Method of conditioning a wall of a bore section

Abstract

A method to condition a portion of a wall surrounding a borehole section drilled in a formation fluid-bearing formation comprising locally injecting a gas to displace working fluid from a laser path adjacent a drill head, providing an underbalanced pressure at the portion of the borehole section to be conditioned, impinging laser light on the portion of the wall to be conditioned to melt a component of the formation material in the portion of the bore wall to be conditioned, and drawing fluid from the formation through the solidifying component of the material to create fluid flow passageways to facilitate the flow of fluid from the formation into the borehole section. Injected gas may be provided to the drill head through a conduit within an umbilical that includes a plurality of optical fibers to transmit laser light to the drill head.

We claim: 
     
         1 . A method comprising:
 providing an umbilical having a plurality of optical fibers, a gas conduit and a leading end connected to a drill head;   introducing the drill head through a surface end of a borehole system drilled in the earth's crust:   positioning the drill head within a bore section of the borehbole system penetrating a geologic formation in which a formation fluid resides;   introducing a volume of gas through the gas conduit into a portion of the bore section to be conditioned to displace laser obstructing materials;   transmitting laser light through the plurality of optical fibers to the drill head;   impinging laser light on a portion of the wall of the bore section to be conditioned to melt at least a component of the formation material of the wall;   providing an underbalanced pressure at the portion of the wall to be conditioned; and   inducing a flow of the formation fluid from the formation across the portion of the wall to be conditioned and into the bore section as the melted component of the formation material solidifies;   wherein the flow of formation fluid across the solidifying component of the portion of the wall to be conditioned creates formation fluid flow passages through which the formation fluid may flow from the formation into the bore section.   
     
     
         2 . The method of  claim 1  wherein the gas is one of nitrogen, a noble gas, and a combination thereof. 
     
     
         3 . The method of  claim 1  wherein providing an underbalanced pressure at the portion of the wall to be conditioned comprises:
 reducing the average density of a working fluid circulated into the borehole system. 
 
     
     
         4 . The method of  claim 3  wherein reducing the average density of the working fluid circulated into the borehole system comprises:
 introducing a low density fluid into the borehole system through a working fluid conduit within at least a portion of a length of the umbilical. 
 
     
     
         5 . The method of  claim 1  wherein providing the underbalanced pressure at the portion of the wall to be conditioned comprises:
 reducing the volume of a working fluid disposed within the borehole system to hydrostatically balance formation pressure. 
 
     
     
         6 . The method of  claim 1  wherein providing the underbalanced pressure at the portion of the wall to be conditioned comprises:
 deploying a seal on the drill head to isolate the portion of the wall to be conditioned from a remaining portion of the borehole system. 
 
     
     
         7 . The method of  claim 1  wherein the drill head connected to the leading end of the umbilical comprises:
 at least one gas injection port connected to the gas conduit. 
 
     
     
         8 . The method of  claim 1  wherein the drill head connected to the leading end of the umbilical comprises:
 at least one optical element optically connected to the plurality of optical fibers. 
 
     
     
         9 . The method of  claim 8  wherein the drill head connected to the leading end of the umbilical comprises:
 a plurality of optical elements optically connected to the plurality of transmission fibers. 
 
     
     
         10 . The method of  claim 7  wherein the drill bead connected to the leading end of the umbilical comprises:
 at least one optical element optically connected to the plurality of optical fibers. 
 
     
     
         11 . A method of conditioning a portion of a wall of a bore section of a borehole system comprising:
 disposing a drill head into the bore section of the borehole system;   positioning the drill head within the bore section and proximal to the portion of the wall to be conditioned;   injecting a gas into the bore section to displace laser obstructing material from a laser path intermediate the drill head and the portion of the wall to be conditioned;   irradiating the portion of the wall to be conditioned using laser light emitted from the drill head to melt at least a component of the wall opposite the laser path from the drill head;   providing an underbalanced pressure at the portion of the wall to be conditioned; and   drawing a formation fluid residing in the formation across the portion of the wall to be conditioned and into the bore section as the melted component of the wall solidifies to create passageways within the portion of the wall of the bore section for the flow of the formation fluid from the formation into the bore section.   
     
     
         12 . The method of  claim 11  wherein the gas is one of nitrogen, a noble gas, and a combination thereof. 
     
     
         13 . The method of  claim 11  wherein providing the underbalanced pressure at the portion of the wall to be conditioned comprises:
 reducing the volume of working fluid disposed within the borehole system. 
 
     
     
         14 . The method of  claim 11  further comprising:
 providing an umbilical having a plurality of optical fibers, a gas conduit and a leading end connected to the drill head; 
 connecting the gas conduit to a gas injection port in the drill head; 
 optically connecting the plurality of optical fibers to a plurality of optical elements in the drill head; and 
 deploying a seal on the drill head to isolate the portion of the wall to be conditioned from a remaining portion of the borehole system. 
 
     
     
         15 . The method of  claim 14  wherein irradiating the portion of the wall using laser light emitted from the apparatus to melt at least a component of the formation adjacent to the drill head comprises:
 transmitting laser light through the plurality of optical fibers to the optical elements in the drill head; and 
 emitting laser light from the drill head through the laser path onto the portion of the wall to be conditioned. 
 
     
     
         16 . The method of  claim 11  wherein the drill head connected to the leading end of the umbilical comprises:
 at least one gas injection port connected to the gas conduit. 
 
     
     
         17 . The method of  claim 11  wherein the drill head connected to the leading end of the umbilical comprises:
 an optical element optically coupled to the plurality of optical fibers. 
 
     
     
         18 . The method of  claim 17  wherein the drill head connected to the leading end of the umbilical comprises:
 a plurality of optical elements optically coupled to the plurality of optical fibers. 
 
     
     
         19 . The method of  claim 17  wherein the drill head connected to the leading end of the umbilical comprises:
 at least one gas injection port connected to the gas conduit.