bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rheology of Fracturing Fluids at Low-Shear Conditions
Authors: Acharya A. , Deysarkar A. K. 
Published: December 2007

ABSTRACT
The rheological evaluation of cross-linked and uncross-linked fracturing fluids has drawn considerable attention in the recent years. These fluids are widely used in massive hydraulic fracturing jobs where they have to endure long hours of exposure to the reservoir temperature. They are also used in deep (&gt;10,000 feet) formations which are significantly hotter than normal shallow reservoirs. Such demand on the stability of fracturing fluids at elevated temperatures for long hours has motivated researchers to study the rheology of fracturing fluids in detail.
Research efforts have been made to understand (i) the effect of in-line mixing of polymer gel and cross-linker, (ii) the effect of wall slip, and (iii) the effect of breaker (oxidizer) type and concentration at reservoir temperature on rheology of fracturing fluids. Considerations have been given to include the effect of pressure for compressive fluids like foam fracturing fluids. The effect of viscoelasticity and molecular structure of cross-linked fracturing fluids on proppant transport are also being studied.
An important aspect of fracturing fluid rheology that remained almost unattended is the low shear and zero-shear rheological characteristics of the commonly used fracturing fluids. In a typical fracturing job, the fluid experiences low shear in various locations of the fracture. Also, the proppant exerts very low shear to the fluid while settling in the fracture. Therefore, a good knowledge of the rheological characteristics of the fracturing fluids at low shear is very important.
The purpose of this paper is to evaluate rheology of commonly used fracturing fluids at low shear rates. The low shear rheology will include measurement of low shear viscosity and yield stress. The low shear rheological data was gathered from Rheometrics pressure rheometer (RPR) and a mini rotary viscometer (MRV). The MRV is commonly used in the low temperature characterization of automotive lubricants. This paper will compare the low shear rheological data obtained from RPR and MRV with those calculated from a typical Fann 50 viscometer. The final part of this paper will discuss the importance of the presence of yield stress on proppant transport for cross-linked CMHPG and guar fracturing fluids.
Determination of Interaction Coefficients and Critical Properties of Heavy Fractions for Equation of State Computations: An Automated Algorithmic Approach
Authors: Obut S. T. , Ertekin T. 
Published: December 2007

ABSTRACT
Equations of state are widely used in compositional simulation to predict phase distribution and composition, which in turn facilitates prediction of compositionally dependent properties such as density, viscosity, interfacial tension, and enthalpy. A well-known problem confronted with naturally occuring hydrocarbon systems is characterization of the high molecular weight fraction (usually C7 +). The high molecular weight fraction must be split into an optimum number of pseudo-components each having a prescribed set of critical properties and interaction coefficients. Since procedures for doing this are largely empirical, typical equation of state packages must be tuned to available experimental data.
Often available experimental data are limited in scope, or the ultimate simulation involves significant changes in temperature, pressure or composition. In each situation, tuned pseudo-component critical properties and/ or interaction parameters will manifest important temperature, pressure, and composition dependencies. Thus, a versatile phase description can effectively be ensured if tuning is automated internally within the equation of state package.
In this paper, a methodology for achieving this task is described. First, the heavy fraction is split into a defined number of pseudo-components and starting values of binary interaction parameters and critical properties are obtained by using readily available correlations in the literature and/or mixing rules. Then, a linear optimization technique (two-phase method) is adopted for non-linear applications by using iterative techniques (iterative variables being pseudo-component binary interaction coefficients with CH4 and pseudo-component critical properties). Tuned sets of binary interaction parameters and critical properties of pseudo-components for a cubic equation of state are generated by using experimental depletion curves.
As the computation progresses the tuned set replaces the default set to achieve further improvements. The success of this linear optimization routine is demonstrated for different reservoir oils.
Investigation of Gas/Oil Relative Permeabilities: High-Permeability Oil Reservoir Application
Authors: Delclaud J. , Rochon J. , Nectoux A. 
Published: December 2007

