One Well, Five Sciences
Ogbon-1 is one borehole through one reservoir, and five disciplines each claim a piece of it. Read the logs like a petrophysicist, count the water like an interpreter of resistivity, calibrate the velocities like a rock physicist, build the stress model like a geomechanicist, and close the loop on net pay and barrels. Same well, start to finish: the disciplines stop being subjects and become chapters of one argument.
You can take a raw log display through the full well review: read invasion and pick true resistivity, compute water saturation and defend the cutoffs, calibrate a rock-physics model to the measured velocities, assemble the vertical stress and pore pressure into a stress model, tie the well to the seismic, and report net pay and volumes with the uncertainty attached, all on one real well whose numbers agree across every discipline because they were built to.
Meet the well
Every discipline downstream reads from the same tracks; learn the display's grammar once, depth, curves, scales, and flags, and the rest of the path is reading, not deciphering.
The borehole is a wound, and mud filtrate floods the rock nearest every tool; flushed zone, transition, virgin zone is the geometry that decides which measurement reads which fluid.
The shale flag comes first: gamma ray and SP sort reservoir from non-reservoir, and the neutron-density crossplot then reads lithology and porosity together in the zones that survive.
Density and sonic each count the pore space through different physics; where they agree the porosity is real, and where they disagree the disagreement is itself information.
Count the water
Saturation math is only as good as the resistivity it eats; correcting the deep reading back to virgin-zone Rt is the quiet step every water saturation silently depends on.
The well's own resistivity profile, read for real: invasion effects, thin beds, and the honest Rt in the sand that everything downstream will use.
One equation turns porosity and resistivity into water saturation, and the Pickett plot is the graphical version that also confesses Rw and m while it works.
The saturation log is the first number a partner meeting asks for; computing it on the real well, with the real Rw and the real porosity, is the competency.
The rock physics of the same well
The sonic is the bridge out of the borehole: velocity and density become impedance, impedance becomes the reflection, and the well becomes visible to the survey that found it.
A rock-physics model is an instrument only after calibration: fit the stiff-sand line to the well's own velocity-porosity cloud and the model earns the right to predict what the well did not measure.
The stress on the well
The same logs that counted the pay also carry the load story: a mechanical earth model assembles stresses, pressure, and strength into the depth-continuous profile every drilling decision reads from.
The two easiest rungs of the stress ladder come straight from the well: integrate the density log for the overburden and read the pressure points for the pore pressure, and the effective stress falls out between them.
The image log turns the borehole wall into outcrop: bedding, fractures, and breakouts on the same well tie the log response to the geology and the stress field at once.
The RFT survey reads the fluid system directly: gradients give densities, crossings give contacts, and the pressure profile is the arbiter when logs and geology disagree.
Close the loop
Every discipline converges on two numbers, net pay and barrels, and the honest report carries the uncertainty that survived all of them; this is the well review's last slide, built from everything above it.