In May 2017, Ophir announced that the ultra-deep water, Ayame-1X exploration well had reached its total depth of 5394 m TVDss. The well targeted multiple Cretaceous turbidite channel and fan complexes, which were encountered as prognosed. Furthermore, the well cased the longest riser-less surface section in the region and reached total depth in the subsequent open hole section with a single bit run, again, another basin first. From a pressure perspective the well was drilled safely and the pore pressure and fracture gradient were accurately predicted pre-drill.

Although detailed analysis of the work is still ongoing, we present the workflow that enabled a robust pre-drill pore pressure model to be derived. The pre-drill model utilised lithofacies estimates derived through seismic inversion combined with a thorough assessment of local and regional pressures in order to capture and quantify uncertainty. The pre-drill estimates of lithology and pressure were subsequently validated during and after drilling of the exploration well.

Author associations
1 Ikon Science
2 Ophir Energy