bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dos Cuadras Offshore Polymer Flood
Authors: Dovan H. T. , Hutchins R. D. , Terzian G. A. 
Published: December 2007

Abstract
An offshore polymer flood in the Dos Cuadras field near Santa Barbara, California was implemented early in 1986. The polymer selection process included laboratory screening and a month long field injectivity test with three prospective polymer suppliers. Polymer injectivity, required polymer concentrations to meet design viscosities, the need for additional polymer inversion chemicals and core plugging behavior of the polymer solution were critical parameters in this evaluation. Full-scale equipment design was aided by observing the performance of skids supplied by each vendor for polymer inversion and injection. Following the selection of a polymer product, shear tests were conducted to improve polymer solution injectivity through Berea core plugs. Although these tests were sufficient to ensure injection into the EP zone, additional shearing of the polymer solution was required to improve injectivity into the FP zone. A filtration test, which was found to be more sensitive than the core plug test to the plugging behavior of polymer solutions, was used to compare properties of injected solutions for the FP zone, Hall plots have been found to be useful for understanding the response of the injection wells to the various injectants.
Evaluating the Effectiveness of Corrective Actions Involving Groundwater
Authors: Johnson W. B. , Jennings K. V. B. 
Published: December 2007

Abstract
General methodological recommendations and relevant specific literature references are provided for determining when ground-water cleanups are complete. These methods can be used for cleanups required after spills from gas stations, pipe leakage, tank failure, and petro-chemical processing accidents.
The primary premise of this paper is that the degree of cleanup is defined by more than simply establishment of numerical thresholds. Measurement control, sampling methodology, and data analysis methodologies also influence the degree of cleanup.
Further Characterization of Surfactants as Steamflood Additives
Authors: Hamida F. M. , Demiral B. M. R. , Shallcross D. C. , Castanier L. M. , Brigham W. E. 
Published: December 2007

Abstract
It has been known that steamflood efficiency can be increased by adding surface active agents to steam such that foam can be generated, preferentially reduces permeability to steam in previously invaded zones, and diverts it through undepleted regions of the reservoir. In this study the partial results of a continuing project which aims to optimize surfactant use as additives in steamflood field applications are reported. Two steps of the project were completed up to date. As a first step, the foamability of seventeen surfactants was evaluated at steam injection conditions (160 °C and 75 psig) and linked to their chemical structure. As previously reported by D. C. Shallcross et.al.1, a linear model saturated with only water was used to compare and characterize different surfactants as steamflood additives. During the experiments surfactant solutions were injected as slugs into the sand pack after steam breakthrough. Nitrogen was injected as a noncondensible gas. The evaluation of foamability is based on pressure gradient changes and steam mobility reduction along the model. Under the conditions of the experiments, the alpha olefin sulfonates generated the strongest foam at low concentrations. Internal olefin sulfonates, linear toluene sulfonates and linear xylene sulfonates all generated stable foams at higher concentrations. Flow resistance due to foam also increased as the alkyl chain length increased.
In the second step, first the previous experiments were repeated by using eight selected surfactants to check if they were reproducible. During the runs two 10% PV slugs of surfactant solution with 0.5 weight percent concentration were injected into the sand pack. The second slug was injected after the foam created by the first one completely collapsed. Then these runs were repeated under the same operating conditions as the water runs except for the presence of oil. West Newport crude oil was used at residual saturation after steam flooding during these runs. The analysis of the results showed that both the pressure gradients and the reduction in steam mobility after surfactant solution injection were affected by the presence of oil. In the presence of oil no increase in pressure was observed to date.
The two sets of experiments were compared and discussed in detail using maximum pressure drops and duration of pressure changes, pressure increases with distance from the inlet and time, steam mobility reduction, and thermal parameters. One interesting result is the fact that relative permeability to steam was reduced to between 0.005 and 0.02 when no oil was present.
Laboratory Design and Field Demonstration of Steam Diversion with Foam
Authors: Djabbarah N. F. , Weber S. L. , Freeman D. C. , Muscatello J. A. , Ashbaugh J. P. , Covington T. E. 
Published: December 2007

