The Jethro-1 discovery has confirmed the Tertiary play in Guyana, proving Tullow’s geological model and verifing the UK/Irish explorer’s seismic interpretation of the Guiana Basin. The well is Tullow’s first in Guyana and is the first discovery outside ExxonMobil’s prolific Stabroek block, which contains over 5.5 Bboe of in place reserves.
The 20 sq. km Jethro Lobe prospect lies in approximately 1350m water depth and was investigated using the Stena Forth drillship. The well was drilled to a PTD of 4400m and encountered 55m of net oil pay, in high-quality sandstone reservoirs of Lower Tertiary age, reportedly exceeding Tullow’s pre-drill forecast of 100 MMboe in place, by at least 50%.
The discovery significantly de-risks around 16 prospects on Orinduik, which Tullow reported could contain up to 2.5 Bboe of gross unrisked resources. One of these prospects is the Upper Tertiary Joe prospect which lies in shallower waters (650m) and will be drilled in late August 2019, when operations on Jethro have concluded. It also abuts ExxonMobil’s Stabroek block, where 11 out of 13 discoveries have been in Lower Cretaceous turbidite fans and channelised sand complexes. Just one discovery, Hammerhead-1 has a similar Tertiary sandstone channel play and may extend into the Orinduik block whilst another, Ranger-1, which lies to the north-east of the giant Liza field, is a carbonate play.
Tullow identified four prospects in the north-east corner of Orinduik block, which could be developed as a cluster with the Jethro Lobe, these include; the untested Jethro Channel prospect, two other Tertiary prospects and possibly ExxonMobil’s Prospect 17 which may be contiguous to the Jethro Lobe in the Stabroek block. The extension of an active, mapable oil play outside of Stabroek also bodes well for other operating groups exploring the Guiana Basin in Q3 2019, notably Repsol which will test the Carapa Cretaceous oil play on its Kanuku block and Apache which will investigate the Maka prospect on Block 58 in Suriname.
Tullow was awarded the Orinduik licence in 2016 and interest is split between Tullow Guyana B.V. (60% + Operator), with Total E&P Guyana B.V. (25%) and Eco (Atlantic) Guyana Inc. (15%). It’s success today proves that exploration focused independents can emulate ExxonMobil’s success in Guyana, in half the time.