Chimney Atlas
A global, peer-reviewed collection of fluid migration path studies — published papers, books, posters, videos and annotated presentations on seismic chimney processing and interpretation.
Chimney Detection & Fluid Migration Studies
Maari Oil Field — Taranaki Basin, New Zealand
Chimney Atlas case study quantifying top-seal and charge risk over the Maari oil field using Chimney Cubes.
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Green Canyon — Gulf of Mexico
Interpretation of hydrocarbon migration pathways using machine learning–based chimney detection.
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Vertical HC Migration — Dutch North Sea
Visualization of vertical hydrocarbon migration in seismic data, with case studies from the Dutch North Sea.
Read studyPurpose
Most hydrocarbon producing basins are dominated by vertical hydrocarbon migration. This vertical migration is often directly detected in the seismic record as zones of vertically chaotic, low-energy data — "gas chimneys". Chimneys have frequently been observed near producing oil and gas fields and dry holes, yet their presence has never been systematically documented.
The purpose of the Chimney Atlas is to improve risk assessment for vertical charge and seal by providing analogs for exploration prospect evaluations. Chimney morphology immediately below the reservoir provides information about vertical hydrocarbon charge; chimney morphology immediately above the reservoir provides information about top seal integrity.
The Atlas is a collection of published papers, books, posters, videos and annotated PowerPoint presentations concerning seismic chimney processing and interpretation. Where possible, material is geographically referenced and accessible from a map.
The Atlas is open to all peer-reviewed material. Please contact info@dgbes.com if you wish to share your work. All material is shared under the Creative Commons CC BY-SA 3.0 license.
Atlas Setup
The Chimney Atlas gives an overview of published material concerning processing and interpretation of Chimney Cubes. The material is grouped in four categories:
Annotated PowerPoints document gas chimney studies over known oil and gas reservoirs and over dry structures — examples drilled in valid structural traps with effective reservoirs that failed for lack of charge or seal. They serve as analogs to improve risk assessment for vertical charge and seal in exploration & development prospect evaluations.
History
In 1998 dGB and Statoil developed a technique to visualize seismic chimneys. The neural network-based pattern recognition technique delivered a new seismic volume called the "Chimney Cube". The technology was originally intended to facilitate geo-hazard interpretation — amplitude anomalies linked to chimneys were likely to be gas-filled and had to be avoided when drilling.
It was soon realized that the Chimney Cube also had potential for deep hydrocarbon exploration. Chimneys proved traceable from deep down in the basin to the shallow subsurface, allowing fluid migration paths to be mapped from source-rock levels to reservoirs and beyond.
In the years that followed, hundreds of Chimney Cubes were processed to study petroleum systems in basins around the world. This led to a workflow for de-risking prospects for charge and seal, in which chimneys are classified by morphology (gas clouds, blowout pipes, along faults) and by their spatial connection to the trap.
Methodology
Gas chimneys are detected using a supervised neural network trained on reliable examples of gas chimneys. The resulting chimney probability meta-attribute (the Chimney Cube) can be displayed on key seismic lines. Not all detected chimneys are related to hydrocarbon migration — they must be validated against criteria such as pock-mark morphology on time-slices and the spatial relationship with other recognized features of the petroleum system.
Validated chimneys can then be output as 3D geo-bodies and superimposed on 3D reservoir geo-bodies based on seismic facies attributes. This facilitates the study of spatial relationships between chimneys, faults, traps and other features such as amplitude anomalies, pockmarks, and (paleo-) mud volcanoes. The combined information is compared to analogs classified into categories with different risk profiles for seal and charge.
Applications
Chimney Cubes visualize vertical noise trails in seismic records, facilitating interpretation of fluid migration paths. There are two main application domains:
Geo-hazard Interpretation
Focuses on the shallow subsurface. Seismic chimneys are co-visualized with amplitude anomalies, faults and geo-morphological features such as pockmarks and mud volcanoes — helping identify shallow gas pockets and other hazards that need to be avoided when drilling.
Deep Hydrocarbon Exploration & Production
- Prospect risk assessment for charge and seal
- Fault seal analysis
- Petroleum system understanding from source to trap
Scientific Publications
Books
Posters
Connolly, D. and De Groot, P. (2016). Chimney Atlas to Quantify Top Seal and Charge Risk: Case Study from Maari Oil Field, Taranaki Basin, New Zealand. EAGE 78th Conference & Exhibition, Vienna.
Download PDFConnolly, D., Heggland, R., Brouwer, F., de Bruin, G. and De Groot, P. Workflow for Prospect Risking Using HC-Chimneys.
Download PDFArticles
Rimaila, K. (2019). Interpretation of Hydrocarbon Migration Pathways Using Latest Developments in Machine Learning – Green Canyon, Gulf of Mexico. GeoGulf (GCAGS).
Download PDFSingh, D., Kumar, P.C. and Sain, K. (2016). Interpretation of gas chimney from seismic data using artificial neural network: A study from Maari 3D prospect in the Taranaki basin, New Zealand. Journal of Natural Gas Science and Engineering.
Download PDFConnolly, D. and De Groot, P. (2016). Chimney Atlas to Quantify Top Seal and Charge Risk: Case Study from Maari Oil Field, Taranaki Basin, New Zealand. EAGE 78th Conference & Exhibition, Vienna.
Download PDFContribute to the Chimney Atlas
Have a peer-reviewed chimney study you'd like to share? Contact us to add your work to this growing global collection.