Tripping (pipe)
Encyclopedia
Tripping pipe is the physical act of pulling the drill string
out of the wellbore
and then running it back in. This is done by physically breaking out or disconnecting (when pulling out of the hole) every other 2 or 3 joints of drill pipe
at a time (called a stand
) and racking them vertically in the derrick
. When feasible the driller
will start each successive trip on a different "break" so that after several trips fresh pipe dope
will have been applied (when running back in the hole) to every segment of the drill string.
The most typical reason for tripping pipe is to replace a worn-out drill bit
. Though there are many problems that occur to warrant the tripping of pipe. Downhole tools such as MWD
(measurement while drilling), LWD
(logging while drilling) or mud motor
s break down quite often. Another common reason for tripping is to replace damaged drill pipe. It is important to get the pipe out of the wellbore quickly and safely before it can snap.
. This can result from something being dropped in the hole, i.e. a tool, that would cause damage to the bit if the crew attempted to drill with it on bottom.
of the open hole may take place at various depths while drilling, and almost always at the end of the drilling operation. The drill string will be removed from the wellbore to allow a logging crew to conduct a survey of the well. After the logging is completed at total depth, the crew will run the drill string back into the well and then proceed to lay it down when coming out of the hole prior to installing the final set of casing (the "production casing").
See Drilling rig (petroleum)
for a diagram of a drilling rig.
Drill string
A drill string on a drilling rig is a column, or string, of drill pipe that transmits drilling fluid and torque to the drill bit. The term is loosely applied as the assembled collection of the drill pipe, drill collars, tools and drill bit...
out of the wellbore
Wellbore
A wellbore is any hole drilled for the purpose of exploration or extraction of natural resources such as water, gas or oil where a well may be produced and a resource is extracted for a protracted period of time....
and then running it back in. This is done by physically breaking out or disconnecting (when pulling out of the hole) every other 2 or 3 joints of drill pipe
Drill pipe
Drill pipe, is hollow, thick-walled, steel piping that is used on drilling rigs to facilitate the drilling of a wellbore and comes in a variety of sizes, strengths, and weights but are typically 30 to 33 feet in length...
at a time (called a stand
Stand (drill pipe)
A Stand is two or three joints of drill pipe connected together and stood in the derrick vertically, usually while tripping pipe. A stand of collars is similar, only made up of collars and a collar head. The collar head is screwed into the collar to allow it to be picked up by the elevators.Stands...
) and racking them vertically in the derrick
Derrick
A derrick is a lifting device composed of one tower, or guyed mast such as a pole which is hinged freely at the bottom. It is controlled by lines powered by some means such as man-hauling or motors, so that the pole can move in all four directions. A line runs up it and over its top with a hook on...
. When feasible the driller
Driller (oil)
The driller is a team leader in charge during the process of well drilling. The term is commonly used in the context of an oil well drilling rig....
will start each successive trip on a different "break" so that after several trips fresh pipe dope
Pipe dope
Pipe dope is slang for thread lubricants, thread sealing compounds and anaerobic chemical sealant that is used to make a pipe thread joint leak proof and pressure tight...
will have been applied (when running back in the hole) to every segment of the drill string.
The most typical reason for tripping pipe is to replace a worn-out drill bit
Drill bit
Drill bits are cutting tools used to create cylindrical holes. Bits are held in a tool called a drill, which rotates them and provides torque and axial force to create the hole. Specialized bits are also available for non-cylindrical-shaped holes....
. Though there are many problems that occur to warrant the tripping of pipe. Downhole tools such as MWD
Measurement While Drilling
MWD stands for Measurement While Drilling in the oil & gas industry. The simplest way to describe MWD is to relate it to the measurements a pilot takes. A pilot needs to know the direction they are flying , the angle they are fly at , and what type of skies they will be flying through...
(measurement while drilling), LWD
Logging While Drilling
Logging While Drilling is a technique of conveying well logging tools into the well borehole downhole as part of the bottom hole assembly ....
