Methods of using a laser to perforate composite structures of steel casing, cement and rocks

摘要

Apparatus and methods of using lasers are provided for the perforation of oil and gas well casings and rock formations. A rock removal process called laser spallation is provided that utilizes a combination of laser-induced thermal stress and laser induced superheated steam explosions just below the surface of the laser/rock interaction to spall or fracture the rock into small fragments that can then be easily removed from the rock formation. The use of high power laser beams of kilowatt level is provided to rapidly cut the steel casings and perforate into the formation. Techniques of the invention increase permeability and reduce hole tapering while perforating a deep hole in reservoir rock formations.