Title:

Anti-Clogging Rock Bit Nozzle

Abstract:

Nozzles are added to rock bits to provide hydraulic power in a flow for hole and cone cleaning and jetting. These parts are subject to clogging due to sediments coagulation in the jetting fluid as well as inadequate mud cleaning. In addition, nozzle clogging can also be achieved by forcing cuttings or sediments back through the nozzle (ie. Dropping the bit on bottom of hole). When a nozzle or nozzles becomes clogged, the hydraulics systems become less than effective or nonexistent if all nozzles are clogged. This disclosure is a method of design of a self unclogging nozzle which expands as a function of pressure. If a Nozzle becomes clogged, an increase in pressure will result. This increase will allow the nozzle to expand through the use of a calibrated spring mechanism, thus providing an enlarged area for the blockage or clog to be removed. Once removed, the nozzle self adjust back to its designed size, restoring the hydraulics. (new embodyment)

Description:

See below:

Abstract

Nozzles are added to rock bits to provide hydraulic power in a flow for hole and cone cleaning. As the rock bit boars deeper, the hydraulic system requires more pump power to overcome additional pressure losses. The pressure losses may increase to a point that the available pump power is insufficient to operate the current hydraulic parameters. The most common ways of reducing the pressure losses is by reducing the fluid’s volumetric flow rate, or by increasing the nozzle size, thus reducing the pressure drop across the bit. This disclosure captures an invention that allows the nozzles to vary precisely and directly with fluid volumetric flow rate in order to maintain a constant pressure drop across the bit while drilling; thus maintaining a more optimized hydraulics while drilling.

Description of Design

Opportunity

#1

Factors that affect pump pressure are flow rates, flow area, distance, and fluid properties. Considering a common condition which the available mud pump power is reached for the given flow rate, flow area, distance, and fluid properties; changes to one or more of these variables are necessary in order to not over load the pumps and maintain the hydraulics. The distance drilled is always increasing and will always be adding to the consumption of pump power based on the added circulation length and the associated line losses. The fluid properties are limited to change based on the well conditions. However, as previously stated in the above abstract, the flow rate can be reduced to in order to reduce required pump power. When the flow rate is reduced, the velocity of the flow is reduces and therefore the frictional losses are reduced through each component of the hydraulic system. This in turn reduces the pressure drop across the bit. O...