1. n. [Enhanced Oil Recovery]
Natural or induced production impairments that can develop in the reservoir, the near-wellbore area, the perforations, the gravel-pack completion or the production pipelines, such as the tubing. Natural damage occurs as produced reservoir fluids move through the reservoir, while induced damage is the result of external operations and fluids in the well, such as drilling, well completion, workover operations or stimulation treatments. Some induced damage triggers natural damage mechanisms. Natural damage includes phenomena such as fines migration, clay swelling, scale formation, organic deposition, including paraffins or asphaltenes, and mixed organic and inorganic deposition. Induced damage includes plugging caused by foreign particles in the injected fluid, wettability changes, emulsions, precipitates or sludges caused by acid reactions, bacterial activity and water blocks. Wellbore cleanup or matrix stimulation treatments are two different operations that can remove natural or induced damage. Selecting the proper operation depends on the location and nature of the damage.