Subsurface Alliance

Image logs provide important information on lithology, sedimentary textures, paleoflow directions, fractures, in situ stress analysis... and much more. The images below show some nice examples of conglomerate facies imaged by a resistivity image tool. #wireline #imagelogs #reservoir #geology #oilandgas

Mechanical properties play a crucial role in how rocks deform. Following up on our latest post, below is a short video generated using LiDAR on a small outcrop. White patches correspond to quartz that exhibits a very different deformation pattern that the surrounding metapelites and schist. #outcrops #geology #lidar #structuralgeology #deformation #rocks

⛏ Small scale disharmonic folds (in which the different layers show different fold shapes) developed in fine-grained, thin-layered phyllites and schists. ⚒ A great reminder of how mechanical properties drive rock deformation. Note how the more competent quartz elements (white colors near the bottom of the picture) break up and form the so called boudinage (sausage-shaped boudins). Not only does the nature of the rock (composition, grain-size) itself play a role in how rocks deform, but also external factors such as the confining pressure and temperature together with stress and strain rate. #rheology #rockmechanics #rocks #deformation #stress #strain #folds #structuralgeology #mining #engineering #geology #subsurface

Based on our recent conversation about narrow drilling windows, let's explore how geometry impacts geomechanics, specifically focusing on the upper side of the window: fracturing pressure. #drilling #geomechanics #fracture #drillingfluid

Stress concentrations around a cavity (borehole or tunnel) are directly influenced by its shape. When comparing a triangle and a circle cavity, the question arises: which one will have the higher stress concentration? #borehole #geomechanics #fracturing

To continue our geomechanical discussion on the narrow mud window due to depletion, check out this video on how to drill a triangular hole using circular motion. Ever wondered why drilling boreholes with a triangular shape may not be the most strategic choice from a geomechanics perspective? 🤔 #geomechanics #drilling #borehole Watch the video here: https://lnkd.in/gCHsFbGB

✨ One of the challenges of drilling into a depleted reservoir is that the decrease in pore pressure due to production lowers the fracture gradient, thus resulting in narrow operating mud windows. 💡 How much the fracture gradient gets reduced is a function of the amount of depletion and the stress path. Geomechanics can help in optimizing a drilling trajectory that widens the operating mud window. This is a challenge in both producing oil and gas reservoir, as well as in severely depleted reservoirs that are now being considered for carbon capture. 💡 Understanding your relative stress magnitudes and orientations is a great start to optimize your drilling trajectory. #geomechanics #drilling #oilandgas #ccs #ccus #malaysia #indonesia #northsea #offshore #engineering #structuralgeology #gulfofmexico #mexico #australia #vietnam #india #argentina #colombia #mexico #nigeria

Love these heat maps using the Mohr space. They make a nice visual when looking at the normal/shear ratio in a large fracture population. Thanks to Doolaeghe, D. and coauthors for this contribution! It is an open access paper worth reading if you are interested: Doolaeghe, D., Darcel, C., Selroos, JO. et al. Controls on fracture openness and reactivation in Forsmark, Sweden. Sci Rep 13, 6686 (2023). https://lnkd.in/djnq7dXQ #fractures #geomechanics #Mohrcircle #insitustress #faults

Beautiful polished surface and slickensides along bedding planes. We sometimes come across examples like this when describing core. Have you seen them before? What's your interpretation? #structuralgeology #unconventionals #core #geoscience #geology #mining #oilandgas

The poll results are in. The majority of votes are for a USD 2MM average associated to wellbore instability in a well, which is actually the reported number in a recent study from a drilling company including 93 wells in the North Sea (see comments) between 2006 and 2019. Although the numbers may be skewed to that specific region, other regions like GoM can experience even higher numbers as the wells are more complex and expensive.