By Marcel Chin-A-Lien – Global Petroleum & Energy Advisor – Golden Lane Investments Advisory Group
Published: March 2026
Executive Summary
I set out to find a practical, decision-grade application of UEP (Ultimate Expellable Potential) research developed in the context of Oceanic Anoxic Events (OAEs) and apply it to the Guyana–Suriname Basin (GSB), refined specifically for Suriname using Staatsolie’s GeoAtlas facies maps (Coniacian–Santonian example).
The key improvement is simple but powerful: UEP must be facies-weighted — Demerara Rise-style “best preserved” basinal conditions are not basin-representative.
Using globally published UEP benchmarks (where available) and transparent “screening UEP” calculations (where UEP is not openly published), the GSB Canje/ACT system ranks as:
- Strong to very strong in the distal Demerara Plateau basinal domain (screening UEP ~10 MMboe/km²)
- Moderate across slope shale belts (screening UEP ~2 MMboe/km²)
- Low to moderate across shelf/delta-influenced belts (screening UEP ~0.4–0.7 MMboe/km²)
In other words: the GSB is not “small,” but it is heterogeneous.
Treating it as uniform creates avoidable dry holes, thin columns, and unrealistic expectations.
For investors and decision-makers, the message is equally direct: follow the facies and the expulsion pulses—ignore the adjectives.
1) UEP in One Paragraph (What It Is, What It Isn’t)
UEP (Ultimate Expellable Potential) is the cumulative oil+gas volume a source rock section can expel per unit area if it passes through the generation window.
It is commonly expressed in MMboe/km² and can be calculated using organofacies-dependent expulsion schemes (e.g., Pepper/Corvi-style workflows) implemented in basin modeling tools. [oai_citation:0‡searchanddiscovery.com](https://www.searchanddiscovery.com/abstracts/html/2017/90291ace/abstracts/2611211.html?utm_source=chatgpt.com)
Importantly, UEP is not “TOC” and not “a single OAE number.”
It is an integrated consequence of: effective thickness, TOC, HI, kinetics, transformation ratio, and expulsion efficiency.
2) Why Demerara Rise is Valuable — and Why It Cannot Be Applied Basin-Wide
The Demerara Rise deep-marine core record is a superb time-calibrated end-member for OAE-style preservation under low dilution. It is extremely useful for identifying “acmes” (high-yield pulses) and for bounding what “best preserved” can look like.
But Suriname’s margin is facies-partitioned: shelf/delta dilution belts, slope shale belts with turbidite routing and MTC activity, and a distal basinal/plateau domain.
This is exactly what the GeoAtlas facies maps demonstrate.
Therefore, Demerara Rise-style UEP must be translated through a facies-weighted framework.
3) How the Guyana–Suriname Basin Ranks Globally (Published UEP vs Screening UEP)
Many iconic source rocks do not publish UEP openly; where UEP is published, it provides strong calibration anchors.
Below are two complementary tables:
- Table A: UEP values explicitly reported in accessible sources (direct benchmarks).
- Table B: “Screening UEP” computed transparently from representative TOC/HI/thickness scenarios (for cross-basin comparability).
Table A — Published UEP Benchmarks (MMboe/km²)
| Source rock / Province | Published UEP (MMboe/km²) | Why it matters |
|---|---|---|
| Arabia (Tuwaiq Mountain–Hanifa) | Up to ~37 | “World-class” marine benchmark |
| West Siberia (Bazhenov) | Up to ~57 | “World-class” marine shale benchmark |
| Danish North Sea (Farsund Fm, thick section) | ~142 | Shows how extreme UEP can become where effective thickness is very large |
The Arabia and Bazhenov “world-class” UEP values are explicitly stated in a widely cited AAPG Bulletin study. [oai_citation:1‡pubs.geoscienceworld.org](https://pubs.geoscienceworld.org/aapg/aapgbull/article/105/6/1069/599890/Ultimate-expellable-potentials-of-source-rocks?utm_source=chatgpt.com).
