The “striking of oil” at Moturoa, near the Town of New Plymouth, at a depth exceeding 2,000 ft., has again drawn attention to the oil-prospects along the east coast of this Island. For many years Poverty Bay has been regarded as the centre of an oil district of large extent, and in the years gone by, when travelling and means of conveyance were both difficult and expensive, quite a number of “enterprises” were undertaken in the hope of striking oil by those who knew something of American enterprises and had faith in a payable oil-field being discovered within the limits of Poverty Bay And so long ago as eighteen years the news was spread over the colony that oil had been struck by the South Pacific Company. Speculation at the time ran high as to whether the news was a mere flash in the pan—a repetition of many similar reported successes—for a successful oil-well at that time meant much for the future prosperity of Poverty Bay and for the colony as a whole. Ten years previously a visit had been paid by me to the site where the first oil-bore had been attempted, on the top of a hill certainly 1,300 ft. above sea-level. At the time of my visit work had been stopped, but it was possible to collect in the well-holes scattered about a “barrel of crude petroleum. This site was subsequently abandoned, and a new bore was tried on the bank of a small stream known as Wairongamea, some five miles or so below the place of the first sinking, and not far from the junction of the stream with the Waipaoa River that flows into Poverty Bay. This place is about thirty miles to the north-west of Gisborne, and is situated, within an extensive district which geologically might be set down as Cretaceo-tertiary. Some distance further up the river, and near the junction of the Mangatu Stream with the Waipaoa, another well known as the Minerva was being put down by a company. This bore was about a mile or a little more from the Pacific Company's well. Having work to do within a few miles of the workings, and being interested in the alleged striking of oil, the opportunity was taken to visit the wells, and a paper in the Transactions for 1888 contains the results of my visit at that time.
The “striking of oil” had been followed by disaster, for an explosion had taken place, and the derrick had been burnt, and the tools lost in the well. There were, of course, rumours
that things were not satisfactory—in fact, it was said that a dray-load of kerosene had been sent from Gisborne to the well a few weeks previous to the explosion, and the inference was that the oil in the well-tube was none other than the kerosene that had been taken from Gisborne. Be that as it may, I visited the well in company with the late R. T. Walker, of the Hawke's Bay Herald, and we drew oil from the well that was certainly not kerosene. Since then till now I have kept a bottle of the crude oil, and the sample shown here is taken from the bottle into which the oil was put so long since. It will be seen that when held against the light it possesses a fine rich colour, almost rubyred, but otherwise it appears to possess a dull muddy-greenish tinge. The report that will be found in the context from an American manager of oil-wells will give information as to the quality of the oil. But when speculators grow suspicious, when “calls” are made upon investors in shares, and when times are bad, there is danger of a collapse unless directors can show something for the expenditure of large sums of money. And so it came to pass that the destruction of the derrick in the Pacific Company's well destroyed also public confidence, and soon afterwards the Minerva and Pacific bores were abandoned, and everything was sold that could be sold to meet liabilities.
Since then till now nothing has been done along the east coast in the way of further attempts at boring for oil, except that some years ago a gentleman from England, interested in oil, spent some time in Poverty Bay obtaining “options” in places where traces of oil or of gas-springs were known to exist. Those “options,” I am informed, are not now of any value, so that there appears no hindrance in the way of any one that chooses to try for oil in the places formerly worked.
The discovery of oil at Moturoa at a depth exceeding 2,000 ft. has brought up this question for reconsideration. The sinkings in the east coast district were not as deep by nearly 1,000 ft. as is the Moturoa bore. Fortunately a sectional copy of the Pacific Company's well is available, showing the general character of the various beds passed through in the 1,321 ft. of the Pacific Company's well. This section appears in vol. xxi of the New Zealand Transactions, and a comparison between it and the Moturoa well sections (Plate XXIV) should prove both suggestive and of value in any future work that may be undertaken to test the oil-deposits along the east coast of this Island.