(logging while drilling) or mud motor
Mud motor
Mud motor refers to a Progressive Cavity Positive Displacement Pump placed in the Drill string to provide additional power to the bit while drilling. The PCPD Pump uses Drilling Fluid to create eccentric motion in the power section of the motor which is transferred as concentric power to the...
s break down quite often. Another common reason for tripping is to replace damaged drill pipe. It is important to get the pipe out of the wellbore quickly and safely before it can snap.
Bit Trip
Drill bits wear and tear like most any other piece of equipment. Once a bit becomes too worn to drill at an adequate rate or make a full-gauge hole, or if the bearings are thought to be near failure, a trip is undertaken to replace the bit. A trip is not considered a bit trip when the purpose of replacing the bit is to change sizes. This is only done when the crew "sets surface, intermediate or longstring" as appropriate.Fishing Trip
A fishing trip is when a crew is forced to trip pipe to retrieve loose items in the wellboreWellbore
A wellbore is any hole drilled for the purpose of exploration or extraction of natural resources such as water, gas or oil where a well may be produced and a resource is extracted for a protracted period of time....
. This can result from something being dropped in the hole, i.e. a tool, that would cause damage to the bit if the crew attempted to drill with it on bottom.
Twisting Off
Another major cause is known as a "twist off". Twisting off is when the drill string parts by failing catastrophically under the torsional stress. This may happen if the drill string below is pinched in the wellbore, or as the result of a structural weakening of the pipe caused by a washout or a crack in a threaded connection member.Broken String/Broken Bit
When pipe snaps or a part of the bit breaks off, the crew has to recover all of the separated items from the wellbore. Recovering snapped pipe usually involves placing a specialized tool (an "overshot") with grips set inside of it over the broken pipe in an attempt to capture it. The grip works in a manner similar to Chinese fingercuffs. Sometimes the jagged top of the fish must be milled back to a round outside shape before the overshot can slip over it. The overshot contains a packoff device to make a pressure seal so circulation can be reestablished through the bit to facilitate recovery of the fish. For a broken bit, a magnet is commonly used to remove all of the broken parts.Cracked Pipe/Collar
A cracked pipe can lead to a broken string. Extra care is taken when tripping for one so that too much pull doesn't cause the cracked pipe to snap. Cracked pipes (i.e., washouts) are usually noticed by a sudden drop in pressure. The crew will usually pump "fastline" (small lengths of manila rope taken from unraveled catline) down the drill string to make a temporary plug and time the pressure to see when it rises back to normal. This enables the crew to know how far down to expect the cracked pipe to be within a few stands; also strands of these rope segments may be seen at the point of washout. Most trips for a cracked pipe are not complete trips like a fishing trip or a bit trip. These can be as simple as only going a few stands down, to pulling the drill collars.Logging
LoggingWell logging
Well logging, also known as borehole logging is the practice of making a detailed record of the geologic formations penetrated by a borehole. The log may be based either on visual inspection of samples brought to the surface or on physical measurements made by instruments lowered into the hole...
of the open hole may take place at various depths while drilling, and almost always at the end of the drilling operation. The drill string will be removed from the wellbore to allow a logging crew to conduct a survey of the well. After the logging is completed at total depth, the crew will run the drill string back into the well and then proceed to lay it down when coming out of the hole prior to installing the final set of casing (the "production casing").
Setting Surface, Intermediate and Longstring
These trips are routinely expected by the crew. Setting surface occurs after the wellbore is drilled to the predetermined surface depth (e.g., after drilling below fresh water strata). The crew will remove the entire drill string to allow surface casing to be emplaced. The procedure is similar for setting intermediate, only that it typically involves a much longer drill string to be removed. Setting longstring is usually a one time operation combining both surface and intermediate casing. This saves the time of only having to undertake one pipe trip as opposed to two pipe trips.See Drilling rig (petroleum)
Drilling rig (petroleum)
This article lists the main components of a petroleum onshore drilling rig.Offshore drilling rigs have similar elements, but are configured with a number of different drilling systems to suit drilling in the marine environment....
for a diagram of a drilling rig.