Acidizing asphaltenic oil reservoirs with acids containing salicylic acid
AssigneeShell Oil Company
InventorsWilliam A. McLaughlin, Edwin A. Richardson
Life of this patent
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Abstract
A reservoir which contains an asphaltenic oil can be acidized with an aqueous acid without causing a deposition of permeability impairing iron-asphaltene compounds by dissolving or dispersing an effective amount of salicylic acid within at least the first injected portion of the aqueous acid.
Claims10
In a well treating process in which an aqueous hydrochloric acid-containing acid capable of dissolving solids in a manner increasing the permeability of a subterranean earth formation is brought into successive contacts with iron and an asphaltene-containing oil that is present within a subterreanean reservoir in a manner that may form permeability impairing iron-asphaltene solids, the improvement which comprises, including within at least the first portion of the aqueous hydrochloric acid-containing acid, a solution or homogeneous dispersion of at least enough salicylic acid to chelate with and prevent the formation of iron-asphaltene solids by substantially all of the ferric ions that become dissolved within the acid that enters the earth formation.
Dependencies are inferred from the claim text.