Many years ago Sir James Hector, the late Director of the Geological Survey, published in one of his reports an account of the east coast district extending, I believe, from Hicks Bay to Poverty Bay. Unfortunately the report is not available in the library of our Institute, and whatever is stated here must be
the result of my own personal knowledge of the district under notice. The east coast district has been travelled by me for a period of twenty-eight years, and there are few places on the coast and inland for twenty-five miles that have not been visited during that time between Hicks Bay and the southern boundary of the old Hawke's Bay Provincial District—that is, for a distance of more than 320 miles. The facts referred to in this paper, however, will have reference to the district from the mouth of the Waiapu River in the north, nearly opposite East Cape Island, and Herbertville, locally known as Wainui.
The coast rocks that extend southwards from the Waiapu River belong to the Cretaceo-tertiary series. At Port Awanui they run into a remarkable variety of beds, from a coal-black and brown earthy type to a greenish and pale-blue clay rock as stiff and as sticky as the proverbial sticking-plaster. Sandstone grits are also met with, and the whole series is moving seawards, winter and summer alike, exactly like an enormous glacier. These rocks between Port Awanui and Reperoa, a distance of five miles, are seen to rest on an outcrop of the Maitai slates, which are exposed in a high bluff and extend for about half a mile along the coast. Between Reperoa and Tuparoa the country presents the same characteristics as along the coast already described. Gas-springs are met with here and there and inland, but striking to the south-west the same rock-characteristics continue. Between Tuparoa and Whareponga the lower beds are seen to be topped by the older Tertiaries, but these again disappear in the direction of Waipiro, so that at Aku Aku the Cretaceo-tertiaries again make their appearance, and continue along the coast to the southern end of Waipiro Bay, where they are topped by the Tawhiti sandstones, which have their connection with the conelike hills that are to be seen inland between Tokomarua Bay and Waipiro Bay. The road between these two places now runs inland and passes some fine hot springs, where also are to be seen some remarkable gas-holes, where sufficient gas is given off to supply the requirements of many households. The rocks in the vicinity of the springs belong to the Cretaceous series, and they are evidently in close connection with the green-tinged sandstones which appear in several places within a couple of miles of the springs. The rocks between Tokomarua Bay and Tolago Bay belong to the sandstone series, of which Tawhiti Hill, 1,750 ft., is an offshoot. The Uawa River, that empties itself into Tolago Bay, runs through the valley, and on either hand the hills are made up of fairly soft sandstones of a light-brown colour. The rocks on the north side of Tolago Bay are similar to those at Cape Kidnappers and at the mouth of the Mohaka River, and a pumice band about 15 in. in thickness, with Foraminifera
and other fossils, is met with. On the south side of Tolago Bay, as also in Cook's Cove adjoining, limestones appear, and are connected with the small islands that are seen on the north of the entrance to the bay. The hill that is crossed when going south from Tolago Bay towards Pakarae is made up of banded sandstone interbedded with a bluish sandy clay. It is fossiliferous, and belongs to the Miocene series. At Gable End Foreland the upper beds of the Cretaceo-tertiaries, with the characteristic greensands, again appear, and at Whangara, an island peninsula, the greensand tops blue clays interbedded with sandstone bands, but the black and brown shales are not exposed. They are seen, however, a little further along the coast, where there is the only other exposure of the Cretaceo-tertiaries until nearing Tua Motu Island, on the north side of Poverty Bay, where the sandstones again are met with and numerous gassprings make their appearance. At Whareongaonga, south of Poverty Bay, celebrated as the landin-gplace of Te Kooti on his escape from the Chathams in the “Rifleman,” the Cretaceotertiaries again appear, and there is a large development of sandstone between the Mahia and Nuhaka, where both hot springs and gas-springs abound, and limestones again are met with corresponding to the limestones at Tolago Bay. Inside Hawke's Bay the rocks are younger Tertiaries, and there is an absence of the older rocks; but proceeding along the coast to the south of the Kidnappers the rocks between Waimarama and Pourere are Cretaceo-tertiaries, and the green sandstone is very largely developed between Porangahau and Wainui, and gas-springs are fairly abundant there. All the exposures to which reference has been made show that the general strike of the beds is to the south-west, and the various roads inland from the coast pass across the strike of the beds; and the exposures show that the Cretaceo-tertiaries have a fairly wide distribution.
