The Effects of Isolated Permeability Interferences on the Sweep Efficiency and Conductivity of a Five-Spot Network

1967 ◽  
Vol 7 (01) ◽  
pp. 20-30 ◽  
Author(s):  
Rafael J. Sandrea ◽  
S.M. Farouq Ali
Keyword(s):  
Porous Medium ◽  
Homogeneous Medium ◽  
Simple Expression ◽  
Computational Scheme ◽  
Critical Parameters ◽  
Quantitative Prediction ◽  
Spot Pattern ◽  
Sweep Efficiency ◽  
Visual Model ◽  
Physical Limitations

Abstract The results of an experimental and theoretical study of the effects of rectilinear impermeable barriers and highly permeable channels on the sweep efficiency and conductivity of a five-spot network are presented. The study was carried out using Hele-Shaw and conductive sheet analogs for both normal and inverted flood patterns. A functional relationship was developed which provides quantitative prediction of the above parameters; i.e., sweep efficiency and conductivity, for the nonhomogeneous system. To evaluate this, it is necessary only to measure the interference modulus of the obstacle using a simple expression. The results indicate that impermeable barriers, with an interference modulus greater than zero, always cause a decrease in the conductivity and the sweep efficiency of the pattern. On the other hand, permeability channels do not have a significant effect on these parameters, unless they are located along the streamlines. The study also discusses a method of formulating the difference equations pertaining to the two-dimensional Laplacian in a system containing rectilinear barriers. In addition, a technique is described for tracing the progress of a free surface, using marked particles, in a stream containing discontinuities such as those occurring at the extremities of barriers. The above computational scheme was used in a digital computer program to simulate results of the Hele-Shaw analog. The computed values of sweep efficiency were in good agreement with the experimental values. INTRODUCTION At the present time waterflooding remains the most widely used technique for the secondary recovery of oil. Among the numerous factors that affect the performance of a waterflood, the areal sweep efficiency constitutes one of the most critical parameters. It is a function only of the geometric distribution of the wells for a homogeneous medium and unit mobility ratio. Geological considerations, however, such as the presence of sealing faults or solution channels in the rock matrix, would generally exert an adverse effect on the areal sweep efficiency of a waterflood network. Surprisingly little information is presently available1-3 on the quantitative implications of such permeability interferences. It was the object of this investigation to consider the presence of rectilinear, impermeable and highly permeable interferences in an otherwise homogeneous five-spot pattern, and to analyze their effects on the resulting sweep efficiency and pattern conductivity. The experimental phase of the study was conducted using two different models: the Hele-Shaw flow cell and the field plotter. For experimental convenience, the geometric boundaries of the five-spot were assumed to constitute streamlines even in the case where the interference was asymmetrically placed with respect to a repeated five-spot pattern. A second object of the study was to develop a computational scheme for numerically calculating the pressure distribution in a five-spot flow pattern containing rectilinear, impermeable barriers, and to use this distribution to compute the sweep efficiency. EXPERIMENTAL PROCEDURE HELE-SHAW ANALOG The Hele-Shaw analog was used both as a visual model and for determining the sweep efficiency for systems involving impermeable barriers. The physical limitations of this model as a means of experimentally studying the motion of a fluid in porous medium have been adequately discussed elsewhere.2,7 Likewise, it can be easily verified that the analogy remain s valid when a portion of the region between the plates contains an obstacle of the same thickness as the distance between the plates.4 HELE-SHAW ANALOG The Hele-Shaw analog was used both as a visual model and for determining the sweep efficiency for systems involving impermeable barriers. The physical limitations of this model as a means of experimentally studying the motion of a fluid in porous medium have been adequately discussed elsewhere.2,7 Likewise, it can be easily verified that the analogy remain s valid when a portion of the region between the plates contains an obstacle of the same thickness as the distance between the plates.4

Areal Sweep Efficiency of Pseudoplastic Fluids in a Five-Spot Hele-Shaw Model

1968 ◽  
Vol 8 (01) ◽  
pp. 52-62 ◽  
Author(s):  
K.S. Lee ◽  
E.L. Claridge
Keyword(s):  
Porous Medium ◽  
Oil Recovery ◽  
Polymer Solutions ◽  
Newtonian Fluids ◽  
Mobility Ratio ◽  
Spot Pattern ◽  
Sweep Efficiency ◽  
Flood Water ◽  
Miscible Displacements ◽  
Connate Water

