Definition of "undivided"?

I am a rookie to the oil and gas field and still trying to learn and understand the language. I have accepted the term such as 1/3 "undivided" interest. But in my simple logic, 1/3 says something is divided??? Why isn't it just "1/3 interest"??

I realize this is not an earth shaking item but would like to know what is meant by "undivided".

Can anybody save me? THANKS

As an example, a "section" of land is typically 640 acres. Let's pretend you own an undivided 1/2 interest.

One half of 640 acres is 320 acres. So your pretend 1/2 interest means you own 320 net acres. Since this is an "undivided" interest you own 50% of the minerals under that entire 640 acre section. That is as opposed to your 320 acres being the west half of the 640, while another party owns the east half. I hope this makes sense.

You could say 1/3rd interest. The word undivided is added to indicate it is a partial interest in a tract and the owners have not agreed to partition the minerals among themselves.

If you have 3 brothers who were devised a 100 acre tract of land by their father, they can partition the surface into 3 separate tracts of 33.333 acres each. One brother may own the north 33.33 acres. One brother might own the middle 33.33 acres, and the third brother would own the south 33.33 acres. However, in the Partition Deed, all three brothers may agree to leave the minerals undivided. If they elected to word the Partition Deed like that, they would each own an undivided 1/3rd of the minerals in the entire 100 acres, even though they elected to divide the surface. They might also choose to not partition the surface. In that case, they would each own an undivided 1/3rd each of the both the surface estate and the mineral estate. This example assumes that there were no prior mineral reservations , or that the father died owning 100% of both the surface and minerals.

Thanks for the example. I now understand.

I'm glad that I could clear it up for you. That's what this site is all about.

But in my simple logic, 1/3 says something is divided???

This (very reasonable) conclusion is a perfect example of how the language of the law and the language of common sense are far too often different things.