LIQUID CARBON DIOXIDE CLEANING OF WELLBORES AND NEAR-WELLBORE AREAS

摘要

A method to clean the wellbore and the near wellbore formation adjacent to the wellbore of the gas bearing formation adjacent to the production zone of the wellbore. The method includes the steps of injecting a treatment liquid containing from 84.5 to 100% of liquid carbon dioxide, 0 to 15% of an alcohol, and 0 to 0.5% of a surfactant into the well in a predetermined quantity and maintaining the pressure of the treatment liquid in the near wellbore formation of the gas bearing formation below the fracturing pressure of the formation, releasing the pressure on the wellbore and allowing the liquid CO2 to vaporize and other materials to blow out of the well.