Field application of phenol formaldehyde gel in oil reservoir matrix for water shut-off purposes

A phenol formaldehyde gelation system was developed and successfully tested in one of the wells that ceased production due to 100% excessive water-cut (WCT) levels. A rise in the oil-water contact level in combination with a coning effect was diagnosed as a possible cause of the high WCT that was later controlled by a newly developed gelant treatment. The gelation time was the lowest at 10.4. The water shut-off job resulted in an impressive commercial success; technical success, however, was less than satisfactory due to the fact that, in spite of using a water-thin monomeric solution, only 40% of the designed volume could be injected due to low injectivity resulting in an abnormal pressure buildup.