Study and Application of a New Complex Plug Removal System

摘要

Aiming at solving small effective acid reaction range and causing second damage in the acidizing in low permeability reservoirs, a new kind of deep penetration and little damage complex plug removal system was developed through laboratory research, which consists of an organic acid, a phosphoric acid, an ammonium organic acid, an ammonium fluoride and a strong oxidizer. The properties were evaluated and the results indicate that it has advantages of proper dissolving capacity to rock with dissolving ratio of 38.9%, little corrosion to the pipeline of equipment with corrosion rate of 2.9 g/m2·h-1, low interfacial tension, anti-acid-sludge, and ability to stabilize ferric ion. The plugging in deep formations can be removed with low damage to rock skeleton, which the damage rate is less than 20%. It has been applied in 19 wells with success ratio of 100% and long term of validity, average validity is more than 200 days. The oil production and water injection have been increased obviously.