Similar characteristics are found in all the places named— that is, there are springs giving traces of oil or gas or salt. The well that has caused so much hope in Taranaki has reached a depth of 2,240 ft. This is nearly 1,000 ft. deeper than the deepest bore hitherto put down in the Poverty Bay district, as in the case of the Wairongamea well, and it may be worth while to continue the sinking further, as there are abundant traces of brackish water and gas and oil at the depth where work ceased.
The foregoing portion of my paper was written on Monday night, and on Wednesday last I received a letter from Akiteo dated the 1st September, as follows:—
“Dear sir,—Hearing from Mr. Somerville, Postmaster, Herbertville, that you are fond of geology and follow it up, I am sending you a piece of stone which when taken from the
reef is fairly saturated with kerosene. The reef smells strongly as you stand alongside. It was found by a metal-contractor who was getting metal for the road and put a shot in the reef, and when he found it the smell was very strong. The seams and the stone are quite damp and greasy, and smell very strong. What do you advise? Is there any way of testing in any way? What should we look for, &c.?
This illustrates the remark already made as to the east coast being in a large measure an oil-bearing area, and it is of the utmost importance that a more particular survey be made, so that specified areas may be tested to find out whether the oil-bearing beds lie below the 1,321 ft. which have already been tried, or whether the oil-bearing strata have been passed through without discovering the fact.
The height of the well above sea-level at Wairongamea is 450 ft., and oil-indications are met with much higher than this. At Port Awanui in the north, and at Herbertville in the south, the oil-shale beds are within 50 ft. of sea-level. To the north-west of Wairongamea, on the left bank of the Mangatu, similar shale-beds crop out 800 ft. or more above sea-level. At Waipawa, forty miles from Napier, the shales are exposed on the left bank of the river, near the brewery, 460 ft. above sea-level; and similar rocks occur in the hills overlooking Porangahau, 300 ft. above sea-level, and at Wimbledon and Weber, on the Wainui—Dannevirke Road. It will be seen from these remarks how widely distributed are the rocks that bear traces of containing oil.
In the early days of oil-explorations, and before “corners” had been heard of, the relationship between salt springs and petroleum was so intimate in American wells that in the case of oil-borers in certain districts “No salt, no oil” became a maxim among them. And in these days of discovery, when scores of districts are worked for “oil,” gas-springs, salt springs, and sulphurous waters are looked upon by experts as important indications of petroleum.
The oil-fields of the world are now so numerous that it would be difficult to enumerate all the districts where petroleum is obtained; but no doubt there are many places where oil will be struck when geological surveys will have been carried on systematically and proper records obtained of the surface-characteristics of a country. The greatest oil-producing countries at the present time are Russia, North America, Roumania, further India, Japan, the Dutch Indies, Italy, and Algiers; but Russia, the United States, and Roumania are the only three countries from which oil is exported—in other words, countries where the supply is in excess of each country's requirements.
As to the depth of wells, it appears that in the various oil-bearing districts there is a great difference in the depths, and even in the same district a greater depth has to be tried after wells have been running for some time, as it is found the pressure is constantly diminishing. The Pennsylvania wells have an average depth from 1,600 ft. to 1,800 ft., but some wells reach about 3,000 ft.; and in West Virginia they are numerous between 2,000 ft. and 3,000 ft., whilst one actually reaches 5,000 ft. In the Baku district, bordering on the Caspian Sea, the pumping - wells exceed 1,000 ft. in depth, and there are fountains of flowing ones much deeper than this; and the tendency year by year as new wells are put down is to sink deeper.
These varying depths are given here to show that the depth of the Moturoa well is not excessive. Wells situated within continental areas may be supposed to contain larger oil-bearing basins than in the case of islands like New Zealand, and overlying beds may become saturated with oil by the chemical changes that may be assumed to have been in progress for long periods of time. In the case of the Baku field, for instance, it occupies an area where the rocks at a little distance below the surface were so saturated with oil that large quantities were obtained from wells less than 100 ft. in depth; but these supplies have ceased, and deeper wells have been put down, as in America and elsewhere.
