Manual Drifting

How to manually drift safely in the derrick - if you don't have a Drift Catcher™

Manual drifting involves repeatedly lifting the drift up to the derrickman if it drops or becomes dislodged it will hit the rig floor at over 50 miles per hour (80 kph) which could be fatal.

Manual drifting can be made safe but it takes good team discipline (see right) to ensure that the rig floor is clear of any personnel when the drift is being moved at height. Drifting on POOH or RIH pose differing costs and risks.

Manual drifting: POOH versus RIH with liner
Drifting out of hole is slower (see ** to right) than into it however, it allows more time to focus on safety as speed of exit from hole is rarely critical to success. When running liner into open hole, extending static times is highly undesirable. Drifting into hole lengthens significantly the time at rest and therefore increases risks of getting stuck and losing production.

Drifting out of hole is more time consuming because it contains two separate risk time zones. Firstly, whilst the drift is being lifted with the pulled stand the crew must leave the floor. Once the drift is secure on the derrick monkey-boards they can return to the floor to break the connection before leaving again for a second time whilst the drift is retrieved and then dropped. If back reaming out of hole there could be additional complications, however the open hole stands will not normally be used for RIH with liner and drifting can often be skipped during reaming. Once in cased hole technical risks are minimal allowing crew to focus on safe procedures.

Drifting into hole appears the smart move by comparison, but it does involve drifting in open-hole approaching TD. In open hole technical risk is much higher and crew will be under pressure to minimise static*** time to prevent sticking. Any delays increase the chance of the liner getting stuck and lost production.

T	Drifting Sequence Pooh	Drifting Sequence RIH	T
25	Lower elevator	Run in stand	45
25	Latch onto next stand	Disconnect from stand in hole	25
10	PU drift	PU drift	10
10	Loop securely to elevator arm	Loop securely to elevator arm	10
15	Clear deck	Clear deck	15
10	Confirm deck clear	Confirm deck clear	10
25	Lift stand with drift on elevator	Lift drift on elevator	25
10	Derrickman removes drift	Derrickman selects next stand	10
10	Store drift securely and confirm	and removes drift from elevator	10
15	Return to deck	Drop drift and confirm	10
20	Unscrew connection	Return to deck	15
10	Lift away connection	Lift pipe and PU drift	10
10	Lower pipe to floor	Screw in connection	20
10	Clear deck and confirm
10	Derrickman retrieves drift	Key
10	Drop drift and confirm	Liner at risk static in hole***
15	Return to deck	Additional drifting time
10	Lift pipe and PU drift
10	Rack back pipe

145	Additional drifting seconds per stand	100
260	Total seconds per stand	215
43.3	Minutes per 1000 ft	35.8
13.8	Stands per hour	16.7