THE HYDROCARBON POTENTIAL OF THE LOCKATONG FORMATION IN THE NEWARK BASIN

The hydrocarbon potential of the organic matter-rich Lockatong Formation in the Newark basin is evaluated. The total organic carbon (TOC) values range from 0.50 to 2.72% (mean=1.2%), indicating a fair to good source rock. The plot of the data in the Hydrogen Index (HI) vs the Oxygen Index (OI) diagram put the studied samples at the end of the evolutionary paths of Type I, II, and III. This position of the data is due to over maturity of organic matter. With a maximum TOC of 2.72wt%, an estimated PI of 90% - given the overmaturity of organic matter -, and the maximum HI of 32 mg HC/mg of rock, the calculated initial HI (HI₀) is about 320 mg HC/mg rock. This initial HI value fall into the HI range of Type II/III kerogen. The pyrolysis analysis also reveals that the organic matter is overmature as indicated by the position of the data in the HI versus T_max diagram with the calculated T_max varying between 506 °C and 547 °C. It is concluded that this formation has no generative hydrocarbon potential. Almost all hydrocarbons in the Lockatong Formation have been already generated.

Key words: Source rock, Lockatong Formation, Organic matter, Hydrocarbon potential