Regarding the depth that ought to be tried along the east coast, it seems that the question is one of location. Hitherto the sinkings have been inland and at a comparatively high elevation, but the experience of American and other oil-explorers shows that it is not essential at all to put down a bore in the vicinity of a petroleum-spring. The oil usually finds a means to escape along the lines of rocks that are much fractured and broken, whilst the actual source of the oil may be miles away. In putting down a well all indications favourable to the work should be taken into account, such as gas-springs, salt springs, accessibility and probable cost of carriage of material. Thus it has been suggested again and again that trial bores might be put down within a few miles of Gisborne at very little expense, and with quite as good prospects of testing for oil as at Mangatu. The rocks are certainly similar, and gas, salt, and sulphurous springs are met with near Tua Motu, where the rocks indicate the close proximity of the black shales by the appearance of the overlying greensands. The troughing of the beds gives an advantage in favour of the last-named place as compared with Mangatu, and should oil ever be struck along the line indicated the flow should be better towards the coast than at any place further inland.
It has been pointed out that petroleum is widely distributed over the earth's surface, but, although the indications in the different countries are generally similar, it is curious how widely the rock-formations differ in which the petroleum is found Thus, according to Professor Zuber, who is an authority on oil and its distribution, petroleum is found in every geological formation from the Silurian upwards. The oil-wells of Canada are supplied from Silurian rocks; those of the United States from Devonian; those in Argentine, Asia Minor, and Egypt from the Cretaceous system; and those in Italy, the Caucasus Roumania, and Burma mainly from the Tertiaries—lower or upper.
Professor Engler, another high authority on oil-fields, says that “petroleum formations always consist of bituminous clay shales and other (chiefly variegated) clays, alternating with sandstones and conglomerates, while the limestones which are met with in these formations always contain tarry matters though very rarely pure petroleum. Petroleum,” continues the professor, “occurs solely in sandstone rocks, and the most, reliable indications of the existence of petroleum are the occurrence of salt springs or salt beds and sulphuretted-hydrogen springs.” This information is of value to the geologist in making observations favourable to the occurrence of a petroleum basin. The characteristics here indicated are to be found irrespective of formation or geological age, and certainly, if there are indications of underlying beds of petroleum, there can hardly be reason to doubt that the petroleum-beds of the east coast are fairly extensive.
Another point of importance deserves to be noticed in connection with what is known as the “crude oil.” It has been explained that petroleum is not limited to a particular system or rock-formation, and just as the formations differ so do the qualities and varieties of petroleum obtained. In the trade it has been laid down by Professor Mabery that four special kinds or types of petroleum are derived from the wells. These are paraffin petroleum, Russian or napthene petroleum, sulphur petroleum, and nitrogen petroleum. In the first, paraffins are found in the largest proportion; in the second, napthenes; whilst in the third and fourth there is either a trace of sulphur or of nitrogen.
The origin of petroleum is not known. There are various theories, some chemists holding it to be of vegetable origin, others of animal, whilst others, among whom may be named the famous Russian chemist, Professor Mendelieff, affirm that it is of chemical origin.
As showing the closeness of the compositions of coal and
petroleum respectively the following percentages are interesting:—
[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]
But although the percentages approximate each other in the case of carbon, the inference cannot be accepted that they have the same origin.
In the case of the rock sent to me from Akiteo, it is certainly saturated with oil that has the smell of petroleum. The rock is a greensand, and is always present with the black earthy-looking shales scattered along the east coast in the places indicated, and which contain traces of fish-scales, small hollow whitish tubes, and an abundance of gas. The greensands are more largely developed in certain localities to the south of the Kidnappers than further north, and they have their greatest development in the line of hills running parallel to the coast between Porangahau and Herbertville, Cook's Tooth being the culminating point. In the Poverty Bay district the greensands beginning at Whangara strike to the south-west, cross the upper portion of the Waimata Valley, and appear in the range of hills that contains the petroleum-springs where the first attempts were made to put down a well. They continue to the south-west, where the greensands meet, at Whakarau, the light sandstones similar to those between Waipiro Bay and Tokomarua Bay. They appear to run in the direction of Waikaremoana, and it may be that the range of sandhills in the Wharekopae district, owned by Murphy brothers, belong to the series, but I have not been sufficiently close to determine their age.
