Addressing Uncertainty in Unconventional Exploration

Sequence Stratigraphy of Carbonate Ramp Systems: Implications for “Sweet-Spot” Prediction in the Vaca Muerta Unconventional Resource Play.

The development of unconventional resource plays presents many challenges and is often associated with a high degree of uncertainty. In particular, heterogenous depositional systems make subsurface prediction difficult due to extensive vertical and lateral facies variation. The Vaca Muerta play in the Neuquén Basin, Argentina is an emerging resource play hosted within a heterogeneous carbonate ramp system where the integration of multiple dataset within a predictive sequence stratigraphic framework is key to addressing this uncertainty.


AAPG 2017 International Conference & Exhibition, London

This year’s AAPG International Conference & Exhibition will take place from 15th October to 18th October in London, UK, during which Alex Bromhead (Geoscientist,  Halliburton Landmark) will present on the: Sequence Stratigraphy of Carbonate Ramp Systems: Implications for “Sweet-Spot” Prediction in the Vaca Muerta Unconventional Resource Play.

Abstract: There are many examples in the geological record where carbonate ramp systems are located adjacent to organically-enriched sediments. In such scenarios, the potential exists for source units and brittle carbonate units to be juxtaposed, which is a stratigraphic arrangement conducive to the development of an unconventional resource play. The emergence of the Vaca Muerta play in the Neuquén Basin, Argentina, has highlighted the importance of carbonate ramp systems as potential hosts for unconventional resource plays and emphasized that these plays can be successfully produced.

Carbonate ramps are generally characterized by a low-angle of slope, which makes them highly sensitive to eustatic variations in sea level. This typically results in a heterogeneous system with a high degree of vertical and lateral facies variation, which can make subsurface prediction challenging. In these instances, sequence stratigraphy is a fundamental tool to characterize stratigraphic architecture/variability in the depositional system and address subsurface uncertainty.

This study uses an integrated dataset (seismic, wireline, geomechanical, and production data) within the predictive framework of a sequence stratigraphic model to establish a relationship between production rate and systems tract in the emerging Vaca Muerta play. Interval-specific production data demonstrate that the highest-producing stratigraphic units are not necessarily the most organic-rich but contain high-frequency, cyclical intercalations of organic-rich units and brittle fractured target horizons. These geomechanically favorable units predominantly occur within the lowstand systems tract, where forced regression of the carbonate ramp induces reworking and detrital carbonate input into the anoxic basin.

By upscaling these concepts, an unconventional exploration model can be formulated to guide regional sweet-spot prediction. The unconventional exploration model uses gross depositional environment maps to help identify the aerial extent of geomechanical sweet-spots within each defined eustatic sequence. The output is a valuable predictive tool that allows frontier acreage in the Vaca Muerta, and other analogous unconventional resource plays, to be evaluated, compared, and ultimately high-graded.


This is one of a series of technical presentations, which will be delivered by Halliburton experts at the AAPG International Conference & Exhibition, London event on 15-18 October 2017. The full details of the event and agenda can be found here.

Join us to learn about key geological challenges facing exploration and the latest developments to optimize production.