Chapter 2: History of petroleum exploration and development - PIRSA

Petroleum geology of South Australia. Vol. 4: Cooper Basin.The Moomba Natural Gas Processing Plant in November 1969.(Photo 43830)conservation of resources, the prevention of operationscontaminating water or petroleum-bearing formations,‘proper’ drilling operations and the disposal of associatedwaste products. Pipeline construction and operationrequired licences. A Petroleum Advisory Committee wasestablished to consider appeals and objections to theMinister’s decisions under the Act.Delhi–Santos’s OELs 20 and 21 were reissued in March1969 but were not converted to PELs 5 and 6 (an area of497 450 km 2 ) until after 30 June 1969 (Fig. 2.5). At that timethe licensees reduced their area by surrendering the regionseaward of Eyre Peninsula. PELs 5 and 6 were issued for aguaranteed 20 years without area relinquishments and withnominal exploration requirements and the right of renewalfor a further 20 years, an option which was revised at thestart of 1979.The Natural Gas Pipelines Authority Act and PetroleumAct extended the Government’s powers and authorised it tocontrol and regulate the oil and gas exploration,development and production processes. The oil and gasbelow the surface and the production and transport facilitiesabove were increasingly under Crown control.PROVING UP THE COOPER BASINGas and oil explorationThe perception of South Australia being deficient inenergy resources was slowly overturned. Natural gas in thePermian reservoirs at Gidgealpa and Moomba showed thatthe Cooper Basin was a gas province and the opening of theMoomba–Adelaide pipeline demonstrated the commercialviability of the region. The oil potential remained atantalising possibility however.The boom that permeated the Australian mining scene inthe 1960s introduced several exploration companies to theCooper Basin as partners with Delhi–Santos in specific areas(farmout blocks). Farmin arrangements injected badlyneeded capital to the petroleum search in 1969 and 1970 and,partly as a result, sufficient discoveries were made tocompete with Esso–BHP’s Gippsland Basin gas for supplyto Sydney. Participants in the Cooper Basin includedVamgas, Bridge Oil, Alliance Petroleum Australia,Crusader Oil, Pexa Oil and Western Mining.In 1970 more than 5000 km of seismic data wererecorded and 20 exploration wells drilled in the CooperBasin region. The Della gas field was discovered in July1970 by Pursuit–Delhi–Santos–Vamgas with their first wellon the Nappacoongee–Murteree Ridge (Pyecroft, 1973). In1969 Alliance had earnt a 50% interest in theMerrimelia–Innamincka Block through an agreement withDelhi–Santos–Vamgas: Alliance then drilled Merrimelia 5which was completed as a gas producer in 1970 (Boweringand Harrison, 1986). Other Cooper Basin gas discoveries in1970 were Packsaddle, Tirrawarra, Mudrangie andStrzelecki. Bridge Oil’s announcement in July 1970 of a gasflow from the Patchawarra Formation and light crude oil inthe Tirrawarra Sandstone at Tirrawarra 1 indicated that thelong search for oil might at last pay dividends. Although thisfirst oil to flow to the surface in the basin indicated that oil incommercial quantities existed in South Australia, the extentof the reservoir and how it might best be brought to marketremained to be established.Tirrawarra brought a liquids pipeline to the coast intoserious contention but flooding at Moomba during 1971slowed an evaluation of the area. The discovery set thescene for more exploration in the basin with gas being foundat Big Lake, Coonatie, Dullingari, Burke, Brumby andKanowana in 1971 and 1972, as well as oil and gas at FlyLake and Moorari. In addition, the gas reserves were revisedand upgraded in several instances such as Toolachee, Dellaand Tirrawarra (Hollingsworth, 1989). Between July 1970and April 1972 a further six wells were drilled on structure atA small-scale Department of Mines seismic refraction survey,1973. (Photo T023007)25