bluuebunny/crossref_metadata_2025_split huggingface dataset:
Semianalytical Modeling of Pressure Transients in Fractured Reservoirs
Authors: van Kruysdijk C. P. J. W. 
Published: December 2007

ABSTRACT
By combining the boundary-element technique introduced by Cinco-Ley with the Laplace transform, a powerful technique has been developed for modelling transient flow in complex reservoir geometries. Applied to a finite-conductivity fracture in an infinite (if desired, dual-porosity) reservoir, the technique offers both a robust and fast algorithm for calculating the transient pressure response. Furthermore, it describes flow impairment in the vicinity of the fracture and fracture-wall damage in terms of a fracture-wall skin factor. As shown by the model, the presence of this phenomenon is clearly indicated by a. distinct hump on the pressure-derivative plot (t∂p∂t versus t). An application of the technique to actual field data demonstrates the importance of the fracture-wall skin factor in well-test analysis. The speed of the algorithm enables automatic type-curve matching by least-squares methods. Since the solution is given in Laplace space, it is possible to handle multi-layer fractured reservoirs at very low cost. Furthermore, convolution to obtain variable-rate solutions can be performed in Laplace space. The same technique has also been applied to a two-fracture system and to a horizontal well intersecting a zone of natural fractures.
Estimation of Matrix Block Size Distribution in Naturally Fractured Reservoirs
Authors: Belani A. K. , Jalali Y. 
Published: December 2007

ABSTRACT
Interporosity flow in a naturally fractured reservoir is modelled by a new formulation incorporating variability in matrix block size. Matrix block size is inversely related to fracture intensity. The size of matrix elements contributing to interporosity flow is expressed as a distribution in the source term of the diffusivity equation. The pressure transient response for uniform and bimodal distributions of block size is investigated. Both pseudo-steady state and transient models of flow are analysed. It is shown that features observed on the pressure derivative curve can yield the parameters of the distribution. Thus, observed pressure response from fractured reservoirs can be analysed to obtain the matrix block size distribution in the volume of the reservoir investigated by the test.
The solution to the uniform distribution can be extended to more general distributions. Other sources of information, like logs and geological observations, can give an estimation of the shape of the distribution, and this model can be used to compute the reservoir parameters.
A Computational Model of Well Completion Design
Authors: Dunn-Norman S. , Peden J. M. , Bedford D. R. 
Published: December 2007

ABSTRACT
The design of well completions is a complex process which requires the engineer to select, rationalize and integrate a large number of design elements. In the literature, it has been recognized that a systems approach to well completion design must be adopted if optimum and cost-efficient completions are to be generated. Historically, diagrammatical representations, such as logic diagrams, have been used to model and implement the systems approach for well completion design.
This paper discusses, as an alternative, a computational model of well completion design developed through an industry sponsored collaborative research project. The model formalizes the relationships and interaction between conventional computations for completion design, such as tubing hydraulics or stress analysis, and design knowledge gained through design and operating experience.
This model provides a comprehensive representation of the systems approach to well completion design, and serves as the basis for a computerized implementation. The implementation integrates both conventional and expert systems programming techniques. Program development and the advantages of using a computer design program to provide a rational and consistently optimum design capability are discussed.
Application of Electrical Submersible Pumps in Natural and Artificial Water-Drive Reservoirs
Authors: Whiting R. L. 
Published: December 2007

