As oil and gas exploration has moved into increasingly deep water in the Gulf of Mexico, the potential to find increasingly higher pressure and higher temperature reservoirs has increased. High integrity pressure protection systems (HIIPPS) are seen as essential for development of these prospects. This paper will cover the key differences between applying HIPPS in the Gulf of Mexico compared to North Sea applications, as well as the associated regulatory process involving the Minerals Management Service (MMS), the regulatory authority in the Gulf of Mexico.
The installation of HIPPS has been limited to the North Sea for subsea applications. As exploration and drilling have moved into deeper water in the Gulf of Mexico, discoveries have increased in pressure and also temperature, resulting in an increased need to address the application of HIPPS technology in this region. Although there are a number of subsea systems operating successfully in the North Sea, it has not been possible to transfer this experience directly to the Gulf of Mexico without a significant amount of ground work. This paper will discuss the key differences, the impact on subsea architecture and the work with the regulatory authority associated with HIPPS technology.
During a gap analysis for extreme high-pressure high-temperature (XHPHT) systems completed in 2004, BP identified that HIPPS technology would be a key enabler to develop the new prospects. This was also based on the experiences at Thunder Horse, which was fully rated and with a shut-in pressure of less than 15000 psi. Thunder Horse has shown the many challenges around trying to develop equipment for high pressure systems resulting in some equipment being de-rated to less than 15000 psi in order to reduce the challenge and hence risk. Also, other HPHT projects have been seen to experience cost and schedule impacts.
Where systems are fully rated to the wellhead pressure, there is also the potential for this pressure to be present on the surface facility. By moving to a subsea specification break with the adoption of HIPPS, the topside pressures can be reduced.
It is not the intent of this paper to present the details associated with determining integrity levels in accordance with International Electrotechnical Commission (IEC) standards, as this has been well documented in the literature.
During a review of available technology for XHPHT systems conducted by BP during 2004, it was identified that HIPPS would be a key enabling technology for deepwater applications in the Gulf of Mexico.
It also became clear that implementing this new technology would not be a direct transfer from the North Sea experience due to a number of key differences. These included a lack of clear understanding on how the application of this technology would be viewed by the MMS (which is the regulatory body for hydrocarbon developments in the Gulf of Mexico), the impact of increased water depth on system design and the impact on high flow rate wells in the region of 20000 barrels a day on both HIPPS design and system architecture.