INA confirms new offshore gas reserves in Croatia’s Northern Adriatic

(WO) - Croatian oil and gas company INA has confirmed new offshore natural gas reserves in the Northern Adriatic, following the successful drilling and early testing of a development well on the IKA-A production platform. 

The IKA A-1 R DIR well, drilled by Crosco’s jackup rig Labin, is the first of two planned development wells in the current drilling campaign. Testing began in early December—around two months ahead of schedule—and initial production is averaging about 120,000 cu m/day of natural gas, making it INA’s second most productive gas well in Croatia.

Gas produced during testing is being routed through existing infrastructure and delivered directly into Croatia’s national gas system.

INA estimates the newly developed reserves at approximately 220 MMcm of natural gas, equivalent to about 1.3 MMboe. The wells are being developed through sidetracks from depleted parent wells, allowing INA to access previously untapped reservoirs while leveraging existing platform infrastructure.

Work is continuing on the second development well, IKA A-4 R DIR, which is expected to be completed with a potential production start in first-quarter 2026. Both wells will be fully tied back to the IKA-A platform following completion and technical adjustments.

INA said the project marks the start of a new offshore investment cycle aimed at boosting domestic gas output. Additional offshore drilling activities are planned through 2026, as the company looks to strengthen Croatia’s energy security amid ongoing volatility in global gas markets.