FISHING ECONOMICS
The option of abandoning fishing operations and sidetracking the well should be taken oneconomic grounds unless there are exceptional logistical, legislative or safety grounds.
Before giving up on a fishing job the cost of sidetracking operations together with re-drilling
to the original depth needs to be calculated. This cost when converted to equivalent rig day
rate days can be used to assess the amount of time that it is economic to pursue fishing
operations. The procedure is as follows:
a. Calculate the total cost of the fish to be left in hole.
b. Calculate the cost of backing-off and setting of a cement plug prior to sidetracking. This
should include all rental and consumable items, including personnel.
c. Calculate the cost of the sidetrack including directional equipment and casing milling
equipment (if applicable).
d. Calculate the cost of drilling to the original depth. This should be based on the time to drill
the original section plus an additional 10% to account for the directional aspects.
Total cost is therefore = a + b + c + d.
This should be converted to rig days by dividing the total cost by the rig day rate.
Abandonment of fishing operations should be considered when the fishing time has reached
½ the above number of days, and the probability of completing the fishing operation is
gradually becoming small.