Hydrocarbon Prospectivity and Structure of the North Panama Deformed Belt: Observations From Regional Seismic Mapping

Abstract

Newly-acquired 2D seismic reflection data provides unprecedented insights into the structure and potential petroleum system(s) of the North Panama Deformed Belt (NPDB) and its vicinity. The NPDB is an arcuate accretionary wedge situated north of the Panamanian isthmus in the Caribbean Sea. It is flanked by the San Blas basin to the south and the underthrusting Colombian Basin to the north. The complex faulting within the accretionary wedge shows changes in vergence, mechanical variations in the detachment horizon, and regional stresses. Basinward of the trench a wedge of sediment onlap Colombian Basin strata highlighting the foreland flexure and obduction of Panama onto the Colombian Basin. The depth-imaged data suggests a complex internal structure of the prism with multiple thrust fronts and nappe belts. Structural mapping demonstrates that shortening within the prism is driven by a rising thrust under the island arc (oroclinal basement wedge) to the south. The rising thrust model implies the uplift of the arc ridge itself, which leads to erosion and addition of sediment to the prism section to the north. Options for possible source rocks calibrated with known hydrocarbon occurrences in Southern Costa Rica, the Atrato-Uraba area and the Sinú-San Jacinto basin are discussed. Turonian-Coniacian source rock equivalent shales found in Costa Rica may also be present in the deeper section of the prism throughout the foldbelt. Sediment thickness (8km) above the Cretaceous coupled with a rising thrust model increases the likelihood of thermal maturation along with geothermal fluids. Multiple trap types including basin floor fans, MTDs, channel fills, pinchouts, reef-like features are seen in addition to the numerous fault-controlled structures within the bulk and toe of the prism. These observations present all elements of a functional petroleum system in the frontier region of offshore Panama.

AAPG Datapages/Search and Discovery Article #90332 © 2018 AAPG International Conference and Exhibition, Cape Town, South Africa, November 4-11, 2018