Changes

Near wellbore [[permeability]] reduction, that is, formation damage, can result from the interaction of the reservoir rock with extraneous drilling, completion, [[stimulation]], or enhanced recovery fluids. Rock-fluid reaction can occur from any of the following operations:

Near wellbore [[permeability]] reduction, that is, formation damage, can result from the interaction of the reservoir rock with extraneous drilling, completion, [[stimulation]], or enhanced recovery fluids. Rock-fluid reaction can occur from any of the following operations:

* Mixing of formation water with extraneous brine in which the total cation concentration is below a critical salinity value

* Mixing of formation water with extraneous brine in which the total [http://en.wikipedia.org/wiki/Ion#Anions_and_cations cation] concentration is below a critical salinity value

* Displacement of one brine by another whose divalent cation concentration is lower than the level required to prevent clay dispersion

* Displacement of one brine by another whose divalent cation concentration is lower than the level required to prevent clay dispersion

* Injection or production of fluids at rates exceeding the critical velocity beyond which mobilization of rock fines by mechanical (drag) forces is initiated

* Injection or production of fluids at rates exceeding the critical velocity beyond which mobilization of rock fines by mechanical (drag) forces is initiated