South Atlantic Source Rock De-risking Workflow

Authors: Karyna Rodriguez (presenter), Neil Hodgson, Searcher

The largely underexplored West Malvinas Basin lies just to the east of the Austral Basin in southern Argentina, where up to 2 billion barrels of oil equivalent have been discovered to date. Source rock presence and quality is still considered to be one of the key risks in the Malvinas basin.Reprocessed 2D seismic data was integrated with conditioned well logs in a full petroleum systems evaluation together with a regional geological review, plate tectonics and magnetics/gravity data, allowing the definition of a synchronised sequence stratigraphic scheme unifying 8 basins.The main source rocks in the Malvinas Basin are considered to be Upper Cretaceous shales of the Lower Inoceramus Fm, with source potential also identified in the Early Cretaceous post-rift Springhill and Margas Verdes Formations and seismic observations, from reprocessed seismic data, strongly point to the syn-rift lacustrine shales in the Jurassic Tobifera Formation. Understanding the lateral distribution of lacustrine shales is key to unlocking the charge story. Data quality of reprocessed 2D seismic data allowed a detailed interpretation below the Base Cretaceous unconformity, enabling interpretation of the Jurassic source rock section. Shallow gas indicators in the Malvinas Basin provide proof of a working petroleum system. Their distribution was mapped within the basin using both traditional methods and a Machine Learning process. Indications of greater density of shallow anomalies can be attributed to a potential Jurassic syn-rift charge origin. By integrating the understanding from South African basins, there is greater confidence in the results from this study on the presence of a potential dual source working petroleum system, further addressing one of the key risks in the Malvinas Basin and increasing the chance of success in future exploration activities.

Bio:

Karyna Rodriguez, Searcher

Karyna earned a BS and a MSc in Geology from the Oxford University and a MSc in Stratigraphy from the University College London.

With 31 years of experience in the industry, Karyna is VP Global New Ventures at Searcher, UK, where she is responsible for developing and managing Searcher projects which support energy companies’ ongoing and future energy exploration campaigns. She previously worked in companies as British Gas, PEMEX, Apache, Pioneer.

Her professional affiliations include AAPG, EAGE, PESGB, London Geological Society.