Playbook Rule 6: “Don’t Leave Oil Behind. Model EOR Before You Abandon”

For over a decade, unconventional wells were seen as one-shot deals: frac it, flow it, and move on. But now, operators are asking: What if the story doesn’t end at primary recovery? Enter unconventional EOR, the next chapter of shale optimization.

The math is compelling. Most shale wells recover less than 10% of the oil in place. That means 90% remains, trapped in nanodarcy pores. And unlike conventional reservoirs, you can’t just waterflood your way to higher recovery, at least not without risking geomechanical damage or lost injectants.

EOR in shale demands smarter strategies: gas huff-n-puff, miscible injection, and even nanofluid surfactants. The goal is not sweeping displacement, but pressure maintenance and rock-fluid interaction at the microfracture scale.

Take the Permian Basin, where several operators have piloted huff-and-puff with natural gas or rich NGL slugs. In one project, soaking a depleted well with gas increased oil production 30x over baseline for a period. In the Eagle Ford, an operator reported EOR projects with rates of return rivalling primary drilling, but only when done early, before the rock loses responsiveness.

The unconventional wisdom here is clear: model EOR before you abandon a well.

Simulation: Make EOR Predictable, Not Experimental: EOR in shale is complex because timing, injectant selection, and reservoir response all vary by location. That’s where simulation presents an answer. The users can model:

• Soaking times and shut-in behavior
• Multiphase flow with changing viscosities and miscibility
• Fracture conductivity changes during pressure cycling
• Reservoir-fluid interactions under huff-n-puff or cyclic injection

Before investing in custom completions, simulation can predict uplift, identify prime candidates, and help you design the most cost-effective program.

Simulation is the bridge from trial-and-error to confident rollout.