ABSTRACT
A comprehensive review of theory and laboratory research pertaining to the recovery of oil from porous media is presented leading to the conclusion, contrary to earlier views, reservoir rocks are considered to have heterogeneous wettability. Because of this, oil will flow at very low oil saturations and hence yields much lower residual oil saturation. Further immobile oil may be made mobile and residual oil saturation decreased by increasing the pressure gradient in' the reservoir.
During the past forty years the author has been active in evaluating the performance of petroleum reservoirs. Use of electrical submersible pumps (ESP) has been demonstrated to increase oil production rate, ultimate oil recovery, and economics based on evaluations of strong bottom and edge water drive and waterflood operations at high fluid withdrawal rates. This paper presents the state-of-the-art and science of theory, laboratory research and field studies on this subject.
The scope of ESP field applications presented includes operations in eight countries and eight U.S. states. A wide range of structures, formation, rock and fluid properties, types of drive, oil and total fluid production rates, and ESP capacities are included.
Two production performance type-curves (percent oil cut-cumulative oil production and oil production rate-cumulative oil production) for ESP operations are presented and explained in accordance with theory and laboratory studies.
Production performance curves for seven fields in which ESP have been used for increasing oil production rate, ultimate oil recovery, and economics are presented.
A comparison of the economics including lifting costs, pump life, and payout of ESP operations in 78 Indonesian fields and 14 U.S.
fields is included. Comments from thirteen major companies worldwide are included citing their favorable results from use of ESP.
General Model of Fluid Flow (Leakoff) From Fractures Induced in Injection Operations
Authors: Settari A. 
Published: December 2007

Abstract
The paper describes a new general model of leak-off from fractures. The model is an extension of earlier work, generalized to handle multi-phase flow conditions, influence of reservoir boundaries and faults, well interference and voidage replacement in a pattern, and the compressibility of the injected fluid. The model was successfully incorporated in a 3-D fracture simulator. The capabilities of the method are demonstrated on examples of fractures in waterflood injector, in tar sands and in a WAG injection scheme.
Multiple Fluids, Proppant Transport, and Thermal Effects in Three-Dimensional Simulation of Hydraulic Fracturing
Authors: Clifton R. J. , Wang J-J. 
Published: December 2007

ABSTRACT
Realistic simulation of hydraulic fracturing requires the modeling of the flow of the fluid and proppant when multiple fluids, proppants and proppant concentrations are injected in a single fracturing treatment. Furthermore, the temperature of the fracturing fluid is required throughout the fracture for realistic modeling of the rheological properties of temperature-sensitive fluids. Such a detailed model for two-dimensional flow of fluid and proppant in a vertical fracture is presented in this paper. This flow is coupled to a fully three-dimensional elasticity model for the propagation and opening of the fracture. Fluid and proppant particles are tracked during their flow in order to allow the determination of which of the fluids and proppants being injected are at a given position in the fracture at any time. Each fluid is modeled as a non-Newtonian, power-law fluid. Modeling of proppant transport includes the effects of proppant diameter and crack opening; empirical relations are used to account for the effects of proppant concentration, including bridging. Temperature distributions within the fracture are calculated by solving a two-dimensional heat equation obtained by averaging across the width of the fracture. This equation includes the primary effects of convection within the fracture and heat exchange between the fluid and the reservoir. Secondary effects of heat conduction and heat dissipation in the fluid are included for completeness. The numerical method used for fluid tracking, proppant transport, and heat transfer involves integration along backward-drawn streamlines through the nodes at which the respective quantities are being evaluated. Numerical results are presented for representative types of fracture treatments in order to illustrate the nature of the above effects on the fracture geometry, proppant distribution, and injection pressure in the various types of hydraulic fractures.
New Test Kit for Rapid Detection of SRB in the Oil Field
Authors: Horacek G. L. , Gawel L. J. 
Published: December 2007

ABSTRACT
A new test method for detecting and enumerating sulfate-reducing bacteria (SRB) often associated with the petroleum environment has been developed and field tested. The new test method rapidly and accurately defects SRB at concentrations as low as 1,000 cells/cm3. Results are available in fifteen minutes compared to the three to four weeks required by the standard API RP 38 culture method. In addition, the new test method detects SRB species that do not grow on culture media used in the oil field. The method is not limited by unique growth or environmental conditions which may be required by the particular SRB species being assayed. The new test method uses an immunoassay which is specific for an enzyme system found only in SRB. The new method is not affected by oil, sulfides, iron, common oil field chemicals including biocides, or any other constituent of oil field water. The test method is a joint development of Conoco and Du Pont; a field test kit version is marketed by Conoco Specialty Products Inc. This paper substantiates the above performance claims through field comparison testing between the new test method and the industry standard API RP 38 method.
Helical Screw Rheometer: A New Tool for Stimulation Fluid Evaluation
Authors: Lord D. L. 
Published: December 2007

