how do you know if your interests are part of a wells 640acre area
I would have to compare your legal description to the spacing order to be certain, but most 640 acre spacings are the entire section. So if the spacing is for all of Section 8, Township 4 North, Range 6 West and at the end of your legal description it says the same thing then you are probably a part of the spacing.
If you received a notice of a spacing and you are named as a respondent then you are probably a part of it.
what is "spacing"?
Not trying to be rude. A lot of us really don't mind answering questions, but it might be best if you do some reading. At the top of the page under mineral help is a section on recommended reading and oil and gas 101, etc. You might read through some of those headings and then ask questions or friend one of us to help you figure out what you really need to know or how to apply what you read to your situation. Oklahoma does things a little differently than other states so not everything you read will apply to every state.
How many acres per well.