Print this pageThe Foreland Bulge of the Marañfrom Basin of Peru: A Frontier Play in from Established Basin
In 2008, 20,000 line kilometers of high resolution aerogravity and aeromagnetic data were acquired along the crest of the Iquitos Arch, a foreland budge on the eastern margin of the Marañon Basin in Peru. The similarity between magnetic and gravity trends indicate that basement structure influenced sedimentation and structuration. Long wavelength trends correspond with shorter wavelength trends that may reflect shallow anomalies. A prominent northeast oriented lineament runs approximately through Iquitos and is interpreted to be a left lateral strike slip fault. North of this fault, the dominant lineation is northwest following the structural trend that controls most of the existing fields in the basin. South of this fault the dominant lineation is northeast, possibly related to the influence of the northeast trending failed rift Solimões Basin in Brazil. A 500 km 2D seismic program is planned to investigate features identified on the basis of gravity, magnetics and surficial data.
Identified leads target Cretaceous sandstones in fault-related folds and stratigraphic pinchouts with estimated recoverable resource potential exceeding 2.5 Bbo. Structural movement occurred in the late Paleocene as noted by thinning of the Yahaurango Fm isopach adjacent to the Iquitos Arch, and was reactivated in the late Miocene. Based on foreland basin models and regional isopachs, the Iquitos Arch had an estimated 200 m of vertical relief. The Jurassic Pucará Fm source rock is correlated to the 27° API, Corrientes Field (200+ mmbo), 175 km to the west. This contrasts the 10-21° API Chonta Fm-sourced oil of the fields in Blocks 39 and 67 to the north. The heavier oil is attributed to early hydrocarbon generation from a carbonate source rock as well as biodegradation due to shallow burial. The higher maturity of the clastic prone Pucará Fm may source lighter gravity oils to the southern portion of the Iquitos Arch. The Eocene Pozo Fm shale deposited during a period of tectonic quiescence provides the regional seal.
Potential discoveries will be developed using multi-well pads to reduce environmental impact. Pads will be connected via pipelines to a CFP located near the river to facilitate logistics. If the oil gravity is less than 20° API, it will be blended with diluent supplied via barge and transported by barge from the CFP to Station 1 of the Nor-Peruano Pipeline.
AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil