Wellbore cleanout tool and method

Abstract

The present invention is directed to a method and apparatus for cleaning a wellbore. The method is designed to remove debris particles from the wellbore by suspending the debris within the wellbore and then forming an approximately helical flow stream in the wellbore to remove the particles. One apparatus includes a body with a flow channel and multiple nozzles connecting to the flow channel and extending to the circumference of the body. Each nozzle has a nozzle axis that bisects the circumference forming a nozzle axis-circumference intersection; the nozzle axis is not on a plane that is formed by the vertical axis and the nozzle-axis-circumference intersection.

1 . A method of removing debris particles from a wellbore section, wherein the wellbore has a wellbore axis and a sidewall, comprising the steps of: 
 (a) suspending the debris particles in a fluid to form suspended debris particles;    (b) forming an approximately helical flow stream in at least part of the wellbore section about an axis of rotation, wherein the axis of rotation is generally parallel to the wellbore axis and further, wherein the helical flow stream has a rotational velocity; and    (c) removing the suspended debris particles from the wellbore.    
   
   
       2 . The method of  claim 1  wherein the rotational velocity is controlled so as to achieve at least 85% removal of the suspended debris particles from the wellbore section.  
   
   
       3 . The method of  claim 2  wherein the rotational velocity is controlled so as to achieve at least 90% removal of the suspended debris particles from the wellbore section.  
   
   
       4 . The method of  claim 3  wherein the rotational velocity is controlled so as to achieve at least 95% removal of the suspended debris particles from the wellbore section.  
   
   
       5 . The method of  claim 4  wherein the rotational velocity is controlled so as to remove substantially all of the suspended debris particles in the wellbore section.  
   
   
       6 . The method of  claim 1  wherein the helical flow stream is formed by jetting a high pressure fluid through a nozzle.  
   
   
       7 . The method of  claim 1  wherein the axis of rotation is approximately coincident with the wellbore axis.  
   
   
       8 . The method of  claim 1  further comprising after step (a) the step of imparting a velocity generally parallel to the wellbore axis to the suspended debris particles.  
   
   
       9 . The method of  claim 1  further comprising following step (a) the step of impelling the fluid against the sidewall of the wellbore.  
   
   
       10 . The method of  claim 1  wherein the fluid comprises water.  
   
   
       11 . The method of  claim 10  wherein the fluid further comprises NaCl, CaCl, CaBr ZnBr or NH 4 Cl.  
   
   
       12 . The method of  claim 10  wherein the fluid further comprises Xanthan Biopolymer or Liquid HEC Polymer.  
   
   
       13 . The method of  claim 10  wherein the fluid further comprises a nitrogen foam.  
   
   
       14 . The method of  claim 13  wherein the fluid further comprises a foaming agent.  
   
   
       15 . A wellbore cleanout tool comprising: 
 a generally cylindrical body having a flow channel therethrough, a vertical axis, a top surface plane, an outer surface, and a circumference; and    a plurality of nozzles connecting to the flow channel and further extending to the circumference, wherein each nozzle has a nozzle axis that bisects the circumference forming a nozzle axis-circumference intersection, and the nozzle axis is not on a plane that is formed by the vertical axis and the nozzle-axis-circumference intersection.    
   
   
       16 . The wellbore cleanout tool of  claim 15  wherein the nozzle axis of each nozzle is at an angle perpendicular to the vertical axis of the generally cylindrical body.  
   
   
       17 . The wellbore cleanout tool of  claim 15  wherein the nozzle axis of at least one nozzle is at an acute angle to the vertical axis, and the nozzle axis of at least one nozzle bisects the top surface plane.  
   
   
       18 . The wellbore cleanout tool of  claim 15  wherein the nozzles comprise between 2 and 100 nozzles.  
   
   
       19 . The wellbore cleanout tool of  claim 15  wherein the nozzles protrude beyond the outer surface.  
   
   
       20 . The wellbore cleanout tool of  claim 15  wherein the wellbore cleanout tool is capable of connection to a coiled tubing.  
   
   
       21 . The wellbore cleanout tool of  claim 15  further comprising a bottom orifice connected to the flow channel.  
   
   
       22 . The wellbore cleanout tool of  claim 15  wherein the nozzles are arranged in at least one row of nozzles.  
   
   
       23 . The wellbore cleanout tool of  claim 22  wherein the row of nozzles is perpendicular to the vertical axis.  
   
   
       24 . The wellbore cleanout tool of  claim 15  wherein the nozzles are arranged in at least two row of nozzles, and each row of nozzles is perpendicular to the vertical axis.  
   
   
       25 . A method of cleaning debris from a wellbore having a sidewall, comprising: 
 (a) providing a wellbore cleanout tool comprising: 
 a body having a flow channel therethrough, a vertical axis, a top surface plane, and a circumference;  
 a plurality of nozzles connecting to the flow channel and further extending to the circumference, wherein each nozzle has a nozzle axis that bisects the circumference forming a nozzle axis-circumference intersection, and the nozzle axis is not on a plane that is formed by the vertical axis and the nozzle-axis-circumference intersection; and  
 a bottom orifice connected to the flow channel;  
   (b) lowering the wellbore cleanout tool in the wellbore;    (c) flowing a fluid through the bottom orifice to form debris particles; and    (d) raising the wellbore cleanout tool in the wellbore while jetting the fluid through the nozzles.    
   
   
       26 . The method of  claim 25  wherein pressure of the fluid flowed through the bottom orifice is less than 2000 psig.  
   
   
       27 . The method of  claim 25  wherein pressure of the fluid jetted through the nozzles is less than 2000 psig.  
   
   
       28 . The method of  claim 25  further comprising suspending the debris particles in the fluid.  
   
   
       29 . The method of  claim 25  further comprising imparting a horizontal velocity to the fluid to induce lift on the debris particles.  
   
   
       30 . The method of  claim 29  further comprising imparting a vertical velocity on the fluid.  
   
   
       31 . A wellbore cleanout tool comprising: 
 a member having an outer surface, a fluid inlet, a fluid outlet, and a flow channel therethrough connecting the fluid inlet and fluid outlet; and    a helical vane mechanically attached to the outer surface.    
   
   
       32 . The wellbore cleanout tool of  claim 31  further comprising a plurality of helical vanes.  
   
   
       33 . A method of cleaning debris from a wellbore having a wellbore axis, comprising: 
 (a) providing a wellbore cleanout tool having an outer surface, a fluid outlet, and a helical vane attached to the outer surface;    (b) lowering the wellbore cleanout tool in the wellbore;    (c) flowing a fluid through the fluid outlet;    (d) suspending debris particles in the fluid; and    (e) forming a helical flow pattern in the fluid along the wellbore axis.