Development and application of retrievable bridge plugs

In view of the shortcomings of the currently used bridge plug seal technology, retrievable bridge plugs of A, B, and C types are developed. They are composed of the anchoring, unsetting, and sealing mechanism, and may be used to setting by tubes or cables, fulfilling the operation of temporary and permanent plugging, separate zone production, fracturing, socket ash squeezing, socket production, and test. After innumerable times of field application, all technical indexes meet the demand of design, with the maximum working pressure ratio 105 MPa and the success rate higher than 98%, and resistant to high temperature of 175 ℃. Successful field application shows that the retrievable bridge plug is the ideal tool for well plugging