Method and apparatus for wellbore perforation

摘要

A method for wellbore perforation in which a section of the wellbore to be perforated is isolated and purged of wellbore fluid to provide a clear path for laser beam transmittal. A laser beam emitter in the purged wellbore section transmits a laser beam pulse from the laser beam emitter to a target area of a sidewall and formation lithology of the purged wellbore section, thereby altering a mechanical property of a material of the sidewall and formation lithology and producing material debris. A liquid jet pulse of a liquid is transmitted immediately following termination of the laser beam pulse to the target area, thereby removing the material debris from the target area. This cycle is then repeated until the desired perforation depth has been achieved.

主权项

1. A method for wellbore perforation comprising the steps of:
a) purging wellbore fluid from a wellbore section of a wellbore using a pressurized gaseous fluid, producing a purged wellbore section; b) providing a laser beam emitter in said purged wellbore section; c) transmitting a laser beam pulse from said laser beam emitter to a target area of a sidewall of said purged wellbore section, thereby altering a mechanical property of a material of said sidewall, forming a perforation with a hole taper and producing material debris; d) jetting a pulse of a liquid along an axis of penetration of the laser beam pulse following termination of said laser beam pulse to said target area, thereby reducing said hole taper and removing said material debris from said target area and exposing an underlying virgin material not previously subjected to significant optical power levels; and e) following termination of the pulse of liquid, spraying a pressurized gas to the target area to remove moisture from the target area and repeating steps c) and d) to remove the underlying virgin material until a desired perforation depth has been achieved.