Application of Lasers for Perforation of Petroleum Wells

Abstract This thesis presents the results of a study evaluating the application of high powered lasers when perforating cement-lined wells in carbonate rock reservoirs. The focus is on the creation of lateral channels in the walls of the well to allow the flow of the oil into the well. Through an intensive literature review of the international patents published in the last decade, the current state-of-the-art use of lasers in the perforation of rocks was evaluated. Specifically, 226 patent documents were found to have been published since 2008, showing the great importance of lasertechnology in this field. The results of the microtomography analysis are presented, showing samples of the cement slurry formulation used in pre-salt wells and carbonate rocks with characteristics close to the ones found in these types of reservoirs. The fiber laserutilized presented an output of up to 1.5kW and a wavelength of 1,064µm. To evaluate the structure of the samples, X-ray tomography and microtomography were employed. The specific energy was estimated at 243 J/mm3 for the carbonate rocks. The final tests to represent the well architecture were realized with samples of liner/cement/carbonate. By means of lasers with the power of 1.5kW for 80 seconds, channels with 5mm diameters and 50mm depths were produced. The results obtained show, although only preliminarily, the potential of using this technology in perforation operations.