More than once remarks have been made as to the benefits that would accrue to the country were the Government to undertake trial bores for water, for oil, for coal, and even for gold. If there should be a failure the country as a whole sustains the loss, and if success is obtained the rights to sink or mine should be put up to public auction for a term of years, just as land is put up to lease for a term of years. The State equally with individuals would derive benefit by this plan. That there are numerous traces of oil throughout the whole of the district indicated is evident to the most superficial observer, and trial bores would have been made long ere this had the Government taken in hand the testing for minerals for the common benefit. The State is able to carry out detail work in geological matters better than a private individual. To go over a large extent of unbroken country at any time is by no means an easy task,
but geology necessitates careful inspection, and inspection means expense. Unless, therefore, we can afford to spend generously both time and money, geological detail work cannot be carried out over any extensive area of country. We hear now and again a good deal about technical education, but one has yet to learn what has been and is being done to further scientific investigation by research methods. The country might easily benefit a thousandfold by the mere establishment of funds for the purpose of helping those capable of carrying out research work. The collecting of facts all bearing upon the question of petroleum need not be either a costly or a difficult undertaking were proper means taken, and there can be no doubt whatever as to the likely benefits that would accrue to the country. But, as in my own case, it is possible to traverse a whole district for several hundred miles from north to south and for fifty miles from east to west, and know all the characteristic rocks, but field geology requires more than this, for it needs patient observation and the keeping of all records as to the character of the rocks, the dip and strike of beds, the location of springs and places of suggestive importance.
These remarks are here made in the hope of directing attention to the duty of Parliament in relation to the practical application of scientific information. There is no need to encourage speculation for the discovery of a payable oil-field along the east coast, but there is need for the State to supply to the people that practical information, based upon inquiry and experiments, that will determine the course to be taken in searching for oil. And as showing the importance of the question, I venture to indicate a line of country to the south of the Kidnappers, and to the north of the Mahia Peninsula, that ought to be fully investigated. These places are between Pourere and Herbertville on the coast, and Waikopiro and Weber inland, in the south, and between Te Mahia and Morere, and Pakarae and Whakarau on the Motu Road, in the north. These districts contain all the characteristics that are to be found in the important oil-bearing districts in America, in Asia, and in Europe, but they require investigating in detail and tests made with a view to the discovery of payable petroleum. Having traversed the districts for more than a quarter of a century, and being acquainted with the general character and distribution of the oil-bearing rocks and the location of wells—oil, gaseous, and mineral—I am convinced that a proper geological survey would pay many times over for the work that must be done and would readily be done but for the fact that a private and non-interested party cannot be expected to carry out work that properly belongs to a Government undertaking.
As to the quality of the petroleum found in New Zealand, the following copy of a letter that appeared in the Poverty Bay Herald of the 11th December, 1887, from Mr. P. G. McPherson, manager of the Pacific Coast Oil Company of San Francisco, will suffice. A sample of the oil from the Minerva well was sent to him by Mr. J. H. Stubbs, and he replied,—
“Yours of October 8th, 1885, was duly received, also sample of oil so kindly sent by you. I take pleasure in giving you the results of its distillation at our refinery. The oil proves to be exceedingly sweet, easily distilled and treated, furnishing an illuminating-oil of fine quality and high fire-test, and the largest percentage of same of any oil I have seen; in fact, I can say it is the best sample of crude petroleum that I have ever examined in an experience of twenty-five years. The same as received was 79 gravity, and yielded an illuminating-oil of 94.4 per cent.; paraffin, 2.95 per cent.; waste or loss, 2.55 per cent.: total, 100. Fire test was 190°. Should you obtain this oil in payable quantities its fine natural qualities would enable you to refine the same with works of exceedingly inexpensive construction.”
