Tight formation water shut off method with silica gel
AssigneeSchlumberger Technology Corporation
InventorsNadir M. M. Odeh, Hassan Chaabouni, Keng Seng Chan, Philippe Enkababian
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Abstract
A delayed gelling system useful in conformance control in the production of petroleum from subterranean formations, especially low permeability formations, is disclosed. The gelling system comprises a basic silica sol, an activator comprising a hydroxyl donor, and an optional syneresis inhibitor. In the disclosed method of using the gelling system, the gelling system may be pumped into formations with excessive water and/or gas production and thermally activated in the formation at downhole conditions to form a hard gel to reduce water and/or gas production.
Claims15
A method of inhibiting permeability of a portion of a subterranean formation, comprising:
- preparing a stable aqueous colloidal dispersion comprising from about 15 to about 70 weight percent of silica particles having an average particle size from 4 to 300 nm and a surface modification with negative ions, from 0.1 to 5 weight percent of a thermally activatable hydroxyl donor, and having a pH of from about 9 to about 12;
- injecting the colloidal dispersion into a portion of a subterranean formation having a temperature above the thermal activation temperature of the hydroxyl donor to elevate the pH;
- setting the colloidal dispersion into a hard gel in place for from 1 to 12 hours in the formation to inhibit water permeability of the portion of the formation;
- and
- producing a fluid selected from oil, gas and water from a remaining portion of the formation.
Dependencies are inferred from the claim text.