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UDW 26in top hole effect of flowrate?
27 July 2018
Playing around with the numbers, working a section and conducting a 5min set of generic  worksheet calcs, at simulated extremes conditions to establish where drilling limits may potential reside as per data input i.e.
2000m water depth
700m 26" section
In gauge well (which is likely unrealistic)
100% claystone (drilling at its easiest and max)
100% sandstone (drilling dead slow to avoid an induced well fracture)
@ variant ROP's
At different flow rates?
Using simple hole cleaning chart for this example.
- Sand very poor hole cleaning. (cannon ball particle size*)
- Clay extremely high cleaning. (micron sized particles*)
*Ref. Wentworth scales.

Singular drilling improvement concluded is >flowrate?

Step change to be asked being
1. Where is the next generation of high flow MWD/LWD tools arriving?
i.e. 1600-2000gpm capability would be nice!
Cuz this is the evident constraint as per calcs attached.

2. What size degree of washout are engineers using for standard wellbore sizes?
17 1/2"
14 3/4" 
What premise and evidence drives this?

Comments, other best practices experience to share in above aspects? 


Documents uploaded by user:
UDW 26in riserless drilling example.xps
0 answer(s)
Posted by

Peter Aird

Drilling Specialist/Well Engineer/Training Consultant

Kingdom Drilling

Total Posts: 362
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