The Farsund example is documented in North Sea source rock review literature. [oai_citation:2‡ResearchGate](https://www.researchgate.net/publication/323743581_A_REVIEW_OF_THE_COALY_SOURCE_ROCKS_AND_GENERATED_PETROLEUMS_IN_THE_DANISH_NORTH_SEA_AN_UNDEREXPLORED_MIDDLE_JURASSIC_PETROLEUM_SYSTEM?utm_source=chatgpt.com)
Table B — Screening UEP (MMboe/km²) for the GSB and Famous Analog Source Rocks
Screening UEP values below are calculated using a transparent first-order method consistent with how UEP is framed in petroleum systems workflows (UEP depends on TOC/HI/organofacies, maturity and expulsion).
[oai_citation:3‡searchanddiscovery.com](https://www.searchanddiscovery.com/abstracts/html/2017/90291ace/abstracts/2611211.html?utm_source=chatgpt.com).
These are scenario-grade numbers intended for ranking and sensitivity testing.
| System | Representative setting | Screening UEP (MMboe/km²) | Interpretation |
|---|---|---|---|
| GSB Canje/ACT | Distal Demerara Plateau (low dilution) | ~10 | Strong kitchen tier; can support major fairways if migration is focused |
| GSB Canje/ACT | Slope shale belts (variable dilution/reworking) | ~2 | Moderate tier; success depends on retention and charge focus |
| GSB Canje/ACT | Shelf/delta-influenced belts (diluted) | ~0.4–0.7 | Low–moderate tier; higher risk of thin stacked columns and phase variability |
| Green River (USA) | Lacustrine oil shale (Type I end-member) | ~40–80 | Potentially world-class in richness; TOC and generation potential can be extreme |
| Monterey (USA) | Type IIS-rich (sulfur) system | ~10–25 | Strong tier; high TOC and HI reported in USGS assessments |
Green River published organic carbon range (up to ~33.7 wt%) supports the plausibility of very high end-member scenarios. [oai_citation:4‡Springer](https://link.springer.com/chapter/10.1007/978-3-642-78911-3_16?utm_source=chatgpt.com) Monterey source rock parameters (TOC up to ~14 wt%, HI >600) are documented in recent USGS assessment work. [oai_citation:5‡pubs.usgs.gov](https://pubs.usgs.gov/fs/2025/3052/fs20253052.pdf?utm_source=chatgpt.com)
4) So Where Does the GSB Rank?
Using the global UEP spectrum above, the GSB Canje/ACT system ranks as a “strong kitchen” in its distal basinal domain (screening ~10 MMboe/km²), comparable to strong tiers in mature provinces.
It is not uniformly “world-class” everywhere.
The key is the facies filter:
- World-class tier (typical): ~30–60+ MMboe/km² (Arabia/Bazhenov benchmarks; some very thick North Sea sections can exceed this). [oai_citation:6‡pubs.geoscienceworld.org](https://pubs.geoscienceworld.org/aapg/aapgbull/article/105/6/1069/599890/Ultimate-expellable-potentials-of-source-rocks?utm_source=chatgpt.com)
- Strong commercial tier: ~8–20 MMboe/km² (GSB distal Canje/ACT fits here; many excellent basins live in this band).
- Moderate tier: ~2–8 MMboe/km² (GSB slope belts; commercial outcomes depend heavily on capture/retention efficiency).
- Low–moderate tier: <~2 MMboe/km² (diluted shelf/delta belts; higher risk of thin columns and phase complexity).
Strategic implication:
When GSB exploration fails, it is often not because the petroleum system “doesn’t work,” but because the drilling target lies in a lower-UEP facies belt, or because migration/retention efficiency is low.
This is how “promotion” quietly turns into disappointment: not by bad science, but by applying the wrong end-member across the map.
5) How This Changes Petroleum Systems Modelling for Suriname
5.1 Implement a facies-weighted source term
Effective UEP(x,y,t) = UEP(acme,t) × Ffacies(x,y)
- UEP(acme,t): time-sliced expulsion pulses (acmes) derived from OAE/Caribbean margin research logic.
- Ffacies(x,y): GeoAtlas-derived preservation/dilution weighting by depositional belt.
5.2 Improve multiphase prediction (oil → condensate → gas)
Facies-weighted UEP improves phase prediction because it better captures organofacies quality and expulsion intensity, not just maturity.
