A deep well at Zakum reached 17,370 feet and was still above the salt pillow
which forms this large, low-amplitude feature whose surface area is 660 sq km.
The offshore fields to the east are related to salt pillows
. The nearby Halul island is a salt piercement feature.
Oil at Shaybah occurs in reefal facies of the Shuaiba formation, with the reservoir being 122m thick at a depth of 1,494m, the origin of which is similar to that of Abu Dhabi's large fields in swells developed over salt pillows
triggered by deeper basement faulting.
The origin of these fields is believed to be similar to that of the big fields in Abu Dhabi, where large swells developed over salt pillows
possibly triggered by deeper basement faulting.