THE QUEST FOR OIL.

Poverty Bay Herald, Volume XXXIX, Issue 12815, 15 July 1912, Page 5

THE QUEST FOR OIL.

N.Z. OILFIELDS COS NEW "PLANT

Mr C. I\ Williams, Avho has had considerable experience on the oilfields of' Russia, Trinidad, Persia, and other fields, and who was sent out from London to report on tho properties of the New Zealand Oilfields, Ltd., Avith a view to overcoming the drilling problem, which up to ,the present has been _n insurmountable difficulty td the exploiting of v Poverty Bay as an oil-producing centre, after mature deliberation advised the installation of a rotary drilling plant, capable of boring to a depth of 4COO feet if necessary. As this is the .first rotary m Australasia; the folloAving description may be of interest: — The Elant Avas manufactured by the Oil Well upply Co. of America and shipped through their agehcy m Los Angelos, and is under the supervision of Mr J. C.' White, who is an exeprt of the rotary drill, and has had considerable experience on the' Califbrnian and other fields throughout America. The rotary drill is , furnished with a geared table, which is designed m such a Avay as to rotate the flushing rods and also the casing if desired. A hollow cast iron table with bevel gearing on itlower outer edge works freely on a base plate, to Avhich is led a shaft Avith a mitre pinion engaging with the bevel gearing of the table. ; Ori the upper face of the table is fitted a device by Avhichi casing or rods of any size beween 2_ and 14 inches can be firmly held by grip rings Avhich, whilst holding the casing or rods, enables them tb move readily m a vertical direction. The driving shaft is provided with a clutch for throwing the rotary table m and out of gear; and the motion is transmitted by a driving chain engaging m sprocket wheels. To one side of the derrick is fitted a wooden frameAvork, on which are two shafts connected, by a transmission chain working on sprocket wheels. The driving shaft receives the drive by chain from the engine, and' on the second' shaft is fitted a' hoisting drum with brake pulley for manipulating the pulley rope that . operates the casing or rods'. To alloAv for tiie rotation and descent of the rods a specially constructed liy> draulip swivel is attached' to 1 a cap which screAvp into the top of .the rods,,; and; d flexible, armored,, rubber hose .extends: from the swivel to, tho pump. The rods and., swivel attachments' are suspended by ai hook from pulley blboks manipulated by the aforementioned hoisting, drum so that the rods can be, lowered, as required-. The bits are, lbwered- on>.specially strong, 4ih pipes in* lengths- of 18 tto** 1 20 ft*. DuplUx direct driven steam *, pumps iarie employed, specially made to-take muddy* water, with^oapacitie's oMSO t0. 200 gaU: lons per minute AvijLh a pi*essureva,rying' from 150 tpV3OQ have two. pumps coupled^! to the, tubing: connected; Avith the swivelj, so thai m the event of one- failing ,the, : seoondi can be started m a few minutea;. The •water is pumped doyrn, the casing : or. fubes'f. at a pressure which ensures sufficient velocity.! m the space behind the flushing tubes to raise the particles of sand and detached debris to the surface. The quantity of water needed varies immensely with the absorptive capacity of the strata penetrated and the character .of the beds. When highly porous sands are penetrated, the whole of the Avater pumped down . the well ' will often be absorbed and ho . liquid Avill reach tbe surface. In such cases it is only possible to make progress by mixing clay with water and pumping down the Avell a thick; puddle which enters-, the pores of the sand and* renders them partly, if not entirely, impermeable. By the liberal employment of thick clay puddle, highly porous gravels and even badly caving ground can be passed and cased off. The rotary system, Avhich has revolutionised drilling m several fields, both m America and elsewhere, proved on a trial here last week to be the only system AvHidh vyill overcome the difficult formation of this district.