column to give a concentration profile while being separated from the impurities. Continuous measurement of concentration and Rayleigh ratio of the dispersed slug by UV and LALLS detectors allows the calculation of the M¯w for the whole sample. The precision of this measurement is expected to be better than ±5% at a 95% confidence level. The M¯w determined for a Polyacrylamide molecular-weight standard was in good agreement with the reported value (0.98 million compared to 1 million). Such a procedure substantially minimizes the interference by dust and requires only a single injection, thereby improving both the accuracy and efficiency of the M¯w measurement.
Experimental and Theoretical Investigation of Time-Setting Polymer Gels in Porous Media
Authors: Hubbard S. , Roberts L. J. , Sorbie K. S. 
Published: December 2007

SummaryThis paper comprises studies of the kinetics of the xanthan/chromium gel system. The central objective of this work is to perform well-characterized core flow experiments with a simple gelling system that may then be mathematically simulated to obtain a detailed knowledge of the processes that are occurring. Gamma-labeled51 Cr is used so that in-situ chromium profiles may be observed during gel emplacement. These are required to distinguish between different kinetic/transport models because effluent profiles alone are insufficient for this purpose. A generalized multicomponent transport equation including terms describing the crosslinking reaction is used to simulate the experiments.
Development of a Mechanistic Foam Simulator: The Population Balance and Generation by Snap-Off
Authors: Falls A. H. , Hirasaki G. J. , Patzek T. W. , Gauglitz D. A. , Miller D. D. , Ratulowski T. 
Published: December 2007

Summary
The mobility of a foam depends heavily on its texture, which is the distribution of bubble sizes in the dispersion. To incorporate this variable in a mechanistic simulator, the usual conservation equations are coupled with balances on the densities of flowing and stationary bubbles in the foam. This approach to modeling foam flow is illustrated with a simulation of a displacement in which foam is generated in situ by capillary snap-off.
Theoretical Stability Analysis of Flowing Oil Wells and Gas Lift Wells
Authors: Blick E. F. , Enga P. N. , Lin P. C. 
Published: December 2007

Summary
The unsteady equations of motion for flow out of naturally flowing and gas-lift wells are derived and then solved by the Laplace transform method. This analysis produces a characteristic equation with coefficients that allow determination of the stability of a particular well.
Factors Affecting Waterflood Pattern Performance and Selection
Authors: Crawford Paul B. 
Published: December 2007

Abstract
A review is given of the results of early work showing sweep efficiency and steady-state injection rates for various types of patterns which may be used for waterflooding programs. This early work indicated that the sweep efficiency may be near 72 per cent for the five-spot pattern, 56 per cent for the direct, line-drive square pattern and may range from 45 to 90 per cent for the nine-spot pattern. The results were calculated on the basis that the mobility ratio was one, the reservoir was uniform and homogeneous, steady-state conditions existed, and gravity and capillary effects could be neglected. In actual flooding operations it is found that all reservoirs are heterogeneous, steady-state conditions do not exist, the mobility ratio is not one, and gravity and capillary phenomena undoubtedly play a role.
Theoretical calculations show that rock heterogeneities can cause the sweep efficiency of both the five-spot and direct, line-drive square patterns to vary from near zero to 100 per cent. Actual laboratory data have been obtained to show that the oil recovery by water flooding in depleted reservoirs results in the production of substantially the same quantity of oil for the five-spot, direct, line-drive square pattern and nine-spot pattern for a wide range of initial fluid saturations. The experimentally observed sweep efficiency of the five-spot pattern is shown to depend on the initial connate-water saturation and oil saturation.

Introduction
It is believed quite likely that many of the decisions affecting the selection of the pattern to be used in water flooding are based largely on information and conclusions which were made many years ago. The purpose of this paper is to review this early work and include recent work showing various factors which affect the performance of pattern-type floods. In the mid 1930's Muskat and his associates presented the first analytical solutions showing the sweep efficiency and injectivity for the five-spot, direct, line-drive, staggered, seven-spot and nine-spot patterns.
Steam-Foam Pilot Project in Guadalupe Field, California
Authors: Mohammadi Shane S. , McCollum Thomas J. 
Published: December 2007