Abstract
Mobil conducted a foam-steam diversion test to achieve the following objectives:
Confirm laboratory results which show foam generation with steam in unconsolidated sands. Establish the feasibility of steam flow diversion by foam in complex reservoir sands. Determine the effect of varied injection strategies on the steam-foam generation process, and Determine incremental oil recovery attributed to foam.
Laboratory experiments are presented which evaluate foaming surfactants at simulated steamflood conditions using reservoir rock and fluids. Surfactant loss due to adsorption, partitioning, and thermal decomposition are all included, together with displacement results in sandpacks. It is shown that foam will form and propagate at steamflood conditions. A satisfactory injection strategy involves continuous balance between surfactant loss and foam propagation.
Feasibility was demonstrated in a heavy oil reservoir in two contiguous ten-acre inverted nine-spot patterns. Foam, generated at the surface by mixing surfactant with a noncondensible gas (and steam) and injected in a reservoir-specific intermittent on/off cycle, was maintained in the reservoir, as proven by injector wellhead pressure increases. Tracer tests and casing gas analyses showed that foam redistributed steam across the vertically heterogeneous oil sand, increasing volumetric sweep and oil production. Approximately 178,000 lbs of surfactant and 15 MMSCF of nitrogen were injected.
Experimental Studies of Capillary Pressure Effects of Foams in Porous Media
Authors: Chen H.-L. , Ke M-J. , Chuang T-K. , Flumerfelt R. W. 
Published: December 2007

Abstract
Although foams have been recognized for improving in oil recovery process, detailed descriptions of the relative importance of viscous and capillary effects are still lacking. Previous work has largely been concerned with the measurement of effective viscosities or dispersed phase permeabilities which masks both viscous and capillary effects. A first step in separating such effects requires the measurement of capillary pressure for foam systems in porous media. To date, only isolated data of this type have been reported.
In this work, a capillary pressure cell has been designed to investigate capillary behavior of foams in bead packs. This experimental setup has several unique and versatile features such as: (1) Hydrophobic and hydrophilic membranes placed at the entrance and exit ends of the bead pack to selectively restrict the flow of gas and liquid to and from the cell and hence insure correct capillary pressure (PC = PG-PL) measurement; (2) a compression spring imposed on the top of the bead pack to insure a stable bead pack and good capillary contact between the bead pack and the membranes; and (3) back pressure control to allow high pressure testing and to minimize in situ bubble size changes (compressibility effects) during testing. With the above system, sequential drainage and imbibition cycles can be repeatedly traversed without interruption.
Multicycle drainage and imbibition experiments were performed under conditions where the foam was generated in situ, and the static capillary effects were obtained for both non-dispersed phase (gas-water system with no film stabilizing surface active agents) and dispersed phase (surface active agent present) systems. While only two drainage-imbibition cycles are necessary for non-dispersed
phase systems to achieve invariant capillary pressure curves, 4 to 6 cycles are required for dispersed phase systems. In all cases, the irreducible and residual wetting phase saturations at the end of drainage and imbibition are lower than for those of non-dispersed phase systems. Studies of pore structure effects provide direct evidence that dispersed phase systems effectively reduce the degree of heterogeneous behavior in a bed. Studies of wetting effects show that both the irreducible and residual saturations at the end of drainage and imbibition are significantly decreased as the degree of oil wettability is increased. Finally, from tests at different surfactant concentrations, the largest changes in gas trapping occur as the concentration is increased below the CMC (critical micelle concentration); at higher concentrations additional trapping takes place but the effect is less dramatic.
Mechanics of Bubble Flow in Heavy Oil Reservoirs
Authors: Islam M. R. , Chakma A. 
Published: December 2007

Abstract
A new mechanism of fluid flow in solution-gas drive heavy oil reservoirs is identified through experimental studies. This paper presents experimental results in order to verify previous hypothesis on fluid flow in heavy oil reservoirs in Canada. It has been postulated that solution-gas drive in these reservoirs involves simultaneous flow of gas and oil. However, gas remains in tiny droplets under reservoir conditions1. A new mathematical model was proposed in order to describe peculiar pressure-dependent multiphase flow properties. This paper presents experimental validation of some of the hypotheses offered by Smith1. More than 40 experimental tests are performed both in a capillary tube and in a core packed with unconsolidated reservoir fluids and sands. The effects of decreasing bubble size on total fluid production and pressure drop across a pipe are observed. Experiments with live oil and reservoir sands enable one to quantify the contribution of bubble flow in solution gas drive process involved in heavy oil reservoirs. Some of these results help explaining the anomalies observed in heavy oil reservoirs in Canada.
An Automated System for Closed-Chamber Drillstem Testing
Authors: Poulsen D. K. , Bass A. O. 
Published: December 2007