Abstract
The helical screw rheometer (HSR) is a new rotational viscometer with many unique features which provide distinct improvements in operation over those found in conventional couette, cone and plate, parallel plate, or other rotational type viscometers. Unlike these other rotational viscometers, the HSR response to rotation rate is measured in terms of pressure drop rather than torque. Access to a bank of multi-range pressure transducers external to the HSR provides a means for obtaining wide rangeability with this device. To achieve similar rangeability with a conventional rotational viscometer, it would be necessary to change the torque transducer, which is often an integral part of the instrument.
With an open discharge, the HSR acts as a single screw extruder capable of circulating test fluid and/or drawing a new fluid sample for testing. Viscometric measurements are made by first closing the HSR discharge and then measuring pressure drop response as a function of rotation rate. Fluids containing particulates create measurement problems for conventional rotational viscometers. Particle settling leads to erroneous torque readings with these instruments. In contrast, HSR operation promotes mixing and prevents sedimentation.
Although the HSR is an instrument applicable to a number of industry fluids, the scope of this paper is limited to the characterization of time independent, isothermal, power-law model stimulation fluids. A 2-in. diameter, square-pitch HSR with 0.1-in. thread depth was used to evaluate rheological properties of several different hydroxypropyl guar (HPG) solutions. Analysis procedures used to convert pressure drop versus rotation rate data to power-law n' and K'v values are described.
Prediction of Dispersion Viscosity of Oil/Water Mixture Flow in Horizontal Pipes
Authors: Martinez A. E. , Arirachakaran S. , Shoham O. , Brill J. P. 
Published: December 2007

ABSTRACT
A pipe viscometer facility was constructed to investigate the flow of oil-water dispersions in horizontal pipes. Pressure drop, liquid mass flow rate, mixture temperature, input water fraction, and mixing intensity data were obtained for 490 oil-water tests. Mixture velocities ranged from 2.5 to 15.5 ft/sec, while input water fractions ranged from 0.0 to 0.35. Mixture temperatures ranged from 60 °F to 90 °F. A refined oil with a viscosity of 85 cp at 80 °F was used.
Data analysis showed that when the phase inversion point was reached, mixture viscosities were considerably higher than the viscosities for single-phase oil. Also, the frictional pressure gradients were found to be strongly dependent on whether oil or water was the continuous phase of the dispersions.
A model was developed for the prediction of the oil-water mixture frictional pressure gradient in horizontal pipes. The model assumes homogeneous flow and a power-law rheological behavior for the dispersion. The application of the model to the design of a non-Newtonian pipeline system is also presented.
The Membrane Alternative for Natural Gas Treating: Two Case Studies
Authors: Markiewicz G. S. , Losin M. S. , Campbell K. M. 
Published: December 2007

Abstract
Separex® membrane systems are a commercially proven technology for gas treatment that is an attractive alternative for many treatment requirements. This paper presents case histories of two natural gas treating facilities designed to sweeten and dehydrate gas to meet pipeline specifications. The Separex plant at a Major gas producer's facility near Baton Rouge, Louisiana is an excellent example of the type of innovative and economic solutions achievable with membranes to meet gas treating requirements. The membrane system replaced existing amine and dehydration plants to lower treating costs by as much as 8.5%. The Separex membrane unit at another Major gas producer's well in South Texas demonstrates the unattended operability of membrane systems. Production costs associated with the remote membrane system are lower than the previous gas blending option utilized. Membrane system design, process selection criteria and economics, and operation are discussed.
Design Alternatives for Sweetening LPG's and Liquid Hydrocarbons With Amines
Authors: Fleming K. B. , Spears M. L. , Bullin J. A. 
Published: December 2007

