Sell Mineral Rights in Michigan

If you own minerals in Michigan's northern lower peninsula, there's a good chance your check comes from an Antrim shale well that's been in decline, slowly and predictably, for a very long time.

The Antrim Shale, centered on counties like Otsego, Antrim, and Grand Traverse in the northern lower peninsula, was one of the earliest commercially significant shale gas plays in the country, developed heavily through the 1980s and 1990s, well before the horizontal drilling boom most people associate with shale today. Most Antrim wells still producing now are decades old, drilled vertically, and have been on a long, gradual decline for years.

That age is actually the single most useful fact for setting up a value calculator here. Michigan isn't a state where you should expect the steep early-life decline curve of a modern horizontal well, and mistaking one for the other in a calculator will understate your interest's value.

Decline rate: the input to get right

Coalbed methane and shale gas wells of the Antrim's vintage tend to flatten out considerably once they get past their first several years, and a well that's now twenty or thirty years old is often producing at a steady, low, predictable rate rather than continuing a sharp downward trend. A conservative single-digit annual decline assumption usually reflects reality better than a generic default modeled on newer unconventional wells. Getting this input close to accurate matters more here than getting commodity price exactly right, since the production curve itself is the more distinctive feature of an Antrim interest.

No oil credit means gas price does the heavy lifting

Antrim wells are gas producers without meaningful associated liquids, so your monthly income tracks Henry Hub pricing directly, without the cushion an oil-weighted play would have during a soft gas market. When gas prices dip, Antrim royalty checks feel it in a way an oil-heavy Permian interest wouldn't, and that's a genuine reason no calculator can promise a stable number quarter to quarter.

Buyer depth reflects an older, quieter play

New drilling in the Antrim has slowed to a trickle compared to its development-era peak, and the buyer pool actively pursuing small legacy Michigan gas interests is smaller than what you'd find in a currently hot shale basin. That doesn't mean your interest lacks value, mature, steady-decline assets can be genuinely attractive to the right buyer, but it does mean a realistic multiple should reflect a quieter market rather than borrowing assumptions from a basin still in active development.

Title work often runs through multiple generations

Because so much Antrim production dates back thirty-plus years, it's common for the original mineral owner to have passed the interest down through one or more generations since the well was drilled, sometimes without a formal title update at each step. Confirming your current decimal interest may require tracing probate records at the relevant county register of deeds before a value estimate can be treated as reliable.

What actually moves a Michigan estimate

Because the production curve is so stable for most Antrim wells, small differences in how you enter decline rate matter less here than in a play with more volatile behavior. What tends to move the estimate most is the trailing twelve-month average income you use as your baseline, since a single unusually high or low month can skew a shorter average meaningfully for a small well. It's also worth checking whether your well has had any recent workover or recompletion, since even mature Antrim wells occasionally see a modest production bump after mechanical work, and that bump should be smoothed into a longer average rather than treated as a new baseline going forward.

It's also worth asking the operator, or checking Michigan's public well records, whether your specific well has been shut in temporarily rather than permanently plugged. A shut-in well with no current income still has value tied to the reserves left in place, but a calculator relying on monthly income can't estimate that on its own, and treating a shut-in well the same as a plugged one, or the same as a steadily producing one, will give you a misleading number either way.