Abstract Areal sweep efficiency of oil displacement by enhanced-viscosity water exhibiting pseudoplastic behavior was measured in a Hele-Shaw model representing one-quarter of a five-spot pattern. The pseudoplasticity of polymer solutions and the velocity distribution in the five-spot pattern produced a condition under which the mobility ratio between the displacing and the displaced fluid could not be assigned a single value. Instead, the movement of the displacement front is governed by local mobility ratios which are also time dependent. The areal sweep at breakthrough with polymer solutions was poorer than the sweep obtained with Newtonian fluids of comparable viscosity. However, the areal sweep and 1 PV throughput was greatly improved as compared to flood water without polymer. It was also demonstrated that, even after the oil-cut had declined to a low value during a regular waterflood, switching to polymer flood efficiently swept out the oil remaining in the model. Introduction The behavior of fluid displacements in isotropic porous media for various patterns of injection and production wells has been extensively investigated. These investigations all concerned Newtonian fluids, i.e., the viscosity of each fluid was constant regardless of flow rate. The generally unfavorable influence on areal sweep efficiency of higher mobility of the displacing fluid as compared to the mobility of the displaced fluid has been established for both miscible and immiscible fluids. The principle was also established that a close correspondence exists between miscible and immiscible flood front behavior, although oil recovery in a waterflood at unfavorable mobility ratio may be less than that observed in a miscible displacement at the same mobility ratio. This is true even when oil recovery is expressed on the basis of movable oil. The reason is that oil saturation only slowly achieves its final value behind the waterflood front in accordance with the Buckley-Leverett simultaneous flow relations. It is convenient to use miscible displacements for laboratory simulation of waterflood frontal advance since the interfacial tension forces which are negligible in proportion to viscous forces on a reservoir scales are thus made nonoperative in the laboratory model. For miscible displacements, the Hele-Shaw type of model adequately represents a porous medium so long as the appropriate scaling rules are observed in its design and operation. During simulation of waterflood front behavior in the laboratory by using miscible displacements, the behavior of connate water may ordinarily be disregarded since it is usually indistinguishable from flood water in this process. However, when the flood water is deliberately thickened to improve the mobility ratio between water and oil, the effect on the sweep efficiency due to generation of a connate water bank during the process must be considered. In a uniform porous medium, such a bank is generated and efficiently displaced by injection of thickened water. The oil originally in-place at the start of the waterflood is then displaced by connate water followed by thickened water. If the flood water must be thickened to obtain a favorable mobility ratio, the mobility of the oil phase is appreciably less than that of the connate water. Hence, the oil phase is inefficiently displaced by the connate water bank, and a considerable proportion of the oil comes in contact with and is displaced by the thickened waterflood front. SPEJ P. 52ˆ

Stability of Fibrous Composites

1992 ◽  
Vol 45 (2) ◽  
pp. 61-80 ◽  
Author(s):  
I. Yu. Babich ◽  
A. N. Guz’
Keyword(s):  
Composite Materials ◽  
Fibrous Composite ◽  
Homogeneous Medium ◽  
Stability Loss ◽  
Critical Parameters ◽  
Filler Concentration ◽  
Arbitrary Form ◽  
Fibrous Materials ◽  
Low Concentration ◽  
The Stability

In this review article the three-dimensional linearized theory is presented of the internal and the surface instability of fibrous composite materials. The possible mechanisms of the stability loss in the structure of these materials are investigated. In this investigation the strict model is used of the nonlinearly elastic compressible and incompressible piecewise-homogeneous medium with the arbitrary form of the elastic potential for the theory of finite deformation and for two variants of the theory of small precritical deformations. Problems for a single fiber (fibrous materials with low concentration of the filler, when at stability loss the interaction between fibers is not accounted for), for two fibers (fibrous materials with low concentration of the filler, when as a result of the structure irregularity at the stability loss two neighbouring fibers may interact) for the infinite row and for a doubly periodic system of fibers (fiber materials with nonsmall filler concentration, taking into account fiber interaction), in the infinite and semiinfinite matrix, are considered. Results are obtained for these cases, predominantly when conditions are satisfied of the complete contact on the fiber and matrix polymer or metal interfaces. In the case of the metal matrix at plastic deformations the conception of continuing loading is used, and the change of the unloading zones in the process of stability loss is not accounted for. The influence of the inhomogeneity of the precritical stressed state, resulting from the difference of coefficients of the transverse expansion, of the mechanical properties, and of the volume concentrations of the fibers and the matrix, on the critical parameters is investigated. Application is presented of the obtained results in the fracture mechanics of fibrous composite materials under compression along the reinforcing elements.

