Tripping refers to the process of removing and/or replacing pipe from the well when it is necessary to change the bit or other piece of the drill string, or when preparing to run certain tests in the well bore.
A driller “trips” the drill string by removing the entire string from the borehole and then goes back to bottom with it. This may be for a “bit trip” to replace a worn or broken bit, to adjust the number and type of joints in the bottom hole assembly or to just inspect the string for damage or leaks.
Tripping is typically counted as non-productive time and is therefore to be minimized as much as possible. The more time spent turning to the right (actually drilling and making progress) the better the crew, driller and pusher look to the higher-ups.
Tripping Operations - Best Practices
1. Preparation The Drilling Supervisor shall approve and provide written instructions to the Contractor Toolpusher prior to any trip out of the hole. These instructions shall include the:
sequence of operations i.e. flow check, circulate bottoms up, drop survey, etc.
maximum allowed overpull
procedures if tight hole is encountered
maximum running/pulling speeds
preparation of equipment for the following operation when out of the hole
Pipe Tally The drilling contractor shall ensure that a master drill pipe tally book is maintained at all times. This shall include stand number, single number, single identification, drill pipe grade, single length, stand length and total length. Trip Tank Prior to pulling out of the hole, the trip tank shall be filled. The fill-up pump to the trip tank should never be left running while tripping out.
For any trip out of the hole, a minimum of one bottoms up circulation, or appropriate circulation for deviated wells, shall be performed.
When circulating to condition mud, a circulating rate of 50 - 75% of the normal circulating rate shall be used.
A trip sheet shall be filled out by the Driller and Mud logging contractor for each trip out of the hole.
2 - General Guidelines
The Drilling Supervisor shall be on the rig floor for the first 10 stands during tripping out to observe for correct hole fill, overpull, etc. He shall also be on the rig floor for the last five stands when tripping in, tight hole problems, testing mud motors & MWD, RIH across liner hanger and when casing 3 stands off bottom.
Care shall be exercised to minimise surge/swab pressures by controlling the speed of pipe movements.
Pull the pipe carefully and check for swabbing. In the event of the hole swabbing, the pipe shall be run back to bottom and the hole circulated bottoms up. Mudloggers shall run the swab programme prior to each round trip to determine the maximum trip speed.
Notes: A hole is swabbing whenever the volume of fluid required to fill the hole is less than the volume of steel pulled out of the hole. THE HOLE CAN BE SWABBING WITHOUT FLOW AT THE FLOWLINE.
Circulation, Hole Fill, and Pipe Fill
During tripping operations, the hole shall be kept full at all times.
The pipe shall be filled every 10 stands while running in the hole and the displacement checked.
When pulling the pipe, the hole shall be kept full from the trip tank. The hole shall be checked regularly to ensure that it is taking the correct amount of fluid.
The volume required to fill the hole every 3-5 stands shall be recorded in the Trip Sheet until the bit is out of the hole.
Tight Hole / Bridging Conditions
If tight hole or bridging conditions occur during trips, the pipe shall be pulled back to the nearest stand and reaming/washing commenced in accordance with stuck pipe procedure.
If tight spots occur while tripping out, the top drive or kelly shall be engaged to commence reaming and circulating out.
Reaming trips might be required prior to running LWD/density tools and/or 7in liner.
While tripping out of the hole from below the surface casing in directional wells:
reciprocate at all times and rotate the pipe at intervals while circulating and conditioning the mud prior to POOH
record the pick-up, slack-off and rotating weight indicator readings with the mud pump off. Note: These values shall be used to monitor changes in drag during pulling out.
the top drive, if available, shall be used to pump out and/or ream out the first 5 to 10 stands off bottom.
While tripping flow checks shall be taken:
just off bottom
at the cement casing shoe
prior to pulling drill collars through BOP stack
after BHA out of horizontal section
while RIH after drilling out shoe
while RIH before BHA enters horizontal section.
3 - Requirements When Out Of Hole
Time Out of the Hole
The time spent with the pipe out of the hole shall be minimised wherever possible. Operations such as routine repairs and slipping and cutting of the drill-line shall be performed with pipe at the casing shoe whenever possible.
Requirements When Out of Hole
The trip tank volume indicator shall be set at 1/2 barrel gain or loss whenever the trip tank is being circulated on the hole.
Whenever the blind rams are closed, the Driller and the Assistant Driller shall open the rams and check the fluid level at least every half hour, fill the hole as required and report any losses to the Drilling Supervisor. (Before opening blind ram open choke)
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