The following organic geochemical analyses were performed on 6 oil samples produced from five different Cretaceous to Permian age reservoirs in 4 wells drilled by Delhi Petroleum: 1) C1-C31 whole oil gas-liquid chromatography; 2) C4-C7 gasoline range gas-liquid chromatography; 3) liquid chromatography; 4) C12+ saturate gas-liquid chromatography; 5) GC-MS of saturate fraction; 6) C13/C12 carbon isotope ratio determination. Detailed analytical results in the form of labelled chromatograms and tabulated quantitative data are presented to qualify the interpretative discussion. In general the data obtained from these analyses does not give a very clear picture of the genetic relationship between the oil samples, which appear to have experienced varying degrees of water-washing and consequent loss of gasoline range aromatic hydrocarbons, thus rendering unreliable an important correlation parameter. However, the study indicates that at least 2 oil families exist within the samples, with the Permian oil from Brumby 1 representing one family and the Narcoonowie Mesozoic crudes representing another. The Limestone Creek and Kerinna oil samples, on the other hand, cannot clearly be assigned either to these two or any other particular group. Additional analytical data covering both oil samples and source rocks from several wells covering a large geographic area is needed before any crude oil - parent source rock genetic relationships can be established.