Rocks fluid flow characteristics

Polymers are used for mobility control in chemical flooding processes such as micellar-polymer and caustic-polymer flooding and in polymer augmented waterflooding. Selection of a polymer for mobility control is a complex process because it is not possible to predict the behavior of a polymer in porous rock from rheological measurements such as viscosity/ shear rate curves. Polymers used for mobility control are non-Newtonian fluids. Flow characteristics are controlled by the shear field to which the polymer is subjected. Properties of polymers can be measured under steady shear in rheometers. However, in porous rock, it is difficult to define the shear environment a polymer experiences as it flows through tortuous pores. 

Pore shape is a characteristic of pore geometry, which is important for fluid flow and especially multi-phase flow. It can be studied by analyzing three-dimensional images of the pore space [2, 3]. Also, long time diffusion coefficient measurements on rocks have been used to argue that the shapes of pores in many rocks are sheetlike and tube-like [16]. It has been shown in a recent study [57] that a combination of DDIF, mercury intrusion porosimetry and a simple analysis of two-dimensional thin-section images provides a characterization of pore shape (described below) from just the geometric properties. 

To establish the well drainage boundaries and fluid flow patterns within the TFSA-waterflood pilot, an interwell chemical tracer study was conducted. Sodium thiocyanate was selected as the tracer on the basis of its low adsorption characteristics on reservoir rocks (36-38), its low and constant background concentration (0.9 mg/kg) in produced fluids and its ease and accuracy of analysis(39). On July 8, 1986, 500 lb (227 kg) of sodium thiocyanate dissolved in 500 gal (1.89 m3> of injection brine (76700 mg/kg of thiocyanate ion) were injected into Well TU-120. For the next five months, samples of produced fluids were obtained three times per week from each production well. The thiocyanate concentration in the produced brine samples were analyzed in duplicate by the standard ferric nitrate method(39) and in all cases, the precision of the thiocyanate determinations were within 0.3 mg/kg. The concentration of the ion in the produced brine returned to background levels when the sampling and analysis was concluded. 

As much as two-thirds of conventional crude oil discovered in U.S. fields remain unproduced, left behind because of the physics of fluid flow. In addition, hydrocarbons in unconventional rocks or that have unconventional characteristics (such as oil in fractured shales, kerogen in oil shale or bitumen in tar sands) constitute an enormous potential domestic supply of energy. 

The long time scales (104 to 10s m.y.) involved in deformation and synkinematic isotope exchange in white mica provide a robust, long-term average of meteoric water-rock interaction, characteristic for the time scales of major readjustments in surface elevation. Thus the hydrogen isotope record in recrystallized muscovite provides a direct link between the tectonic and fluid flow history in the shear zone and temporal variations in meteoric water composition due to changing surface elevation. 

Homogeneous Models. The basic assumption in these models is that the emulsion is a continuum, single-phase liquid that is, its microscopic features are unimportant in describing the physical properties or bulk flow characteristics. It ignores interactions between the droplets in the emulsions and the rock surface. The emulsion is considered to be a single-phase homogeneous fluid, and its flow in a porous medium is modeled by using well-documented concepts of Newtonian and non-Newtonian fluid flow in porous media (26, 38). 

Successful fradure acidizing treatments do not depend solely on good fluid-loss properties (30). Adequate fracture flow capadty must be established by the add system used. The quantity of rock removed and the pattern in which it is removed from the fracture face are important. Fracture flow capadty is dependent on the nature of the rock and the characteristics of the add, such as add type, volume, and concentration. Other factors that lead to increased fracture flow conductivity include foam quality and pumping rate. As long as the foam is stable, foamed add of any quality increases the fracture flow conductivity when compared with non-foamed adds. As well, increases in total treatment pumping rates achieve better fracture conductivities because of greater acidized fradure lengths. 

Tsang Y W Witherspoon P A., 1982. Correlation between fracture roughness characteristics and fracture mechanical and fluid flow properties[C]. Proc. 23rd US Symp. on Rock Mech., 560-567. 

The requirements for the presentation of the general flow characteristics of polymer solutions were best met by high molecular mass (3.5 10 ) hydrolyzed (40%) polymer. Concentration of the polymer was 100 ppm, viscosity of the solution under laboratory conditions (24 C) was 3.05 mPas. Taking into consideration the rock s permeability (59 10 and 62 10" ym ) and the equivalent diameter of the random coils (2600A), the polymer-rock system may be regarded as compatible. In the course of the experiments, comparison is made between the flow phenomena observed in the porous cores considered to be water wet and oil wet, respectively. When the permeability was determined by "connate water" (2% sodium chloride solution), the injection sequence of the fluids was as follows 1) polymer solution, 2) connate water, and 3) distilled... 

Geothermal reservoir rocks are typically fractured and therefore exhibit variable and anisotropic permeability. For that reason it is neither possible to predict with confidence how an injection well may perform with respect to its injectivity nor with respect to which way the injected fluid will flow once it is in the reservoir. Because of this complication, the success of injection varies between fields and it is anticipated that a special injection scheme must be developed for each field depending on its characteristics, mainly the three-dimensional distribution of permeability and the waste fluid composition. Injection may require drilling of special wells. Alternatively, wells drilled for the purpose of production may not have adequate yield but can be used successfully as injection wells. When this is the case, no special wells need to be drilled for injection purposes, which reduces road building and therefore scenery spoliation. 

A critical review of emulsion flow in porous media has been presented. An attempt has been made to identify the various factors that affect the flow of OAV and W/O emulsions in the reservoir. The present methods of investigation are only the beginning of an effort to try to develop an understanding of the transport behavior of emulsions in porous media. The work toward this end has been difficult because of the complex nature of emulsions themselves and their flow in a complex medium. Presently there are only qualitative descriptions and hypotheses available as to the mechanisms involved. A comprehensive model that would describe the transport phenomenon of emulsions in porous media should take into account emulsion and porous medium characteristics, hydrodynamics, as well as the complex fluid-rock interactions. To implement such a study will require a number of experi-... 

Since the fluid velocity within the geothermal reservoirs created in the fractured rock can be relatively high and the characteristic sizes of the solid blocks of the rock, which constitute the fissured reservoir media, are relatively large, the high mean values of heat flow rates are typically attained within the stimulated region. In this situation the effect of thermal dispersion is an important factor that should be included into the mathematical model of the heat transport within the natural or artificially developed fissured geothermal reservoirs. Employing different... 

The fluid (oil) flow in any reservoir has characteristics that are the same as the flow of fluid through porous rock media. The fluid inside a pore has characteristic properties due to the shape of the liquid surface. The shape of a liquid surface in a capillary determines many physical characteristics. Aflat liquid surface (such as a liquid drop or soap bubble) has different properties than a curved surface (Figure 12.5). 

Formation testers are measurement instruments that retrieve reservoir fluid samples from wells during pauses in drilling operations. Various practical questions arise. A type of reverse invasion problem appears how long must pumps be operated in order to obtain true formation fluids and not mud filtrate contaminants How do pump power requirements vary in permeable versus tight zones Can measured pressure transients be interpreted for rock characteristics like permeability and anisotropy Different answers are obtained depending on the fluid model assumed. Later in this book, we will consider constant density, immiscible, two-phase flows with and without mudcake effects. For now we assume transient, compressible, single-phase flow, but within this framework, we formulate and solve a very general problem. 

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