Salt: ESCO – Frisia well BAS-3 workover

Salt producing well BAS-3 workover and cementing operation

Start execution: October 2013
End execution: December 2013

Result: Successful technical complicated workover and cementing operation carried out

Depth (AH): 4444m
Depth (TVD): 2876m

Project Summary

Client: ESCO - Frisia Zout B.V.
Location: Sexbierum
Wells: BAS-3
Start Execution: October 2013
End Execution: December 2013
Target: Milling out a cemented drill pipe sticking up at high depth.
Result: Successful technical complicated workover and cementing operation carried out
Depths (AH): 4444m
Depths (TVD): 2876m
Role of WEP: Well Engineering Partners provided project planning, tendering engineering, coordination, management and supervision for the project while other companies provided materials and services.
Challenges: Many challenges, e.g. high depth and well under pressure

Project Description

With a successful technical complicated workover and cementing operation carried out on well BAS-3 for Frisia Zout BV, part of ESCO, the planned sidetrack for this well can be performed. Only with an integer seal of the old wellbore, this sidetrack is possible.

As part of abandonment operations and as preparation for the sidetrack a remaining string of cemented drill pipe had to be removed. Removal of this pipe was necessary to be able to secure the well with an additional column of cement on top of the balanced cement plug present. The balanced plug on itself is not an integer seal.

An HWU was selected to be able to gain access to the drill pipe with coiled tubing, work under well pressure and to be able to provide pulling/pushing force. A coiled tubing unit had to be rigged up on top of the HWU for milling. A crane supported the weight of the coiled tubing equipment.

To be able to get an integer and sealing cementation in another way, “gravitational” cementation was carried out around the “fish”; between the casing wall and the “sticking out” cemented drill pipe.

This workover can be considered high flying because:

  • Milling out a cemented drill pipe sticking out at 3350 m AH depth with coiled tubing at very small clearances, very poor hole cleaning, in a deviated section, and under pressure.
  • Gravitational cementing of the annular space between a cemented drill pipe fish (5”) and casing (11 ¾”) in this deviated part of the well.
  • Latching with workstring to fish without any problems/ releasing from fish without any problems.
  • Rig up of coil on top of a “snubbing” unit.