Shelf and slope belts are more likely to exhibit mixed phases and thinner columns, even when charge exists.
5.3 Migration realism: focus vs diffusion
Strong distal kitchens can generate large expelled volumes, but commercial accumulations require: carrier continuity, migration focus, trap capture efficiency and retention.
This is why a basin can host a Golden Lane-style fairway and still show thin stacked pays updip: the system is heterogeneous, not contradictory.
Conclusion
A modern, realistic view of Suriname’s offshore petroleum system is not “OAE = huge everywhere.”
It is: acmes + facies + efficiency.
On that basis, the GSB ranks as a strong global system in its distal basinal domain, but its economics and outcomes are controlled by facies belts and migration/retention efficiency.
For operators: this is a blueprint for better well placement and better pre-drill phase prediction.
For investors: it is a disciplined filter to separate structural signal from promotional noise.
About the Author
Marcel Chin-A-Lien is a Global Petroleum & Energy Advisor with nearly five decades of experience spanning frontier and mature basins.
He advises governments, NOCs and IOCs on exploration strategy, petroleum systems analysis, PSC/fiscal optimization, M&A/asset valuation, and negotiation strategy.
He is a Certified Petroleum Geologist (AAPG CPG #5201) and a Chartered European Geologist (EFG EurGeol #92), and a member of the International Petroleum & Energy Negotiators Society.
Contact: marcelchinalien@gmail.com
References (Selected, Annotated)
- Pepper, A.S. & Roller, D. (2021). “Ultimate expellable potentials of source rocks…” (AAPG Bulletin). Defines “world-class” marine benchmarks and explicitly cites UEP reaching ~37 (Tuwaiq–Hanifa) and ~57 (Bazhenov) MMboe/km². [oai_citation:7‡pubs.geoscienceworld.org](https://pubs.geoscienceworld.org/aapg/aapgbull/article/105/6/1069/599890/Ultimate-expellable-potentials-of-source-rocks?utm_source=chatgpt.com)
- Petersen, H.I. et al. (2018). Danish North Sea review summarizing UEP methodology (Pepper/Corvi expulsion scheme) and UEP reporting in MMboe/km². [oai_citation:8‡people.wou.edu](https://people.wou.edu/~taylors/es486_petro/readings/Petersen_et_al-2018.pdf?utm_source=chatgpt.com)
- North Sea Farsund Formation UEP (~142 MMboe/km²). Reported in accessible review literature for a very thick section, illustrating high UEP in thick effective source intervals. [oai_citation:9‡ResearchGate](https://www.researchgate.net/publication/323743581_A_REVIEW_OF_THE_COALY_SOURCE_ROCKS_AND_GENERATED_PETROLEUMS_IN_THE_DANISH_NORTH_SEA_AN_UNDEREXPLORED_MIDDLE_JURASSIC_PETROLEUM_SYSTEM?utm_source=chatgpt.com)
- Katz, B.J. (Springer chapter). Green River Formation shows organic carbon range up to ~33.7 wt% and high generation potential, supporting high UEP end-member plausibility. [oai_citation:10‡Springer](https://link.springer.com/chapter/10.1007/978-3-642-78911-3_16?utm_source=chatgpt.com)
- USGS (2025) Monterey Assessment. Reports Monterey source rock TOC up to ~14 wt% and HI >600, supporting strong screening scenarios for Type IIS systems. [oai_citation:11‡pubs.usgs.gov](https://pubs.usgs.gov/fs/2025/3052/fs20253052.pdf?utm_source=chatgpt.com)
- Roller (Search and Discovery abstract). Provides a clear public description of UEP as ultimate expellable volume and the conceptual basis for “world-class” comparisons. [oai_citation:12‡searchanddiscovery.com](https://www.searchanddiscovery.com/abstracts/html/2017/90291ace/abstracts/2611211.html?utm_source=chatgpt.com)
- APT glossary. Practical definition of UEP and its dependence on organofacies and TOC/HI/transformational parameters, consistent with petroleum systems modelling workflows. [oai_citation:13‡English](https://www.apt-int.com/glossary/ultimate-expellable-potential?utm_source=chatgpt.com)