I do not know whether any other analyses of the Poverty Bay oil were made, but the oil in my possession will be forwarded to Mr. Aston, the Government chemist in Wellington, and it will be discovered whether it is a natural oil or whether previously distilled oil was used in making it up.
Of the Moturoa petroleum as stated in the Taranaki company's prospectus, Professor Easterfield, of Wellington, reports:—
“I have examined the crude petroleum sent by you on the 6th instant, and certified as having been drawn in Mr.— — —'s presence:—
“The crude oil: The sample was of a greenish colour, red in transmitted light, without offensive smell. It was semi-solid at the ordinary temperature but completely liquid at 80° Fahr. It contains sufficient volatile matters to flash at the ordinary temperature. The specific gravity was 0.84 at 65° Fahr. The sample was free from water and grit.
“Distillation test: When distilled the oil gave the following products:—
[The section below cannot be correctly rendered as it contains complex formatting. See the image of the page for a more accurate rendering.]
|Benzine, distilling between 55° and 150° C||20|
|Burning-oil, distilling between 150° and 300° C||40|
|Heavy oil for lubricating, between 300° and 440° C||37|
It will be noticed that the qualities of the Poverty Bay and
Taranaki oils are widely different, the former being similar to the Pennsylvania oil in the very high percentage of kerosene that is in it, whilst the Taranaki oil belongs to the Caucasus or Baku series—the naphthene series—which produces a less percentage of kerosene but a larger percentage of oils suitable as a lubricant or even as fuel.
The oil from the first well attempted in Poverty Bay when drawn had a pale light-muddy-green tinge if held up to the light, but this appearance was not noticed in the oil collected on the surface of the water in the springs. The greenish tinge was similar in colour to the greensand rock when hammered and mixed with water, and which is characteristic in the Cretaceotertiary oil-beds along the east coast. The greensand is composed of rotten quartz, feldspar, and minute black specks scattered through the mass. It may be that the minute black particles, which are lustrous like pitch, are bitumen, but I do not think so; still, the matter is one for the chemist to decide. The greensandstone seems to be impregnated with oil, possibly from the underlying beds, and should the minute particles be bitumen they were probably formed by the evaporation, solidification, and consequent partial oxidation of the petroleum gases. But this is merely a suggestion.
The sketch-map accompanying this paper indicates the location of oil-springs, gas-springs, &c., personally known to me. Many others are no doubt known to shepherds and settlers in the more remote districts, but interest in the discovery of oil along the east coast had almost died away in Poverty Bay until the news was spread that oil had been struck near New Plymouth at a depth exceeding 2,000 ft. Already there is evidence of growing interest, and more than one inquiry has been made to me by outside parties anxious to know the most likely places for trial bores.
I have seen the oil from three widely separate localities in the east coast north of the Mahia Peninsula, and the rock from Akiteo furnishes another proof that the gas-springs, oil-shales, and other gas-bearing rocks are connected with petroleum districts in the southern portion of the Hawke's Bay District. For several years I have been aware of curious gas-bearing rocks between Waikopiro and Wallingford, and gas and salt springs certainly occur in the same locality. But careful geological investigation is wanted, and this it is the duty of the Government to undertake, just as they undertake the search for gold and coal and other minerals.
My purpose to-night is merely to direct attention to the great possibilities of the east coast should petroleum oil-beds be struck, as in the case of Taranaki. Trial bores can settle the
question, and these, after a proper geological survey, the Government ought to undertake, to assure to the people as a whole benefits to which all are entitled.
Inland the rocks are more broken and shattered than towards the coast, and so the oil reaches the surface by means of the fractures, it being forced upward by the gases that are seeking an exit. But the practical tests must settle the question. As far as my own personal knowledge goes I have indicated the location of the greensands and oil-bearing shales, and it is for those who desire to obtain oil and who have faith in the facts to put theory to the test, or else call on the Government to carry out a proper geological survey, with a view to obtaining more reliable data than I have been able to give here.