Case Studies
Case Study #1
Application of Time-Lapse Geochemistry to determine Upper Eagle Ford production contribution to Lower Eagle Ford lateral wells.
In 2021, GeoMark Research engaged with Ensign Natural Resources (ENR) to investigate oil production of a three well pad in their South Texas, Karnes County Lower Eagle Ford development. Details of this study were published in 2022; URTeC: 3720662
The Goals
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Does geochemistry suggest independent flow units for LEF, UEF, and Austin Chalk?
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Are LEF sticks stealing from the adjacent formations?
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Can value be applied or justify multiple stacked / staggered stick layers?
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Does geochemistry suggest influence from/or variance across significant natural fracture corridors (underlying reef trends)?
​Five oils* from three new wells were assessed with high resolution gas chromatography (HRGC), Quad pole GCMS (QQQ), and Whole oil bulk properties (isotopes, API, Saturate/Aromatic fractions). These oils were compared to a baseline of legacy oils sampled by a previous operator and housed at GeoMark.
*The oils depicted above are correlated to the Rack Diagram below.
The Results
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The new well oils are consistent with other LEF production and do not suggest mixing with an UEF source.
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As the geochemistry of these new oils indicates only LEF sourcing, the contribution and allocation are both 100% suggesting a single flow unit for these target wells in the LEF.
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With this development/stimulation pattern, additional well layers are justified to efficiently drain both the LEF and UEF stratigraphy.
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There is variation between LEF targets suggesting differences in geochemistry of oils by area and stratigraphy.
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Observed pattern variation within the LEF oils can be used to suggest influence from offset parent stimulations/production and potentially LEF communication with a natural fracture network, but does not suggest communication from adjacent formations.
The Conclusion
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The application of GeoMark’s TLG&PA has illuminated a crucial insight: the Upper Eagle Ford was not significantly contributing to the production of the Lower Eagle Ford wells. This finding underscores the necessity for further development to tap into the Upper Eagle Ford resources within the study area, thereby unlocking increased production potential. The use of non-invasive, cost-effective quantitative geochemical and statistical analyses not only confirmed this need but also added incremental value to the asset, highlighting the transformative potential of advanced geochemical and statistical tools in optimizing resource plays.
Want to Learn More About This Project?
URTeC: 3720662
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Timelapse Geochemistry production allocation; end member definition and selection; case studies, Delaware Basin and Eagle Ford
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Adam Turner*¹, Catherine Donohue¹, J. Alex Zumberge¹, Andrew Muñoz², Philip Bergeron²
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GeoMark Research, Houston TX
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Ensign Natural Resources, Houston TX
Case Study #2
Application of Time-Lapse Geochemistry within the HFTS-2, Delaware Basin.
This case study was completed on the Hydraulic Fracturing Test Site-2 (HFTS-2), which is a well-studied industry and government consortium project area to better understand the hydraulic fracturing interaction efficiencies within the subsurface. Several techniques were deployed at the test site to better understand flow units from the initial Stimulated Rock Volume (SRV) to the actual Drained Rock Volume (DRV) over time in the Wolfcamp Formation.
The Database
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Four wells analyzed (1H, 2H, 3H, and 4H)
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Five time stamp oil samples collected and analyzed over 400 days of production
The Results
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Principal Component Analysis (PCA) performed on the geochemical data identified a variation in fluid properties over time. Wells 2H and 4H maintained a similar famly throughout production with wells 1H and 3H hosting a similar oil family at the start and then deviating from one another over production time. This observation reflects the variation in oil character between Wolfcamp Y and Wolfcamp A.
The Conclusion
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The implication of these results clearly indicated some sort of permeability ‘baffle’ between Wolfcamp A and Wolfcamp Y. From other subsurface monitoring analysis (microseismic), and early oil production, it was noted that fracturing event did propagate up into Wolfcamp Y which is further confirmed by the presence of Wolfcamp Y oils in the Wolfcamp A landed wells (1H & 3H).
Ultimately, this information can assist in the optimization of both development and completion approaches to maximize wellbore contact and drainage within the subsurface, while reducing expenses on ineffective completions.