Rock breaker is a downhole tool for well drilling of petroleum, natural gas etc., the main function of which is to effectively prevent the formation of cuttings bed during drilling horizontal well, high angle well and extended reach well and to remove existing cuttings bed timely and efficiently. This tool is able to eliminate the risk from pipe sticking caused by the cuttings sedimentation or bonding to group in the build section and horizontal section of complex structure well such as horizontal well and high angle well, to prevent the occurrence of down hole accidents and to ensure the normal running of drilling work.
As Picture 1 shown, the operation principle and effects of rock breaker is:
①Prevent the cuttings from sedimentation.
The rock breaker is able to stir and excavate cuttings bed located at bottom edge of borehole by “V” shape strand, excavate cuttings bed out through “V” shape slot from low speed area to high speed area of high edge of borehole, and then bring the sedimentary cuttings back to annulus.
② Due to the large sectional area of “V” shape strand, which means the annular sectional area around rock breaker is far less than the area of location between drill pipe and drill joint, the increasing drilling fluid speed can take strong flushing effect on cuttings around rock breaker.
③ The special outline structure has the function of crushing and breaking to transform large cuttings into portable small ones.
④ “V” shape strand functions as strong re-leading to incoming flow. The change of incoming flow direction and speed increasing can enhance the turbulent flow to fluid around rock breaker, which is favorable to carry and remove cuttings in the aspect of drilling hydraulics.
3. Features (Advantages)
(1)Single component, no moving parts and higher strength than the connected drill pipe;
(2)Break and remove cuttings bed driven by hydraulic power and machinery force;
(3)Tungsten carbide inserted in surface of “V” shape strand to improve wear resistance.
4. Application Scope
(1)Applied to borehole with 215.9 mm, 241.3 mm and 244.5 mm;
(2)All borehole section in horizontal wells with well deviation larger than 38°;
(3)Extended reach well;
(4)Long horizontal well.
5. Regular Usage Method
Based on the borehole trajectory and the actual drilling conditions, rock breaker shall be installed and applied in well section with large well deviation