The operator also used a heavier FlexSTONE HT system to cement the HPHT production liner. This gave the needed control in the production zone and provided a tight-sealing flexible cement at temperatures up to 193 degC [380 degF].
Both FlexSTONE HT cemented strings were pressure-tested to 69 MPa [10,000 psi] and were subject to a drawdown test in excess of 41 MPa [6,000 psi] with no indications of a failed cement sheath.
Cost-effective long-term zonal isolation for HPHT wells
The success of the HPHT cementation approach can be measured by the absence of any pres-sured B-annuli in 2 years of operation. Compared to other North Sea HPHT developments, this field provided the first experience of simultaneous drilling and production with proven depletion levels up to 11 MPa [1,600 psi], and no well integrity issues disrupting production. This design, which also remained under budget, was the basis upon which best-in-class drilling performance was achieved.
