This report is on the summary of a play in the Snark dataset from the northwest coast of Australia. I have used Petrel to analyze and interpret this dataset. The Snark dataset lies within the Barrow basin which is home to many promising and producing oil fields such as Barrow Island which is the largest onshore discovery in Australia.
Figure 1. Northwest coast of Australia with red star showing location of Snark survey.
Off the coast of northwest Australia there are four basins which include the Northern Carnarvon, Offshore Canning, Browse, and Bonaparte basins. The shelf has experienced many periods of continental rifting dating back to the Cambrian around 500mya (King, 2008). ...view middle of the document...
The BCU was located by determining where the sinusoidal strata of the Jurassic ended and terminated against the more horizontal beds of the Cretaceous.
To begin this interpretation project I first read literature on the regional geology of the overall northwest coast of Australia and then narrowed my research to the North Carnavaron Basin and finally the Barrow sub-basin. This gave me a general understanding of the events that shaped the survey area. This was followed by looking through time slices of the dataset to grow accustomed to the survey. I then began to pick important horizons and faults such as the Base Cretaceous Unconformity. I then tried methods such as flattening and using attributes to locate potential reservoirs. The next step was to bring everything together and make an interpretation from my observations of the dataset.
Figure 3. Inline 265 showing 4 main horizons, the BCU is shown in teal
I noticed many prominent sinuous features running through the area of mid Cretaceous age. Many of these features were overlain by areas of high amplitude which caught my eye right away. These sinuous features were all along the same horizon throughout the dataset between 1750 and 2000ms.
I interpreted the sinuous features as channels that ran through the area during the Cretaceous period. Since channels transport sediment I knew this was a good start in my hunt for a reservoir. The channels are narrower towards the east suggesting the source of the river to be to the east. This is...