New lessons for an aging geologist

When I was a young geology student, I learned the basics of petroleum production as they were then understood. Deep layers of sedimentary rocks, including shale, were the “source rocks” for hydrocarbons. The source rocks were too difficult to exploit directly – it just wasn’t economical to mess with them.

But through natural processes, the petroleum and natural gas in the source rocks sometimes migrated to “reservoir rocks.” From Saudi Arabia to Texas, the name of the game was to sink wells into reservoir rocks and extract the hydrocarbons that had accumulated there over the ages.

But sustaine...