Method and apparatus for optimizing a well drilling operation
In a snubbing operation, a method is used for determining when a wellbore should be circulated by comparing calculated torque and drag values from a clean wellbore against actual torque and drag values. In a more expansive application, for working a well, a method is used for optimizing performance of the drilling operation by comparing calculated torque and drag values from a clean well against actual torque and drag values.
1. For completion of a non-conventional well, with perforated well casings in place within the wellbore and frac plugs separating segments of the well casing, a method of optimizing clean out of residual materials from the well casings to allow gas to flow from the well comprising the steps of:
A) inserting a tubular string within an actual well casing and monitoring in real time actual tripping speed, actual string rotation speed, and actual surface torque imparted to the tubular string at a particular string depth;
B) for the given tubular string and for a predefined clean well casing based upon the actual well casing using mathematical modeling of the predefined clean well casing and a friction factor, generating a calculated value of surface torque at the particular string depth, the actual tripping speed, and at the actual rotation speed of the tubular string;
C) comparing an actual value of surface torque at the particular string depth to the calculated value of surface torque for the predefined clean well casing and a friction factor over a range of string depths; and
D) when the actual values of surface torque exceed the calculated values of surface torque for the predefined clean well casing and a friction factor over the range of string depths by a predetermined amount, then circulating the well to clean out the residual material.
2. The method according to claim 1 , wherein the predetermined amount is between 1-5%.
3. The method according to claim 1 , wherein the method comprising the further steps of:
E) after the well is circulated, then comparing over the range of string depths the actual values of the surface torque at a string depth to the calculated values of the surface torque over the range of string depths for the predefined clean well casing and a friction factor; and
F) when the actual values of the surface torque continue to exceed the calculated values of the surface torque for the predefined clean well casing and a friction factor by a predetermined amount, then adjusting the friction factor such that the calculated torque values more closely conform with the calculated values of the surface torque for the predefined clean well casing and a friction factor over the range of string depths.
4. The method according to claim 3 , wherein the predetermined amount is between 1-5%.
5. The method according to claim 1 , wherein the actual value of the surface torque is measured and the calculated value of the surface torque is calculated for the predefined clean well casing and a friction factor and compared continuously during an active drilling operation.
6. The method according to claim 1 , wherein circulating the well is performed manually by an operator.
7. The method according to claim 1 , wherein circulating the well is done automatically by switching over from drilling to circulate without manual intervention.
8. The method according to claim 1 , wherein prior to the step of circulating the well, sending an alert to a drilling rig operator when the actual value of the surface torque exceeds the calculated value of surface torque for the predefined well casing 4114 and a friction factor by a predetermined amount.
9. The method according to claim 8 , wherein the predetermined amount is between 1-5%.
10. For completion of a non-conventional well, with perforated well casings in place within the wellbore and frac plugs separating segments of the well casing, a method of optimizing clean out of residual materials from the well casings to allow gas to flow from the well comprising the steps of:
A) inserting a tubular string within the well casing and monitoring in real time actual tripping speed, actual string rotation speed, and actual surface torque imparted to the tubular string at a particular string depth;
B) for the given tubular string and for a predefined clean well casing based upon the actual well casing using mathematical modeling of the predefined clean well casing and a friction factor, generating a calculated value of surface torque at the particular string depth, the actual tripping speed, and at the actual rotation speed of the tubular string;
C) comparing an actual value of surface torque at the particular string depth to the calculated value of surface torque for the predefined clean well casing and a friction factor over a range of string depths; and
D) when the actual values of the surface torque exceed the calculated values of the surface torque for the predefined clean well casing and a friction factor over the range of string depths by a predetermined amount, then sending an alert to inform a drilling rig operator that circulating the well may be needed.
11. The method according to claim 10 , wherein the predetermined amount is between 1-5%.
12. A system for completion of a non-conventional well, with perforated well casings in place within the wellbore and frac plugs separating segments of the well casing, comprising:
A) sensors mounted upon a drill rig to provide in real time actual tripping speed, actual string rotation speed, and actual surface torque imparted to the tubular string at a particular string depth;
B) for the given tubular string and for a predefined clean well casing based upon characteristics of the actual well casing, a computer configured to use mathematical modeling for the predefined clean well casing and a friction factor for generating a calculated value of surface torque for the predefined clean well casing and a friction factor at the particular string depth, at the actual tripping speed, and at the actual rotation speed of the tubular string;
C) wherein the computer configured to compare actual values of surface torque at the actual string depth to the calculated value of surface torque for the predefined clean well casing and a friction factor over a range of string depths; and
D) wherein the computer is also configured to generate an alert or an alarm that is actuated when the actual values of surface torque exceeds the calculated values of surface torque for the predefined clean well casing and a friction factor over the range of string depths by a predetermined percentage.
13. The system according to claim 12 , wherein the predetermined percentage is between 1-5%.
14. For working a well, a method of optimizing performance of the drilling operation comprising the steps of:
A) inserting a tubular string within the well and monitoring in real time actual tripping speed, actual string rotation speed, and actual surface torque imparted to the tubular string at a particular string depth;
B) for the given tubular string and for a predefined clean well using mathematical modeling of the predefined clean well and a friction factor, generating a calculated value of surface torque with respect to actual tubular depth at the particular string depth, the actual tripping speed, and at the actual rotation speed of the tubular string;
C) comparing an actual value of surface torque and string depth to the calculated value of the surface torque for the predefined clean well casing and a friction factor over a range of string depths; and
D) when the actual values of surface torque exceeds the calculated values of surface torque for the predefined clean well casing and a friction factor over the range of string depths by a predetermined amount, then adjusting the well operation.
15. The method according to claim 14 , wherein the predetermined amount is between 1-5%.
16. The method according to claim 14 , wherein the predetermined amount is 5%.
17. The method according to claim 14 , wherein comprising the further steps of:
E) after the well is circulated, then comparing over the range of string depths the actual values of the surface torque at a string depth to the calculated values of the surface torque for the predefined clean well casing and a friction factor over the range of string depths; and
F) when the actual values of the surface torque continue to exceed the calculated values of the surface torque for a predefined well casing and a friction factor by a predetermined amount, then adjusting the friction factor such that the calculated torque values more closely conform with the calculated values of the surface torque for the predefined clean well casing and a friction factor over the range of string depths.
18. The method according to claim 17 , wherein the predetermined amount is between 1-5%.
19. The method according to claim 14 , wherein the actual value of the surface torque is measured and the calculated value of the surface torque for the predefined clean well casing and a friction factor is calculated continuously during an active drilling operation.
20. The method according to claim 14 , wherein circulating the well is performed manually by an operator.