Onshore oil and gas drilling
Exploration steps up in the Cooper and Eromanga basins.
Oil and gas exploration drilling in the South Australian Cooper and Eromanga basins is recovering since the low point in 2016 when 34 wells were drilled in the region, only 10 of which were exploration wells (Fig. 1). The resurgence commenced in 2017 when 21 exploration wells were drilled, including two in the Otway Basin.
The 2018 year saw 82 oil and gas exploration, appraisal and development wells drilled in the Cooper and Eromanga basins including 14 exploration wells (Fig. 2). Licence operators focused on maximising production via horizontal appraisal and development wells. Nine horizontal wells were drilled in Eromanga oil reservoirs and three in Cooper gas reservoirs to enhance production.
The recovery in exploration drilling levels in South Australia reflects a national trend with more offshore drilling and more drilling planned in other onshore jurisdictions in 2019. Early indications are that an increased level of drilling will continue in South Australia. In financial year 2018–19, Senex plans a 10-well Cooper and Eromanga basins program and Beach plans up to 15 horizontal wells addressing western flank oil reservoirs. In addition to activity in the Cooper and Eromanga basins, two PACE Gas grant co-funded gas exploration wells (Vintage-Lakes Nangwarry 1 and Beach Dombey 1) and one gas development well (Haselgrove 4) will be drilled in the South Australian Otway Basin.
2018 drilling summary
There were two gas discoveries – Beach Coalinga 001 DW1 and Webb 001 on the western flank play trend. The wells tested exploration targets around Brownlow–Middleton Gas Field in Petroleum Production Licence 239.
Senex Breguet 1 was the only exploration well to discover oil. Senex Snatcher North 1 and Beach Kalladeina North 1 appraisal wells made new field oil discoveries.
Four wells explored resource plays:
- Santos Casimir 1 tested the deep coal play in the Patchawarra Trough and is cased and suspended for further evaluation.
- Senex Gemba 1 was drilled in the Allunga Trough and fracture stimulated in November – stabilised flow rates of approximately 8 million standard cubic feet per day with associated liquids were recorded during a seven-day production test. Gemba 1 was co-funded with a $5.26 million PACE Gas grant from the state government.
- Strike Oil drilled Klebb 5 and Jaws 1 ST1 horizontal well as part of their Southern Cooper Basin Coal Project. Jaws 1 ST1 was co-funded by a $2 million PACE Gas grant and is the first horizontal well drilled to intersect a vertical well.
Drilling on a company-by-company basis:
- Santos – 46 exploration, appraisal and development wells including:
- 1 Eromanga oil horizontal well
- 3 Cooper gas horizontal wells
- 1 resource play well
- Beach – 23 wells (7 exploration, 16 appraisal/development) including:
- 6 Eromanga oil horizontal wells
- Senex – 11 wells (7 exploration, 5 appraisal/development) including:
- 2 Eromanga oil horizontal wells
- 1 resource play well
- Strike – 2 exploration wells
- Leigh Creek Energy – 20 shallow wells in the Telford Basin as part of their in situ coal gasification project.
– Elinor Alexander, February 2019