This gas and condensate (light oil) field is classified as high pressure and high temperature (HPHT).

This gas and condensate (light oil) field is classified as high pressure and high temperature (HPHT).

With a reservoir pressure of 910 bar and temperature of roughly 170°C at a depth of 4,800 metres, Kristin is the first field in the world to use subsea production with such a tough combination of conditions.

It has been developed with 12 subsea wells on four subsea templates, with six 10-inch steel flowlines transporting the wellstream from the templates to the floating production unit.

The subsea system is designed to accommodate the field’s shut-in wellhead pressure, which is 740 bar, and a flowing wellhead temperature of 157°C in 380 metres of water.

This has called for the development of:

  • a high integrity pressure protection system (Hipps) to protect the flowlines and risers from overpressure
  • upgrading of direct electric heating (DEH) technology to inhibit the formation of hydrate (hydrocarbon ice) in the pipelines during shut-downs
  • implementation of a new cathodic protection (CP) system for the flowlines
  • extensive qualification work related to flowline materials and flexible risers.

Comprehensive dynamic flow assurance work has been carried out as the basis for all qualification and development tasks.

The complete well, completion and workover system has also required extensive qualification and upgrading to accommodate Kristin’s demanding reservoir conditions.