Closed loop drilling mud cooling system for land-based drilling operations

1. A method for cooling drilling mud, the method comprising:

routing the drilling mud from a wellhead to a first heat exchanger in fluid communication with an air-cooled and closed-loop cooling system;

controlling the air-cooled and closed-loop cooling system to cool the drilling mud via the first heat exchanger when a first temperature of the drilling mud exceeds a first predetermined mud set point temperature;

routing the drilling mud from the first heat-exchanger to a second heat exchanger in fluid communication with a refrigeration chiller unit; and

controlling the refrigeration chiller unit to further cool the mud via the second heat exchanger when a second temperature of said flow of drilling mud that has been cooled by said air-cooled and closed-loop cooling system exceeds a second predetermined mud set point temperature.

2. The method of claim 1 , wherein controlling operation of said air-cooled and closed-loop cooling system comprises:

maintaining said air-cooled and closed-loop cooling system in a mud cooling standby mode when said first temperature is below said first predetermined mud set point temperature; and

cooling said flow of drilling mud with a first cooling fluid circulating through said air-cooled and closed-loop cooling system when said first temperature rises to at least said first predetermined mud set point temperature.

3. The method of claim 2 , wherein controlling operation of said refrigeration chiller unit comprises:

maintaining said refrigeration chiller unit in a mud cooling standby mode when said second temperature is below said second predetermined mud set point temperature; and

cooling said flow of drilling mud with a second cooling fluid circulating through said refrigeration chiller unit when said second temperature rises to at least said second predetermined mud set point temperature.

4. The method of claim 1 , wherein the first predetermined mud set point temperature and the second predetermined mud set point temperature are a same temperature.

5. The method of claim 1 , further comprising receiving drilling mud from a shaker into a first mud tank and circulating the drilling mud from the first mud tank directly into a second mud tank.

6. The method of claim 5 , further comprising circulating drilling mud from the second mud tank to the air-cooled and closed-loop cooling system.

7. The method of claim 6 , further comprising circulating drilling mud from the air-cooled and closed loop cooling system or the refrigeration chiller unit to the first mud tank.

8. A method for cooling drilling mud, the method comprising:

routing the drilling mud from a wellhead to a first heat exchanger in fluid communication with an air-cooled and closed-loop cooling system;

controlling the air-cooled and closed-loop cooling system to cool the drilling mud when a first temperature of the drilling mud exceeds a first predetermined mud set point temperature, wherein controlling the air-cooled and closed-loop cooling system comprises circulating a first cooling fluid through the first air-cooled closed-loop cooling system and cooling the drilling mud with the first cooling fluid via the first heat exchanger;

routing the drilling mud from the first heat exchanger to a second heat exchanger in fluid communication with a refrigeration chiller unit; and

controlling the refrigeration chiller unit to cool the drilling mud when a second temperature of the drilling mud that has been cooled by the air-cooled closed-loop cooling system exceeds a second predetermined mud set point temperature, wherein controlling the refrigeration chiller unit comprises circulating a second cooling fluid through the refrigeration chiller unit and cooling the drilling mud with the second cooling fluid via the second heat exchanger.

9. The method of claim 8 , wherein controlling operation of said air-cooled and closed-loop cooling system comprises maintaining said closed-loop cooling system in a mud cooling standby mode when said first temperature is below said first predetermined mud set point temperature and initiating operation of said air-cooled and closed-loop cooling system when said first temperature rises to at least said first predetermined mud set point temperature.

10. The method of claim 9 , wherein controlling operation of said refrigeration chiller unit comprises maintaining said refrigeration chiller unit in a mud cooling standby mode when said second temperature is below said second predetermined mud set point temperature and initiating operation of said refrigeration chiller unit when said first temperature rises to at least said second predetermined mud set point temperature.

11. The method of claim 8 , wherein the first predetermined mud set point temperature and the second predetermined mud set point temperature are a same temperature.

12. The method of claim 8 , wherein said refrigeration chiller unit comprises first and second refrigeration chiller units and the method further comprises sequentially staging operation of the first and second refrigeration chiller units.

13. The method of claim 8 , further comprising receiving drilling mud from a shaker into a first mud tank and circulating the drilling mud from the first mud tank directly into a second mud tank.

14. The method of claim 13 , further comprising circulating drilling mud from the second mud tank to the air-cooled and closed-loop cooling system.

15. The method of claim 14 , further comprising circulating drilling mud from the air-cooled and closed-loop cooling system or the refrigeration chiller unit to the first mud tank.