Hi @RPBuyer, your situation is fairly typical. Subdivsion developers often retain the mineral rights as a standard practice, even though the chances of the minerals actually being found or developed seem remote.
The area west of Sacramento towards Davis, CA had a good number
of gas wells in the past. You can verify whether your property was included
on the California Oil & Gas map https://maps.conservation.ca.gov/doggr/wellfinder/
In many parts of the country it is more of a norm than the exception to
buy surface land without mineral rights. Check out any real estate listings
for ranchland in Oklahoma or Texas and usually the mineral rights are not
included, or can be purchased only as an extra.
The mineral rights in your area could still have value even with the
setback rules recently passed. With horizontal drilling, wells could pass
underneath your property without having a well head or other other oil
facility within 2 or 3 miles. Also, the setback doesn’t seem to include
mining operations, so if for example lithium, is found in your area, the
mineral rights would still be valuable. (Most likely there are, or could be,
separate rules passed for mining)
Some note has been made that mineral rights owners still retain rights
of entry to surface property where they own mineral rights to explore
for hydrocarbons or minerals. This usually isn’t a problem since this
entry right is for legitimate exploration only and not to play softball or
lazer tag.
Hope that these answers are somewhat helpful and reduce your concerns.