To prevent diferential sticking, Strict attention should be paid to drilling practices at all times whilst in open hole.
- Hold toolbox meetings with all crews including mud engineer and mud logging engineer to discuss differential sticking and the action to be taken to avoid it. Holld meetings before starting the interval and a refresher whilst in the reservoir.
- The drillstring has EPDP pipe to help stabilise the string and minimize wall contact.
- Minimize time in the slips and keep pipe moving at all other times when not in the slips. Reciprocation is preferable to rotation in this respect.
- Drillers to utilize a hand over sheet detailing all overpulls experienced, on/off bottom torques, mud properties, etc.
- The bridging materials in the mud and programmed filtration properties will assist in reducing the risk.
- Maintain mud weight at a safe minimum
- Keep solids content and fluid loss to an economic minimum
- Stuck pipe analysis has shown that most incidents occur within two hours either side of shift change. Drilling Supervisor and Parker Toolpusher will ensure that either of them is on the rig floor at least 1 hour before and 1 hour after the driller’s have crew changed.
- Should a stuck pipe incident occur due to differential sticking it is important to act fast and pump a pill to try and free the pipe. Consult Mud Engineer for the stuck pipe chemicals available for use. These should be at the rigsite ready for use.
- Minimise the time which the drill string is not being reciprocated or rotated
The drilling fluids programme contains further information and details of spotting fluids which may be used in the event that differential sticking is observed.
Lost Circulation
Lost Circulation is a risk in the production zone. Should losses occur, reduce ROP, minimize flowrate (considering hole cleaning at the new ROP). Under no circumstances add any LCM without pre-discussion with town. .
Sour Gas (H2S, CO2)
Maintain lime excess in the appropriate range: average >9 kg/m³