System and method for well drilling control based on borehole cleaning
Systems and methods for determining the cleaning effectiveness of a well borehole during drilling. A control system may monitor various parameters, including the volume of drilling mud and any materials entering a borehole, including by a flow rate, and the volume of fluids and materials (such as drilling mud and rock) exiting a borehole, including by a flow rate, and determining if there is a difference, the value of any such difference, whether the value is within one or more target ranges, falls below a threshold therefor, or exceeds a threshold therefor. If the control system determines that the value of the difference in volumes indicates that corrective action is appropriate, then taking such corrective action by modifying one or more drilling parameters.
1. A control system for controlling drilling of a borehole by a drilling rig system, the system comprising:
a processor coupled to the drilling rig system; and
a memory coupled to the processor, wherein the memory comprises instructions executable by the processor for performing the following:
a) obtaining, by the control system, data associated with fluid entering the borehole being drilled, fluid exiting the borehole, and a first value, the first value corresponding to a volume of solids exiting the borehole;
b) obtaining, by the control system, data associated with rate of penetration (ROP) of the borehole and a second value, the second value corresponding to a volume of rock drilled;
c) determining, by the control system, whether a difference between the first value and the second value exists and, if so, a value for the difference;
d) determining, by the control system, whether the value of the difference is within a target range therefor;
e) if the value of the difference between the volume of the solids exiting the borehole and the volume of rock drilled falls below the target range, then determining, by the control system, whether one or more first adjustments to one or more drilling parameters are indicated and, if so, sending one or more control signals to one or more components of the drilling rig system to make the one or more first adjustments to thereby increase the volume of the solids exiting the borehole relative to the volume of rock drilled; and
f) if the value of the difference between the volume of the solids exiting the borehole and the volume of rock drilled exceeds the target range, then determining, by the control system, whether one or more second adjustments to one or more drilling parameters are indicated to increase the ROP and, if so, sending one or more control signals to the one or more components of the drilling rig system to make one or more second adjustments to thereby increase ROP.
2. The control system according to claim 1 further comprising instructions for repeating (a)-(f) a plurality of times during drilling of the borehole.
3. The control system according to claim 1 further comprising instructions for providing an alert signal if the value of the difference falls below a threshold value therefor.
4. The control system according to claim 1 further comprising instructions wherein the one or more first adjustments and the one or more second adjustments comprise instructions for adjusting at least one of ROP, WOB, mud flow rate, torque applied to a drill string, differential pressure, and adding one or more additives to drilling mud.
5. The control system according to claim 4 wherein the instructions further comprise instructions for causing at least one drilling parameter to be modified comprises stopping drilling operations or lifting a drill bit.
6. The control system according to claim 1 wherein the instructions further comprise instructions for determining whether the value of the difference falls within one of a plurality of target ranges.
7. The control system according to claim 1 , wherein the instructions for determining whether a difference between the first value and the second value exists, and, if so, a value for the difference, further comprise instructions for determining a first flow rate or volume of the fluid entering the borehole during a specified time period, determining a second flow rate or volume of a combination of the fluid and the solids exiting the borehole during a time period that corresponds to the specified time period, determining the volume of rock drilled during the time period that corresponds to the specified time period, and comparing the difference between the volume of the solids exiting the borehole during the time period that corresponds to the specified time period and the volume of rock drilled during the time period that corresponds to the specified time period.
8. The control system according to claim 7 wherein the instructions further comprise instructions for determining a first time required for the fluid entering the borehole to reach a drill bit and a second time required for fluid and cuttings to travel from the drill bit to a surface location, and, responsive to the first time and the second time, determining the first flow rate or volume and the second flow rate or volume, wherein the first flow rate or volume and the second flow rate or volume correspond to the specified time period.
9. The control system according to claim 1 wherein the instructions for determining whether one or more first adjustments to one or more drilling parameters are indicated further comprise instructions for receiving data associated with a well plan for the borehole and, responsive to the data associated with the well plan, determining whether to continue drilling for a selected time or depth.
10. The control system according to claim 9 wherein the instructions for determining whether to continue drilling for the selected time or depth further comprise instructions for determining, responsive to an expected drilling operation or mode if no adjustment of drilling parameters is indicated.
11. The control system according to claim 10 wherein the expected drilling operation or mode comprises a slide drilling operation.
12. The control system according to claim 1 , wherein the first and second values correspond to volumes per unit of time.
13. The control system according to claim 12 , wherein the unit of time for the first and second values is the same, and wherein the first and second values are obtained at different times from one another, wherein the different times are associated with length of the borehole.
14. A method for controlling drilling of a well, the method comprising:
a) obtaining, by a control system, data associated with fluid entering a borehole being drilled, fluid exiting the borehole, and a first value, the first value corresponding to a volume of solids exiting the borehole;
b) obtaining, by the control system, data associated with rate of penetration (ROP) of the borehole and a second value, the second value corresponding to a volume of rock drilled;
c) determining, by the control system, whether a difference between the first value and the second value exists and, if so, a value for the difference;
d) determining, by the control system, whether the value of the difference is within a target range therefor;
e) if the value of the difference between the volume of the solids exiting the borehole and the volume of rock drilled falls below the target range, then determining, by the control system, one or more first adjustments to one or more drilling parameters, and sending one or more control signals to one or more components of a drilling rig system to make the one or more first adjustments to increase the volume of the solids exiting the borehole relative to the volume of rock drilled; and
f) if the value of the difference between the volume of the solids exiting the borehole and the volume of rock drilled exceeds the target range, then determining, by the control system, one or more second adjustments to one or more drilling parameters to increase the ROP, and sending one or more control signals to the one or more components of the drilling rig system to make one or more second adjustments to increase ROP.
15. The method according to claim 14 further comprising the step of repeating steps (a)-(f) a plurality of time while drilling the borehole.
16. The method according to claim 14 further comprising the step of providing to the control system the target range.
17. The method according to claim 14 , wherein the one or more control signals are sent to one or more drilling rig control systems, an autodriller system, one or more drilling rig component systems, or a combination thereof.
18. The method according to claim 14 further comprising a plurality of target ranges, each target range associated with one or more formations or borehole segments, and further comprising the step of determining, by the control system, the one or more formations or borehole segments in which a bottom hole assembly (BHA) is located.
19. The method according to claim 14 wherein a plurality of target ranges, each associated with one or more formations or borehole segments, are provided to the control system.
20. The method according to claim 14 further comprising comparing, by the control system, total volume of the fluid and the solids exiting the borehole and total volume of the fluid entering the borehole and rock drilled and, if the total volume of the fluid and the solids exiting the borehole is less than the total volume of the fluid entering the borehole and the rock drilled by a predetermined amount, sending, by the control system, one or more control signals to the one or more components of the drilling rig system to decrease the ROP.