Book / Drilling costs general5 Sep 2010 11:35
Finished reading as far as the AFE Well cost estimate.
Companies can budget to within circa 25% (minimum + 25%) in the early planning stages and to within 15% when many of the actual costs are agreed with suppliers etc. So an outsider probably can't expect to estimate better than to within minimum + 40% range?
The books example was based on an off shore well drilled in 1997 (probably western hemisphere) in 60 days to a depth of 2765m below sea bed, budgeted to cost (assuming success) $7.6 million to $8.7 million.
Successive casings from 30 in down to 7 in were used and internal hole diameter was constant except for the very last section. This suggests casing costs at the top are significantly higher than at the bottom due to the sheer amounts of steel required in the casings.
By category: "time dependant costs" were 50%, "depth dependant costs" were 20%, "fixed costs" were 20% and "support costs" were 10% of budget, for the off shore well.
By removing rig hire, casing above sea bed and other off shore looking costs, I reckon the cost profile for a land based well is approximately as follows...
DEPTH DEPENDANT COSTS 50% (2/3 Steel, 1/6 drilling mud, 1/6 cement and drill bits)
FIXED COSTS 30% (2/3 well testing, 1/3 logging)
SUPPORT COSTS 10% (share of general admin)
TIME DEPENDANT COSTS 10% (rig running costs excluding rig hire costs)