Publications

The drilling of the Uba Deep-1 exploration well was completed in March 2019. The well was drilled with two objectives, 1) to explore the extent of the Permian petroleum system in the Bintuni Basin, and 2) to appraise the larger resource of Jurassic gas pool discovered by the Ubadari-1 as illuminated by the outcome of the Seismic Full Waveform Inversion of the Ubadari 3D volume previously acquired in 2009. The well successfully appraised the Jurassic reservoir, allowing the commercial development of the Ubadari field, but failed to fully evaluate the deeper exploration objective due to technical challenges during drilling. The Permian section was the primary target of this well. The presence of gas in Permian reservoir such as in Mogoi Deep-1, as well as in the tail section of some Vorwata wells, triggered further evaluation of the Permian reservoir for potential additional gas resource for Tangguh. The Uba Deep-1 successfully penetrated the Permian objectives but failed to find good-quality reservoir. The well penetrated a total of 2,550 ft of pre-Jurassic section, of which around 1000 ft has been interpreted of Permian age. The Permian section showed high gas readings. This observation strengthens the general concept of the existence of a Permian petroleum system in the Bintuni Basin, possibly separated from the more recognized Jurassic petroleum system itself. The well also penetrated a Triassic interval which was not expected to be present in this area. The Triassic section showed minor gas shows. The objective of this paper is to revisit the pre-Jurassic petroleum system of the Bintuni Basin using the knowledge gained from the Uba Deep-1 well. The well has provided a lot more additional information of this system which was not available before. Our analysis suggests that the onshore Bird’s Head is probably the right area to find better quality Permian reservoir. However, the onshore area has poor data coverage and quality and exploring there would require the acquisition of new quality data.