ABSTRACT
Gravity drainage can result in a high recovery efficiency for high permeability oil reservoirs with low viscosity oil and low interfacial tension.
In order to make reliable field wide performance predictions of this production mechanism, it is necessary to obtain accurate determination of gas-oil relative permeabilities and residual oil saturation.
Gas-oil relative permeabilities have been extensively investigated, by performing: –displacement experiments in various conditions (differential pressure, interfacial tension, connate water or not, short or long core, room or reservoir conditions).–dynamic capillary desorption experiments.
Special emphasis has been given to the actual physical meaning of the residual oil saturation and the way it is reached.
The main results are: –Gas-oil displacement experiments performed in laboratory conditions (high interfacial tension) with various pressure drops give the same relative permeability if interpreted taking capillary effect into account. The final experimental oil saturation, which depends on the maximum acceptable injection pressure (turbulent flow problems) is different from the "true" ROS (corresponding to kro = 0).–Capillary desorption experiments in lab conditions with numerical interpretation of the transient production, may be used to determine ROS and oil relative permeability at high gas saturation.–Interfacial tension (in the range 0.6 – 30 mN/m) has little influence on the relative permeabilities.–Presence of connate water has little influence: oil and water behave as a single liquid phase.–Relative permeabilities obtained from laboratory conditions (short core) and reservoir conditions (long core) experiments are very close.–The final desaturation (ROS around 5 %PV) is reached very slowly, due to the very low level of oil relative permeability (about 10−5).
A reliable method to determine relative permeabilities in laboratory conditions has been established, by performing both displacement and capillary desorption experiments.
Scale Inhibitor Precipitation Squeeze for Non-Carbonate Reservoirs
Authors: Carlberg B. L. 
Published: December 2007

ABSTRACT
There has been evidence of a need for scale inhibitor precipitation squeeze treatment in sandstone as well as in carbonate reservoirs. The Mixed Chelate process was designed to meet that need with the injection of a single solution. Success in the laboratory has been verified with numerous experiments. Success has also been evidenced in a field test initiated in late 1986.
A One-Dimensional Formation Damage Simulator for Damage Due to Fines Migration
Authors: Vitthal S. , Sharma M. M. , Sepehrnoori K. 
Published: December 2007

ABSTRACT
One of the major causes of formation damage is the movement and trapping of fine particles in pores. These fines may be generated in-situ by the interaction of injected fluids with the formation or they may be injected along with the fluids.
A model is presented that simulates the permeability impairment caused by fines migration or injection in a radial geometry. The physical basis for the equations are the same as for a linear model that has been presented earlier 1,2. The equations are quite general and can be used to model the permeability reduction for any given pore or particle size distribution.
The fines migration phenomenon is a moving boundary type problem. The position of the boundary is determined by assuming that it propagates as an ideal sharp front. The set of coupled, non-linear partial differential equations for the model are solved by an implicit finite-differencing technique.
The validity of the simulator is tested against analytical equations that have been developed for some special cases. The agreement between the simulator and the analytical solutions is found to be excellent. The simulator is also used to investigate the importance of various parameters. For example it is found that the pore and particle size distributions, as well as their concentrations have a significant effect on the permeability reduction. Other factors of importance are the rate of release of attached particles and the geometry of the pores. Methods of estimating these parameters are suggested. The use of the simulator to calculate the extent and depth of damage of damage, when fluids are injected into the formation, is demonstrated. It is expected that the simulator will prove useful in the design of such operations.
Key Factors for Enhanced Results of Matrix Stimulation Treatments
Authors: Paccaloni G. , Tambini M. , Galoppini M. 
Published: December 2007

ABSTRACT
Most of the failures of matrix stimulation treatments can be imputed to incorrect field procedures.
To improve the success ratio of the jobs, the tailoring of field stimulation procedures must be strictly linked with the clear identification of the target and with the optimization of the design. Objectives are set to meet different well situations, and require specific design and field procedures.
Maximizing the injection pressure andrate during matrix stimulations has proven to be a very successful technique, particularly effective over extensive pay zones.
Geothermal Well Damage in the Paris Basin: A Review of Existing and Suggested Workover Inhibition Procedures
Authors: Ungemach P. , Turon R. 
Published: December 2007

