Impact excavation system and method with particle separation

Abstract

A system and method for excavating a subterranean formation, according to which a suspension of liquid and a plurality of impactors are introduced into at least one cavity formed in a body member and are discharging from the cavity so that the impactors remove a portion of the formation. The impactors are separated from at least a portion of the fluid, and are passed to a conduit so that the impactors accumulate in the conduit before being removed from the conduit.

1 . A system for excavating a subterranean formation, the system comprising:
 a body member for receiving a suspension of liquid and a plurality of impactors and discharging the suspension so that the impactors remove a portion of the formation;   a first conduit for receiving the suspension after the removal;   an impactor separation system for separating the impactors from at least a portion of the liquid; and   a second conduit for receiving the separated impactors from the separator.   
     
     
         2 . The system of  claim 1  wherein the impactor separation system comprises a screen separation process. 
     
     
         3 . The system of  claim 1  wherein the impactor separation system comprises a magnetic separation process. 
     
     
         4 . The system of  claim 2  wherein the impactor separation system further comprises a magnetic separation process. 
     
     
         5 . The system of  claim 3  wherein the magnetic separation process includes a rotary drum magnetic separator. 
     
     
         6 . The system of  claim 1  further comprising means for washing the suspension upstream of the magnetic separation system. 
     
     
         7 . The system of  claim 1  further comprising a demagnetizer. 
     
     
         8 . The system of  claim 8  wherein the demagnetizer is downstream of the impactor separation system. 
     
     
         9 . The system of  claim 1  further comprising means for controlling the flow of impactors into the second conduit. 
     
     
         10 . A method for excavating a subterranean formation, the system comprising:
 introducing a suspension of liquid and a plurality of impactors into at least one cavity formed in a body member;   discharging the suspension from the cavity so that the impactors remove a portion of the formation;   separating the impactors from at least a portion of the liquid; and   passing the impactors to a conduit so that a substantial portion of the impactors accumulate in the conduit.   
     
     
         11 . The method of  claim 10  wherein the separation step includes using screens to separate impactors from other particles and liquids. 
     
     
         12 . The method of  claim 10  wherein the separation step includes using a rotary magnetic separator to separate impactors from other particles and liquids. 
     
     
         13 . The method of  claim 11  wherein the separation step further comprises using a rotary magnetic separator. 
     
     
         14 . The method of  claim 10  further comprising washing the suspension of liquid and impactors prior to the separation step. 
     
     
         15 . A system for excavating a subterranean formation, the system comprising:
 a body member;   first means disposed in the body member for receiving a suspension of liquid and a plurality of impactors and discharging the suspension so that the impactors remove a portion of the formation;   a first conduit for receiving the suspension after the removal;   second means in the first conduit for separating the impactors from at least a portion of the liquids;   a second conduit for receiving the separated impactors from the separator; and   third means for controlling the flow of impactors to the second conduit so that a substantial portion of the impactors can accumulate in the second conduit.   
     
     
         16 . The system of  claim 15  wherein the separation means further comprises screen or magnetic separation means. 
     
     
         17 . A method for excavating a subterranean formation comprising:
 introducing a suspension of liquid and a plurality of impactors into at least one cavity formed in a body member;   discharging the suspension from the cavity so that the impactors remove a portion of the formation;   separating the impactors from at least a portion of the liquids; and   passing the impactors to a conduit.   
     
     
         18 . The method of  claim 17  wherein the separation step includes using a magnetic separator. 
     
     
         19 . The method of  claim 17  further comprising using a magnetic rotary drum separator rotating at a speed between 50 and 400 RPM. 
     
     
         20 . The method of  claim 18  wherein the separation step results in impactor loss of less than 3%. 
     
     
         21 . The method of  claim 18  wherein the conduit for recovering impactors comprises at least 97% by weight impactors. 
     
     
         22 . The method of  claim 17  further comprising separating the impactors from the liquid with a screen separation process prior to the magnetic separation. 
     
     
         23 . A system for excavating a subterranean formation, the system comprising:
 means for introducing a suspension of liquid and a plurality of impactors into at least one cavity formed in a body member;   means for discharging the suspension from the cavity so that the impactors remove a portion of the formation;   means for washing the suspension;   means for physically separating the impactors from at least a portion of the liquid; and   means for magnetically separating the impactors from at least a portion of the liquid and/or non-magnetic particles.   
     
     
         24 . A method for excavating a subterranean formation, the system comprising:
 magnetically introducing a suspension of liquid and a plurality of impactors into at least one cavity formed in a body member;   discharging the suspension from the cavity so that the impactors remove a portion of the formation; and   separating the impactors from at least a portion of the liquid by a screening process.   
     
     
         25 . The method of  claim 24  further comprising washing the suspension prior to the separation step. 
     
     
         26 . The method of  claim 24  further comprising washing the suspension after the separation step. 
     
     
         27 . A system for excavating a subterranean formation, the system comprising:
 means for magnetically introducing a suspension of liquid and a plurality of impactors into at least one cavity formed in a body member;   means for discharging the suspension from the cavity so that the impactors remove a portion of the formation; and   means for magnetically separating the impactors from at least a portion of the liquid.   
     
     
         28 . A system for separation ferrous impactors from circulation fluid comprising:
 means for receiving circulation fluid from a wellbore, wherein said circulation fluid comprises drilling fluid, drill cuttings and ferrous impactors;   a separation system, said separation system comprising a screen separator and a magnetic separator; and   means for receiving impactors from the separation system.   
     
     
         29 . A system for excavating a subterranean formation, the system comprising:
 a drill bit;   a body member for receiving a suspension of liquid and a plurality of impactors and discharging the suspension so that the impactors remove a portion of the formation;   a pump;   a first conduit for receiving the suspension after the removal;   an impactor separation system for separating the impactors from at least a portion of the liquid, wherein said separation systems includes a rotary magnetic separator; and   a second conduit for receiving the separated impactors from the separator.