Ann: Mukuyu-2 Drilling Update, page-61

Everything is going to plan and next is the exiting period. I think the progress has been slower than expected (40 ft per day), which will mean from now on, they will need to maintain an average of 70ft per day to reach 4000m in less than 60 days. That is almost double the current rate. It was also suggested a few days ago that they might need to drill to about 4400m to reach the bottom of the Lower Angwa based on the seismic data.

No mention of a 6" hole section on the well schematic to drill the Lower Angwa, and why is the 9.5/8" casing shoe in the Forest? The Forest is split into Jurassic on top of Triassic. but I'm not sure how much shale is between them.

What concerns me is the prospect of them drilling ahead in 8.5" hole as far as they can go. What if they enter the Lower Angwa (may have a different pressure gradient and have higher overpressure compared to the Upper Angwa), and have to deal with a kick? They would then need to increase the mud weight in order to control the kick, but that could potentially create formation damage in the Upper Angwa. Alternatively, they might drill with higher mud weight than required from the top of the Upper Angwa in order to ensure problem free drilling in the Lower Angwa, but that would also risk causing formation damage. Is it not better to make a definite change in the shale below the Upper Angwa, case off and cement the Upper Angwa before drilling 6" to TD?