Downhole drilling system
A downhole drilling system for reducing effects of overheating comprises a drill string having one or more drill pipes interconnected therebetween, a bottom hole assembly (BHA) connected to a distal end of the drill string, and a controller. The BHA comprises a drill bit disposed at an end portion of the BHA, a downhole motor to rotate the drill bit, a drill collar, in which a centrally disposed passage is formed and drilling mud is supplied to the drill bit through the centrally disposed passage, a measurement instrument disposed in the drill collar to obtain drilling environmental profile and communicating with the controller, and a cooling sub disposed in or on the drill collar or the measurement instrument.
1. A downhole drilling system for reducing effects of overheating, comprising:
a drill string having one or more drill pipes interconnected therebetween;
a bottom hole assembly (BHA) connected to a distal end of the drill string;
a controller;
a borehole wherein the drilling string is disposed in;
a drilling mud that circulates between the borehole and an earth surface;
a plurality of cooling shuttles, each configured to be carried downhole by the drilling mud flow,
wherein the BHA comprises:
a drill bit disposed at an end portion of the BHA,
a downhole motor to rotate the drill bit,
a drill collar, in which a centrally disposed passage is formed and drilling mud is supplied to the drill bit through the centrally disposed passage,
a measurement instrument disposed in the drill collar to obtain drilling environmental profile and communicating with the controller, and a
cooling sub disposed in or on the drill collar or the measurement instrument;
wherein each cooling shuttle has a container made of a dissolvable material and contains a first cooling agent, wherein the dissolvable material is configured to dissolve downhole and to release the first cooling agent.
2. The downhole drilling system of claim 1 , wherein the cooling sub has one or more tanks containing second cooling agent.
3. The downhole drilling system of claim 2 , wherein each of the one or more tanks is in a cylindrical shape or in an annular shape.
4. The downhole drilling system of claim 2 , wherein either the first cooling agent or the second cooling agent is liquid nitrogen or dry ice.
5. The downhole drilling system of claim 2 , wherein the cooling sub has a temperature sensor, and the cooling agent is released from the each of the one or more tanks when the temperature sensor detects a temperature that exceeds a preset value.
6. The downhole drilling system of claim 1 , wherein the dissolvable material is epoxy or silicone.
7. The downhole drilling system of claim 1 , wherein the first cooling agent is water.