OIL EXPLORATION

Poverty Bay Herald, Volume LV, Issue 17438, 9 April 1931, Page 8

OIL EXPLORATION

CHANGE OF SITE NEW WELL AT WAITANGI AVOIDING DRILLING TROUBLE After an exhaustive effort to overcome the drilling difficulties in the Waitangi No. 1 well, Taranaki (N.Z.) Oil Fields, N.L., has decided to remove its operations to another part of tho dome, abandoning the well already started on that dome, and carried down to nearly J7CCft. The decision of the. oil exploration company is conveyed in the following announcement, made available to-day for publication : "The more satisfactory development in the Waitangi No. 1 wejl last week, which encouraged, the hope that.it would be found possible to make further footage, unfortunately did not continue, and after giving further consideration to the situation, the board has decided on the advice of the management that economy of both time and money will be effected by moving the plant a short distance to the north to the loca tiou which was fixed from the second test of this structure, and upon which a considerable amount of preparatory work has already been done. As the overburden of tertiary strata and tho uppermost shale bed of the cretaceous series, which latter has proved so difficult to drill, are non-existent at the location of this second test well, it is believed that drilling conditions will prove quite satisfactory. An indication of the date by which it is expected that drilling will 'be resumed at the No. 2 location will be gnven within a few days." CHANGE FORESHADOWED It was indicated in a notice given last week that .drilling difficulties had caused much delay in connection with the No. 1 well tin the Waitangi dome, and that a change of location was possible. The circumstances which impelled the. directorate to, issue that notice were reviewed to-day by the general manager of Taranaki (N.Z.) Oil Fields. N.L.. Mr. A. H. P. Moline, in a conversation with a pressman, the information given by Mr. Moline being of general interesi to the public, as well a,4 of particular interest to investors in the company's shares, The tertiary overburden to which reference, is made in the company's report, and also the uppermost .bed of the cretaceous series, were penetrated by the drill to a depth of 1682 ft at one stage, but it was found impossible 1o sink the well any deeper owing to trouble developing between 900 and ISCOI't, much of the ground between those two points consisting of dry porous shale. Repeatedly the hole was parially closed by the swelling of the shale, probably as a result of the absorption of water from the liquid mud pumped into the well from the surface as part of the drilling routine. This encroachment on the hole between 900 and 1300 ft made it necessary to ream the hole several times. There were, however, indications that eventually the difficulty would be overcome, and it was only with the greatest reluctance that the management considered the possibility of abandoning the hole. It was held that the site of No. 1 well was the most promising for a quick return of oil on the Waitangi dome, as it was anticipated that oil-bearing sand.would be encontended at a depth not greater than 2000 ft. For this reason, the drilling difficulties were tackled time and again, and it was not until the hole closed up completely at 130Cl't. that abandonment of the site was decided on.

Had it been possible to run casing down to 1200 or 1300 ft. in this well, the trouble might perhaps have been overcome, but the well was never in a condition to permit wising to he run at any time since a depth of about 1200 H. was reached. The final closing of the well occurred just before the Easter holidays, and in the meantime the directors in Melbourne have been considering reports of the management witli a view to determining on what part of the extensive Waitangi structure future 'operations should he concentrated. A DEEP-WELL TEST The decision announced to-day is one that involves the possibility of drilling a deep well in an exhaustive test of the structure. Whereas the Waitangi No. 1 site was calculated to produce oil at a comparatively shallow depth, and was for Chat reason selected for the first attempt by Taranaki (N.Z.) Oil Fields, N.L. to develop this field, the No. 2 site offers the best chance of big pro; diction though it is recognised that It may be necessary to drill a deep well in order to reach Lije oil-bearing sands. There is good reason to expect good drilling conditions al No. 2 well, which should enable the company to carry the test down to whatever depth may prove necessary. Tho selection of Waitangi No. 2 site, as well as that site for the No. 1 well, was made on the recommendation of Mr,. J']. K>. MacPherson, senior geologist to the company, who made a comprehensive geological survey of the locality last year, and has done a> considerable amount of additional work on the structure iii the past few months, gaining further data. The company's, senior geologist is of the opinion that the beds in which the No. 2 well will be- sunk are similar lithologically to those in which the VVaiapu No. 1 well was drilled, that well giving less trouble in the sinking than any other undertaken by Taranaki Oil Fields in its explorations to date. Mr. Molino emphasised, in conveying this information to Hie Herald's representative, that while there is a marked similarity in tho beds, structural conditions at Waitangi are very different from those existing at the Waiapu No. 1 well, and are very much more favorable. There is not the slightest doubt of the existence of oil at Waitangi, and the company's work is directed to proving whether it is there in commercial quantities, as is liopod- In tho case of tho> No. 2 site, there soems to be less likelihood of oil being found at shallow depths than there was at the No. 1 site, but the possibility is not discarded. The management, however, is laying plans for making a deep test of the structure should 1 thai prove to lie necessary. ft is proposed to continue the work through the winter months, despite the considerable transport handicaps imposed by the undeveloped access road to tho camp. This road has been open throughout the summer, the drought conditions being favorable to the operations of the company, but with the break in the weather delays are, possible and even probable, as for several miles the road traverses the bed of the Mangata/luipmi creek.