Exploration on Continental Shelf Off Northwest Australia: ABSTRACT

Abstract

Exploration of a 144,000-sq mi rank wildcat area in offshore northwestern Australia began in 1964 with analog seismic surveys. Each year additional surveys have been carried out with a steady improvement in data quality due to advantage being taken of technological advances of the industry. Interpretation of these data and incorporation of available drilling results have permitted structural and depositional models to be rationalized for post-Paleozoic time-rock sequences. Improvements in drilling technology have allowed locations to be sited in greater water depths confirming depositional and structural models. End_Page 637------------------------------ To overcome seismic data problems associated with the high-speed Tertiary section, navigational problems due to the size of the area, drilling problems associated with geo-pressured shales and the highly porous Tertiary beds, new techniques constantly were required and introduced. To integrate the interpretation of the large volume of data and to apply the maximum amount of geologic rationalization require the cooperation and mutual support of competent geologists and geophysicists. Large areas to be mapped and steadily increasing volume of data from this area required the utilization of computer-assisted mapping. By mid-1971 approximately 40,000 mi of seismic data were in the files. At the same time wells 11 (Scott Reef No. 1) and 12 (North Rankin No. 1) were drilling and located what promise to be commercial accumulations of hydrocarbons. However, feasibility studies still are being evaluated and step-out wells have yet to be drilled. Since completion of these wells, other wildcats have been drilled resulting in several discoveries. Future potential in the area looks very bright with source, reservoir, and cap rocks in Triassic, Jurassic, and Cretaceous rocks. The potential of the Paleozoic section is as yet virtually unknown. End_of_Article - Last_Page 638------------