1. n. [Well Completions]

A condition that occurs when the solids carried in a treatment fluid, such as proppant in a fracture fluid, create a bridge across the perforations or similar restricted flow area. This creates a sudden and significant restriction to fluid flow that causes a rapid rise in pump pressure.

2. n. [Well Completions, Well Workover and Intervention]

A condition encountered during some gravel-pack operations whereby the treatment area cannot accept further pack sand and a sudden increase in treatment pressure occurs. Under ideal conditions, this should signify that the entire void area has been successfully packed with sand. However, if screenout occurs early in the treatment, it may indicate an incomplete treatment and the presence of undesirable voids within the pack zone.