Abstract
Because of its many advantages, including safety, accuracy, and instantaneity, closed-chamber drill stem testing continues to gain popularity as a well testing technique. Although commonly performed, closed-chamber tests typically require manual reading of pressure gauges and manual recording of data.
This paper will describe a computerized system for automatic collection and analysis of closed-chamber test data. Using an IBM-compatible micro-computer and newly developed correlations, the system calculates maximum surface pressures vs. time for pure gas, gas-saturated water and gas-free water influx and displays the curves on the computer's screen. During the test, it reads from any of up to three pressure transducers, records the surface pressures and instantaneously displays them on the pretest planning graph. Following the test, it calculates flow rates for assumed pure gas and pure water flow and, as requested, plots pressure or either of the two rates versus time.
In addition to the computerized system for acquiring the data, the paper will describe and diagram the manifolding system for measuring the surface pressures. The manifolding system was designed to (1) enable pressures to be read from any of a set of three transducers, (2) keep the transducers in a relatively safe area away from the rig floor, (3) tap the chamber's surface pressure at the control head instead of at the floor choke manifold, thereby eliminating chicksan hoses and swings and the accompanying potential for pressure leakage, and (4) allow components to be removed relatively easily for servicing.
In summary, the paper will describe (1) the computerized system for acquiring closed-chamber DST data, (2) the enhanced and newly developed correlations and (3) the transducer manifolding designed for these tests. Diagrams of the manifolding and examples of tests will illustrate the paper.
Solvent/Surfactant Well Stimulations
Authors: Sonka J. K. 
Published: December 2007

Abstract
This paper describes a method to optimize well stimulation treatments using a combination of solvent and surfactant with a jet washing tool to clean clogged liners and perforations. The well selection criteria perforations. The well selection criteria using geologic and production data have been developed to maximize project profitability.
The jet tool is used to selectively place the chemicals in an underpressured reservoir across a large (350-foot plus) completed interval. The chemical used for these jobs is xylene and a nonionic surfactant/demulsifier. The surfactant is mutually soluble in hydrocarbon and water. Xylene acts as a carrier for the surfactant and solubilizes asphaltenes. This combination of xylene and surfactant breaks emulsions and makes the gravel pack and/or formation near the wellbore water-wet.
Twenty-seven wells have been stimulated in the North Midway Sunset Field. The optimal concentration range of surfactant was found to be between 9 and 14%. Treatments using surfactant concentrations in this range have rapid payout.
Monitoring Quality Control and Flowback of Foam Fracturing Treatments
Authors: Cipolla C. L. 
Published: December 2007

ABSTRACT
A comprehensive field data set from foam stimulation treatments is presented that illustrates the use of improved instrumentation, quality control (QC) and flowback practices. The integration of the field instrumentation with computer monitoring and real-time instrument cross-checks is also presented. The field tests of the instrumentation illustrates the application of magnetic flow meters to reliably measure actual foam flow rate. Foam flowback procedures are presented that provide controlled, monitored and clean return of foamed fluid.
Well Analysis Before and After Fracture Stimulation
Authors: Economides Michael J. , Thomas Ron L. 
Published: December 2007

ABSTRACT
Variables affecting the performance of a fractured well (over that of the unstimulated well) have a large impact on fracture design. The reservoir permeability and, often, the horizontal permeability anisotropy are the important variables to measure at the pretreatment state. They generally control the optimum fracture length. Predictions of fracture permeability (affected by stresses and residue damage) and fracture height (affected by the interlayer stress contrast) must also be taken into consideration.
Evaluation of the fracture job requires measurements that would lead to the estimation of actual fracture height, fracture length, and fracture conductivity. These estimations allow the forecast of fractured well performance and the rationalization of the job design. This well performance analysis before and after stimulation should be an integral part of a properly engineered reservoir exploitation strategy.
Significant Factors for Successful Matrix Acidizing
Authors: McLeod Harry O. 
Published: December 2007

ABSTRACT
Successful matrix acidizing depends upon: (1). good evaluation of candidate wells using (a) completion and production histories, (b) producing well flow analysis (nodal analysis) and (c) formation composition analysis, (2). design for effective coverage of all damaged perforations, (3). selection of solvents, acids and acid compositions to prevent or reduce incompatibilities and (4). effective well preparation and job supervision.
Long-Distance Propagation of Foams
Authors: Hudgins D. A. , Chung T-H. 
Published: December 2007

