Methods and systems for drilling

Abstract

Systems and methods of controlling drilling operations including Sliding With Indexing For Toolface (SWIFT) and Variable Weight Drilling (VWD) techniques. The methods and systems may include systems and devices for controlling the drilling operations, including systems and devices capable of automatically determining drilling parameters and setting operating parameters for drilling in a wellbore. The systems and methods may also determine a change in weight on bit, toolface, and/or differential pressure, determine a timeframe for a weight on bit to be delivered to the bit, and/or determine a spindle change to modify the toolface, and/or determine a change in differential pressure to be applied to modify toolface. The systems and methods may also send control signals to apply the spindle change and/or block velocity change and/or differential pressure change to correct any detected or anticipated toolface error.

What is claimed is: 
     
         1 . A method for drilling a wellbore, the method comprising:
 determining a desired wellbore curvature to be drilled;   determining a potential build rate for a bottom hole assembly (BHA) to drill the desired wellbore curvature;   estimating a reactive torque (RT) for a desired weight on bit (WOB) for drilling the curvature;   setting the off bottom toolface of the BHA to a target toolface for drilling the curvature and responsive to the estimated reactive torque;   slide drilling the wellbore for a first time period;   rotary drilling the wellbore for a second time period or a first number of wraps;   slide drilling the wellbore for a third time period; and   rotary drilling the wellbore for a fourth time period or a second number of wraps.   
     
     
         2 . The method of  claim 1 , wherein the first time period and the second time period are different. 
     
     
         3 . The method of  claim 2 , wherein the first time period and the third time period are different. 
     
     
         4 . The method of  claim 3 , wherein the second time period and the fourth time period are the same, or the first number of wraps and the second number of wraps are the same. 
     
     
         5 . The method of  claim 4 , wherein the second slide drilling operation cancels out the first slide drilling operation. 
     
     
         6 . The method of  claim 1 , further comprising:
 determining at least one of the following:
 (i) a time period for drilling parameter changes to propagate to the BHA, 
 (ii) a hardness of the formation being drilled, or 
 (iii) a time delay for receiving toolface information from the wellbore. 
   
     
     
         7 . The method of  claim 6 , further comprising:
 determining an estimated effect on toolface from at least one of:
 (i) a time period for drilling parameter changes to propagate to the BHA, 
 (ii) a hardness of the formation being drilled, or 
 (iii) a time delay for receiving toolface information from the wellbore; and 
   adjusting a spindle position responsive to the determined estimated effect.   
     
     
         8 . The method of  claim 7 , further comprising:
 adjusting one or more of the first time period, the second time period, the third time period, and the fourth time period to correct for a curvature of the wellbore.   
     
     
         9 . A system for drilling a wellbore, the system comprising:
 a processor;   a memory coupled to the processor, the memory comprising instructions executable by the processor for:   determining a desired wellbore curvature to be drilled;   determining a potential build rate for a bottom hole assembly (BHA) to drill the desired wellbore curvature;   estimating a reactive torque (RT) for a desired weight on bit (WOB) for drilling the curvature;   setting the off bottom toolface of the BHA to a target toolface for drilling the curvature and responsive to the estimated reactive torque;   controlling a first slide drilling operation for a first time period;   controlling a first rotary drilling operation for a second time period or a first number of wraps;   controlling a second slide drilling operation for the wellbore for a third time period; and   controlling a second rotary drilling operation for the wellbore for a fourth time period or a second number of wraps.   
     
     
         10 . The system of  claim 9 , wherein the first time period and the second time period are different. 
     
     
         11 . The system of  claim 9 , wherein the first time period and the third time period are different 
     
     
         12 . The system of  claim 9 , wherein the second time period and the fourth time period are the same, or the first number of wraps and the second number of wraps are the same. 
     
     
         13 . The system of  claim 9 , wherein the second slide drilling operation cancels out the first slide drilling operation. 
     
     
         14 . The system of  claim 9 , wherein the instructions further comprise instructions for:
 determining at least one of the following:
 (i) a time period for drilling parameter changes to propagate to the BHA, 
 (ii) a hardness of the formation being drilled, or 
 (iii) a time delay for receiving toolface information from the wellbore. 
   
     
     
         15 . The system of  claim 14 , wherein the instructions further comprise instructions for:
 determining an estimated effect on toolface from at least one of:
 (i) a time period for drilling parameter changes to propagate to the BHA, 
 (ii) a hardness of the formation being drilled, or 
 (iii) a time delay for receiving toolface information from the wellbore; and 
   adjusting a spindle position responsive to the determined estimated effect.   
     
     
         16 . The system of  claim 9 , wherein the instructions further comprise instructions for:
 adjusting one or more of the first time period, the second time period, the third time period, and the fourth time period to correct for a curvature of the wellbore.