The well was drilled with sea water and the formation is soft clay formation. Then, the bit was totally plugged. We did not have any chance to displace well with water based mud prior to coming out of the hole. We flow checked and came out of hole to change the bit.
Because the formation is clay which will react with seawater resulting formation swelling, we need to develop specific rig procedure to deal with when tripping in hole.
What are the foreseeing issues?
• Clay formation swell
• Pack off due to formation instability
• Soft formation tends to get side tracked easily with mud motor
What is the objective?
• Attempt to condition the well before running back in hole with motor assembly to minimize chance of side track.