LESS TALK, MORE DRILLING ‘We have oil — search for it’: geologists

Press, 3 October 1979, Page 19

LESS TALK, MORE DRILLING ‘We have oil — search for it’: geologists

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GARRY ARTHUR

Talk of a big potential oilfield in the Ross Sea, in New Zealand’s sector of Antarctica, has alarmed Professor A. R. Crawford of the geology department at Canterbury University, He is convinced that a much more vigorous search will strike oil in New Zealand or on its continental shelf, and he fears that interest in the Ross Sea might lead to neglect of the need to try harder here. “Oil exploration in New Zealand is too slow,” Professor Crawford says, “and it will be worse if the Antarctic is regarded as an easy option.” It is not that he has serious doubts about the Ross Sea; it might very well prove to have a big oilfield, he adds. On balance it looks a good offshore prospect — but so does New Zealand’s very large continental shelf. Professor Crawford says New Zealand’s geology

matches that of many of those areas of the world where oil has been found in large quantities. But we are not spending the money to drill the large number of holes which overseas experience shows will be necessary before the oil is found. He forecasts that oil in economic quantities will be found in New Zealand three to five years after we really start looking for it. The few holes drilled in New Zealand so far are wildcats. To get a productive well, it is usually necessary to drill 10 or even 20 holes, Professor Crawford says. “New Zealand needs to make the best choice on the best information, and it is all

the more important to get the most out of the geological community. Generally, the scientists have been ignored. The Government has made no rea! effort to consult them.” Professor Crawford is concerned that New Zealand is not looking for oil with the vigour, optimism, and persistence that is necessary. “Oil is not found by talk, and it won’t be found by politicians. It is found by drilling holes in the ground. “Of course it costs a great deal of money, but the costs are commensurate with the material benefits. “There’s a lack of imag-

ination, a lack of vigour, a lack of political consistency. There’s been greed on the part of the Government. It is financially a very risky business, and the Government must recognise this and offer adequate rewards. We have to come to terms with the oil companies.” Canterbury’s foothills might well cover a goodsized oil field, Professor Crawford says. Geologists at Canterbury University know more about the Canterbury geology than anyone else and could give sensible answers to the relevant questions — if they were asked. “Oil very commonly

occurs in association with thick sedimentary sequences, which themselves commonly develop into mountain beits,” Professor Crawford explains. “The older the mountains, the more likely they are to lose their oil. “Oilfields in the Middle East, California. and Alaska are all associated with two great belts of young mountains, one of which is the circum-Paci-fic belt. New Zealand is a part of it. It is very like California; almost a mirror image of it. “The most promising

area is the terrain on each side of the Alps. There is no reason why we should not find oil there, but we need more holes. We can get adequate detail about the underlying structure only by drilling.

"It is in the thick, younger sequences or rocks — those deposited in the last 100 million years — that most oil is found. We’ve got very thick sequences of this age; New Zealand is famous for them. "We should also be looking much harder at the off-shore areas. Many highly experienced geologists are convinced that the world”s continental margins will be extremely productive. "Areas already producing oil are often those where continents have split apart. As many of us think that New Zealand is a fragment of a former large continent, its margins are especially attractive. In proportion to other areas. New Zealand has an enormous continental shelf.”