Many hydrocarbon producing basins in the world are dominated by vertical hydrocarbon migration. This hydrocarbon migration is often directly detected in the seismic record as zones of vertically aligned, chaotic, low energy data. Depending on their morphology we term these features gas chimneys, mud volcanoes, or gas clouds. In 1998, dGB and Statoil invented the Chimney Cube, a volume that has proved to be very useful in the study of petroleum systems. Since the first application dGB created hundreds of chimney cubes and published more than 50 technical papers on fluid migration, fault seal analysis and ranking prospects with seal and charge risks.
Chimney Atlas and Services
dGB Earth Sciences has launched a Joined Industry Project (JIP) aimed at de-risking exploration targets for vertical charge and seal problems. The Chimney Atlas is a compilation of studies of seismic chimney occurrences over known oil and gas producing reservoirs and examples of studies over dry structures. The latter are examples that were drilled in valid structural traps, containing effective reservoirs, which failed for a lack of charge or seal. All studies are described in a systematic manner to serve as analogs for the benefit of JIP members. Analogs are classified and statistics are derived per class to help quantify risks associated with similar, un-drilled prospects.
We use our chimney expertise to help clients rank their prospects and to perform fault seal analysis. Prospect ranking is based on classifying chimneys and calibration against our database of analogs. We classify chimneys on appearance and on spatial relationships between chimneys, faults and traps. In fault seal analysis we compare chimney cubes with fault (similarity) cubes. The output is a qualitative measure of fault leakage.
We use chimney examples identified by a human interpreter to create a learning set for a neural network. The output of the network is a chimney probability cube (or 2D line set) which we then use to interpret fluid migration paths. Often we are able to follow the fluid migration paths all the way from the source rock into the trap and from its spill-point upwards to the surface.
Read more about the Neural Networks plugin
Dip steering is an essential input for the Chimney Cube (e.g. dip-steered similarity, variance of dip, etc..).
Read more about the Dip-Steering plugin