Summary
This paper describes the use of a formulated alkyl toluene sulfonate (ATS) as a foaming agent for improving mobility control in a mature steamdrive. Selection of ATS was based on laboratory experiments and a series of field injectivity tests. The field results show production response to both the injectivity tests and the 9 months of continuous ATS injection. Overall, ATS was found to improve steam mobility and result in incremental oil production.
Stability of Nickel-Coated Sand as Gravel-Pack Material for Thermal Wells
Authors: Sacuta Alec , Nguyen D. M. , Kissel G. A. 
Published: December 2007

Summary
Laboratory flow tests have been carried out to study the stability of various nickel-coated sands under aqueous steam temperature and pH conditions that may exist in thermal recovery operations. Other gravel-pack materials tested include Ottawa sand, sintered bauxite, cement clinker, zirconium oxide, and nickel pellets. A comparison was made between the performances of these materials after exposure to identical thermal and hydrolytic conditions.
Test results indicate that nickel-coated sands are highly resistant to dissolution at temperatures as high as 300°C [570°F] and to solution pH's from 4.75 to 11. Weight losses measured after a 72-hour period were less than 1%. In contrast, weight losses from sintered bauxite, zirconium oxide, and Ottawa sand dissolution tests were 30 to 70 times higher under the same conditions. Cement clinker losses were in the intermediate range under alkaline conditions.
API standard crushing and acid-solubility tests for proppants also were performed on nickel-coated sands. These results were favorable in that they exceeded the recommended standards.
This study of nickel-coated sand stability and mechanical strength has demonstrated its high potential for application as either a gravel-pack material or proppant in thermal recovery operations.
The Influence of an Immobile or Mobile Saturation Upon Non-Darcy Compressible Flow of Real Gases in Propped Fractures (includes associated papers 19901 and 21622 )
Authors: Evans E.V. , Evans R.D. 
Published: December 2007

Summary
The effects of immobile and mobile liquid saturations on the non-Darcy flow coefficient in propped fractures have been investigated. It was observed that an immobile liquid saturation of up to 20% PV can triple the non-Darcy flow coefficient and a small mobile liquid saturation will increase the non-Darcy flow coefficient by nearly an order of magnitude (over that of the dry case). The linear relationship between the logarithm of the non-Darcy flow coefficient and the logarithm of the proppant permeability for propped fractures, as proposed by Cooke, is shown to be invalid in the presence of an immobile or mobile liquid saturation. Constants are presented that can be used to obtain a more accurate approximation than has previously been available on the non-Darcy flow coefficient for single-phase flow in fractures propped with 10/20- and 20/40-mesh Ottawa sand. The experimental data obtained from this research are compared with those of others reported in the literature.

Introduction
In the past several years, there has been considerable interest in the optimization of flow in high-capacity gas wells. As a result of this interest, much attention has been directed toward the phenomenon of non-Darcy flow in porous media, which is very important in high-capacity gas wells.
Viscous flow, where the pressure gradient is proportional to flow velocity, is described by Darcy's equation:
In 1901, Forchheimer proposed an equation that described the additional pressure drop observed in non-Darcy flow at high flow velocities:
For predominantly viscous flow at low flow rates, the first term (or Darcy term) is important, while the second (or non-Darcy) term is negligible. But at higher flow rates, the non-Darcy term becomes significant and may eventually dominate the Darcy term.
Non-Darcy flow effects are much more significant in gas wells than oil wells, chiefly because of the higher flow velocities as a result of the much lower viscosity of the gas. This is especially true in hydraulically fractured gas wells because the velocity in the highly conductive fracture can be very high, resulting in large pressure drops owing to non-Darcy flow. Failure to consider these pressure drops leads to error in the design of hydraulic fracturing treatments and optimum well spacings, which reduces the efficiency of completion methods for these reservoirs.
Work has been reported by both Cooke and Koh to analyze the non-Darcy flow effect in hydraulic fractures quantitatively. However, both investigated the non-Darcy flow effect for single-phase gas flow only, with no immobile or mobile liquid saturation present.
Fracture-Gradient Prediction for Offshore Wells
Authors: Constant W. David , Bourgoyne A. T. 
Published: December 2007

