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Oil System
Reservoirs
- Late Cretaceous units (Escarpada,
Rosa and Rocallosa) have thicker reservoir with more continuity, but
poorer petro physical characteristics than Tertiary reservoirs. Fractured
reservoir are expected
- Early Tertiary units Chorrillo
Chico, Agua Fresca formations have only a few reservoir bodies, generally
of reduced thickness and poorly defined areal extent. Petro physical
characteristics are regular to good quality for a gas reservoir. Has
a proven potential up to 60.000 m3/d.
- Loreto has two bodies of sand
depending on the location in the delta system generally the lower
is better than the middle sand.
Source Rock
- Early Cretaceous (Erezcano/Zapata
Formation) is the source rock.
- Late Cretaceous and Early
Tertiary rocks, lack of significant generating capacity with some exceptions
of some levels with regular to marginal organic content.
Timing, Migration and Trap
- Early Cretaceous source rock
expulsion began around 65 ma within the central structural domain.
- Primary migration fill structural
trap formed between 60 and 33 ma.
- Secondary migration occurred
after seal breach followed by entrapment toward late structures arround
23 ma. Anticline (gas in Chilenita).
- Migration pathways are mainly
vertical and may be fault assisted
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