Identifying the Sweet Spot

The days of easy to find oil and gas have passed and E&P companies are primarily focused on areas of increased complexity and unconventional resources. Whilst the devil is in the detail, a big picture perspective must continue to be at the foundation of exploration and can provide valuable insight into the preservation limits and organic content of potential source rock intervals and, in the case of unconventional resources, the presence of frackable units and their relationship to the organic-rich intervals. These insights, combined with the appropriate geochemical and geomechanical assessment, and an appreciation for maturity, thickness and depth can help you on the hunt for that all important sweet spot.



On Thursday 11th May Landmark Exploration Insights will be hosting the 8th London Earth Model Forum at The Geological Society, during which Alex Bromhead (Exploration Insight Geoscientist), will present on the “Stratigraphic insights into resource play assessments: an example from the Vaca Muerta, Neuquén Basin”.

Abstract: The Vaca Muerta Formation in the Neuquén Basin, Argentina, is widely considered as one of the top emerging unconventional resource plays outside North America. This study demonstrates how an unconventional exploration workflow can be used to delineate the resource-distribution in this unconventional play and critically compare prospective acreage. The integrated workflow is split into multiple components: 1) stratigraphic characterisation; 2) geochemical and geomechanical assessment; 3) regional screening for preservation, organic-content, maturity, thickness and depth; 4) high-grading stratigraphic domains with the likely occurrence of fracture targets; and 5) resource volume and resource concentration estimates.

A sequence stratigraphic framework, built from an integrated seismic and wireline dataset, is used to characterise depositional architecture and stratigraphic variability across a low-angle carbonate ramp system during the deposition of the Vaca Muerta Formation. Interval-specific production data demonstrate that the highest-producing stratigraphic units relate to intervals with high frequency, cyclical intercalation of organic-rich units, and more brittle, carbonate-dominated fracture target horizons. Indeed, many of the best-performing unconventional reservoir zones are situated within the lowstand systems tract, where forced regression induced progradation of the carbonate ramp and reworking of brittle carbonates into the anoxic basin. This concept is used to formulate an unconventional exploration model that uses gross depositional environment maps to help identify the aerial extent of the high-graded stratigraphic domains within each defined eustatic sequence.

A resource volume assessment for the Vaca Muerta is determined using a Monte Carlo simulation performed across a range of reasonable boundary conditions. Technically recoverable P50 estimates confirm a substantial shale oil (40 bbl) and shale gas resource (533 Tcf). Resource overlays are generated to demonstrate spatial variations in resource concentration within both the gross Vaca Muerta and the high-graded stratigraphic domains output from the exploration model. A critical comparison between the two resource overlays demonstrates how a consideration of mechanical stratigraphy can have a profound impact upon resource concentration across the play.



This one of a series of technical presentations which will be delivered by Landmark Exploration Insights on Thursday 11th May at the 8th London Earth Model Forum at The Geological Society, London. The full details of the event and agenda can be found here. Join us as we address some of the key geological challenges facing exploration and unveil the latest developments at the heart of our offering.  


This event is free of charge, but spaces are limited. Reserve your place today by contacting us at