Underwater laser drilling: Drilling underwater granite by CO2 laser

Toshio Kobayashi, Masahiro Nakamura, Komei Okatsu, Kiyonobu Ohtani, Kazuyoshi Takayama

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The purpose of this research is to develop Underwater Laser Drilling Technology in drilling and completing oil and natural gas wells. Recent challenges in oil fields are caused by: the geometry of oil or gas wells is becoming more complicated in profile; drilling in hard formations like granite requires more tripping times for changing rotary bits made of steel; as the water depth at which floater rigs can operate increases, tripping has to take longer than ever. Underwater Laser Drilling is a key to solution of these challenges since the laser may allow for non-contact / non-rotating drilling method. Granite is one of the most difficult rocks to be drilled by lasers. Consequently, no successful report has been found on underwater granites drilled by lasers. This paper describes experimental tests of irradiating carbon dioxide (CO2) laser to granite submerged in water/ bentonite solutions. Sample granite was submerged at 50mm from the water-surface and then a CO2 laser with a wavelength of 10.6μm which has a high absorption coefficient in water was intermittently irradiated into the 4wt% bentonite solutions. A laser induced underwater shock waves, cavitation bubble formations, and micro-water jet formations upon bubble collapse. The high power laser beam locally melted the granite into molten glass, which successively turned to a molten glass bead. The generated glass beads were small enough to be removed out of the created hole. A high-speed video camera was employed to record the laser beam in the water. We observed the generation of initial cone shaped water bubbles through which the laser beams reached bottom rock surface with a minimum absorption energy loss. The laser beam indeed drilled the granite specimen submerged in the solution. The research will continue to collect data for designing a prototype.

Original languageEnglish
Title of host publicationSociety of Petroleum Engineers - SPE Indian Oil and Gas Technical Conference and Exhibition 2008
Subtitle of host publication"The Changing Landscape Emerging Opportunities in the Indian E and P Industry"
PublisherCurran Associates Inc.
Pages93-104
Number of pages12
ISBN (Print)9781605601465
DOIs
Publication statusPublished - 2008 Jan 1
EventSPE Indian Oil and Gas Technical Conference and Exhibition 2008: "The Changing Landscape Emerging Opportunities in the Indian E and P Industry" - Mumbai, India
Duration: 2008 Mar 42008 Mar 6

Publication series

NameSociety of Petroleum Engineers - SPE Indian Oil and Gas Technical Conference and Exhibition 2008: "The Changing Landscape Emerging Opportunities in the Indian E and P Industry"

Other

OtherSPE Indian Oil and Gas Technical Conference and Exhibition 2008: "The Changing Landscape Emerging Opportunities in the Indian E and P Industry"
CountryIndia
CityMumbai
Period08/3/408/3/6

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Fuel Technology

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