Potential New Play in Triassic – Jurassic Saldaña Formation, Putumayo Foothills Colombia

Abstract

For years the Saldaña Formation (SF) has been disregarded as a potential reservoir for exploration in the thrusted areas of Upper Magdalena Basin (UMB) and Putumayo Basin (PUTB), Colombia. This Jurassic complex, accepted as the economic basement, sometimes can be found structurally related with the well-known Cretaceous reservoirs; Caballos and Villeta Formations. Often, and the thick and hard of SF make it difficult and expensive to drill to test the presence of a reservoir. Nevertheless, the new findings and approach show that there is a proven potential for oil bearing in the Putumayo basin; as documented for Misahualli, Chapiza and Santiago Formations in Oriente Basin (OB), Ecuador. The Pre-Cretaceous complex located in the OB –Ecuador- and PUTB and UMB basins–Colombia- is the result of a Triassic – Late Jurassic back-arc extension related to a subduction, during syn and post rift stages. The contact of this sequence with the overlying Caballos Formation is characterized by a regional unconformity between late Jurassic and Albian time. SF includes a wide range of volcano-sedimentary rocks from quartz arenites, siltstones to andesites, tuff and plutonic rocks. It has been tested and produced light oil (28°API, Moqueta Field, Putumayo foothills) from these sandstones intercalated in the volcaniclastic sequence. Three different layers were identified as being reservoirs, they were mapped on 3D seismic showing an interesting areal distribution. Moreover, a careful study of older wells drilled and abandoned in the sixties in PUTB, showed that they have found these sediments intervals in SF bearing oil. In addition, a new surface geological data, acquired in 2013, recognized these sand bodies outcropping in two different areas in the PUT basin. This indicates that these SF sandstones could have a regional extent and constitute a new, play, in the PUTB. Additional work has been performed; absolute dating and petrography studies in outcrop and wells samples were carried out in SF. Compositional character and age of the sequence can be well stablished in PUTB and allow to correlate with the UMB, Colombia and OB, Ecuador. Studies are in progress to predict the presence of these sand bodies using seismic characterization and Inversion.

AAPG Datapages/Search and Discovery Article #90194 © 2014 International Conference & Exhibition, Istanbul, Turkey, September 14-17, 2014