ABSTRACT
A series of experiments was conducted to study foam generation and propagation over long distances through porous media. To simplify the problem, they were performed in a one-dimensional physical model consisting of a 30-ft [9.14-m] -long sand-packed slim tube. All experiments were conducted at reservoir conditions of 2,000 psig [13.79 MPa] backpressure at 150° F [338.7 K]. Alipal CD-128 surfactant was used as the foamer. WAG (water-alternating-gas) ratios and injection sequences were varied and found to have a profound effect upon the foam generation and propagation, with higher WAG ratios (more water) breaking down the foam and washing it out. In some cases, the foam became immobile or very slow-moving, while in other cases, it traveled with the gas front for great distances. Crude oil's presence in the porous media was very detrimental to foaming. For comparison, similar experiments in short Berea sandstone cores without oil failed to produce any evidence of foaming.
Oil Recovery Mechanisms in Fractured Reservoirs During Steam Injection
Authors: Reis J. C. 
Published: December 2007

Abstract
The recovery mechanisms for steam injection in naturally fractured reservoirs and the characteristic recovery times for these mechanisms are reviewed. Laboratory studies suggest that steam injection can recover as much as 50% more oil than waterflooding in fractured reservoirs. This recovery is essentially independent of oil gravity, making steam injection equally attractive in light or heavy oil fractured reservoirs.
One of the most important incremental recovery mechanisms is the differential thermal expansion between the oil and the matrix pore volume. At high temperatures, chemical reactions within the matrix block can generate gases, which will displace oil. In matrix blocks containing organic carbon, additional oil can be generated. Oil can also be recovered during cyclic processes by dropping the pressure and flashing the water in the matrix blocks to steam. The effects of steam injection on capillary imbibition of water are less clear, although the reduced viscosity at the higher temperatures will speed the imbibition process. Other mechanisms like gravity drainage, solution gas drive, and distillation are thought to play a less important role in oil recovery.
The characteristic expulsion times for each of these recovery mechanisms are identified. Most of the oil in matrix blocks as large as 10 ft wide can be recovered within a few months.
A Full-Field Numerical Modeling Study for the Ford Geraldine Unit CO2 Flood
Authors: Lee K. H. , El-Saleh M. M. 
Published: December 2007

ABSTRACT
This paper describes a full field numerical modeling study of the on-going Ford Geraldine Unit CO2 flood. A three-dimensional, miscible-type simulator was used to simulate the project area, which covers 3,850 acres and includes 212 wells. The numerical model was calibrated by matching rates, cumulative production, and pressure history, both field-wide and for individual wells.
The full field model offers the following advantages over a unit or symmetric element model: 1. Proper description of inter-well interference; 2. Honoring the production/injection and workover histories of the individual wells; 3. Preservation of the reservoir heterogeneity; and 4. No scale-up problems or assumptions.
This paper will briefly describe the simulator and the techniques used in the history matching. The effects of adjusting various parameters will be discussed, and the history match for full field and individual wells will be presented.
After satisfactory history matching results were obtained, the model is being used to assist in the Unit CO2 flood operation. Examples will be discussed demonstrating the importance of the simulator in monitoring and operating the flood.
A Comparison of 31 Minnelusa Polymer Floods With 24 Minnelusa Waterfloods
Authors: Hochanadel S. M. , Lunceford M. L. , Farmer C. W. 
Published: December 2007

ABSTRACT
The Minnelusa formation in Wyoming's Powder River Basin exhibits high permeability variations and adverse mobility ratios. Polymer augmented waterflooding has been the chosen technology to overcome these conditions for the past 15 years. The idea is to first unify the permeability distribution by injecting cationic polymer, followed by anionic polymer and aluminum citrate crosslinker. Then straight anionic polymer is injected for mobility control. This paper compares the results of 31 Minnelusa polymer floods with 24 Minnelusa waterfloods.
The paper has two parts. The first part compares oil recoveries, injection volumes, flood lives, and water productions of the two population groups at various recovery efficiency cutoffs. At equal oil recoveries, the polymer floods inject less water, produce less water and recover the oil quicker than the waterfloods.
The second part of the paper determines the economics of a typical polymer flood. The cumulative injection and the cumulative oil production of each field are plotted for both the waterfloods and the polymer floods. The points are curve-fitted to yield an equation which predicts oil recovery versus injection in dimensionless form. The equation of each group is applied to the same generic Minnelusa reservoir at a fixed injection rate to yield oil production in time-rate format. Economics are run based on these two production functions.
Results show the polymer flood is economic and recovers an additional 7.5% OOIP over the waterflood. The polymer plus equipment cost is less than $2.00 per incremental barrel of oil.