SEEING BELOW

Hawke's Bay Tribune, Volume XVII, 1 October 1927, Page 7

SEEING BELOW

SEEKING OIL RESERVOIRS ELBOF GEOPHYSICAL SURVEYS IN HAWKE’S BAY PROVINCE. l> ELATIVE to the exploration for petroleum in New Zealand, two facts stand out prominently: (a) That there are indisputable evidences of the wide distribution of petroleum ir the Dominion; and (b) That competent geologists have expressed the opinion that commercial oilfields will eventually be developed. In spite of these facts, scepticism is unfortunately too prevalent as to the profitable production of petroleum. The doubt that has so generally arisen is probably chiefly due to the numerous disappointments that have been experienced. But it should not be overlooked that exploration has been somewhat spasmodic and to a considerable extent unscientific. The haphazard or faulty methods of the earlier days of oil-seeking in America have been more apparent than the later scientific and sound technical methods. The majority of the wells so tar drilled have been in unsuitable formation, hence the inevitable failure of so many efforts in the quest for a profitably productive oil horizon. The initial desideratum has in most cases not been sought—namely, a favourable geological structure lor the accumulation and retention of petroleum. Bores have usually been put down in proximity to seepages or to gaseous emanations. This is bad practice.

INCOMPLETE GEOLOGICAL SURVEYS. There has not been sufficient detailed geological surveying to locate suitable structures, although it must be admitted that in some petroliferous areas the formation has been so obscured by overlying volcanic, detrital qlud otuer deposits that such necessary l preliminary examination could be partially successful over. Typical instances' of this obscuration of tectonic and stratigraphical features have been disclosed at New Plymouth and Kotuku. However, whilst it is regrettable that hitherto the attempts to discover, or rather to develop, a payable oilfield in the Dominion have been abortive, there is no cogent reason for the rampant scepticism which is so painfull}’ evident among all sections of the community when the widespread occurrences <tt petroleum are considered, and when capable scientists positively assure us that wisely-directed exploration will sooner or later he successful, SCIENCE AND THE SEARCHERS. Fortunately the Science of Geophysics is now coming to our aid. The empirical methods of the past are to be displaced by the modern application of this science in the search for the oil accumulations that are waiting to be tapped by the drill, and which will supply a new factor of, wealth to the Oominion Even if the developments of the petroleum industry were only adequate to satisfy the imperative liquidfuel needs of the Dominions, the millions of money that are now annually paid away to foreign countries for such necessities, and for which there is very little trade in return, would be retained here. The practical application of the recent successful geophysical methods of mineral survey in tne location of commercial petroleum deposits in New Zealand is about to be undertaken through the enterprise of Coal, Oil (N.Z.), Limited, a public company incorporated in New South Wales with an authorised capital of £750,000. It is the first instance of the utilisation of these methods in the Southern Hemisphere, and the Australian Commonwealth Government i* following the lead that has been given by this company. VISITING SCIENTISTS.

At the end of this month a survey group from the famous Elbof Geophysical Research Organisation will arrive in the Dominion to conduct a complete geophysical investigation of the petroliferous areas situated in various districts and aggregating about 65,000 acres. Th* leading member of this group, comprising four specially trained scientists, is Dr. Rudolf Krahmann, the Professor of Applied Geology at Berlin University, and one of the world’s leading authorities on the practical application of the Science of Geophysics. Their advent is not only a compliment, but of transcendent importance to New Zealand, and their work will certainly be watched with keen interest by fellow scientists, if not by the business interests. Whilst in Australia, en route for the Dominion, Dr. Krahmann has accepted the invitations of the Royal . Societies of South Australia, Victoria and New South Wales to deliver illustrated lectures on proved geophysical methods of survey at Adelaide. Melbourne and Sydney respectively. He has also been invited by the Government- of Tasmania to lecture at Hobar. but as his desire is to reach New Zealand without further delay, he has had to reluctantly decline the invitation for the present. Should he be able to spare the time from the group’s surveying operations, it is probable that, before the end of the year, he will consent to give some lectures in the Dominion HAWKE’S BAY POTENTIAL FIELDS. The first potential oilfield to be investigated is that of Waipatiki, on the Weber anticline, which was discovered by Dr. John Wanner, a noted petroleum geologist, in 1911. It is expected that this survey will occupy four months. Thereafter further petroliferous areas in the Hawke’s Bay province will have attention. It is on the Waipatiki field, which Dr. Wanner described as a “broadly-vaulted anticline.” that the pure gaseous petroleum has been tapped in three wells and reticulated to the dwellings and the power plant SUBTERRANEAN SUBVE Y. It is not easy to describe in nontechnical phraseology the various methods which are employed in the practical application of the Science of Geophysics. Suffice it to say that, with the aid of almost inconceivably delicate and sensitive instruments, surveys can be ac- ' -Jo, IS PrptlA .«f Gfioo-

