The R502 series of maps has been replaced by the National Topographic Map Series (NTMS).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.

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These documents have been scanned by the GA Library. Please refer to the document for contents.

These documents have been scanned by the GA Library. Please refer to the document for contents.

These documents have been scanned by the GA Library. Please refer to the document for contents.

These documents have been scanned by the GA Library. Please refer to the document for contents.

During 1950-51 pendulum gravity observations were made at 59 stations throughout Australia using invar pendulums on loan from the Department of Geodesy at Cambridge University. A national gravity base station was established at Melbourne. Subsequent comparisons with gravity meter ties suggest that the pendulum value is about 2 mgal. low. The standard errors of the gravity differences from Melbourne to the other stations have been estimated from internal consistency of the pendulum observations and from comparison with gravity meter measurements; the mean standard error is about 0.6 mgal. A small systematic difference from gravity meter values is assumed to be caused by the effect of the earth's magnetic field on the pendulums; after correction for this, the results agree fairly well with the American calibration system. Free air, Bouguer and isostatic anomalies have been calculated for all stations. The isostatic anomalies are for both Airy-Heiskanen and Pratt-Hayford hypotheses, and for four different assumed crustal thicknesses in each case. The isostatic and Bouguer anomalies are predominantly negative. A degree of isostatic compensation is present, but some large anomalous areas are uncompensated. The pendulum survey forms a basic network to which past and future gravity surveys can be referred.

This publication presents the scientific and technical results obtained from the drilling of a deep test well at Puri in Western Papua, by the Australasian Petroleum Company Pty Ltd. These results were originally submitted by the company in a completion report on the well, written in two parts: Part I, Geology, by C.E.P. Hull, which -includes a report on the palaeontological examination of samples from the well, by F .C. Dilley. Part II, Petroleum Engineering, by M.W. Clegg, including the information obtained from testing and the results of oil, gas anj water analyses. This information has been combined into one volume. The authors of the various chapters are indicated in the table of contents. The formal Papuan stratigraphic nomenclature is at present being studied by the geological staff and advisers of the Australasian Petroleum Company Pty Ltd in London. As this study is not complete, the stratigraphical names in common use by the operating company have not been submitted for the formal approval of the Australian Stratigraphical Nomenclature Committee. Accordingly, within this report Miocene stratigraphical units are designated by informal geographical stage names and an appropriate lithological term. The Eocene and Cretaceous sediments encountered in the well are not subdivided but are merely referred to a Eocene limestone and Cretaceous shale. Two deviated holes, Puri No lA andPuri No 1B, were drilled from Puri No 1, but as these were not subsidized under the Petroleum Search Subsidy Acts, information from these holes is not included in this report.

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.