The class of ’71
I am working on a Brent Province project at the moment. It’s the appraisal of a significant discovery. The Brent is classic petroleum geology – and this project really does…
Geology & Geophysics
Seismic reflections – lithological boundaries or timelines?
In basic terms, acoustic impedance is a measure of how resistant a material is to sound waves passing through it. When that resistance changes across a lithological boundary, some of…
Beyond turbidites: Core insights from the Rovuma Basin
The Rovuma Basin evolved from Early Jurassic rifting into a passive margin by the Mid-Cretaceous, followed by significant clastic infill through the Cretaceous and Tertiary. Uplift associated with the early…
Wadi Nukhul – a glimpse of the Red Sea-Gulf of Suez rift system
During the Oligocene and Miocene, a 2,000 km long zone of extension developed that formed the Red Sea-Gulf of Suez rift system. In this outcrop photo, we are looking south…
The rebellious proto-Riedel shear zones
Classic Riedel shears are the first subsidiary fractures that form prior to breakthrough of a master fault. They appear as low-angle (~15°) en echelon arrays oriented synthetically to the principal…
Mid Atlantic ocean floor at outcrop
The island of Maio, Cabo Verde, 600 km the west of Senegal, is the only place where Cretaceous mid-ocean floor of the distal Mauritania – Senegal – Guinea Bissau – Conakry…
What’s hidden in your reservoir brine?
For more than a century, petroleum exploration has focused on hydrocarbons. Yet, sooner or later, every producing oil and gas field also brings something else to the surface: Formation water.…
The tricky part of resource assessments within gas-dominated basins or petroleum systems
When conducting prospect resource assessments within gas-dominated basins, there is a low likelihood of oil or mixed-phase accumulations being filled to spill. If this is not properly considered, prospect resource…
The very first core cut in the UK North Sea
It is boxing day 1964, a day most people in the countries around the North Sea don’t think about spending a day at sea. Yet, the crew of the Global…
What are we risking and why is it important?
Risk is about the chance of finding producible hydrocarbons; uncertainty is about the volume of hydrocarbons that may be found in the case of success. The geological Probability of Success…
Your fault stability analysis might be lying to you
The Mohr space represents stress states and, combined with fault strength criteria, is used to assess fault stability. It is simple, elegant, and widely accepted. It is also, when applied…
Tectonics or soft-sediment deformation?
Soft-sediment deformation (SSD) refers to structures that form during or shortly after deposition, while sediments remain unlithified, water-saturated, and mechanically weak. These features develop prior to significant compaction and cementation,…