The predominant topic in the oil and gas industry at the moment is cost reduction; a sharp change from a year ago when most conversations centered around technology development for today’s harsh, deepwater environments. There is one technology, however, that can help meet both of these criteria, and that is subsea HIPPS.
High Integrity Pressure Protection Systems are safety instrumented systems (SIS) and have predominantly been used in the North Sea. They have yet to be implemented in the GoM, but offer significant advantages for operators in the region. The subject was among various technologies discussed during the 7th Annual Teledyne Oil & Gas Technology Focus Day, which Clarus attended on 19th November 2015 at the Westin Memorial City. Here’s an overview of what we learned.
How do HIPPS work?
HIPPS protect downstream equipment from exceeding design pressure limitations, allowing for high pressure wells to tie in to flowlines and risers with lower pressure ratings, ultimately reducing cost. They also allow new, higher pressure wells to tie into existing, lower pressure production systems preventing the need for a new facility altogether. HIPPS monitor upstream pressure by using multiple sensors, and close the barrier valves as soon as an increase in pressure exceeds the preset level. This increase can occur due to a number of different reasons. One example could be a malfunction of the subsea tree choke, which during normal operations provides control of production pressures, resulting in an unplanned opening. Another example could be a hydrate blockage downstream of the HIPPS that causes a rapid surge in pressure upstream.
Why have HIPPS not been used in the GoM?
Actually, a subsea HIPPS is currently being developed for the Julia project in the GoM. However, they do remain a non-conventional production technology and therefore require additional approval from BSEE. Since regulatory approval depends on historical safety data, which is lacking, the current regulatory requirements can result in a stringent qualification process.
What are the integrity considerations if I am considering a HIPPS?
The reliability of safety valves is a common challenge in the industry, with malfunctions that often result in lost production, repeated troubleshooting and, in some cases, costly intervention operations. Valve redundancy should be carefully considered during design as it can allow you to continue production operations if one valve was to malfunction.
Valve condition monitoring can establish historical safety data and operational KPIs that increase confidence and provide leading indicators before a shut-in.
The design of the zero burst or fortified zone downstream of your HIPPS, which must be designed to allow for sufficient time for the HIPPS valves to close. The zero burst zone depends on a variety of parameters such as reservoir properties, downstream pressure rating, flow assurance design and field architecture. Early involvement from your integrity team is crucial in ensuring quick access to reliable data and providing engineering support, especially when designing HIPPS for existing fields where there could be more limitations.
In summary, subsea HIPPS can facilitate newer wells at existing facilities to overcome technical challenges at a lower cost. Nonetheless, early involvement of your integrity team is vital in addressing the added complexity that comes with adding a HIPPS to your field and ensuring the long-term health of your asset.
Special thanks to Robert Hernandez, Sr. Technical Advisor at Granherne, whose presentation “Design and Use of Subsea High Integrity Pressure Protection Systems” at the Teledyne Oil & Gas Technology Focus Day was the motivation for this article.