This blog focuses upon stylolites which are structures that either form during burial or by later tectonic movements and have a serrated appearance on rock surfaces.
Mudstones can be extensively fractured - this blog looks at some characteristics of fractures inlcuding connected networks and plumose structures in the Cromlix Mudstone, near Stanley, Perthshire, UK.
Deformation bands (permeability reducing) and open fractures (enhancing) can co-exist in a sandstone reservoir but owing to timing (the d-bands form early during burial), the open fractures can still assist or provide essential reservoir permeability.
A variety of recent and old structures can be found on the karst limestone blocks of the Natih Formation, Oman. These include solution enhanced joints, Rillenkarren and tension gashes.
Here, we have a look at some naturally fractured sandstone outcrops in Caithness Scotland which are an analogue for the giant Clair Field, West of Shetland.
Pink (Devonian age) mudstones on the bank of the River Tay (Perthshire, UK) are intensively fractured - including joints and larger through going fractures Here we look at some of their characteristics including some splaying geometries.
Natural fractures can improve the permeability of tight rock and are therefore often targeted by oil wells. But where do they occur in the reservoir and how do we find them ?