Note that this list was published prior to the completion of the series and thus was intended as a progress report. The R502 series of maps has been replaced by the National Topographic Map Series (NTMS). The R502 series consists of 542 map sheets and covers Australia at a scale of 1:250,000. It was compiled from aerial photography, but only about one quarter of the series was contoured. The standard sheet size is 1 degree of latitude by 1.5 degrees of longitude. Transverse Mercator map projection and Clark 1858 datum were used. Coverage of the country was completed in 1968.

Samphire Marsh No. 1 Well was drilled to a total depth of 6664 feet as a stratigraphic and structural test in the South Canning Basin. The drill passed through 120 feet of Quaternary silt and limestone, 2124 feet of Mesozoic sandstone and siltstone, 1811 feet of Permian marine beds, partly of glacial origin, and 2541 feet of Lower Ordovician shale with sandstone at the base. The drill encountered Precambrian granite at 6610 feet, confirming the geophysical estimate of depth to basement. None of the sediments present in the well are considered likely to be a source for hydrocarbon accumulations. No signs of hydrocarbons were seen in this well.

Frome Rocks No. 1 Well, which is situated on the northern edge of the Jurgurra Terrace, drilled to 734 feet through Recent sand and the normal sequence of Jurassic sediments of the South Canning Basin and then entered the top of the Frome Rocks Salt Dome. The Frome Rocks Salt Dome consists of l,522 feet of dolomite breccia cap rock and 1,747 feet plus of salt. The base of the salt was not reached. The age of the sediments composing the salt dome is not known, but slender evidence suggests that the age is Devonian to Lower Carboniferous. The intrusion of the salt dome probably took place in post-Permian and pre-Jurassic times. No signs of hydrocaroons were seen in the well and no formation tests were conducted. The Frome Rocks No. 2 Well drilled through 206 feet of Recent and Jurassic sandstones, and a standard Permiansequence (3,351 feet thick) to 3,557 feet. A thick sequence of uppermost Devonian (Middle to Upper Famennian) sedimentswas encountered between 3,557 feet and the total depth of 7,504 feet. This thick Devonian succession (3,947 plus feet) has been divided into two formations, one of siltstone and shale with some limestone and sandstone, from 3,557 feet to 6,264 feet, and the other of siltstone, from 6,264 feet to 7,504 plus feet. The primary objective, the Ordovician, was not reached. Persistent, though slight, hydrocarbon shows occurred in several zones throughout the upper two-thirds of the Devonian in the form of fluorescence associated With limestones, and a spotty oil staining in the uppermost sandstone bed. No hydrocarbons were detected by gas detection equipment. None of the hydrocarbon shows was of sufficient significance to warrant testing. In the Frome Rocks area, there is an association of a salt dome, a thick impermeable sequence, source rockpotential, and some reservoir potential. Should the same association occur in other areas along the Jurgurra Terrace, particularly if the reservoir potential improves, the petroleum prospects of the area must be upgraded.

The Overflow No. 1 Well was drilled on the South Moreton Anticline in Authority to Prospect 7lP, south-east Queensland, to a total depth of 2993 feet. The well drilled in Bundamba Sandstone to 310 feet, Ipswich Coal Measures from 310 feet to 1605 feet, and volcanic rocks of probable early Triassic or Upper Palaeozoic age from 1605 feet to total depth. Drilling operations commenced on 8th April, 1960, and the well was abandoned as a dry hole on 18th May, 1960. The drilling contractor was Mines Administration Pty Limited, Brisbane, and the rig used was a National Ideal 55. The operation provided for a programme of electric and mud logging, testing and coring. The well was abandoned short of the target depth of 6500 feet because of the hard drilling and poor petroleum prospects in the thick volcanic sequence. Minor oil and gas showings in the well were closely associated with coal seams.

Thangoo No. lA well was drilled as a result of mechanical difficulties encountered at the drilled depth of 3 ,475 feet in Thangoo No. 1 well which were insurmountable and prevented further operations on this well. Total loss of circulation at 3,475 feet in Thangoo No. 1 well resulted in unexpected total collapse of the hole below the 10 3/4" casing in a section of friable sandstone and conglomerate (Grant Formation). In Thangoo No. lA well these formations were cased off. A lost circulation zone was tested for potential hydrocarbon production and found to contain water only. The well was drilled to 5,429 feet into basement rocks (programmed depth 4,500 feet). Excellent hole control was maintained to total depth by drilling below the 16" conductor shoe with high pH, low shear and waterloss, freshwater mud. The 1,366 feet of Mesozoic and 1,377 feet of Permian section in Thangoo No. lA closely resemble that of Thangoo No. 1. The Ordovician section is 2,318 feet thick, consisting of 695 feet of Goldwyer Formation (new name) and 1,623 feet of Thangoo Limestone (amended name). Basement, consisting of Precambrian phyllite , was encountered at 5,100 feet in Thangoo No. lA. Traces of oil were observed throughout the Ordovician section. Oil shows are confined predominantly to vuggy veins of coarse crystalline dolomite. A minor show was also observed in the sandstone of the basal unit of the Thangoo Limestone. A porous zone within the Thangoo Limestone, causing some lost circulation, appeared at about 3,670 feet in Thangoo No. lA. A formation test of this zone recovered only brackish water (11,999 ppm. total salts) with no signs of oil or gas. It is possible that the small shows of oil in the Thangoo Limestone are retained by the impervious Goldwyer Formation, as no shows were present in the Roebuck Bay and Dampier Downs wells, where porous Permian rocks directly overlie the Thangoo Limestone. The correlation of the sections of the Thangoo Limestone in all the exploratory wells on the Broome Platform indicates that the Thangoo No. lA well occupies a low structural position. Consequently the objectives of testing the structure in the Ordovician and Permian Grant Formation were not achieved. The chances of finding commercial oil accumulations in the Ordovician section of the South Canning Basin in the vicinity of Thangoo Nos. 1 and lA are very small at this time, because of the low source rock potential and flushing by meteoric waters of the Thangoo Limestone, the lack of porosity in the Goldwyer Formation, and the difficulties experienced in resolVing the structure of the Ordovician with present seismic methods.

