This article describes the planning issues to be addressed to ensure successful well control.
Kick Control Work-Sheet
A kick control worksheet shall be used to pre-record the data required for secondary control and shall be kept updated while maintaining primary control. The frequency of updating shall be determined by rate of change of parameters involved in the first part of the worksheet.
The sheet shall be revised every tour, 500 ft drilled, mud weight change or drill string change whichever occurs first.
Note: Kick control sheets generated by a PC are acceptable provided that they provide a fully functional hard copy that is printed out on a regular basis.
Slow Pumping Rate Pressures
Well control operations are performed at reduced pump speeds (30, 40, 50 spm) in order to:
- allow weighting up and degassing of the mud,
- operate within the limits of surface equipment,
- allow for the inclusion of the closed-in drillpipe pressure in the initial pumping pressure.
Circulating pressure (recorded at the standpipe) at reduced pump speeds shall be known in order to pre-plan secondary control.
Slow circulating rates shall be measured prior to pulling out of hole and when back on bottom with a new bit, once normal circulation has been established.
Slow circulating pressure measurements shall be repeated as a minimum following:
- mud gradient changes
- 500 ft of formation drilled
- every tour
- change in drill string
Slow circulating pressures should be reported on the IADC report and Company DDR.
Drilling Fluid Management
When drilling critical hole sections the following drilling fluid management practices should be observed:
- Minimise the active fluid surface area to ensure ease of kick detection. All valves to/from the active system shall be checked for integrity.
- An adequate stock of reserve mud should be held.
- Ensure all pit monitoring systems are fully functioning and calibrated prior to entering possible hydrocarbon bearing zones.
- Keep all mud treatments and transfers to the minimum possible. The Driller and Mud Logging Engineer shall be advised prior to commencement of any transfer of the amount to be transferred and the approximate rate of transfer.
Float Valves
Float valves/subs shall be installed in the bit sub and when using mud motors.
Depth Control
The Drilling Contractor shall ensure a Master Drillpipe Tally Book is maintained at all times. This shall include stand number, single number, single identification number, drillpipe grade, single length, stand length, total length.