Geology & Geophysics Archives - Page 3 of 18

Geology & Geophysics

Porosity in compressional stress regimes

David Rajmon, Consulting Geologist

November 17, 2025

Porosity prediction sits at the heart of basin models and prospect evaluation. It underpins our understanding of reservoir quality, pore pressure, and thermal history. Traditionally, porosity has been modelled as…

Sponge clasts in calciturbidites

Text: Henk Kombrink, Photography: Ali Jaffri, Applied Stratigraphix.

November 7, 2025

At the recent IMAGE Conference in Houston, somebody told me that the Permian Basin in Texas is not only famous for its hydrocarbon resources, but also because the uplifted areas…

Pasties, piskies, pegmatites… and Pliny

Juan Cottier, MMbbls Subsurface Consulting

October 31, 2025

Britain has strong, quiet, ancient communities on its further reaches: Norse Shetland, Gaelic and Doric Scotland, Wales, the Isle of Man, and Cornwall at the southwest tip. All connected by…

Decoding slip with tension gashes

Molly Turko, Devon Energy

October 27, 2025

Tenson gashes are fractures in rocks formed under extensional stress, often filled with minerals like quartz or calcite. These features are key kinematic indicators in structural geology, revealing fault slip…

“The day I cut an 88 ft core of top seal”

Henk Kombrink

September 24, 2025

“LinkedIn seems to be the place to brag about your career successes,” says Luke Johnson from TRACS International in this video. But sometimes, it is things that went wrong that…

Submarine avalanches in a serendipitous find

Marcos Asensio

September 16, 2025

In the depths of the North Sea lies one of the most spectacular records of turbidity currents: The Claymore Sandstone. During the Upper Jurassic, these rocks were born from a…

Bottom-up meets top-down

Henk Kombrink

September 4, 2025

If there is one positive aspect to this day and age, it is the ability to form solid working relationships even when people are living at opposite ends of the…

Flame structures

Ali Jaffri, Applied Stratigraphix

August 29, 2025

Outcrops remind us of the risks of applying a layer-cake approach to correlating well data. Turbidite lobes pinching out, channels abruptly transitioning to floodplain deposits or carbonate platforms only developing…

Energy is politics, is community, is pride

Juan Cottier, MMbbls Subsurface Consulting

August 22, 2025

My dear friend William invited me last month to Brecon, mid Wales. Another dear friend, Ian, lives in Penarth, just outside Cardiff, south Wales, so it made perfect sense to…

The evolution of fault interpretation

Molly Turko, Devon Energy

August 11, 2025

Before the advent of 3D seismic data in the 1980s and 2D seismic in the 1970s, subsurface geologists typically depicted or interpreted faults as vertical or nearly vertical. Consequently, these…

What is a good source rock?

David Rajmon, Consulting Geologist

August 7, 2025

I recently worked in a well-established basin with proven hydrocarbon accumulations. To my surprise, all reports and published papers routinely talked about local source rocks with barely 1 % Total…

Ripples and plane beds

Ali Jaffri, Applied Stratigraphix

July 25, 2025

The Cutoff Formation, currently exposed in the Guadalupe Mountains in Texas, USA, was deposited over a drowned shelf margin in Permian times. The name of the formation is derived from…

The global energy sector from a subsurface perspective