Method for detecting and locating water-producing zones and/or water thief zones in subterranean formations

A method for detecting and locating injection water thief zones in a subterranean formation penetrated by a well bore of an injection which comprises:

• a. injecting into said formation an aqueous solution containing from about 0.01 to 7.5 weight percent of an irradiated water soluble compound selected from the group consisting of sodium silicate, water-soluble polymers, and polysaccharides produced by bacteria of the genus Xanthomonas on carbohydrates, said compound having preferential silica adsorptive characteristics;
• b. passing said radioactivity detection means through the well bore and recording the measurement of radioactivity;
• c. returning the injection well to normal water injection;
• d. passing said radioactivity detection means through the well bore and recording the measurement of radioactivity of said formation;
• and,
• e. comparing the measurements of radioactivity to determine injection water thief zones.