OIL INDICATIONS AT WAIPU.

Auckland Star, Volume LIII, Issue 227, 25 September 1922, Page 3

OIL INDICATIONS AT WAIPU.

A FAVOURABLE REPORT. Of special interest to residents in the Waipu district is the report of the geologioa.] _.-UTvev of that district 'issued by the Mines liepartment. It points out that the even crests and flat tops of the ridges, in the eastern half of the district indicate erosion from an extensive plateau. Under the heading "Oil Indications," appears the following information: "An oil seepage has been known at Rotokautuku for more than half a century and led the Southern Cross Petroleum Company to bore there in 1881-S. At the present time gas and salt water are risimz from the oUI s>haft. and each gas bubble brings to the surface a film of oil. In sandstone at the top of the Tapuwaeroa beds, thin irregular cracks one-twentieth of an inch thick and several inches long are filled with a dark pitch. Many small gas vents occur scat. tered throughout the subdivision. Sample* .from 20 of these have been analysed, and aM are wet, the ethane, they contain ranging up to 22 per cent. A 'wet' gas contains appreciable quantities of hydrocarbons higher in the series than methane. Wet _ras is everywhere considered a favourable indication of oil. It is obvious that tbe heavier j and wetter a gas, the more favourable | the evidence of presence of oil in the I neighbourhood. Though there may be , steady and brisk flows of gas or gas wells at a locality, it does not prove that i oil can be obtained by drilling there. j ■but should the gas be heavy, with a fair j percentage of and a strong odour of j hydrocarbons higher in the series than ! methane, the prospector will be justified j in concluding that a body of liquid hydrocarbon is somewhere in the neigh-: bourhood. These oil indications justify the conclusion that a body of liquid j hydrocarbons exist in the district, j Whether the oil ie concentrated in pe.v- ] able quantities can, of course, be deter- j mined only by drilling. Haphazard drill- j ing is. however, too risky and too expen- | sive, and mod-™ oilfield practice is,based i on geology as the only means in advance of diriittini? by which anything of the underground "conditions can be ascertained." I I