.feet. There are several methods involving the use of different instruments. The chief methods are known as follows:— (1) The electro-magnetic conductivity method. (2) Magnetic intensivity method. (3) Gravity method. (4) Seismic method (elastic waves) (5) Geo-thermic and Radio-active methods. There is a close connection between these methods of survey and practical geology. Dr. Krahmann has stated: “Just as the physical instruments and methods are aids to the study of geophvsics, including meteorology and similar sciences, so the practical geophysical investigations are aids to the study of geology and mining.” Perhaps the most important feature of a geophysical survey is the correct interpretation of the findings or records of the instruments as operated by experts. To place the apparati in the hands of unskilful persons, in the expectation of obtaining reliable results, would be as futile as asking a savage to make a propei microscopic examination of a globule of petroleum. It must therefore be distinctly understood that the application of the Science should not be entrusted to those who have not been thoroughly trained.

ORGANISATION AND METHODS. The Elbof Geophysical Research Organisation now has fifteen groups operating in various countries in the Northern Hemisphere. Each member of each group of four field operators has to be a science graduate of a University, and the preparatory training of each group before it is qualified to engage in a subterranean survey occupies from eighteen months to two years

So rapid has been the development of the Science—almost as sensational as that of Wireless—that in U.S.A, and Europe to-day the leading oil companies do not undertake drilling operations until a geophysical survey has been made. It must not be forgotten that no geophysical survey, however perfect, can discover what does not exist, but if the oil accumulations are present at a depth not exceeding (1300 feet, the Elbof methods’ will not only locate them, but also approximately delimit their boundaries. The suitable sites for the oil wells are then selected, and futile drilling is thereby avoided. MISTAKES OF THE PAST. Many an oilfield that might have been a considerable producer has no doubt been abandoned because the drilling has not. been done in the proper location—the oil accumulations or storages have been missed. A preliminary geophysical survey would either have shown the futility of putting down any boreholes, or indicated the exact spots where the wells should be bored. A notable recent instance of the great /alue of geophysical research on an oilfield will be enlightening. In Texas, U.S.A., one of the leading American oil groups had been prospecting for a long time at enormous cost without success on a new field that had been strongly recommended for exploration after a careful detailed geological survey, The as sumed oil reservoirs could not be located. As a last resort, the services of an Elbof group were secured, and the resultant geophysical survey plainly indicated the exact locations of the oil accumulations, which were soon afterwards tapped by the drill, and another source of petroleum, which might otherwise have remained hidden, was made available.

ACCURACY OF SURVEYS. Numerous similar instances will doubtless be given by Dr. Krahmann in the course of his projected lectures, as he has stated in a treatise published lAst year by the National Geological Institute of Berlin, that “Oil deposits, in all the surveys hitherto carried out, have been clearly indicated.” At the International Oil-boring Congress held at Budapest in October, 1925, Dr. Krahmann delivered a lecture on “The geophysical methods and their employment in connection with oil exploration,” and at its conclusion Professor Dr. Mrazeg, the president of the Congress Committee, made the following signifiefiant comment:— “Dr. Krahmann showed us results of the most vital importance through the employment of geophysical methods. . . The advance in this science is astounding. . . One must confess, in regara to these instruments of geophysical electrical survey, to have realised at last the most important prospecting apparati. They are destined, perhaps during the next ten years, to cause a revolution not alone in the practical science of exploration for mineral ores and oil. but also in our whole knowledge of the strata of the earth.” It is hoped that the enterprise and foresight of Coal, Oil (N.Z.), Limited, in introducing these scientific earth investigations to New Zealand, for the purpose of surveying the extensive petroliferous areas neld by the Company, will be rewarded with complete success, as thecrying need of tne South Pacific is the adequate production of petroleum, the Commonwealth and the Dominion having at present to depend almost entiraly upon the importation of liquid fuals.