This technical report serves as a general design guideline for HPHT application. It provides design guidelines for oil and gas subsea equipment used in high-pressure high-temperature (HPHT) environments. Within this technical report, HPHT environments are meant to be one or a combination of the following well conditions:

1) The completion of the well requires completion equipment or well control equipment assigned a pressure rating greater than 15,000 psia [15 ksi, 103.43 MPa] or a temperature rating greater than 350 °F (177 °C);

2) The maximum anticipated surface pressure, including shut-in tubing pressure, is greater than 15,000 psia [15 ksi, 103.43 MPa] on the seafloor for a well with a subsea wellhead or tied back to the surface and terminated with surface-operated equipment; or

3) The flowing temperature is greater than 350 °F (177 °C) on the seafloor for a well with a subsea wellhead or tied back to the surface and terminated with surface-operated equipment. Service temperature ratings above 550 °F (288 °C) are outside the scope of this technical report.