Reservoir Rock Mechanics and Capillary Pressure Quiz

Interfacial tension is the energy per unit area (force per unit distance) at the surface between phases.

Surface tension is the tension between a liquid and gas phase, while interfacial tension is the tension between two liquid phases (immiscible contact).

Interfacial tension is a function of pressure, temperature, and the composition of each phase.

<p>Imbibition process is a fluid flow process in which the saturation of the wetting phase increases. The mobility of the wetting phase increases as the saturation of the wetting phase increases.</p> Signup and view all the answers

<p>An example of a situation where imbibition process occurs is the accumulation of oil in an oil-wet reservoir.</p> Signup and view all the answers

<p>Wettability is the tendency of one fluid to spread on or adhere to a solid surface in the presence of other immiscible fluids.</p> Signup and view all the answers

<p>The wetting phase fluid preferentially wets the solid rock surface, while the non-wetting phase does not preferentially wet the solid rock surface.</p> Signup and view all the answers

<p>The contact angle, θ, measured through the denser liquid phase, defines which fluid wets the solid surface.</p> Signup and view all the answers

<p>The three classifications of wettability are strongly oil- or water-wetting, neutral wettability, and fractional wettability.</p> Signup and view all the answers

<p>Capillary pressure is the pressure difference existing across the interface separating two immiscible fluids in capillaries (e.g. porous media). It can be calculated using the equation: $Pc = P_{nwt} - P_{wt}$, where $Pc$ is the capillary pressure, $P_{nwt}$ is the pressure in the nonwetting phase, and $P_{wt}$ is the pressure in the wetting phase.</p> Signup and view all the answers

<p>Capillary pressure is important in reservoir engineering because it is a major factor controlling the fluid distributions in a reservoir rock.</p> Signup and view all the answers

<p>The height of water rise in a capillary tube is influenced by the adhesion tension between the air and water, the radius of the tube, and the density difference between the fluids. It can be calculated using the equation: $h = \frac{2\alpha_{aw}\cos\theta},{r\cdot g\cdot\pi_{aw}}$, where $h$ is the height of water rise, $\alpha_{aw}$ is the interfacial tension between air and water, $\theta$ is the air/water contact angle, $r$ is the radius of the capillary tube, $g$ is the acceleration due to gravity, and $\pi_{aw}$ is the density difference between water and air.</p> Signup and view all the answers

<p>The equation for capillary pressure in an oil/water system is: $Pc = \frac{2\chi\rho_{ow}\cos\theta},{r}$, where $Pc$ is the capillary pressure between oil and water, $\chi$ is the interfacial tension between oil and water, $\rho_{ow}$ is the density difference between oil and water, $\theta$ is the oil/water contact angle, and $r$ is the radius of the capillary tube.</p> Signup and view all the answers