Source rocks Kimmeridge Clay Formation

The crude oil used by Bennett and Barter (1997) was a typical North Sea oil generated from Upper Jurassic, Kimmeridge clay formation source rocks. The alkylphenol distribution in a sample of (Miller) crude oil, determined using solid phase extraction (SPE), is shown in Fig. 16.21. The crude oil is dominated by phenol and cresol and contains appreciable quantities of dimethylphenols. The concentrations of 2,3-, 3,4-, and 3,5-dimethylphenol also include a contribution from 2-, 3-, and 4-ethylphenols, because they coelute under the conditions employed (Bennett et ah, 1996). 

Generation and expulsion. In the western source kitchen, petroleum generation from Upper Jurassic source rocks commenced towards the end of the Cretaceous (56.5 Ma bp) and was almost complete by mid Miocene times (10.4 Ma bp) when transformation ratios of 0.9 were reached. In the easterly kitchen, generation from the Kimmeridge Clay Formation (KCF) source rock was only just starting at this time (TR<0.3). At 10.4 Ma bp, no generation has occurred from Upper Jurassic... 

Acetic acid (C2) is typically the most abundant of the monocarboxylic acids and comprises more than 50mol% of the total acids generated from source rocks during hydrous pyrolysis. Barth et al. (1989) conducted a series of hydrous pyrolysis experiments on aliquots of a powdered shale sample from the Kimmeridge Clay Formation. The aliquots were isothermally heated for 72 h at temperatures ranging from 200 to 350 °C. Acetic acid in the reacted waters increased with increasing temperature. The percent of acetic... 

Fig. 3. Organic rich rocks in Haltenbanken include the coals and shales in the Are Formation (Brent equivalent), the Melke (Heather equivalent) and the Spekk (Kimmeridge Clay equivalent) Formations. Petroleum in Haltenbanken is sourced mainly from the Spekk/(Melke) Formation. Petroleum from the Are coals and shales may have increased hydrocarbon saturation in carrier rocks long before the onset of oil expulsion from the Spekk Formation.

---