ABSTRACT
Amine solutions are often used to treat LPG streams that contain acid gases. In this work, the selection of an amine and the method of contacting the amine with a 50 gpm [189 lpm] LPG stream containing 7.7 mol% as CO2 are evaluated. A packed contactor is compared to a static mixer and MEA, DEA, and MDEA are compared as potential solvents. A static mixer using 70 gpm [2 65 lpm] of 25 wt.% DEA is chosen for the final design. The operating data reveal 0.10 mol% CO2 in the sweet LPG compared to the design value of 0.16 mol%.
Corrosion Monitoring in Sour Gas Production Systems – Principles, Practice and Field Experience
Authors: Brier B. B. , Bowman R. W. , Rose G. , Perkins A. J. 
Published: December 2007

ABSTRACT
Two case histories present recent field experience with corrosion monitoring programs in sour gas production facilities. Comparative data from different methods are presented.
Also included are a review of the theory of operation of available corrosion monitoring methods, a review of the types of corrosion encountered in sour gas service and recommendations for an optimized corrosion monitoring program.
Dynamic Simulation of Slug Catcher Behavior
Authors: Genceli H. , Kuenhold K. A. , Shoham O. , Brill J. P. 
Published: December 2007

ABSTRACT
A mathematical model has been developed for a gas-oil separator system, and a computer program has been written to simulate the behavior of the system. The separator is assumed to operate under slug flow conditions at the end of a two-phase flow pipeline. The liquid level and the pressure of the vessel are controlled by proportional integral controllers.
An optimization program has been written based on a linear model of the separator system. The program applies linear control theory to optimize the gains and reset times of the controllers.
The optimization and simulation programs can be used to design the smallest possible separator that will handle given gas and liquid flow rates in slug flow production. A sample design case is given.
Inducing Multiple Hydraulic Fractures from a Horizontal Wellbore
Authors: Overbey W. K. , Yost A. B. , Wilkins D. A. 
Published: December 2007

ABSTRACT
A series of stimulations were designed to open and propagate natural fractures known to exist along a 2000 foot horizontal well in Wayne County, West Virginia. The stimulations were also designed to induce fractures in the formation as well as propagate the natural fractures by manipulating pressure and injection rates. A number of radioactive tracers were used to determine where fractures were opened and propagated at different injection rates. The tracers were found in fractures in zones other than the one pumped into, a fact considered prima facie evidence that natural fractures with two or more orientations had been opened and propagated. Pressure testing and gas sampling of the isolated zones confirm that fracture communication was accomplished along nearly 1000 feet of borehole by stimulation of one 400 foot long section. A technique for inducing multiple hydraulic fractures with multiple orientations was demonstrated.
Laboratory Study of Proppant-Pack Permeability Reduction Caused by Fracturing Fluids Concentrated During Closure
Authors: Hawkins G. W. 
Published: December 2007

