Abstract: Annular Pressure Build-up (APB) is caused by the thermal expansion for the sealed annulus, Heated by the high temperature fluid extracted from the bottom of the well. In order to ensure the safety of the wellbore, considering the development practice in the deep-water, the multi-annulus APB prediction model is proposed based on the semi-steady heat transfer method and coupled pressure and volume annular pressure calculation method. According to the working principle of the rupture disk, the threshold valve determination methods from inside to the outside and from the outside to the inside are established. Taking a Western African well as an example, the wellbore temperature and annulus pressure during production were predicted. Casing strength verification results show that the surface casing and technical casing have the risk of bursting during normal production. When the annular pressure relieved or the production casing annulus evacuated, the production casing is at risk of collapse. After adopting the rupture disk technology, all the casings meet the requirements of verification. Therefore, the rupture disk can effectively protect casing and is significant to safe exploitation of deep-water oil gas resources.

Key words: deep-water oil and gas wells, wellbore temperature, semi-stead state heat transfer, annular pressure build-up, rupture disk