Inhibiting silica dissolution from reservoirs or gravel packs - by adding ammonium cpd. to injected steam

摘要

Dissolution of silica from a formation matrix or gravel pack in contact with injected wet steam is inhibited by adding to the steam, or to the boiler feedwater used to generate the steam, an (opt. substd.) ammonium cpd. (I) selected from NH4 halides, NH4 salts of inorganic acids or carboxylic acids, quat. NH4 halides and (opt. substd.) amine hydrochlorides. (I) is used in amts. of 0.1-2.5 equivs. per equiv. bicarbonate ions in the boiler feed water, or in concns. of 5-5000 (esp. 50-1500) ppm. or in amts. sufficient to lower the pH of the liq. phase of the steam to below 10.5 (pref. 10.5-7, esp. 9.4-8.7).