Pore-throat diameter

Fig. 1 Different primary and secondary textures used in this study, their pore network structures and electrical behaviour. Hg-injection curves give the ditribution of Hg-saturation versus pore-throat diameter. Z the complex electrical impedance vector 9 phase angle by which current and voltage are shifted M-W mudstone-wackestone textures P-G packstone-grainstone texture G grainstone C crystal carbonate.

Mechanical degradation of polymer is much more severe at higher flow rates, longer flow distances, and lower brine permeabilities of porous media. In a lower-permeability porous medium, the average pore throat diameter is smaller, and the stress acting on the polymer is larger. Thus, it is more probable for the polymer chains to be broken and the viscosity to be more heavily reduced. Similarly, we can understand the effects of flow rate and flow distance. 

In emulsification and entrainment, the crude oil is emulsified in situ owing to IFT reduction, and it is entrained by the flowing aqueous alkaline solution (Subkow, 1942). The conditions for this mechanism to occur are high pH, low acid number, low salinity, and OAV emulsion size < pore throat diameter. 

Figure 2. Illustration of possible errors introduced by the characterization of mercury intrusion porosimetry data. 8 is the pore throat diameter and 8b is the pore body diameter.

Depending on the size of the particles and the pore size distribution of the porous medium, solid particles can be removed on the surface of the porous medium (filter cake) or inside the medium (deep filtration). If the particle size is larger than the pore throat diameter of the porous media, then particles will be separated on the face of the porous medium (i.e., form a skin) and will not deeply penetrate the porous medium (Figure 1). If the particle diameter is very small in comparison with pore... 

Other mechanisms for particle capture include particle settling, inertia, and hydrodynamics (I). When a particle is captured in a pore, the pore throat diameter is reduced by a factor dependent on particle size and pore throat diameter. The reduced diameter of the pore throat will lead to a lower permeability. Permeability damage due to flow of suspensions increases with particle size and solids concentration. 

Single Pore Blocking (Screening). This mechanism occurs when the particle size is close to the pore throat diameter. In this case foreign particles will block the pores, thus eliminating them from the flow system. The permeability response is... 

The hydraulic rock type classification provides a physical measure of a rock s flow and storage properties at current conditions. When described on the basis of the dominant pore throat diameter determined from high-pressure mercury capillary pressure data, distinct groupings of rocks having similar flow and storage properties, i.e. hydraulic rock types, are... 

Increases in pressures around the advancing surface, rather than supplying energy for a jump , might alternately provide sufficient energy to cause snap-off of the ganglion when the pore throat diameter separating any two lobes is sufficiently small. 

Micropores, with pore-throat diameters less than 0.5 pm, usually contain mostly irreducible water and little hydrocarbon. 

Mesopores, with pore-throat diameters between 0.5 and 5 pm, may contain significant amounts of oil or gas in pores above the free-water level (FWL). 

Scott and Barker (2003) investigated the correlatiOTi between a dominant pore-throat diameter and the frequency at which a peak in the phase angle versus frequency plot occurs in Triassic sandstones. This does not follow the constant phase-angle model. 

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