By Fred Akanni
Nigerian independent Conoil Producing, is on course of a second significant discovery at relatively great depth on the Ango structure in the Oil Mining Lease (OML) 59 in the Niger Delta Basin.
Ango-2, the company’s second probe on the structure, encountered a reservoir with 295 feet Net hydrocarbon sand at about 17,005ft (5,183 metres) True Vertical Depth (TVD) and was heading for another sand circa 17,500ft TVD before it took a kick in the last week of August 2013. The High Temperature High Pressure (HTHP) swamp barge Majestic pulled back up to13,000 feet TVD to circulate, inject heavier mud and control the well. Drilling resumes soon. “Everything points to liquid hydrocarbons, though the sand encountered looks quite shaly”, says a source at the Department of Petroleum Resources, the industry regulator.
The reservoir at 17,005ft TVD will be the third in the Ango structure. Conoil encountered two shallower sands in Ango-1 Stk 3, the first probe on the structure. Ango-1 Stk 3 flowed around 4,000 barrels of oil per day (BOPD) combined in two sands at 15,550ft (or 4,740metres) TVD and 15400ft (or 4,694 metres) TVD. Those two sands were successfully appraised by Ango-2.
Ango-2 was intentionally planned to probe the reservoirs it could not reach, due to tough drilling conditions, in the last well. It is expected to drill to a total depth (TD) of 18,500ft (or 5,639metres)TVD. It is anticipated that it would encounter a fourth reservoir in the structure, at 18,000ft (or 5,486 metres)TVD.
The Ango discovery has opened up a whole new sequence in the southernmost flank of the mega-structure at the current mouth of the Niger Delta, Africa’s most productive basin.