Can Capillary Pressure Effects be Exploited to Prevent Water-Based Gelants from Entering Oil Zones?
(In field aplications—no. In oil-wet laboratory cores—sometimes.)

Another common misconception is that capillary pressure effects will prevent water-based gelants from entering oil zones. This concept is disproved in Ref. 2. In water-wet reservoirs, capillary pressure will actually enhance imbibition of the aqueous gelant into the oil zones. In oil-wet laboratory cores, capillary pressure can inhibit gelants from entering the porous rock if the injection pressures are low. 2However, in virtually all field applications, the pressure drop between the wellbore and the formation will be much greater than the capillary pressure. Therefore, in field applications, capillary pressure will not prevent gelants from penetrating significant distances into oil zones. 2