ABSTRACT
One of the key challenges in hydraulic fracturing is maximizing fracture permeability. Previously published work has shown that proppant-pack permeability is significantly impaired (damaged) by the fracturing fluid and that the impairment increases with increasing gelling agent concentration. In many hydraulic fracturing treatments, the gelling agent is often concentrated over tenfold upon fracture closure. However, measurement and removal of the permeability damage caused by these highly concentrated gelling agents has rarely been addressed. A laboratory study was undertaken to define the critical physical parameters and fracturing fluid characteristics affecting permeability in proppant-packs containing gelling agent concentrations up to 500 lbm/1,000 gal. The temperature range from 140° to 200°F was studied since it is below the range where thermal degradation of the fluid is believed to be effective.
Proppant-packs formed after hydraulic fracturing treatments were simulated using a modified API-type fracture conductivity cell which permitted fluid-loss through a low-permeability core, concentrating the fracturing fluid. Twenty-forty mesh northern white sand was used as proppant. Special experimental care allowed the measurement of proppant-pack clean-up within the first few pore volumes. Parameters investigated included gelling agent concentration (within proppant-pack), proppant concentration, closure stress, shut-in time, displacement fluid (aqueous and/or hydrocarbon), and displacement fluid flowrate. Un-crosslinked, borate-crosslinked, and metal-crosslinked HPG, and gelled hydrocarbon fracturing fluids were studied. The effects of a fracturing fluid breaker was also determined.
Even at relatively low gelling agent concentrations within the proppant-pack, significant proppant-pack permeability damage was observed. High displacement (well flow-back) rates only marginally removed the damage. High breaker concentrations were necessary to significantly reduce permeability damage.
Recovery of Condensate From a Heterogeneous Reservoir by the Injection of a Slug of Methane Followed by Nitrogen
Authors: Kossack C. A. , Opdal S. T. 
Published: December 2007

Abstract
The process of injecting gas into a gas condensate reservoir during production is vital to maintain the reservoir pressure so that the heavy hydrocarbon fractions will be recovered. One would like to inject a gas into the reservoir that is cheaper than methane, but recent one-dimensional studies have shown that the injection of nitrogen into gas condensate at reservoir conditions will result in the loss of much of the condensate liquid. This is a result from the liquid dropping out of the gas phase when nitrogen mixes with the condensate. A solution to this situation is the initial injection of a slug of methane (or dry gas) followed by the injection of nitrogen for pressure maintenance. If the methane slug is large enough it will separate the nitrogen from the condensate and the liquid recovery will be high. The physical processes that tend to destroy the integrity of the methane slug are mixing due to rock heterogeneity, fluid fingering, and bypassing.
This paper studies the two step injection process numerically with a three-dimensional EOS compositional simulator. The gases are injected into a heterogeneous quarter five spot. The recovery of liquid condensate is studied as a function of the composition of the injection gas, the methane slug size, and the magnitude of the permeability variations (heterogeneities) of the porous media. A fine grid involving 8,000 blocks is used to allow the proper description of the heterogeneities and to keep numerical dispersion, which simulates sub-grid block dispersion, at a reasonable level. Monte Carlo simulations are performed on realizations of reservoirs. The results show that the heterogeneities allow the nitrogen to mix with the condensate when the methane slug is small (5% to 10% of a porevolume) but the incremental recovery over the injection of nitrogen is large enough to pay for the cost of the methane. Economics are given to allow one to size a methane slug for a real heterogeneous reservoir so as to maximize the profit of the project.
Analysis of CO2 Pressure Transient Data With Two- and Three-Region Analytical Radial Composite Models
Authors: Tang R. W. , Ambastha A. K. 
Published: December 2007

SUMMARY
The results from this study show that pressure transients influenced by the interaction of fluid flow and phase behavior can behave as a three region composite reservoir. The intermediate region in this study was a high compressibility region that resulted from CO2-oil interaction.
Although two-region models have been applied successfully in thermal EOR and geothermal projects, a two-region model is unable to explain pseudo-steady state behavior observed in some miscible gas injection falloff tests. Three-region modeling combined with compositional simulation may be appropriate if pseudo-steady state response is observed, especially when mobility ratio is not large enough to manifest in a pseudo-steady state behavior based on two-region models.
A series of injection falloff tests were performed at a West Texas reservoir in an effort to establish injectivities and in situ flow parameters during water and CO2 injection. The results from the field tests in combination with laboratory tests will provide part of the engineering basis for design and operation of future CO2 EOR projects at a West Texas reservoir.
Falloff data and interpretation are presented along with experimental and compositional simulation results. In situ parameters such as mobility ratio, swept volume, and average CO2 saturation in the swept region were estimated from the falloff data. The falloff analyses results are in good agreement with laboratory measurements and theoretical predictions. Therefore, this type of injection testing may be desirable in most EOR projects.