Treating wells with ion-exchange-precipitated scale inhibitor
A scale-inhibiting process is described for treating a well which produces at least some aqueous fluid from a clay- containing subterranean reservoir that tends to exchange cations with those contained within an injected aqueous liquid. A solution is prepared by dissolving at least one compound that contains scale-inhibiting anions in an aqueous solution which contains at least 100 times more monovalent cations than multivalent cations and has a pH at which the multivalent cation salts of the scale-inhibiting anions are only slightly soluble. The solution is injected into the reservoir so that clay surfaces containing significant proportions of adsorbed multivalent cations are contacted by the solution. The rate of the injection is controlled so that the cation-exchange between the solution and those clay surfaces introduces enough cations into the solution to precipitate an effective amount of the multivalent cation salts of the scale-inhibiting anions within a near-well portion of the reservoir. 5 claims.
- Assignee:
- Shell Oil Co.
- Patent Number(s):
- US 4393938
- OSTI ID:
- 5766760
- Country of Publication:
- United States
- Language:
- English
Similar Records
Reservoir preflushing process for increasing the rate of surfactant transport in displacing oil with injected steam and steam-foaming surfactant
Oil recovery with water containing carbonate salt, CO/sub 2/, and surfactant