Laser Drilling Research and Application: An Update

Abstract

TX 75083-3836, U.S.A., fax 1.972.952.9435. AbstractThe paper is an update to the current status of laser drilling technique -the first fundamental change to rotary drilling. We begin with a brief note on history of physical tests in 60's and 70's which were limited by the laser technology and low power available at that time. Seven lasers have been identified for potential use in the upstream oil industry. Each rock type has a set of optimal laser parameters to minimize specific energy as observed in the linear track tests. Current efforts are focused on underwater laser drilling.Next, stress has been put on the basic scientific principles that can bring laser drilling within reach of an industry-supported prototype. Hence, the methods of delivering laser radiation and rock removal from wells drilled followed by parameters like feasibility, economics, benefits and environmental impact related to laser drilling have been discussed.Laser drilling is found to be more efficient, cleaner way to drill and perforate wells through hard rock formations encountered at greater depths. The effects of the laser rock interaction on permeability have also been studied. Laser perforation resulted in permeability improvements. One of the major advantages of laser drilling is its potential to reduce drilling time. Lasers cut drilling time by not contacting the rock, eliminating the need to stop and replace a mechanical bit. Finally, we end with a discussion on the wider scope of laser technology for on-site tasks including cutting windows for side exiting casing or laterals, extended perforations that connect additional reservoir rock to the well bore, and removal of objects lost down hole that would normally require drill out or fishing operations.

Using the Laser Irradiation to Improve the Rate of Production of Iran South West Formation

“…A bulk modulus decreased of 50% causes the compressibility near the wellbore to increase by 50%. Depending on the litho logy, for limestone, sandstone, dolomite and shale, the differences between the modular of lased and un-lased samples and saturated and washed samples were less significant than in sandstone [11] [14]. Compare lasers and the input energy needed for other high -power industries with that of a fiber laser to generate the same output power.…”

“…Spall process is usually attributed to the thermal stresses and photo chemical interactions induced in the rock upon lasing. The rock fails along these transmission lines and finally spalls [11]. Sometimes, in case of thermally conductive rocks, lasing can lead to expand the surface area and hence promotes spall process [14].…”

“…Sometimes, in case of thermally conductive rocks, lasing can lead to expand the surface area and hence promotes spall process [14]. Otherwise the laser energy will break and remove rock without significant melting [11]. Specific energy (SE) for spall process is lowest just before melting.…”

“…At low desired for the laser to work within the spall process zone and as close to the transition zone because we have small narrow line of difference between melting part of the rock and warm part of that. When rock temperature becomes high upon lasing, it turns into an intense source of radiation [11].…”

“…For this matter, water jet can be used as an impressive method [5]. Also, nitrogen gas can be used as a purging gas to blow the ejected gases and debris from the rock surface and to clean the hole [10] [11]. Rock spall process produces chips which have to be removed from the bore.…”