A Comparison of Hydraulic and Electrical Switch-Mode Converters

2017 ◽  
Author(s):  
Travis Wiens ◽  
Debdatta Das
Keyword(s):  
Academic Research ◽  
High Energy ◽  
Critical Parameters ◽  
Specific Power ◽  
Boost Converters ◽  
Switching Losses ◽  
Switch Mode ◽  
Mode Converters ◽  
Operating Limits ◽  
Physical Limitations

Electrical switched-mode DC-DC converters have become ubiquitous in the last decade, primarily driven by their high energy efficiency. Although considerable academic research has been performed on the analogous hydraulic switched-inertance converters, widespread adoption has lagged. This paper presents a comparison of the two technologies, comparing theoretical and practical limits to their performance. First we develop a simple model for the efficiency and specific power capacities of buck and boost converters in the ideal case, so that critical parameters can be identified as well as their physical limitations. We then expand our analysis to include practical effects such as wave propagation, switching losses and operating limits, in an attempt to identify if there are any reasons to continue or discontinue development of the hydraulic switched-inertance converter.

The Use of Tracer Data To Determine Polymer-Flooding Effects in a Heterogeneous Reservoir, 8 Torton Horizon Reservoir, Matzen Field, Austria

2016 ◽  
Vol 19 (04) ◽  
pp. 655-663 ◽  
Author(s):  
Torsten Clemens ◽  
Markus Lüftenegger ◽  
Ajana Laoroongroj ◽  
Rainer Kadnar ◽  
Christoph Puls
Keyword(s):  
Oil Recovery ◽  
Water Injection ◽  
Flow Path ◽  
Injection Well ◽  
Critical Parameters ◽  
Pilot Projects ◽  
Sweep Efficiency ◽  
Full Field ◽  
Polymer Injection ◽  
Production Wells

Summary Polymer-injection pilot projects aim at reducing the uncertainty and risk of full-field polymer-flood implementation. The interpretation of polymer-pilot projects is challenging because of the complexity of the process and fluids moving out of the polymer-pilot area. The interpretation is increasingly more complicated with the heterogeneity of the reservoir. In the polymer pilot performed in the 8 Torton Horizon (TH) reservoir of the Matzen field in Austria, a polymer-injection well surrounded by a number of production wells was selected. A tracer was injected 1 week before polymer injection. The tracer showed that the flow field in the reservoir was dramatically modified with increasing amounts of polymer injected. Despite short breakthrough times of 4 to 10 weeks observed for the tracer, polymer breakthrough occurred only after more than 12 months although injection and production rates were not substantially changed. The tracer signal indicated that the reservoir is heterogeneous, with high flow velocities occurring along a number of flow paths with a limited volume that are strongly connecting the injection and production wells. By injecting polymers, the mobility of the polymer-augmented water was reduced compared with water injection, and led to flow diversion into adjacent layers. The tracer response showed that the speed of the tracer moving from injection to production wells was reduced with increasing amount of polymer injected. This response was used to assess the changes of the amount of water flowing from the injection well to production wells. After a match for the tracer curve was obtained, adsorption, residual resistance factor (RRF), and dispersivity were calculated. The results showed that, even for heterogeneous reservoirs without good conformance of the pilot, the critical parameters for polymer-injection projects can be assessed by analyzing tracer and polymer response. These parameters are required to determine whether implementation of polymer injection at field scale is economically attractive. Along the flow path that is connecting injection and production well, as shown by the tracer response, an incremental recovery of approximately 8% was achieved. The polymer retention and inaccessible pore volume (IPV) in the reservoir were in the same range as in corefloods. Incremental oil recovery caused by acceleration along the flow path was estimated at approximately 20% of the overall incremental oil production caused by polymer injection and 80% was attributed to improved sweep efficiency.

Synthesis and Characterization of Yttrium Iron Garnet (YIG) Nanoparticles Activated by Electromagnetic Wave in Enhanced Oil Recovery

2016 ◽  
Vol 38 ◽  
pp. 40-46 ◽  
Author(s):  
Hassan Soleimani ◽  
Noor Rasyada Ahmad Latiff ◽  
Noorhana Yahya ◽  
Maziyar Sabet ◽  
Leila Khodapanah ◽  
...  
Keyword(s):  
Porous Medium ◽  
Electromagnetic Wave ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Yttrium Iron Garnet ◽  
Saturated Porous Medium ◽  
Yttrium Iron ◽  
Sweep Efficiency ◽  
Remaining Oil ◽  
Iron Garnet

