The Perth Basin extends south from the Southern Carnarvon Basin and covers an area of about 100,000 km2, from the Yilgarn Craton in the east to the edge of the continental shelf in the west. The onshore area is readily accessible, consisting of farming and shrub land in the central region. The undulating northern portion of the basin has relatively simple access from main roads. In the south, forestry and grazing are the main land uses.
The basin is close to petroleum industry infrastructure, including two major gas pipelines and trucking facilities that service an oil refinery 30 km south of Perth. The Parmelia Gas Pipeline provides ready access to market and allows economic exploitation of small discoveries.
The stratigraphy and petroleum system elements of the Perth Basin developed during the tectonic evolution of the basin and vary significantly from north to south. Initial rifting established a series of Permian to Early Triassic depocentres for fluvial and marine siliciclastics with minor carbonates and coals in the north, while in the south fluvial siliciclastics and coals dominated. These Permian- and Early Triassic-age rift-sag deposits are associated with the major petroleum system in the north Perth Basin, particularly the Kockatea Shale which forms an important oil source rock and regional seal to underlying reservoirs.
A second phase of rifting in the Late Triassic and Early Jurassic was associated with widespread fluvial and deltaic deposits, including a thick succession of siliciclastics and coals (Cattamarra Coal Measures), which are overlain by Middle Jurassic marine shales (Cadda Formation) in the north Perth Basin. These Early to Middle Jurassic strata form a second proven petroleum system in the north Perth Basin. The final rift and breakup phase in the Middle Jurassic to Early Cretaceous was associated with deposition of fluvial and marine siliciclastics (Yarragadee Formation, Parmelia Group and Warnbro Group), which form the main petroleum system in the Vlaming Sub-basin.
RCMA, on behalf of the Joint Venture, signed a non-binding letter of intent with Strike Energy Ltd (“Strike”) for the negotiation of a rig sharing agreement to drill the Cervantes-1 exploration well using rig Ensign 970.
The proposed agreement sets the framework for RCMA, on behalf of the Joint Venture, to enter a standalone drilling rig contract with Ensign Australia Pty Ltd, once agreement has been reached with Strike. The Cervantes-1 exploration well is planned to address gross recoverable Prospective Resources (P50) of 15.3 million barrels of oil MMbbl oil (refer ASX release dated 15 November 2019).
The regulatory environmental approval process is now in its final stage, with approval anticipated by the end of November 2021. Construction of the access track and well pad civils work is expected to commence late 2021/early 2022, subject to the environmental approvals.
Vintage executed a farm-out agreement with Metgasco Ltd (30%) and RCMA Australia Pty Ltd for 30% of the Cervantes oil prospect. The joint venture is targeting to spud a well in early 2022 and has an option to drill a second well into a separate prospect. The Cervantes prospect sits within L14, a 39.8 km2 Perth Basin production licence granted over the Jingemia oil field and surrounds. The licence is in good standing and not due to expire until June 2025.
The Cervantes structure is located on an oil discovery trend, comprised of the Hovea, Jingemia and Cliff Head oil fields. These fields, in total, have produced in excess of 27 MMbbl of oil from Permian reservoirs in the Perth Basin and lie within an oil fairway around the western and northern section of the basin. The Cervantes structure is a high-side fault trap with multiple Permian reservoir units, sharing strong similarities with the offset oil fields in terms of structure, potential reservoirs, and access to a mature oil source rock.
Seismic traverse across the Cervantes structure and Kingia Depth Map
The Permian reservoir targets in the prospect are the prolific Dongara, Kingia and High Cliff Sandstones which are expected to yield a combined gross 2U Best Estimate of 15.3 MMbbl (4.6 MMbbl net to Vintage) of oil. Cervantes has a chance of success of 28% and a high chance of development due to its proximity to infrastructure and existing oil and gas fields.
| Cervantes Prospective Oil Resource (MMbbl)1 | |||
|---|---|---|---|
| Sandstone | 1U low estimate | 2U best estimate | 3U high estimate |
| Dongara | 3.7 | 7.4 | 14.6 |
| Kingia | 2.2 | 7.1 | 22.3 |
| High Cliff | 0.1 | 0.8 | 5.0 |
| Total | 6.0 | 15.3 | 41.9 |
| Vintage 30% | 1.8 | 4.6 | 12.6 |