ABSTRACT
The central part of the Paris Basin of France is one of the largest hot water resources developed to date for district heating purposes. Exploitation addresses reservoirs hosted chiefly in consolidated carbonate rocks and, occasionally, in deeper, clastic sandstone formations. Depths and temperatures range from 1,600 to 2,000 m and 50 to 85°C respectively.
For obvious environmental and pressure maintenance reasons, the production technology is based on the so-called doublet concept. It associates a production well, a heat exchanger transferring the geothermal heat to a distribution network and an injection well conveying the heat depleted brine into the source reservoir.
Among the fifty four such schemes presently operating in the Paris area, one third are undergoing severe exploitation problems. Those consist of well damage which, in most instances, has affected first the injection well, then the producing well. This damage originates from a thermochemically sensitive formation fluid, a hot, slightly acid brine with a fairly low gas liquid ratio. It results in casing corrosion and scaling by heavy metal, mainly iron, sulphide deposits. Yet the origin of this scale, either corrosion generated, bacterial or native, is not clear.
Most workover programmes, based on conventional cable and drill stem technologies, have succeeded in restoring initial well injectivities and productivities by combining casing cleaning/scraping and open hole jetting. However their efficiencies, in terms of durability, are limited to hardly one year.
Chemical inhibition has been attempted on a few sites with varying success. It was based on injection at shallow depths of corrosion and scale inhibitors and bactericides.
Alternative methods are contemplated. They consist of (a) a versatile, cost effective, workover technique using a high pressure large diameter flexible coiled tubing, and (b) of continuous injection down hole of crystal growth inhibiting agents.
Existing restoration and inhibition treatments are reviewed and selected examples presented. Candidate procedures are discussed in the light of damage monitoring and identification of source mechanisms.
Gas Injection Performance Of The Pembina "E" Lease
Authors: Kloepfer C.V. , Tracy G.W. , Last G.J. 
Published: December 2007

PUBLICATION RIGHTS RESERVED
This paper is to be presented at the 36th Annual Fall Meeting of the Society of Petroleum Engineers of AIME in Dallas October 8–11, 1961, and is considered the property of the Society of Petroleum Engineers. Permission to publish is hereby restricted to an abstract of not more than 300 words, with no illustrations, unless the paper is specifically released to the press by the Editor of JOURNAL OF PETROLEUM TECHNOLOGY or the Executive Secretary. Such abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in JOURNAL OF PETROLEUM TECHNOLOGY or SOCIETY OF PETROLEUM ENGINEERS JOURNAL is granted on request, providing proper credit is given that publication and the original presentation of the paper.
Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and considered for publication in one of the two SPE magazines with the paper.

Abstract
A review of the performance of the Pan American-Hudson's Bay Pembina E Lease, Cardium Reservoir Pembina Field, has been made. Early in the history of this lease it was thought that primary recovery would be low. Waterflooding was considered uneconomical due to the low well injectivity and productivity. However, gas injection using an inverted nine-spot pattern has been shown to be economical. Gas injection facilities were paid out in eight months.
Rapid rises in gas-oil ratio were experienced shortly after gas injection was started. This was found to be a direct result of local depletion around the individual producing wells and not gas channeling. When the oil producing rates were stabilized, the gas-oil ratio began to decline and is still declining.
Calculated recovery estimates indicate that gas injection may increase the recovery of this lease by over 3,000,000 barrels, representing a 48% increase over ultimate primary recovery.

