Byron Energy Limited provided update on South Marsh Island 58 G3 (G3) and South Marsh Island58 G5 (G5) drilling program at its South Marsh Island 58 G Platform. The Enterprise Offshore Drilling (EOD) 264 jack-up rig arrived at Byron's 100% owned South Marsh Island 58 G Platform at 0830 hours on 18 April 2022 (USCDT) to drill the G3 and G5 wells. Byron is batch drilling these wells to increase efficiency and cost savings.

Since arriving on location, the G3 well was drilled to total depth on 13 May2022 and production casing was run across the productive J and K4 sands. As of 1800 hours on 24 May 22 (USCDT), the G5 has been drilled to a depth of 9,650 feet Measured Depth (MD)/7,672 feet True Vertical Depth (TVD). At that depth, during a planned, routine hole cleaning operation, the top drive transmission on the EOD 264 suffered a complete failure.

Because the drill pipe cannot be rotated without a top drive, the drill string and Log While Drilling (LWD) tools have been pulled to surface and the decision to run 7" production casing has been made to preserve the hydrocarbon sands logged to date. Currently, operations are focussed on running and cementing casing before the top drive is replaced which can take 3 - 4 days. Once the top drive has been replaced, Byron will drill ahead to test the primary N2 Sand.

The G5 is expected to reach a final total depth of 10,240 feet MD/8,196 feet TVD. The G5 well, drilling the Smoked Trout prospect, has penetrated two of the three pre-drill objectives and logged hydrocarbon (most likely oil based on mudlog and LWD responses) in one of those objectives, the K4 Sand. Another secondary target, the J Sand, was found to be pinched-out with no sand in the G5 well.

However, hydrocarbons were logged in two other sands, the I2 Sand (most likely gas), and more importantly, the L2 Sand (most likely oil). The secondary K4 Sand logged 23 feet TVT net pay. Pre-drill gross 1P reserves of 275,000 barrels of oil (mbo) (net 230 mmbo) were provided by Byron's third-party reserve estimator, Collarini Associates (Collarini) as disclosed in the ASX release of 1 February 2022 for the K4 Sand.

Collarini predicted 30 feet TVT net pay at the G5 location as a basis for these reserves. The G5 logged very clean K4 sand which is connected to oil downdip as an attic accumulation to previous K4 Sand production. K4 Sand production rates are estimated to fall in the range of 400 to 500 barrels of oil per day (bopd) depending on reservoir drawdown across the perforations.

Long term stability of the initial rate will depend on the ultimate strength of the aquifer support. The Company will complete the K4 Sand after producing the downhole L2 and N2 sands using modern frac pack sand control techniques. The G5 also logged 47 feet TVT hydrocarbon (most likely oil) in the L2 Sand.

Correlation of this sand with older wells and Byron's 3D seismic data indicates the L2 Sand in the G5 is part of the Steelhead South prospect. As previously mapped, the L2 Sand was not expected to be well developed in the G5, but in fact, the L2 Sand is a clean, high-quality sand. The G5 L2 Sand penetration is part of a large accumulation of oil that is further proved by two other wells down-dip, but never produced.

Collarini ascribed 291 mbo to the L2 Sand in the Steelhead South prospect and used 15 feet TVT of oil at that location for that assessment. This result in the G5 has substantially increased both the area and volume of the Steelhead South L2 Sand prospect and is a very positive outcome in the G5 well. The oil logged in the L2 Sand was the driving factor in deciding to run casing prior to replacing the top drive.

Historical production rates from the L2 Sand in the area range from 700 to 1000 bopd, depending on reservoir drawdown across the perforations. Long term stability of the initial rate will depend on the ultimate strength of the aquifer support. The Company will complete the L2 Sand using modern frac pack sand control techniques.

The thin pay in the I2 Sand will be a future through tubing completion in the G5 well. The I2 Sand is expected to be a modest gas producer many years in the future and lies updip to old I2 Sand production. The G3 and G5 well results will be reflected in the Company's June 30, 2022, reserves report, expected to be released in late August/early September 2022.

To put the results of the G5 thus far in the regional context of the South Marsh Island 73 Field area, it is interesting to look at historical averages for both the K4 and L2 Sands. The K4/B65 sand has produced 12.3 mmbo from 19 wells in the field with an average TVT of 34 feet. The average K4/B65 Sand completion has produced 647 mbo with a range of 152 mbo to 1,700 mbo.

The L2 Sand (also called the C10 Sand) has produced a total of 4.5 mmbo from 17 wells in the field with an average TVT net pay of 25 feet. The average L2 Sand completion has produced 267 mbo with a range of 17 mbo to 689 mbo. The presence of the L2 Sand in the G5 well could lead to an acceleration well if the primary N2 Sand is present as expected.

Production from the N2 Sand would push the uphole recompletion of the L2 Sand out several years and with current commodity prices, it may make economic sense to bring the L2 Sand production forward.