Summary
A key parameter required in the design of offshore wells is the fracture gradient of the formations to be penetrated. Existing fracture-gradient correlations have been developed largely on the basis of empirical data gathered on land and in the nearshore marine environment. They have been extended to deepwater areas through an equivalent intergranular stress concept. In this study, offshore data from several operators were obtained and a new fracture-gradient correlation procedure, based on an assumption of an exponential decline in average porosity with depth in normally pressured formations, was applied. The technique is ideally suited for implementation on a hand-held calculator or personal computer.
An Efficient Approach to Adaptive-Implicit Compositional Simulation With an Equation of State
Authors: Collins D. A. , Nghiem L. X. , Li Y. -K. , Grabonstotter J. E. 
Published: December 2007

Summary
This paper describes a robust and efficient method for solving the equations corresponding to an equation-of-state (EOS) compositional model. The method is developed for an adaptive-implicit simulator in which only a small number of blocks need to be solved implicitly while the remaining blocks are solved explicitly. The salient features of the method are decoupling of the solution of flow equations from the flash calculations and switching from explicit to implicit formulations on the basis of a stability criterion. The performance of the adaptive-implicit approach is compared with that of a hilly implicit approach and an explicit-transmissibility approach. Results show that the adaptive-implicit approach is two to three times faster than the other two methods.
Application of the Horner Method for a Well Produced at a Constant Bottomhole Pressure
Authors: Kutasov I. M. 
Published: December 2007

SummaryThis paper presents an analytical solution to describe the pressure buildup for wells produced at constant bottomhole pressures (BHP's) in an infinite-acting reservoir. The buildup equation is derived on the basis of an initial condition approximating the pressure profile in the wellbore and in the reservoir at the time of shut-in.
Chemical and Physical Applications in Treating Produced-Fluid Emulsions of the Bell Creek Micellar/Polymer Flood
Authors: Johnson R. E. , Kennelly R. G. , Schwarz J. R. 
Published: December 2007

Summary
Unforeseen chemical and physical treating problems arose in obtaining acceptable oil and water quality when produced micellar petroleum sulfonates created unique phase changes in the produced-fluid emulsion. Production facilities had to be modified continuously to adapt to the changing emulsion characteristics.
Although the production facilities were adapted to meet the changing phase concentrations of the produced fluid, their undersized capacity would not allow the retention time necessary to break the oil and water emulsions effectively in the presence of sulfonates. Conventional reverse chemicals and demulsifiers proved ineffective in treating the produced-fluid emulsion. New chemicals had to be developed to treat the sulfonated production in an environment conducive to the undersized production facilities.
Controls on Reservoir Quality in Tight Sandstones of the Travis Peak Formation, East Texas
Authors: Dutton Shirley P. , Finley Robert J. 
Published: December 2007

Summary
Most sandstone in the gas-bearing Travis Peak formation has undergone compaction and extensive cementation during its burial history, resulting in low porosity and permeability. Diagenetically induced permeability variations are superimposed on original permeability variations produced by depositional processes. Sandstones range from fluvial-channel to shallow-marine, bay, and tidal-flat deposits. Three types of sandstone that differ in their original permeability distribution and lateral continuity are distinguished.
Travis Peak sandstones have undergone a complex series of diagenetic modifications. Precipitation of authigenic quartz, ankerite, dolomite, illite, and chlorite, and the introduction of reservoir bitumen, were the most important causes of occlusion of primary porosity and reduction of permeability. Porosimeter measured porosity is the best predictor of permeability, and there is a statistically significant inverse correlation between total volume of cement and permeability. Permeability decreases with depth in the Travis Peak, suggesting that the diagenetic processes that caused extensive cementation and resultant low permeability throughout most of the formation did not operate as completely on sediments deposited near the top of the formation.
Transient, Semisteady-State, and Steady-State Flow
Authors: Matthews C.S. 
Published: December 2007

Technology Today Series articles provide useful summary informationon both classic and emerging concepts in petroleum engineering. Purpose:To provide the general reader with a basic understanding of a significantconcept, technique, or development within a specific area of technology.

Transient Flow
The pressure behavior at a well producing at constant flow rate is shown inFig.
During early producing times, the pressure behavior is essentially thesame as that in an infinite reservoir. This is the transient flow period. Thepressure at the well can be described by the following equation for most timesof practical interests:
well pressure = initial pressure - A [log (producing time)-B], where A and Bare constants.
During this period, the plot of well pressure vs. the logarithm of time willbe a straight line. On Cartesian coordinates (Fig. 1) the well pressure willdecline rapidly at first, then less rapidly with time.

