Method and apparatus for laser treatment of geological formations
AssigneeNygaard-Welch-Rushing Partnership
InventorAlbert B. Welch
Life of this patent
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Abstract
A method and apparatus are disclosed for drilling gas, oil or geothermal wells in geological formations and for "fracing" the pay zones of such wells to increase recovery, using a laser beam projected into the well bore along a beam guide so as to make available laser energy adequate to melt or vaporize the formation under down-hole conditions. Fluid circulation is established via the beam guide to keep the beam path adequately free of contaminants to permit drilling. A novel orifice window is provided to allow transmitting the high energy beam from the surface into a high-pressure, down-hole environment.
Claims38
A method of drilling through a subterraneous formation by a laser beam of sufficient energy to penetrate through the formation by melting or vaporizing the material in its path comprising:
- a. introducing under pressure a gas which is substantially transparent to the laser beam into a bore extending through such formation;
- b. directing the beam through the pressurized gas to the surface to be drilled;
- and
- c. guiding and confining the beam passing through the pressurized gas over a substantial portion of the beam path along the bore to overcome effects of beam spreading so that adequate energy density is delivered at said surface to at least melt the material thereat.
A method of drilling through a subterraneous formation by a laser beam of sufficient energy to penetrate through the formation by melting or vaporizing the material in its path comprising:
- a. inserting a tubular member into a bore extending through such formation with one end of the tubular member positioned generally at the surface to be drilled;
- b. introducing under pressure into the other end of the tubular member a gas which is substantially transparent to the laser beam;
- c. directing the beam through the pressurized gas to the surface to be drilled;
- and
- d. producing a radially increasing thermal distribution across the pressurized gas in the tubular member thereby establishing a radially decreasing transverse index of refraction distribution which confines the beam passing therethrough.
Apparatus for drilling a bore hole through a subterranean formation comprising:
- a. means for generating a radiant beam of sufficient energy to penetrate through such formation by melting or vaporizing the material in its path;
- b. a tubular member extending into the formation to a point generally at the surface to be drilled;
- c. means for directing the beam through said tubular member to progressively penetrate through the formation at such surface;
- and
- d. means for producing a fluid flow said tubular member in the path traversed by the beam for maintaining the beam path therethrough substantially free from energy-dissipating contaminants.
Apparatus for fracing a subterranean pay zone of a well to increase the recovery of minerals or energy therefrom by drilling through the pay zone formation comprising:
- a. a laser for generating a beam of sufficient energy to penetrate through such formation by melting or vaporizing the material in its path;
- b. a tubular member extending into the formation to a point generally in the area to be drilled;
- c. means for directing the beam through said tubular member;
- d. means for producing a pressurized gas flow down said tubular member in the path traversed by the beam for maintaining the beam path therethrough substantially free from energy-dissipating contaminants;
- and
- e. reflector means disposed below the lower end of said tubular member and in the path of said beam for directing the incident beam laterally against the surrounding formation.
A pressure window for passing a radiant beam between two regions of different gas pressures comprising a gas-impervious partition separating the two regions of different pressures, said partition having a small diameter orifice formed therethrough, means disposed on one side of said partition for converging the radiant beam to a spot at said orifice of a sufficiently small size to pass the beam through said orifice into the region on the other side of said partition, and means disposed on said other side of said partition for collimating the divergent beam emerging from said orifice.
A pressure window for passing a radiant beam between two regions of different gas pressures comprising a gas-impervious partition separating the two regions of different pressures, said partition having a small diameter orifice formed therethrough, said partition further having on at least one side thereof a generally conical inner surface surrounding said orifice, means disposed on said one side of said partition for focusing the radiant beam to pass through said orifice into the region on the other side of said partition, and means disposed on said other side of said partition for collimating the divergent beam emerging from said orifice.
A pressure window for passing a radiant beam between two regions of different gas pressures comprising a gas-impervious partition separating the two regions of different pressures, said partition having a small diameter orifice formed therethrough, means disposed on one side of said partition for focusing the radiant beam to pass through said orifice into the region on the other side of said partition, means disposed on said other side of said partition for collimating the divergent beam emerging from said orifice and means for increasing the pressure of the gas in the region of said orifice to prevent gas breakdown.
A method of drilling through a subterraneous formation by a radiant beam of sufficient energy to penetrate through the formation by melting or vaporizing the material in its path comprising:
- a. directing the beam into a bore extending through the formation to the surface to be drilled;
- b. introducing into the bore a gas which is substantially transparent to the beam at a pressure sufficient to force debris produced by drilling into the formation at said surface and maintain the path of the beam passing through the bore substantially free from beam-degrading contaminants;
- and
- c. producing a radially increasing temperature distribution across the pressurized gas in the bore to establish a radially decreasing transverse index of refraction distribution for confining the beam passing therethrough along the axis of the bore so that adequate energy density is delivered to said surface to at least melt the material thereat.
Apparatus for drilling a bore hole through a subterranean formation comprising:
- a. means for generating a radiant beam of sufficient energy to penetrate through such formation by melting or vaporizing the material in its path;
- b. a tubular member extending into the formation to a point generally at the surface to be drilled;
- c. means for directing the beam through said tubular member to progressively penetrate through the formation at such surface;
- d. means for producing a flow of gas under pressure along said tubular member in the path of the beam for maintaining the beam path therethrough substantially free from energy-dissipating contaminants;
- and
- e. pressure window means for passing said beam into said pressurized gas.
Dependencies are inferred from the claim text.