Andrew Longdon, UK technical manager of Trelleborg Sealing Solutions, says oil operators are increasingly turning to unconventional wells, previously believed to be too deep and extreme for existing capabilities, in response to the planet’s shrinking supply of natural resources.
Energy’s holy grail
The Institution of Mechanical Engineers says there are an estimated 1.3 trillion barrels of proven oil reserves left in the world’s major fields, which at present rates of consumption will last for 40 years.
However, Mr Longdon said: “The race to develop a biofuel which is a genuinely credible alternative to oil, both sustainable and commercially available, is, as yet, failing. So until energy’s holy grail is found, oilfield operators are left with the challenge of buying the world more time.
“We are therefore having to consider uncharted deepwater territories like unconventional wells, but to do this operators need to rely on subsea processing technology to meet new high pressure / high temperature conditions (HP / HT).
“Conventional subsea operating temperatures of up to +120 °C/+248 °F increase to over +200 °C/+392 °F in deepwater locations, whereas typical pressures occasionally treble from a previously accepted high point of 69 MPa/10,000 psi to 207 MPa/30,000 psi.”
Critical sealing elements
Energy giant Total has estimated deep offshore could hold seven per cent of the world’s oil and gas resources, unlocking the potential of 330 billion barrels of oil reserves representing seven years’ worth of global consumption. This equates to almost a quarter of the planet’s undiscovered resources.
Seals are critical within subsea systems, especially in valves and downhole tools. They ensure optimum operation of equipment and are the primary barrier to system fluid loss or system fluid contamination from external sources. Subsea seals are the main source of prevention of hydrocarbon leakage from oilfield completion or production equipment and as such, perform a vital role in meeting environmental and workforce safety concerns, in addition to enhancing performance of the tools themselves.
Mr Longdon added: “We have developed application-specific seal designs to provide high-integrity sealing able to stand up to the extreme operating temperatures and pressures of deepwater locations.
“Deep offshore is the future of oil harvesting and also the emerging present. It is the next generation of oil exploration and Trelleborg Sealing Solutions will continue to invest in developing sealing innovations to support this trend.”
Multi-Contact Turcon® Variseal®
The company’s Multi-Contact Turcon® Variseal® has been developed to replace multiple chevron seals or V-stack type products in subsea valve stems requiring high-integrity sealing capability. It comprises of a series of single-acting spring-energised seals housed within a U-shaped Turcon® polytetrafluoroethylene (PTFE) based-material seal profile.
The unique single-piece design significantly improves sealing integrity and leak tightness in high-pressure applications by providing higher contact force across multiple seal hardware interfaces.