Appraisal of the hydrocarbon charging histories and reservoir filling as exploration tool in mature areas, Mantiales Behr oil field, Northern Flank of the San Jorge Basin, Argentina

JALFIN G., G. LAFFITTE, E. BELLOSI AND H. VILLAR

Mendoza

Conferencia; AAPG Hedberg Conference; 2001

American Association of Petroleum Geologists

The reconstruction of the thermal and tectonic history of the area allowed to build a migration model where four main kitchens (Granson, Diadema-Escalante and Cañadon Perdido, Cañadón Botella) are recognized as responsible for filling the Manantiales Behr’s traps. The expulsion started at 65 Ma in the Granson kitchen from Neocomian source rock. Since 50 Ma the area received oils from the Diadema-Escalante kitchen generated from Neocomian-D-129 beds. Then, the expulsion rim reached the Cañadón Perdido kitchen at 40 Ma. The generative oil system is totally developed at 30 Ma when the Neocomian sequence at Cañadón Botella kitchen attains oil window maturities. The continue subsidence of the Neocomian+D-129 sources at Granson kitchen leaded to the first expulsion of very light oil/gas/condensate at 20 Ma. This charge has played a main role in the solubilization of oils previously biodegradated oil by meteoric waters. It is assumed that the main superficial water charge occurred at 40 Ma coeval with the hiatus that exist between Sarmiento and Río Chico Formations which expand as long as 18 Ma. Whether or not this pulse is present in the oil blend marks in Manantiales Behr the difference between the producible oils from the dead oils (<10 °API). The remaining expulsed oil from Granson begun to fill the deeper reservoirs at the top of D-129 closures. Finally, in the last 10 Ma the Diadema-Escalante kitchen also starts to expulse very light/gas/condensate filling the southernmost traps developed against the Escalante lineament (Pampa del Castillo Norte and Granson blocks).