MURCHISON OILFIELDS

Hokitika Guardian, 17 May 1926, Page 4

MURCHISON OILFIELDS

A good deal of interest is being taken at the present time in the drilling’' operations undertaken by the Murchison, Oil Company. Oil lias been known for many years, to have, been floating in more or less quantities down the Rullcr River. Percolations or seepages through surface rocks into various creeks running into the Maruia, Matakitaki and Manglees—tributaries of the Bullcr—have been found from time time but no systematic search for the'oil reservoirs from which- these seepages came Rive ever been made till the present Company was formed to bore for the oil wells supposed to exist in the Mangles and Blackwafer Valleys. Some years ago three seepages if oil were found at the head waters of the Warwick—a. tribuflary of the Maruia. One day some bushmen were felling timber. At dinner time one of the party was told off to "bail the billy.” ell filled the billy at a nearby stream. When the party sat down to dinner and tasted the lea none could drink it and the culprit who made it got no small amount of chaff for making the tea from water lie had cleaned the cylinders of his motor cycle with. Of course lie stoutly denied the soft impeachment and took the party to the creek from which the dipped the water. On the water being tasted there was no doubt that- it. tasted of petroleum, also the smell was- quite apparent. This led to the formation of a Syndicate' which made some enquiries into the prospects of a payable oil field in the district. Mr John Bassett, of Hokitika, and some others then took up areas in the vicinity.

Some Auckland gentlemen interested themselves in the matter and a Com-

pany was formed. Mr Spencer, the promoter of the Papuan Oilfields, and an oil engineer of no mean repute, was brought over to investigate and report. He reported most favourably on the field as a rich oil producing country and after investigating the several oil seepages and strata-graphieal structure ultimately fixed upon the Mangles as the best site for commencing operations, partly because there were several good seepages of oil in the valley and nearby was a strong exit of gas from the rocks. Mr Spencer in Ins report says:—"L was particularly fortunate in having the services of Mr John Bassett, whose long experience and close knowledge of the district was a prominent factor in deciding my visit to Murchison from tlie Mandated Territory of Xew Guinea, in which region 1 had. ill .Tune last, lifted payable oil of 'try high quality. Air Bassett’s lucid description of the Afurehison district, by letter, convinced me that similar slra-ta-gralipieal conditions obtained in the Mangles River area to that in Xew Guinea, Sumatra and Borneo.. Aly 10cent observations fully justified this assumption. Included in the area is a stretch of about live miles along the Afangles River in which oil seepages and gas evolutions exist. Petroleum and gas are steadily issuing from the sandstone with an excessive dip. Higher up the river the dips flatten out to almost 10 degrees.” The Dominion Analyst reported that a speciinent of the Afurehison oils sent to him contained as much as 27.5 per cent of benzine, 32.5 per cent, burning 1 oil and 32.0 per cent of lubricating oil. ending bis report with ‘‘This is j crude petroleum of excellent quality.” I Fortified with these and other ro- , ports the directors purchased a drilling plant and early tins year commenced I drilling operations. The drilling is in full operation. ! averaging a little over 20 feet per day. I The drill hole is now down 37G feet. The strata, passed through has been mostly composed of sandstone with a I good deal of lime in it and thin hands lof very pure limestone. The hole has I reached a big bed of grey mudstone and as there is some water in the hole j tho engineer in charge has stopped , drilling to put in a 10-inch casing i which he wants to end in the mudj stone as he considers at this point, he can better stop the water getting into the pipe than at, any other time. The engineer is well pleased with the geological structure passed through, being mostly a hard sandstone.' This is followed by the mudstone. The next strata is hoped to he tho Silurian or shale and beneath tlint the porous strata which contains the. oil. Tn some places ‘Xaturo” says Brice in "The New Geology (1023)” Ins often performed the extraction of oils on a gigantic scale, the percolating waters j having carried the oil with them and , accumulated it under heavy pressure I in porobs sandstones or .conglomerates where the oil may lie found in -a vast sheet lying on the top of the water, with some impervious layer of rock situated above it. like a shale, or clay bed which keens the oil (and its associated gasses) from rising to a higher level.” And Schurchert says:—"Oil and gas are usually found ill the flattened tops of depressed geologic arches and lown the slopes anticlines where (he dip of the strata is arrested so ns to form shelves or terrace (“the terrace structure” of oil experts) but there is ’always above the productive, zones an impervious and usually a thick shale cover.” Broadly stated “the thicker the shale formation, the more impervious the cover; the deeper the storeago bed, the richer the gas or oilfield.” The author (Pri.ee) spmking of the formation of oils says:—“Tn some instances, marine invertebrates or c\en microscopic organisms, may have "on- . tributed largely to produce the organic materials from which these oils have been derived. Afore often, however, it seems to blare been fish or even < mamalian remains. At Lompoc, Cali-1 j fornia. and in many similar formations ( the petroleum in the rocks very evi- I ( :lently came from millions of fish there entombed.” j At the Afangles tho Geologists say j that the structure of the rocks is most j, lavourahle for tho formation of oil ■ | itorages and that the seepages through j,

:ke rocks are forced from below by the ipwanl pressure of water and oil. The

oil being the lighter floats on top of the water and as the oil is formed it is forced upward through cracks in the rocks, [fence the seepnges of oil and gas evolutions. Time alone can tell whether the oil reservoirs or pools at Mangles are cx- j tensive enough to give payable results j but the great length of the anticline | and other indications point to this ns | being a most successful venture. j