Introduction
The Pan American-Hudson's Bay Pembina E Lease comprises approximately 5,760 acres and is representative of the large portion of the Pembina Cardium Field characterized by a low producing capacity sand development. The E Lease is located in Township 47 and 48, Ranges 9 and 10, W5M in the Province of Alberta. (Figure 1) Under primary depletion the wells on this lease exhibited a gas-oil ratio performance abnormal to most oil reservoirs.
Obtaining Native-State Cores with a Specially Designed Water-Free Coring Fluid
Authors: Hemphill A. T. , Mayes T. M. 
Published: December 2007

Abstract
With the development of a new water-free oil-base coring fluid, extraction of cores in their native or unaltered state is possible. Improvements in laboratory measurements of formation rock properties can now be obtained. In addition to its application as a coring fluid, this system can be used as a drilling fluid.
Advances in Fracturing Techniques in Carbonate Reservoirs in the Howard Glasscock Field in West Texas
Authors: Hoover R. S. , Adams R. L. 
Published: December 2007

ABSTRACT
Significantly increased volumes of proppants have been placed in carbonate reservoirs such as the San Andres formation in the Howard Glasscock field in Howard County, Texas. The treatments that have been performed were accomplished using significantly smaller volumes of liquid. The treatment placement success can be attributed to the incorporation of recent advances in wireline inputs, perforating techniques, and computer design capabilities using accurate reservoir data. New blending equipment capable of computer interaction has also contributed to the ability to accurately schedule and place the higher proppant concentrations.
The use of the previously mentioned components have resulted in controlled fracture heights while taking advantage of in-situ stress barriers. The greater created fracture conductivity will allow for increased production of fluids once this waterflood has been completely implemented.
Cryogenic Nitrogen or Carbon Dioxide Rejection
Authors: Philcox J. E. , Grader R. J. , Gilchrist R. E. 
Published: December 2007

ABSTRACT
The rapid growth of Carbon Dioxide (CO2) and/or Nitrogen (N2) Enhanced Oil Recovery (EOR) projects has resulted in the need for efficient low cost rejection technology. This is particularly true if the Nitrogen or Carbon Dioxide is produced with a natural gas that has an existing market. Basic rejection cycles are described and compared. Key process and mechanical design considerations, especially those unique to Nitrogen and Carbon Dioxide, are emphasized.
The Carbon Dioxide or Nitrogen content in the produced gas increases with time over the life of a project, so the rejection equipment must perform satisfactorily over a broad range of feed compositions. Recycling the rejected Carbon Dioxide or Nitrogen is a cheaper source of injection gas than its original source. A rejection unit can be designed as an add-on unit to existing natural gas processing facilities in which much of the stabilization, pre-treatment, and liquid recovery already exists.
A sample application for nitrogen rejection is presented including process performance and simple economics for a "typical" case.
Carbonate Production Decline Rates Are Reduced Through Improvements in Gelled Acid Technology
Authors: Johnson D. E. , Fox K. B. , Burns L. D. , O'Mara E. M. 
Published: December 2007

ABSTRACT
Over 300 matrix and fracture acidizing treatments, utilizing a thermally stable acid gelling agent, were performed in carbonate formations, worldwide. The initial results of several treatments were presented earlier (Ref. 1). Since then, trends toward sustained increases in production have been documented and are presented. Reductions in production decline rates have resulted in improved recovery of reserves.
Improved live acid penetration results from the effects of stable viscosity, retarded reaction rate and proper treatment design. In addition, the gelling agent must be non-damaging, requiring tolerance to calcium and magnesium ions in the spent acid during cleanup. A gelling agent is described that provides the features of thermal stability and solubility in the live and spent acid.
A Review of the Methods of Estimating Stabilized Absolute Open-Flow Potential of Gas Wells
Authors: Poe B. D. , Jennings J. W. 
Published: December 2007

