A gelation system for reducing the permeability of a subterranean region is provided by sequentially injecting slugs of a polymer solution and a crosslinking agent solution capable of crosslinking the polymer. The viscosity of the crosslinking agent solution is adjusted to facilitate mixing of the slugs in the desired treatment region to a form gel therein and minimize premature gelation outside of the treatment region.
A method of enhancing the amount of oil recovered from a subterranean oil-bearing formation by controlling the profile of the formation by introducing a predetermined first amount of a permeability control agent in a non-gelatinous state into the formation so that it contacts at least a portion of the formation. A portion of the pores of the formation are plugged by allowing contact to be maintained for a sufficient period of time allowing the first portion to gel. The first amount constitutes a portion of the total amount required to improve the profile of the formation. A predetermined second amount of permeability control agent is thereafter introduced, in a non-gelatinous state, into the formation which contacts the first amount and the portion of the formation not contacted by the first amount for a time period sufficient to gelatinize the second amount so as to plug the remaining unproductive pores of the formation. The second amount constitutes the remaining portion of the total amount required to improve the profile of the formation. Complete profile control is attained while not requiring any greater quantities of permeability control agent than those typically required in a single step profile control treatment.
Permeability of a highly permeable zone in a subterranean formation is reduced by injecting into the formation a polymerizable material which expands on polymerization, and thereafter effecting such polymerization.
A process for treating a subterranean formation comprises adding a crosslinking agent intermittently to a stream of gellable polymer wherein the gellable polymer forms a gel in the formation, in the presence of the crosslinking agent.
A metal-containing oxidizing solution is injected through wellbores which reacts in a subterranean reservoir which has naturally-ocurring reduction capacity to form a slightly soluble compound of metal having a valence of +3. Thereafter, the metal crosslinks a water-soluble polymer which is injected into the metal-containing pore volume resulting in a decreased flow in the treated portion of the reservoir.
A method of preventing gas coning or fingering from a gas cap in an oil producing well is provided. A polymerizable material is injected into the gas cap under conditions such that it polymerizes to form a substantially impermeable zone or layer above the oil bearing formation to prevent gas from flowing into the oil well during production.