Semisteady-State Flow
Curves of pressure in the reservoir vs. radial distance are shown in Fig. 2. If there is no flow across the drainage boundary as more producing timeelapses, the pressure behavior will begin to deviate producing time elapses, the pressure behavior will begin to deviate from the infinite-reservoir case. At a time shown as "late transient" in Fig. 2, the pressure at points insidethe drainage boundary will begin to decline at a rate higher than that in aninfinite reservoir. Finally, as shown in Fig. 2, if compressibility is smalland constant, the rate of pressure decline becomes equal through the drainageboundary. This is the semisteady-state period. All pressures in the drainagearea of the well now decrease by the same pressures in the drainage area of thewell now decrease by the same amount in a given time. The difference betweenaverage reservoir pressure and wellbore pressure remains constant during thisperiod. pressure and wellbore pressure remains constant during this period.
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Effect of Salt Composition on Clay Release in Berea Sandstones
Authors: Kia S. F. , Fogler H. Scott , Reed M. G. , Vaidya R. N. 
Published: December 2007

Summary
The effect of salt composition of fluid injected into clay-bearing Berea sandstones on the water-sensitivity phenomenon has been studied. Experiments were carried out with solutions of sodium and/or calcium ions, which are the ions commonly found in the formation. Freshwater flooding of sandstones previously exposed to sodium salt solutions results in the release of clay particles and a drastic reduction in permeability. The permeability reduction is lessened, however, when calcium ions are also present in the salt solution. Formation damage is virtually eliminated when the solution composition is adjusted to give calcium surface coverages greater than a critical value of 75 %. The effect of the fluid composition on the damage process is explained by the double-layer interactions between the surface of the clay particles and the pore walls.
Comparison of Alternating Direction Explicit and Implicit Procedures in Two-Dimensional Flow Calculations
Authors: Coats K.H. , Terhune M.H. 
Published: December 2007

Abstract
Analysis and example applications have been performed to compare the accuracy and computing speed of alternating-direction explicit and implicit procedures (ADEP and ADIP) in numerical solution of reservoir fluid flow problems. ADIP yields significantly greater accuracy and requires about 60 per cent more computing time than ADEP, not 300 or 500 per cent more as reported elsewhere.

Introduction
Several recent papers discuss an alternating-direction explicit difference approximation (ADEP) to the diffusion equation. Example applications of ADEP and ADIP were reported to support conclusions that ADEP is comparable in accuracy to ADIP and requires one-fifth to one-third the computing time of ADIP. Applications of ADEP in calculation of two-phase flow in reservoirs was also proposed. This study was performed to compare further the relative merits of ADEP and ADIP in simulation of two-dimensional flow of one and two fluid phases in reservoirs. Since two-phase flow equations are often essentially elliptic rather than parabolic, the efficiency of ADEP in solving the elliptic equation was also examined.
A Model To Assess Economic Feasibility And Optimum Prod. Volume
Authors: MARKS R. 
Published: December 2007

Abstract
The State of Alaska's revenue forecasting model computes the economic rent of prospective fields to assess whether or not they are feasible to produce given price and volume scenarios. When economic rent is negative production is delayed until a start-up year generating a positive rent is found. If economic rent is positive the model finds the profit maximing amount of enhanced recovery.

Introduction
The Department of Revenue of the State of Alaska is responsible for forecasting the State's revenue for planning and budgeting purposes. Petroleum revenues. accounted for $2.7 billion in fiscal year (FY) 1985 (July 1984 – June 1985), 84 percent of the total State revenue. These took the form of severance taxes, royalties, corporate income taxes, property taxes, bonuses, rents, and intergovernmental receipts. Eighty-eight percent of these petroleum revenues were derived from either severance taxes (both production and conservation taxes, the latter being very small), or royalties.
Nearly all oil revenues accrue from the North Slope. The very mature Cook Inlet fields are relatively insignificant from a revenue standpoint.
The petroleum production revenue forecasting model is designed to calculate oil and gas severance taxes and royalty payments due each year to the State of Alaska under provisions of existing State laws and contracts.
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