Published on 26 avril 2018
Successful off-bottom cementing campaign, onshore
100% success rate recorded on 140 wells completed and fractured
The client has numerous oil fields under development in Western Siberia. Featuring low depletion reserves, these fields have a strategic importance, since they are a significant part of client’s overall oil production. The client found an effective way to reduce the drilling time by switching from standard design ( 123/4in surface pipe with a 95/8in conductor casing, followed with 7in production string, and 4.5in liner with MSF equipment), to new well design (two-string horizontal well: 123/4in surface pipe with a 95/8in conductor casing, connected to a 7in-5.5in combined production string, for wall lining, installation of MSF equipment and further operations).
As a result, this change excludes an entire stage in the drilling cycle. The client was then looking for a reliable and solid External Casing Packer (ECP) to perform off-bottom cementing. In addition the packer must be more robust than conventional inflatable packer to sustain tough running conditions and pass thru obstructions, usual situation due to geology in the Priobskoye Oil Field (called the Pearl of West Siberia), one of the largest fields in Russia by oil reserves.
The client selected Saltel Steel ECP-C 7in (Crimped design) for its extraordinary solidity during RIH, and disruptive slack-off weight capacity.
Combined with a cementing port, the ECP-C is run as part of the production string just above the crossover between 7in and 5.5in strings. The Packer is expanded with 2,700psi to seal against 8.66in Open Hole. After expansion, the ECP expansion port permanently closes. Then the cementing port can be hydraulically opened ; Cement is pumped through and supported by the ECP-C. After closure of the cement port, the casing integrity is restored. allowing high internal pressure to be applied (HP stimulation).