Towa.:ccis the end of 1960 , the Bureau. of Mineral Resources, Geology and Geophysics made a brief seismic survey in the Winton area of Queensland to resolve an apparent contradiction between the interpretations of gravity and aeromagnetic results previously obtained in the area. Gravity and aeromagnetic results both suggested the occurrence of a large fault or fault zone about 20 miles north-west of Winton, but the gravity and aeromagnetic interpretations differed regarding the direction of throw of the fault. A nine-mile seismic reflection traverse was surveyed across the supposed fault. The seismic results indicate the presence of a large fault or monoclinal fold with dowthrown side nouth-wast as suggested by the gravity values and also a smaller fault or monocline about two miles south-east with downthrown side south-east. The variations in thckness of Mesozoic rocks caused by these features were insufficient to explain the observed Bouguer gravity anomaly values, but the seismic results left open the possibilitues that there may be a considerable thickness of pre-Mesozoic sedimemts north-west of the main monocline or fault. It is postulated that the steep gravity gradient observed may be due to a large fault whose main movement took place in pre-Mesozoic times. Indications are that there is 5000 to 6000 ft of Mesozoic sediments in tha area.

A seismic velocity survey of the APM Development Pty Limited No. 1 bore at Rosedale, Victoria, was made by the Geophysical Branch of the Bureau on the 3rd May 1960 using a TIC three-component well geophone. Measurements were taken with the geophone suspended in the well at selected intervals down to 5500 ft. It was apparent that signals reached the geophone by transmission along the cable by which it was suspended, and these interfered with the signals reaching the geophone along a path directly through the ground. This made interpretation difficult; however, by careful inspection of both the vertical and horizontal components of the signals received by the geophone at each depth, an interpretation has been made that yields a series of velocity/depth determinations. The average vertical velocity increases from 5000 ft/sec at the surface to 8930 ft/sec at a depth of 5500 ft. The average velocity in the Tertiary (0-2159 ft below datum) was computed to be 6420 ft/sec; the -werage velocity in the Mesozoic rocks penetrated (2159-5314 ft below datum) was 12,180 ft/sec. Two reflection spreads laid out and recorded in the vicinity of the bore showed the presence of reflectors at depths estimated to be in excess of 7700ft.

Between April and July 1962, a seismic party from the Bureau of Mineral Resources, Geology and Geophysics made a seismic reflection and refraction survey in the Moree area of New South Wales. The main purpose of the survey was to investigate whether the southern extension of the Bowen Basin beneath the Great Artesian Basin from Meandarra to Toobeah continued as far south as Moree and joined the Sydney Basin. Three east-west traverses were shot using a method of reconnaissance reflection shooting, the first near Dolgelly Bore, the second through Moree, and the third through Bellata. The third traverse was extended eastward as far as the Horton River to investigate the Hunter-Bowen Thrust zone. In addition, three north-south refraction traverses were shot in the middle, and on both ends, of the east-west traverse through Moree. A north-south reflection traverse was shot north of Dolgelly Bore.Results in the Moree and Bellata areas were of poor quality and in the Bellata area in particular, owing to surface basalt flows, little information was obtained. The Hunter-Bowen Thrust area was not distinguished by the seismic work. The seismic results indicated that the trough of sediments extending southwards through Dolgelly Bore was at least 7500 ft deep south of Dolgelly Bore. The eastern margin of the trough is probably an overthrust fault. In the Moree area, two troughs were indicated, viz. the Biniguy Trough in the east where about 7000 ft of sediments was estimated separated by the Pallamallawa Ridge from the Moree Trough in the west where about 11,000 ft of sediments was estimated. Poor results in the Bellata area failed to indicate whether the Moree Trough joined the Sydney Basin.

