3sun Group’s subsea division has installed its first Time Delay Block Valve (TDBV) for use on hydrocarbon producing wells.

The valve was designed and manufactured by Bifold Group, in accordance with a Qualification Specification approved by 3sun Group. The prototype TDBV was installed in June 2015 on a North Sea Platform and has since been operating at excellent capacity, 3sun said.

Graham Hacon, CEO, explained: “Hydrocarbon producing wells have a Down Hole Safety Valve (DHSV or SCSSV – Surface Controlled Sub Sea Safety Valve) which shuts the well quickly when required, and is usually controlled hydraulically from the surface. Due to the large amount of solid debris (mainly sand) carried in the recovered hydrocarbons, contamination damage commonly occurs to the DHSV, causing leakage into the hydraulic control line. This can result in escaping gases which are toxic to the surrounding workforce with high risk fire/explosion potential.

“TDBV allows absolute control of the DHSV. By blocking the hydraulic control line, it prevents migration of gaseous and fluid hydrocarbons into working areas, which in general are not hazardous area classified for such ingress – until the DHSV is to be reopened to resume recovery of hydrocarbons, at which point the time-delayed blocking valve reopens to allow hydraulic communication. The TDBV is the only valve type suitable for this requirement, for which the valve concept was designed.”