Scale-Up Device For Testing Bit Balling Characteristics

Abstract

An apparatus and method for testing the effects of mud chemistry and bit design on bit balling is disclosed The apparatus includes a replica bit coupled to a rotary drive and having at least one nozzle, a test container, a test formation located within the test container through which the replica bit will be drive, wherein the test formation includes a plurality of layers of pre-manufactured cuttings The apparatus further includes a lifting device applying a force to the bottom of the container to drive the test formation into the replica bit while the replica bit is rotating, a second container within which is a drilling fluid, and a pump for communicating drilling fluid from the container through a conduit to the replica bit.

1 . An apparatus for testing the effects of mud chemistry and bit design on bit balling comprising:
 a replica bit coupled to a rotary drive and having at least one nozzle;   a test container;   a test formation located within the container, wherein the test formation includes:
 a plurality of layers of pre-manufactured cuttings; 
   a lifting device applying a force to the bottom of the test container to drive the test formation into the replica bit while the replica bit is rotated by the rotary drive;   a second container within which is a drilling fluid;   a conduit providing fluid communication from the second container to the replica bit; and   a pump for circulating drilling fluid from the second container through the conduit to the replica bit.   
     
     
         2 . The apparatus of  claim 1  further comprising a camera focused on the replica bit. 
     
     
         3 . The apparatus of  claim 1 , wherein the test container is transparent, and further comprising a camera located outside of the test container, wherein the camera is focused on the replica bit inside the test container. 
     
     
         4 . The apparatus of  claim 1  further comprising a computer including inputs to track test parameters, wherein the test parameters include at least one of time, torque on the replica bit, rotary speed, and position of the replica bit relative to the bottom of the test formation. 
     
     
         5 . The apparatus of  claim 4 , wherein the computer is used to calculate at least one of weight on bit, rate of penetration, and mechanical specific energy. 
     
     
         6 . The apparatus of  claim 1 , wherein the pre-manufactured cuttings comprise ground rock material and reactive clay. 
     
     
         7 . The apparatus of  claim 6 , wherein the ground rock material is selected from the group consisting of shale, marble, a combination of shale and marble. 
     
     
         8 . The apparatus of  claim 1 , wherein the replica bit is a three-dimensionally printed, plastic model of a PDC bit. 
     
     
         9 . The apparatus of  claim 8 , wherein the replica bit is coated with a metallic finish. 
     
     
         10 . A method of testing the effects of mud chemistry and bit design on bit balling comprising:
 mixing a plurality of mixtures of ground rock material and reactive clay;   layering the mixtures into a test container to create a test formation;   coupling a replica bit to a rotary drive;   fluidly connecting the replica bit to a second container containing drilling fluid;   positioning the replica bit within the test container to a position above the test formation;   rotating the replica bit;   pumping fluid from the container and through the replica bit; and   lifting the test formation to the rotating replica bit so that the bit rotates into the formation.   
     
     
         11 . The method of  claim 10 , further comprising:
 layering the mixtures into the test container such that the first layer loaded into the container has a lower concentration of reactive clay than the next successive layer and each successive layer has a higher concentration of reactive clay than the previous layer.   
     
     
         12 . The method of  claim 10 , further comprising:
 layering the mixtures into the test container such that the first layer loaded into the container has a higher concentration of reactive clay than the next successive layer and each successive layer has a lower concentration of reactive clay than the previous layer.   
     
     
         13 . The method of  claim 10 , wherein the mixtures are layered to create a formation with varied layers. 
     
     
         14 . The method of  claim 10 , wherein the mixtures are layered to create a formation with homogenous layers. 
     
     
         15 . The method of  claim 10  further comprising measuring test parameters;
 wherein the test parameters include at least one of time, torque on the replica bit, rotary speed, and position of the replica bit relative to the bottom of the test formation. 
 
     
     
         16 . The method of  claim 15  further comprising calculating at least one of rate of penetration, weight on bit, and mechanical specific energy. 
     
     
         17 . The method of  claim 10  further comprising using a camera to video the replica bit as it is rotated through the formation. 
     
     
         18 . The method of  claim 10  further comprising using a camera to take pictures of the replica bit as it is rotated through the formation.