Operations Manual
Drilling/Steering trouble shooting cont.… Drilling Issue Corrective Actions Sudden reduction in ROP
1. Verify if bit balling is occurring, did WOB suddenly increase? Was there a reduction in differential pressure? 2. Pick up off bottom and increase flow and RPM, ensure to not exceed the RST limits for both 3. Continue drilling and monitor situation Verify if the gradual decrease in ROP corresponds with a gradual decrease in differential pressure 1. If confirmed this is a sign that the bit is worn. 2. If the decrease in differential pressure is erratic, this is a sign of motor failure The following should be considered if RST steering is inconsistent and/or unpredictable 1. Are stick-slip conditions present? If so follow mitigation practices 2. Are optimum drilling parameters being used? Can flow be increased as per RST hydraulic calculation? 3. Has there been any changes which may cause issues with downlinking process, are guidelines regarding coming to bottom before a downlink being followed? If a gradual or sudden change in azimuth occurs while trying to hold inclination. 1. Downlink to INC Hold R/L to steer in appropriate direction to counteract change, this may be enough to combat formation tendency 2. If change in azimuth persists or required turn is not produced, downlink to INC Hold RR/LL 3. If the required change in azimuth is not produced, downlink to an appropriate gravity steering toolface with a high steering percentage of at least 80%, be cautious and monitor as change in azimuth may be more than required. If a gradual or sudden undesired change in inclination occurs when below 20º follow best practices for steering at low angles, If Inclination is above 20º. 1. If using MWD continuous inclination, verify if change occurred at point where last downlink was taken as an incorrect steering mode may have been decoded by the RST, if so come off bottom and repeat downlink to correct steering mode and monitor for change 2. If not using continuous inclination, downlink to desired INC Hold mode and monitor for change using checkshot surveys. 3. If expected change in inclination is not seen, downlink to an appropriate gravity steering toolface with a high steering percentage of at least 80%, be cautious and monitor as change in inclination may be more than required.
Gradual reduction in ROP
The RST steering results are inconsistent, and/ or unpredictable Unexpected change in azimuth / formation tendency.
Unexpected change in Inclination / formation tendency.
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