Block Energy PLC (LON:BLOE) has updated investors on its activities at its flagship West Rustavi field, in the Republic of Georgia, where it is advancing to deliver a fully-funded multi-well work campaign.
A sidetrack programme has now begun for the new WR-38Z well, targeting the Middle and Upper Eocene formations, which is located ‘on-trend’ and ‘up-dip’ of the previously drilled WR-16aZ sidetrack.
The company, meanwhile, noted that production from WR-16aZ has “varied significantly’ due to the performance of downhole equipment, which failed during the attempted cementing of the well during the course of drilling.
Nonetheless, Block said that the sidetrack well “continues to flow strongly” – flowing oil, water and gas.
Well flows measured 230 barrels per day in the period between 17 September and 23 September, with a water cut of 78%. The gas flow was described by Block as “significantly higher than anticipated”.
Block also advised that a 3D seismic survey of West Rustavi has now begun with the mobilisation of its contractor.
"Encouragingly, the WR-16aZ appraisal well has proved the productivity of the Middle Eocene naturally fractured oil reservoir,” said Paul Haywood, Block chief executive.
“It has also confirmed unassociated gas flows above our expectations.
“The flow test results have varied over time due to lost drilling fluid and a mechanical failure when drilling the well.
He added: “In the course of drilling WR-16aZ we have strengthened our understanding of the drilling techniques applicable to Georgia which will be invaluable as we begin drilling well WR-38Z, the second of five wells we plan to horizontally sidetrack in our fully-funded campaign. I look forward to updating you on our progress at WR-38Z."
WR-16aZ in detail
The well has so far produced over 9,000 barrels of light, sweet crude oil since the well testing programme began.
At a sales price of US$65 per barrel the company expects to have generated some US$300,000 which represents a quarter of the drilling costs.
Gas rates are significantly higher than the company had expected, occasionally reaching 500,000 cubic feet per day which equates to 80 barrels of oil per day.
Most recent data, for 17 September to 23 September, the sidetrack well yielded some 230 bpd with a 78% water cut, and, the gas rate averaged 130,000 cubic feet which equates to 22 bopd.
WR-16aZ was the first sidetrack to be drilled by Block at West Rustavi and it is being followed up with three further sidetracks (the first of which is WR-38Z).
Equipment problems and potential intervention
In relation to the operational problems experienced with the WR-16aZ well, Block noted: “When certain downhole equipment failed prior to cementing operations of the seven inch liner, a well-considered decision was made to continue with WR-16aZ operations without cementing the liner.
“At the time, the downhole condition of the wellbore was deteriorating and becoming unstable (as is common for geological formations with high clay and shale content such as the Upper Eocene).
“The option of an operation to attempt to retrieve the liner, recondition the open hole and re-run the liner was considered. It was rejected due to the high risk of losing the new sidetrack.”
Consequently, it means that the producing Middle Eocene reservoir and the non-producing Upper Eocene are both ‘open’ in the well.
“Block is implementing an evaluation and intervention programme designed to isolate and reduce the water the well is producing, and to increase net oil production,” the company added.
Ahead of any intervention, the company intends to use downhole production logging equipment to identify the respective origins of the oil, water and gas the well is flowing.