The company flowed in excess of 2,000BOPD of light oil in one of the two reservoirs in which it conducted Drill Stem Test in Ango 1Stk 3, in Oil Mining Lease(OML) 59. The tested reservoirs are located  between 15,400ft True Vertical Depth and 15,550ft TVD. This probe has opened up a whole new sequence in the southwestern, swampy part of the continent’s most productive basin.

The name Ango-1 Stk3, is a reflection of the journey of the drillbit(it means that there has been three sidetracks since Ango-1, the original hole was spudded), but sources say it has provided useful lessons. “The drilling design was done to avoid overpressure”, says one impeccable source at the Department of Petroleum Resources, the industry regulator,” and thus the well turned out to be over-designed. The well did not encounter overpressure”.

The pressure at the 15000+ft depths is hydrostatic pressure. Ango 1stk3 is located in one of the sections of the basin with the thickest sedimentary sequences. In this area, the Benin Formation  (consisting of beach sands), gets as deep  as 7-8,000ft TVD, so provides the “aerating” influence to cool the rest of the sequence below.

Prior to the DST, Conoil ran wireline logs after drilling to 16,000ft TVD, but the logs were inconclusive for fluid typing(you couldn’t tell if it was gas or oil). An attempt to run the RDT tool to take fluid samples and  pressure points also failed as the tool got stuck. This was why the third sidetrack was embarked on.

Conoil , a Nigerian independent operator, has bet  big on a new play by drilling this deep,  opening up a whole new development opportunity. Sources say the play will add at least 30Million barrels to Conoil’s portfolio. Conoil produces 25,000BOPD currently, mostly from Otuo South field, located 30km southwest of the new well. This may just be a gamechanger.