Structural characterization of the Catatumbo Basin (Colombia): a review based on microtectonic analysis of well cores

Caracterização estrutural da Bacia de Catatumbo (Colômbia): uma revisão baseada na análise microtectônica de testemunhos de poços

Abstract

From the microtectonic analysis of drill cores from oil fields in the Catatumbo Basin, complemented with well image data and regional interpretations, two major tectosedimentary episodes are recognized that influence the definition of its petroleum system: a) an early extensional one where the sequences exhibit progressive evidence of compaction by burial associated with Mesozoic and Paleogene sedimentation that generates subvertical fractures with carbonate fillings originating from the dissolution of stylolitic surfaces by overloading of the overlying sequences and b) another late Cenozoic episode associated with the consequences of the ENE-WSW Andean convergence that provides a submeridian transpressive context that reactivates the venulations as more fragile mechanical discontinuities in senestral transpression. The evolutionary history of deformation expressed by microtectonic core data provides information on the chronology of the petroleum system, whose first stage of compaction is associated with the maturation and expulsion of fluids and the second stage with the generation of fracturing that increases the secondary porosity and permeability of the fields. In the case of reinterventions and development of unconventional hydrocarbons, wells should be directed in the WSW-ENE direction and subhorizontally of the minimum principal stress (s3) to traverse the greatest number of potentially open subvertical fractures per linear meter.