Andy McDonald
Andy McDonaldPetrophysicist · Product manager
PETROPHYSICS / PYTHON / AI & ML

Subsurface data, made usable.

I'm Andy McDonald, a petrophysicist and product manager. I turn messy, incomplete well data into something trusted, before the machine learning ever gets a look in.

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Petrophysicist · Product manager
LATEST ARTICLE · 26 SEPT 2026

Pore Lab: Seeing Inside Reservoir Sandstone

From an X Post to a 3D Pore-Scale Simulator in an Hour

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NEWSLETTER
200+

readers of Subsurface Syntax: AI, ML and Python for the subsurface.

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PAPERS
10

Journal and conference publications
OPEN DATA
13

Public well data sources, catalogued
LATEST VIDEO

Structuring and Organising Streamlit Apps
BOOK · WORKING COPY

Python for Well Log Analysis

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LABS · 600 m

Interactive labs

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Interactive 3D explainers for subsurface concepts. Change the rock, drill the well, and see what happens.

Pore Lab: a magnified cube of sandstone grains with water and oil in the pore space
3D · ROCK PHYSICS

Pore Lab

A magnified cube of reservoir sandstone. Change the porosity, grain size, clay and water saturation and watch the grains, water films and oil or gas rebuild in front of you, then slice through it or pull it apart into its bulk volumes.

Open Pore Lab →
Bore Lab: a 3D earth section with the well drilling through an oil sand beside logs filling in as it drills
3D · LOGGING WHILE DRILLING

Bore Lab

Drill a well and watch its logs being made. Sensors trail the bit, gas and cuttings take time to reach surface, and mud filtrate creeps into the rock as you drill, so you can see why a log depends on when it was run.

Open Bore Lab →
Probe Lab: a density tool in a cut-away borehole with simulated gamma rays scattering through sandstone, beside its detector spectra
3D · LOGGING TOOLS

Probe Lab

Put a logging tool in a cut-away borehole and watch it measure. Gamma rays scatter, neutrons slow, currents flow and sound waves travel through the rock you set, so you can see what each tool responds to and what fools it.

Open Probe Lab →
WRITING · 1,100 m

More from the blog

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13 SEPT 2026 · SUBSTACK ↗

Adding a Geological Facies Display to a Well Log Plot in Matplotlib and Plotly

Adding a column of colour to a well log plot using Python
12 SEPT 2026 · SUBSTACK ↗

6 Ways to Customise Your Raincloud Plot
06 SEPT 2026 · SUBSTACK ↗

PetroPlots - A New Python Plotting Library for Well Log Data

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PROJECTS · 1,800 m

Selected work

PUBLIC / OPEN

Python & Petrophysics Notebook Series

A series of notebooks showing how I load, QC, analyse, and visualise well log and petrophysical data in Python, using real-world messy datasets rather than perfect examples.

GitHub →
PUBLIC / SPWLA

SPWLA 2021 Machine Learning Workshop

Co-instructor workshop materials covering applied ML workflows for well logs, with emphasis on QA/QC, interpretability, and what breaks when real data gets involved.

GitHub →
UK CONTINENTAL SHELF (UKCS)

Building Consistent Sand Flags at Regional Scale

Standardised QC and sand flagging across a large mixed-vintage dataset to produce comparable sand flags for fairway, reservoir, and seal analysis.

OFFSHORE INDONESIA (WEST MADURA)

Petrophysics & Geomechanics Under Incomplete Log Data

QA/QC, conditioning, and repair of log data to support 1D/3D geomechanical modelling, including synthetic shear where key inputs were missing.

TD · 2,500 m

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