Sequence Stratigraphic Framework in a Humid Alluvial Fan Complex, Quiriquire Oil Field, Venezuela
Fanchen Kong, Guillermo Jalfin, Pujianto Lukito, Ichsan Sarkawi, 2002. "Sequence Stratigraphic Framework in a Humid Alluvial Fan Complex, Quiriquire Oil Field, Venezuela", Sequence Stratigraphic Models for Exploration and Production: Evolving Methodology, Emerging Models and Application Histories, John M. Armentrout, Norman C. Rosen
Download citation file:
The giant Quiriquire Shallow oil field is located in the southeastern foothills of the Serrania del Interior in northeastern Venezuela. The main reservoir interval, the Quiriquire Formation, consists of conglomerates and sandstones deposited during 2.4-0.9 Ma in a humid alluvial fan complex inter-fingered with axial fluvial systems. Sequence stratigraphic concepts are applied to interpret 3D seismic volume to establish an accurate tectono-stratigraphic depositional model for facies prediction. Sequence boundary recognition criteria are explored for humid alluvial fans.
Five regionally extensive erosional unconformities are recognized as sequence boundaries. Maximum fluvial flooding surfaces and correlatives are recognizable as continuous high amplitude reflectors with overlying wide troughs. Each sequence may have rising base level, high base level, and falling base level systems tracts. At least five levels of cyclicity are interpreted. The three higher levels are controlled by intermittent tectonic events of hill uplift and basin subsidence from southeast contraction in a clockwise wrench-fault setting. Episodic growth strata, stratal truncations, and linear shale diapirs are associated with these tectonic events. Smaller cycles appear associated with sediment supply and climatic changes or autocyclic processes.
Analyses of seismic reflection facies, trace shape facies, and various attributes reveal a general basinward decrease of conglomerates and sandstones and an increase of shales. Alluvial-fluvial evolution shows a general northward fluvial onlapping trend and two major alluvial fan progradations, in which conglomerates and conglomeratic sandstones prograde farther basinward. Analyzing and imaging alluvial and fluvial internal architectural complexity and vertical/lateral alluvial-fluvial boundaries plays a critical role in our detailed reservoir correlation and characterization.