ABSTRACT
This paper presents a review of the practical backpressure test analyses available for estimation of the stabilized absolute open flow (AOF) potential of natural gas wells. Linear regression analysis techniques have been used to correlate the field-recorded deliverability data and statistical influence tests have been used to identify possible outliers in the test data.
The types of backpressure tests considered in this study are the conventional flow-after-flow (four point), single point, regular and modified isochronal backpressure tests, and the multiple modified isochronal test. The deliverability analyses considered in this paper are the Rawlins-Schellhardt pressure-squared, and the Houpeurt (quadratic) real gas pseudopressure and pressure-squared analyses. Modified versions of these analyses are used in the analysis of multiple modified isochronal tests.
The analysis techniques developed for multiple modified isochronal tests were reviewed and found to permit a rapid and adequate means of estimating the stabilized AOF potentials of slow-in-stabilizing wells in homogeneous reservoirs, using only the semilog transient isochronal deliverability data. Theoretical considerations are also introduced which may provide a means of estimating stabilized AOF potentials of gas wells completed in naturally fractured reservoirs. A discussion is also included on the estimation of stabilized AOF potentials of wells completed in homogeneous reservoirs, which have been vertically fractured to increase their productivity.
History Match of the Maljamar CO2 Pilot Performance
Authors: Moore J. S. , Clark G. C. 
Published: December 2007

ABSTRACT
A miscible CO2 flood pilot conducted in the Maljamar field, New Mexico, was formally completed January 1, 1986. This paper presents the results and developments of numerically history matching the 6th (Grayburg) and 9th Massive (San Andres) zone CO2 pilots. The purpose of this pilot was to gain information that would reduce the operational and economic uncertainties of a full-scale project. Special features of the 5-acre (20,200 m2) inverted 5-spot pilot include (a) dual (separate) completions in the Grayburg and San Andres zones and (b) two fiberglass-cased logging observation wells for in situ monitoring of oil, brine, and carbon dioxide movement. The logging observation wells illustrated that the miscible CO2 flood process can significantly reduce oil saturations in the 6th and 9th Massive zones at Maljamar. The high CO2 retention, high minimum water saturation, and low CO2 injectivity exhibited in the pilot can be accounted for through relative permeability hysteresis and a possible change in rock wettability. By incorporating these mechanisms into the simulator, a reasonable match of oil and CO2 production, fluid injectivity, and observation well saturation profiles demonstrated the validity of the approach. The calibrated performance parameters were used as a basis for making fieldwide performance predictions for the Maljamar field.
Evaluation of Commercial Crosslinked Polyacrylamide Gel Systems for Injection Profile Modification
Authors: Purkaple J. D. , Summers L. E. 
Published: December 2007

ABSTRACT
This paper describes a unified testing program to identify the best polymer gel systems for a particular field application. Beaker tests are used to rapidly screen gel systems. Coreflood tests are then employed for the final system selection.
Results are presented from a full-scale laboratory evaluation of 15 commercially available polyacrylamide polymers with a Cr(III)-redox crosslinker for profile modification in a thick, multizone reservoir. Beaker tests showed that low levels of polymer hydrolysis were required to produce consistent gels at reservoir conditions. In addition, the pH of the gel solution in the buffered field brine had a large effect on the gel properties. Allied Cglloids Alcoflood ®935L and American Cyanamid Cyanagel ®150 were selected for further evaluation in coreflood tests. Either polymer gel maintained a permeability reduction of at least 97 percent after 50 days of static aging at reservoir conditions. The stability of an Alcoflood 935L gel was evaluated during continuous injection and with exposure to near wellbore pressure gradients.
Miscible Flood Performance Predictions for a Full-Field Project Using Multiple Prototypes To Represent Individual Wells
Authors: Chernik P. S. , Symonds R. W. , Todd M. R. 
Published: December 2007

ABSTRACT
A prototype simulation approach, with appropriate scaling factors, has been devised so that prototype simulations can be scaled to yield the performance of individual sub-segments (zones) within wells. The predicted performance of the sub-segments are summed to yield pattern element performance and these in turn are summed to yield a performance forecast for the area of interest. The prototype approach has been used to generate waterflood and miscible flood performance predictions for a portion of the Virginia Hills Beaverhill Lake Unit.