A reconnaissance seismic survey, subsidised by the Commonwealth of Australia, was made for Phillips Petroleum Company of Bartlesville, Oklahoma, D.S.A. and Sunray Mid-Continent Oil Company of Tulsa, Oldahoma, D.S.A. by Petty Geophysical Engineering Company of San Antonio, Texas. This survey was located within Authority to Prospect 72P in the Quilpie-Thargomindah-Charleville area of South-western Queensland. The purpose of the survey was to obtain information on the regional geology beneath the Mesozoic formations of the Great Artesian Basin north and west of the Eulo Shelf. Three deep structural basins beneath the sub-Mesozoic unconformity are indicated.

The Barlee No. 1 Well was drilled with WAPET's National 100 rig to the total depth of 8101 feet. Below a thin cover of the surface sand, 1562 feet of Mesozoic sediments were encountered, and drilled to the depth of 1594 feet. These sediments are represented by the Broome Sandstone (Lower Cretaceous) and Jurassic rocks, consisting of Jarlemai Siltstone, Alexander Formation, and Wallal Sandstone. The Jarlemai Siltstone interval which is 850 feet thick, is the thickest section of this formation which has been drilled in the Canning Basin. Unconformably below Mesozoic sediments, a uniform section of Carboniferous rocks was encountered and drilled to the total depth. All 6507 feet of the Carboniferous section are included in the Anderson Formation, to which an Upper Carboniferous age is tentatively assigned. In the lower part of the formation (7825 - 7856 feet) an intrusive body of dolerite was encountered. Some induration was observed in rocks adjacent to the intrusion. The well was abandoned in moderately porous sandstone beds of the Anderson Formation. Average dips of 20 degrees were observed in cores and recorded by the dipmeter survey in the Carboniferous section. The dipmeter survey shows that the well was located on the northern flank of the Barlee Anticline. Some very slight shows of gas were present in the sandstone beds of the Anderson Formation. Below 5600 feet some sandstone beds contained impregnations of black, rubbery bituminous material - very probably oil residue. No signs of live oil were observed in the well. The drilling results indicate that the Barlee No. 1 Well (like Fraser River No. 1) is located in the deep Fitzroy Trough on a structure originated by an igneous intrusion. The prospective beds of Ordovician, Devonian, and Lower Carboniferous rocks are buried under the thick cover of the unprospective Upper Carboniferous sediments and probably are intruded by igneous rocks. It seems likely that the sediments of the Fitzroy Trough in the Barlee area extend south as far as the Darnpier Fault; thus the Dampier Fault in the western part of the Canning Basin may replace the Fenton Fault, which dies out before reaching the Dampier Land area. The concept of the Jurgurra Terrace still remains valid, but only for the eastern part as shown on Plate .No. 1.

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.

This report refers to seismic work carried out in the Puri area of Papua by Seismograph Service Ltd. for Australasian Petroleum Co. Pty. Ltd. during the period 6th May - 15th December, 1959. The objective ofthe survey was to determine the structural pattern of the Tertiary limestones in order to define any closed structures that may have economic oil accumulations. Altogether some 75 miles of continuous reflection traverses were observed and also a single refraction in-line profile of two spreads. An anticlinal feature was observed along one line but as there was no evidence of any significant pitch reversal along the strike line it seems there is no structure worth drilling in the area south of the Puri and Kereru Anticlines. The overall quality of the reflection data was poor but was considered adequate to disprove the presence of any major closed structures.

This report covers gravity survey work conducted by Mines Administration Pty. Limited for Associated Freney Oil Fields N. L. during the period 20th June to 31st July 1959. The survey was conducted in conjunction with the seismic survey carried out by the Bureau of Mineral Resources. The purpose of the work was to define at depth the limits of the Cooroorah Anticline, Central Queensland. Gravity values were observed and plotted over the whole of the Cooroorah area, and, in particular, over the Cooroorah Anticline. These values indicate a broad gravity '''low'' south of the Mackenzie River and west of Bluff. This is confirmed by the previous regional gravity survey of 1958. Over the Big Churchyard Culmination of the Cooroorah Anticline the gravity gradient reverses. The axis of this reversal is displaced approximately 1 1/4 miles north-west from the axis of the Cooroorah Anticline. The seismic survey shows that the structure at depth is closely conformable with the surface structure so it appears from this displacement of gravity and geological axes that the gravity "high" is due to some deep-seated density variation.