Unconventional Exploration Potential of the Colombian Basins: Perspectives from Regional Geology and Structural Evolution

Jensen, Luke A.¹; Sanchez-Ferrer, Fernando; Pliego Vidal, Elia; Goudy, Cheryl; and Kertznus, Vanessa
¹[email protected]

The results of the 2012 Ronda Colombia and renewed acreage positioning in the onshore arena by multiple companies highlight the potential of self-sourced to hybrid Unconventional resource plays in the Colombian basins. Unconventional prospectivity is underpinned by the presence of thick and laterally extensive source rocks: the Upper Cretaceous La Luna Formation and the underlying Lower Cretaceous Basal Carbonates (sensu lato), both comprising primarily Type II/IIS marine shales and carbonates. This Cretaceous succession forms one of the region’s most prolific hydrocarbon systems.

Superimposed on these world-class source rocks, however, is the Colombian basins’ complex tectono-stratigraphic evolution, which can significantly impact Unconventional exploration and commercial viability. Dynamic interaction between the South American, Pacific, and Caribbean plates provided the framework for these basins to form and has a first-order regional control, both spatially and temporally, on key petroleum system elements and the ultimate location and size of sweet spots. While many of these basins have been Conventionally explored and produced for nearly a century, the understanding of the source rock systems, and how they will perform as Unconventional plays, is still emerging. In this context, three key regional evaluation methods that can help predict shale play behavior are 1) unraveling younger structuration and its impact on Cretaceous paleogeography in order to identify source rock accumulations of the highest quality and net thickness, 2) understanding the interplay between source rock maturation and deformation or uplift, and 3) examination of stress regime evolution, natural fracture networks, and the present-day stress field in order to properly plan drilling and hydraulic fracturing. In conjunction with these geologic factors, which impact static reservoir properties, source rock maturity and correlative fluid properties exert an additional control on dynamic reservoir performance and ultimately well EUR’s.

Regional study of prospective onshore basins was undertaken using the above methods to help elucidate play elements. Although each basin contains correlative Cretaceous source rock packages, they are unique in terms of their depositional environments, thermal maturation, and structural history. High-level results are presented, including succinct case studies illustrating the importance and impact of understanding shale plays utilizing this perspective.

AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013