Due to the geographical location and technological limitation, various novel enhanced oil recovery (EOR) methods has been proposed to recover the remaining oil from a depleted oil reservoir. Research on application of nanoparticles either on its own or coupled with other stimulating agents has been growing enormously and some of them have shown a promising future. In high temperature and high pressure reservoirs, thermal degradation will cause failure to the conventional chemicals. In this work, temperature-stable YIG magnetic nanoparticles with an electromagnetic wave has been proposed as a new candidate for reservoir stimulating agent. The purpose of nanoparticle injection is to increase the sweep efficiency in the reservoir by increasing the viscosity of displacing fluid. In this research, Yttrium iron garnet (YIG) nanoparticles have been injected into a waterflooded oil saturated porous medium to recover the remaining oil in the presence of an electromagnetic wave. At the sintering temperature 1200°C, a mixture of hematite and YIG was obtained, suggesting a higher temperature for single phase YIG. From VSM analysis, the average magnetic saturation, coercivity and remanence are 18.17 emu/g, 21.73 Oe and 2.38 emu/g, respectively. 1.0 wt% of YIG nanofluid was prepared and subsequently injected into the pre-saturated porous medium in the presence of square electromagnetic wave of 13.6 MHz. As much as 43.64% of the remaining oil in place (ROIP) was recovered following the injection of 2 pore volume of YIG nanofluid.

Factors Affecting Liquid-Liquid Relative Permeabilities of a Consolidated Porous Medium

1973 ◽  
Vol 13 (01) ◽  
pp. 39-47 ◽  
Author(s):  
E.J. Lefebvre du Prey
Keyword(s):  
Porous Medium ◽  
Stainless Steel ◽  
Relative Permeability ◽  
Viscosity Ratio ◽  
Sweep Efficiency ◽  
Factors Affecting ◽  
Continuity Equations ◽  
Relative Permeability Curves ◽  
Solid Liquid ◽  
Flow Laws

Abstract Many laboratory displacement tests have been performed to study factors affecting relative performed to study factors affecting relative permeability curves, residual saturations, and shape permeability curves, residual saturations, and shape of recovery curves. Three sintered artificial porous materials and pure fluid mixtures have been used for this systematic study. The factors were interfacial tension, the viscosity and the velocity of the fluids (in the dimensionless group / v), the wettability, and the viscosity ratio. The results can be used as guidelines for research on recovery processes. Introduction Waterflooding is by far the most common secondary recovery technique. Several processes (polymer injection, surfactant injection, hot water injection, etc.) attempt to improve sweep efficiency by affecting some of the factors involved in the displacement process. For orienting research on these processes, process. For orienting research on these processes, a good knowledge of how these parameters affect local displacement efficiency and over-all sweep efficiency in the reservoir is required. We present here an attempt to understand the effects of such parameters:at the microscopic level on the shape of relative permeability curves and the values of final saturations obtained by flooding, andat the macroscopic level, on the behavior of one-dimensional displacement. Effects of the morphology of the porous medium were not included in this study. We mainly examined the effects of fluid properties on fluid displacement in only three specific porous media. These three artificial sintered media were made of Teflon, stainless steel and alumina. For the following reasons they were very well suited to the systematic investigation undertaken:they are homogeneous and so the results are not subject to macroscopic heterogeneity effects;they are identical in the same series, thus permitting the results to be compared from one experiment to anothertheir constant and well-defined chemical composition makes it possible to perform wettability measurements outside the porous medium;they are consolidated like most of reservoir rocks;they have good mechanical properties and so can be washed successively without being altered andthe three media used correspond to three possible cases of wettability, i.e., Teflon is strongly oil-wet, alumina is strongly water wet, and stainless steel may have intermediate wettability depending on the fluids considered. Some of our results reported here (concerning experiments with Teflon at a viscosity ratio of one) were presented earlier. THEORY The elementary laws governing the distribution and flow of two phases in a porous material are quite well known:(1)viscous-flow laws in each phase (Navier and continuity equations),(2)phase (Navier and continuity equations),(3)solid-liquid boundary condition (zero velocity),(3)dynamic equilibrium laws of liquid-liquid interfaces (capillary law and continuity of velocities and viscosity stresses), and(4)solid-liquid-liquid contact line equilibrium laws with hysteresis and velocity dependency. Nevertheless the complexity of porous media, coupled with the difficulty of introducing the wettability law in a mathematical form, makes it impossible to go from flow properties on a microscopic pore scale to flow laws formulated on a macroscopic scale, i.e., relative permeability curves and capillary pressure curves. Use of dimensional analysis and reasoning with simple pore schemes are two ways of approaching this pore schemes are two ways of approaching this problem. problem. The parameters involved in the phenomenon under study are the following:fluid viscosities 1 and2,specific gravities P1 and P2,interfacial tension,pore dimension and morphology M,the wettability,system evolution prior to the moment of study K, andexternal conditions, i.e., a mean velocity v or a pressure gradient in the zone investigated. Three of these parameters, namely, M, and K, have complex meanings and cannot be specified by a single number. JPT P. 39

