Application of high intensity focused ultrasound to the displacement of drilling mud

Abstract

A method for disrupting an obstruction from a wellbore includes determining a location of an obstruction within a wellbore. An ultrasound transducer is deployed down an interior of a casing in the wellbore. Ultrasound energy is focused, using the ultrasound transducer, to the determined location of the obstruction and the obstruction is disrupted using the focused ultrasound energy.

What is claimed is: 
     
         1 . A method for disrupting an obstruction from a wellbore, comprising:
 determining a location of an obstruction within a wellbore;   deploying an ultrasound transducer down an interior of a casing in the wellbore;   focusing ultrasound energy, using the ultrasound transducer, to the determined location of the obstruction; and   disrupting the obstruction using the focused ultrasound energy.   
     
     
         2 . The method of  claim 1 , wherein determining the location of the obstruction within the wellbore includes:
 acquiring a sequence of ultrasound images, using the ultrasound transducer, of an area exterior to the casing, as the ultrasound transducer is deployed down the interior of the casing;   analyzing the acquired images to detect the obstruction; and   determining the location of the obstruction from the acquired images.   
     
     
         3 . The method of  claim 2 , wherein the acquired sequence of ultrasound images cover a 360° field. 
     
     
         4 . The method of  claim 1 , wherein the ultrasound transducer includes a plurality of ultrasound transducers. 
     
     
         5 . The method of  claim 4 , wherein the plurality of ultrasound transducers are arranged in a circle substantially conforming to a radius of the casing. 
     
     
         6 . The method of  claim 4 , wherein the plurality of ultrasound transducers are arranged along a lengthwise direction of the casing. 
     
     
         7 . The method of  claim 4 , wherein the plurality of ultrasound transducers are arranged in a two-dimensional pattern or grid that is substantially confined to a flat, curved, or irregular surface. 
     
     
         8 . The method of  claim 7 , wherein the two-dimensional pattern or grid is as wide as can be practically accommodated by the diameter of the casing. 
     
     
         9 . The method of  claim 4 , wherein the plurality of ultrasound transducers are arranged as a set of annular rings. 
     
     
         10 . The method of  claim 1 , wherein disrupting the obstruction includes breaking the obstruction down into a plurality of smaller sections or particles. 
     
     
         11 . The method of  claim 1 , wherein disrupting the obstruction includes increasing the movability of the obstruction. 
     
     
         12 . The method of  claim 1 , wherein disrupting the obstruction includes liquefying the obstruction via a pulsed insonication. 
     
     
         13 . The method of  claim 1 , wherein disrupting the obstruction includes performing erosive cavitation. 
     
     
         14 . The method of  claim 1 , wherein disrupting the obstruction includes enlarging the wellbore by ultrasonic erosion. 
     
     
         15 . The method of  claim 1 , wherein disrupting the obstruction includes creating or increasing a bypass channel around the obstruction. 
     
     
         16 . The method of  claim 1 , wherein prior to deploying the ultrasound transducer array down the interior of the casing, the wellbore is drilled, drilling mud is pumped therein, the casing is lowered into the wellbore, and an attempt to clear the drilling mud from an annular region between the exterior of the casing and interior of the wellbore is made. 
     
     
         17 . The method of  claim 1 , wherein the ultrasound transducer includes one or more ultrasound imaging devices for determining the location of the obstruction as the ultrasound transducer is deployed. 
     
     
         18 . The method of  claim 1 , wherein the obstruction includes drilling mud remaining in an annular region between the casing and the wellbore. 
     
     
         19 . The method of  claim 1 , wherein the obstruction includes a channel or other irregularity within cement in an annular region between the casing and the wellbore. 
     
     
         20 . The method of  claim 1 , wherein the obstruction includes material which has separated from the surface of the wellbore and has collapsed into the wellbore. 
     
     
         21 . The method of  claim 1 , wherein focusing the ultrasound energy includes performing high intensity focused ultrasound (HIFU). 
     
     
         22 . The method of  claim 1 , wherein disrupting the obstruction using the focused ultrasound energy includes performing a flushing operation to clear the obstruction after it has been at least partially broken down by the focused ultrasound energy. 
     
     
         23 . A method for establishing a well for deep water drilling, comprising:
 drilling a wellbore below the sea floor;   pumping a drilling mud into the wellbore;   deploying a casing into the wellbore;   partially removing the drilling mud from an annular region between the casing and the wellbore;   determining a location of an area of remaining drilling mud in the annular region;   deploying an ultrasound transducer down an interior of the casing;   focusing ultrasound energy, using the ultrasound transducer array, to the determined location of the remaining drilling mud;   removing the remaining drilling mud using the focused ultrasound energy; and   deploying cement into the annular region having the remaining drilling mud removed therefrom.   
     
     
         24 . A method for establishing a well for deep water drilling, comprising:
 drilling a wellbore below the sea floor;   pumping a drilling mud into the wellbore;   deploying a casing into the wellbore;   removing the drilling mud from an annular region between the casing and the wellbore;   deploying cement into the annular region;   determining a location of a channel or other irregularity in the cement;   deploying an ultrasound transducer down an interior of the casing;   focusing ultrasound energy, using the ultrasound transducer, to the determined location to mitigate the channel or other irregularity in the cement.