Print this pageStratigraphy and Petroleum Potential of the La Paz Formation, Middle Magdalena Valley Basin (Northern Part), Colombia
SUAREZ, MARIO A.
The post-middle Eocene to Pleistocene section of the northern Middle Magdalena Valley Basin is composed of seven tectonosequences (approx. 2nd order sequences), separated by regional unconformities. This framework was constructed from regional dip seismic profiles through the basin tied to well logs. These unconformities developed during the accretion of Western Cordillera, the eastern migration of the Caribbean Plate and collision of the Choco Block with the northwestern Colombian margin. The amount of uplift or tilting produced in the basin by this tectonic interaction controlled the distribution and extension of the sandy facies within each tectonosequence. The three lower tectonosequences were deposited in a foreland basin and the three upper in an intramontane basin.
Of these tectonosequences, the oldest one (upper Eocene) contains the La Paz Formation, which is the most important reservoir and has the greatest future exploration potential in the northern part and eastern foothills of the basin. This unit is diachronous comprising most of the upper Eocene in the western sector and the lowermost upper Eocene in the eastern sector of the basin. In the western margin, it was deposited in alluvial fan systems, grading toward the East to fluvial systems. In most of the central part of the basin this unit was not deposited because of onlap onto the Sogamoso paleohigh.
The results of this regional study suggest that the La Paz Formation could be involved in potential structural plays related to reverse faulting in the eastern foothills, where this unit could be reached at depths about 12,000 to 14,000 feet.