The Use of Capillary Tube Networks in Reservoir Performance Studies: 1. Equal-Viscosity Miscible Displacements

1971 ◽  
Vol 11 (02) ◽  
pp. 99-112 ◽  
Author(s):  
Ralph Simon ◽  
F.J. Kelsey
Keyword(s):  
Flow Behavior ◽  
Three Dimensional ◽  
Reservoir Rock ◽  
Reservoir Engineering ◽  
Interconnected Network ◽  
Spot Pattern ◽  
Capillary Tubes ◽  
Sweep Efficiency ◽  
Miscible Displacements ◽  
Electrical Resistivities

Abstract This paper concerns the use of network principles to study displacement phenomena in porous media. The information presented is for equal-viscosity, equal-density miscible displacements. The paper explains the reasons for using an interconnected network of capillary tubes to model the interconnected network of pores in a reservoir rock. A method is presented for defining the heterogeneity of a presented for defining the heterogeneity of a network of tubes based on tube-size and tube-location distribution functions. A technique is described for constructing a network whose heterogeneity models the heterogeneity of pores in a reservoir rock. The use of networks to provide information which can be used in the solution of reservoir engineering problems is illustrated with example calculations of the effect of heterogeneity on fingering, breakthrough, and selective plugging in linear systems, and the effect of heterogeneity on areal sweep efficiency in a five-spot pattern. Introduction Oil in a reservoir is contained in an interconnected three-dimensional network of pores. Direct evidence of the nature of this network of pores comes from examination of petrographic thin sections and three dimensional Scanning Electron Microscope (SEM) pictures of the pores. The SEM pictures show that the pores in a reservoir rock are channels through which flow can occur. These channels have highly irregular configurations so irregular that it is not practical at this time to calculate flow behavior through individual channels or through the interconnected network of the channels. It is practical, however, to use a computer to calculate flow behavior in an interconnected network of capillary tubes and several investigators have studied the problem of using a network of tubes to model a network of pores. pores. Fatt pioneered the idea of using a network of cubes model for reservoir engineering studies. He demonstrated that capillary pressures, relative permeabilities, and electrical resistivities permeabilities, and electrical resistivities calculated for a network model have the same characteristics as those measured for real pores in reservoir rocks. From this, Fatt concluded that the network of tubes is a valid model of real porous media. Rose reinforced Fatt's conclusion and showed that computers can be used to study the displacement characteristics of networks and to obtain results "…which can be supposed to have a direct bearing on the mechanics of petroleum recovery…" This paper takes two steps beyond the work of Fatt and Rose. First, it describes a technique for constructing a network whose heterogeneity models the heterogeneity of natural pores. This is done by matching calculated equal-viscosity miscible displacement behavior in the network with measured behavior in a laboratory core. Second, it illustrates the use of the network model for calculating the effects of heterogeneity on fingering, breakthrough, and plugging in linear systems and areal sweep efficiency in a five-spot pattern. The networks used in the studies in this paper consist of several hundred interconnected capillary tubes of different sizes. Four different types of connections or configurations were investigated and are shown below. These configurations are discussed in detail later in the paper. SPEJ P. 99

scholarly journals Influence of Critical Parameters on Temperature and Velocity for Convective Flow of a Viscous Fluid Through Porous Medium

2019 ◽  
Vol 8 (11S2) ◽  
pp. 390-394
Keyword(s):  
Porous Medium ◽  
Flow Field ◽  
Viscous Fluid ◽  
Convective Flow ◽  
Critical Parameters ◽  
Huge Variety

We keep in mind a unfastened convective improvement of an impressible and electrically directing thick liquid along a boundless non-fundamental diploma plate thru a permeable medium. The effect of simple parameters on the go with the flow field has been analyzed for this example. it's miles visible that, for everyday estimations of Porosity due to the truth the Prandtl range builds, the temperature likewise increments. similarly, it's far taken into consideration that to be the time expands, the temperature moreover increments. however the abovementioned, due to the fact the time propels and the Grashof huge variety is constant, the rate increments. on the begin, for a decrease estimation of t, the rate profiles are direct and from that trouble the profiles aren't unreasonably right away.

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