The situation in which 10-second and 10-minute gel strengths for a drilling mud have dissimilar values, with the 10-minute number being much higher than the 10-second number. This indicates that the gelation of the mud is rapidly gaining strength with time, which generally is an undesirable feature of a mud. The mud may require excessive pump pressures to break circulation. If gels appear to be too progressive, a 30-minute gel-strength measurement may be warranted as a third check of progress.