Freeing differentially stuck drill pipe can be extremely challenging and often leads to non-productive down time unless you have a proven MPD solution. Pruitt engineers design, plan, and execute constant bottomhole pressure managed pressure drilling (CBHP MPD) solutions to lower differential pressure and work pipe to free it.
What is differentially stuck drill pipe?
Differentially stuck drill pipe is a condition in which the drillstring becomes lodged and cannot be moved or rotated on the axis of the wellbore.
Pruitt engineers have been instrumental in numerous troubleshooting instances where drillpipe was stuck differentially and the pore pressure gradient was very close to the mud density used. Our engineers, using CBHP MPD solutions, successfully released pipe by reducing the wellbore pressure below the pore-pressure to reduce the differential pressure and pulling on the pipe. The influx volume was limited to less than the maximum allowable limit and was circulated out with MPD.
Following is a brief case study describing the process in which an operator in the Canada Pruitt MPD Services unit used to unstick differentially stuck pipe. The CBHP MPD solution optimized the static and dynamic surface backpressures.
- When drilling with 1.32 SG mud, operators encountered an influx. An initially calculated 1.40 SG mud became insufficient and the mud weight was increased to 1.67 SG. The pore pressure was increased causing losses and the pipe becoming differentially stuck.
- Using CBHP MPD and applying 5500 kPa surface backpressure, 363 of .90 SG base oil was placed in the annulus which diluted to 1.37 SG equivalent BHP. Base oil was displaced by 1.67 SG mud.
- The MPD Matrix was generated and a maximum allowable pit gain was agreed to be set at 5 m3.
- When the rig was ready to work pipe, backpressure was released and the pipe was pulled four times, then torqued and pulled twice again to get it free. A total of 2.2 m3 was introduced into the annulus in 18 minutes of operation.
- The 5500 kPa backpressure was re-applied while the influx was circulated out using MPD equipment.
MDP provided enough flexibility for the operator to safely reduce the wellbore pressure below pore-pressure and decrease the differential pressure to free the pipe.
Pruitt’s MPD package with Coriolis meter and dual chokes was used to manage the annular pressure profile. The MPD system could detect fluid gains and losses within a few liters enabling fast response. The choke response was very quick enabling quick control.
CBHP MPD can also help drill through narrow pressure windows, provide early kick detection, improve ROP, minimize surge and swab issues, help with pore-pressure and leak-o prediction, ‘drilling with casing’ and cementing.
If you are experiencing problems with differentially stuck drill pipe or would like to learn more about Pruitt’s MDP solutions, contact us at our corporate headquarters in Fort Smith, Arkansas at (479) 646-1641 or at one of our locations around the world listed here. Save time and money with Pruitt’s affordable MPD solutions