A seismic survey, consisting of a main north-south reflection traverse and several short supplementary reflection and refraction traverses, was made in the Gosses Bluff area, of the Amadeus Basin,Northern Territory by a seismic party of the Bureau of Mineral Resources, Geology and Geophysics between March and July 1962. The purpose of the survey was to obtain information on the lli.ssionary Plain Syncline, the Gosses Bluff uplift; the fault at the northenl flank of the Gardiner Range, and the tectonic features relative to the Archaean/sedimentary contact at the northern edge of the Missionary Plain. The seismic reflection method proved to be an excellent exploratory tool in the undisturbed parts of the sedimentary basin. The Missionary Plain Syncline was shovm. to have a maximum thickness of sediments of 33,000 ft, nine miles north of Gosses Bluff. The results indicate that Gosses Bluff is a diapiric structure of the salt dome type, where the Proterozoic Bitter Springs Limestone has provided the necessary mobile material. The Gardiner Range Fault was shown to be overthrust from the south vdth a hade of 15 to 20 degrees. The problem regarding the Archaean/sedimentary contact was not solved.

Seismic reflection studies in the Perth Basin, between the coast and the Darling Range, 30 miles north of Perth, were conducted in an attempt to derive a suitable recording technique for obtaining reflections when shooting on the Coastal Limestone formation, to investigate geological structure in the basin,and to supplement hydrological studies being madeby the Geological Survey of Western Australia. Experimental work occupying half of the survey period failed to yield a technique for obtaining seismic reflections on the Coastal Limestone, but led to reflections being obtained across the major part of the basin, Record quality with a fairly heavy technique was poor to fair in the western half of the basin off the Coastal Limestone but improved considerably to the east. A complex geological section in the west gave way to a more concordant thick synclinal section in the east, terminated at its eastern end by the Darling Fault. Of interest is an apparent anticlinal reversal of dip in beds lying deeper than 7000 ft,with the reversal axis near the centre of the major gravity 'low' of the basin.

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This publication combines the completion reports of two wells drilled at Port Campbell in the Otway Basin, Victoria, by Frome-Broken Hill Company Proprietary Limited in 1959 and 1960. Port Campbell No. 1 was located near the crest of a seismic "high". The seismic reflection survey showed that there was an increase in thickness of section down dip to the south-east; Port Campbell No. 2 Well was sited about 1-3/4 miles south-east of Port Campbell No. 1. Port Campbell No. 1 Well was spudded in on 9th September, 1959, and reached a total depth of 5965 feet inparalic sediments of Lower Cretaceous age on 9th December, 1959. Miocene and Oligocene marl and calcareous clay were penetrated to 1375 feet, then more than 3000 feet of Lower Tertiary, Eocene and (?)Palaeocene,and 1000 feet of Cretaceous sediments. The only break evident in the succession in Port Campbell No. 1 was at 5656 feet where a lithological change was noted together with a conspicuous break on the electric log. At this depth the well intersected a porous horizon which produced a flow of petroliferous gas. Drilling commenced at Port Campbell No. 2 on 12th July, 196q and was completed on 1st December, 1960, at 8846 feet in sediments of the Otway Group. 1214 feet of Upper Tertiary (Miocene and Oligocene) and approximately 3800 feet of Lower Tertiary (Eocene and Palaeocene) sediments were intersected. Time boundaries are still indefinite but at least 2700 feet of Cretaceous sediments are thought to be present in the well. Two unconformities were deduced: the upper at 7910 feet, between the Waarre Formation and the Belfast Mudstone, corresponds to the break at 5656 feet in Port Campbell No. 1, but represents a hiatus smaller than that in the earlier well as an extra 770 feet (approximately) of basal Belfast Mudstone and topmost Waarre Formation are present in Port Campbell No. 2.* The lower unconformity separates the Waarre Formation and the Otway Group on a horizon lower. than was reached in Port Campbell No. 1, but it was not well defined by the information derived from the one hole. The petroliferous gas, and a small amount of condensate, produced in Port Campbell No. 1 was a strong but not commercial flow and came from a coarse quartz sandstone between 5656 and 5668 feet. On test, flow rate and pressure decreased rather rapidly and recovery, on standing, was practically imperceptible, indicating that the reservoir is small and not connected with any larger reservoir. Port Campbell No. 2 did not show any evidence of free gas or oil. The gas obtained from testing was only minor and derived from solution in formation water.

A,A.O. Pickanjinnie No. 1 was drilled by Associated Australian Oilfields N.L. on a seismic "high" near Pickanjinnie, approximately 20 miles east of Roma. Drilling was commenced on 27th May, 1960, and was completed on 12th July, 1960, at a total depth of 5213 feet. The drilling contractor was Mines Administration Pty Limited, and the rig used was a National T-32. A full programme of logging, testing and coring was undertaken. The well was drilled in Mesozoic sediments to4490 feet; the Roma, Blythesdale, Walloon, Bundamba, Moolayember and Pickanjinnie Formations were penetrated in this section. The Permian Latemore Formationwas then encountered beneath a slight unconformity separating this formation from the overlying Mesozoic rocks. The Timbury Hills Formation, (1) Devonian, taken as local basement, was penetrated at 4835 feet and continued to total depth. Eight formation tests were run, the results of which are summarized in Appendix 7. During the test of the interval 3976 - 4368 feet, over a period of 45 hours, gas flowed at a rate of 6,5 MMcf/D on one inch surface bean. The well was plugged from 4520 feet to total depth, filled with mud and capped, and completed as a gas producer on 29th July, 1960. The results of the velocity survey of Pickanjinnie No. 1, made on 12th July, 1960, have modified the interpretation of an extensive seismic programme carried out in the region.

A detailed gravity survey was carried out in the Barlee area of the Canning Basin of Western Australia during the period 31st August, 1959 to 31st October, 1959, by West Australian Petroleum Pty Limited. The gravity observations were made by L.J. Starkey of Mines Administration Pty Limited and the gravity data were reduced and interpreted by Gravity Meter Exploration Company. A location for a proposed test well had been selected on a complex faulted anticline defined by previous seismic surveys. The objective of the gravity survey was to evaluate the possibility of a salt intrusion being associated with the structure. Analysis of the gravity data in conjunctionwith the results of previous geological and geophysical investigations shows no evidence of domed salt within the detailed survey area, although the presence of a regionally uniform thickness of bedded salt is not precluded. It is recommended that the test well be drilled deeper than 7000 feet in order to determine the nature of older, denser sediments which may bt: present in significant thickness.

Union-Kern-A.O.G. Cabawin No. 1 spudded on 6th October, 1960, was drilled as a structural test of the petroleum potential of sediments underlying a major unconformity within the Surat Basin. The age and nature of the section below the unconformity was questionable prior to drilling the well, but it was presumed to be partly Triassic and partly Permian in age and related to the sedimentation of the Bowen Geosyncline. The drilling of the well confirmed this prognosis. In addition to providing stratigraphic information related to the petroleum potential of the Bowen Group, the well also provided information of regional significance on the Mesozoic rocks of the Great Artesian Group. Under a thin veneer of Tertiary rocks the drill penetrated the Roma, Blythesdale, Walloon and Bundamba Formations of the Great Artesian Group, and the Cabawin, Kianga, and Back Creek Formations of the Bowen Group, before bottoming in volcanic rocks of (?)Permo-Carboniferous age at a depth of 12,035 feet. The drilling of the well confirmed the presence of hydrocarbons in the Surat Basin. During the drilling operation a blowout occurred at a depth of 9938 feet, surfacing free gas and condensate. The blowout was caused by formation pressures, in excess of the mud weight, within an eight-foot sand body of the Permian Kianga Formation. In addition significant gas shows and a flow of salt water were encountered in weathered andesite of the Cracow Formation. Minor gas shows were recorded in the Permian Back Creek Formation, and in the Lower Triassic Cabawin Formation, and Significant shows of hydrocarbons were also present in porous and permeable sandstones of the lower member of the Triassic-Jurassic Bundamba Formation. The number of occurrences of oil and gas showings indicated that only a sustained testing programme through casing would properly evaluate the potential of these hydrocarbons. After reaching total depth, 5 1/2" casing was cemented at 12,033 feet, and there followed a series of production tests of all significant shOWings of oil and gas encountered during the drilling operation. Results were negative with the exception of the one zone in the Permian Kianga Formation. This zone proved to be the only producing horizon. After 22 days of continuous production, this zone was producing 62 barrels per day of 490 API gravity crude through 22/64" choke, with casing and tubing well-head pressures at 550 p.s.i. and 300 p.s.i. respectively, and 534 Mcf/D of gas. A total of 1761 barrels of crude oil and 13,744 Mcf of gas were produced during the testing period. Pressure and temperature surveys were conducted, and the well was shut in and suspended on 17th June, 1961, retained in a condition for production at any future time.