Hi, Kendra -
Congratulations on you and your families inheritance. Be careful with it and remember that a whole lot of people worked very hard to get it down to you.
And don't let anyone buy it from you until you know a whole lot more about how all of this works. Most especially not until you have recovered any royalties owed you that are being held in suspense or the supposed Buyer might be buying your interests using your own money.
I am not an Attorney, and advise you to consult an experienced Oklahoma Oil and Gas Attorney for questions such as this and any other matters regarding your mineral or royalty interests, both now and in the future.
And I am not as familiar with Oklahoma Law as I am Texas', but from my experience if the royalties have been in suspense (non-pay status) because of an incomplete Probate or Inheritance matter, a bad address or any other reason, then once you have (or your Attorney has) completed your paperwork you will need to filed it of record in the appropriate County Clerk's Office(s).
Once you have done that, you will need to send certified copies of the paperwork to whatever company(ies) are presently disbursing the royalties. That will more than likely be the company(ies) currently operating the Well(s), but it may also be an arm's length party, such as an Accounting firm that handles that sort of thing or even a Pipeline Company that is buying all or some of the produced gas and disbursing it's own royalty checks.
Each of them will send you and your family a new set of Royalty Division Orders (RDOs or DOs). It may only be Transfer Orders (TOs) or something similar, but whatever it is once they have their paperwork straight they will release any royalties they are holding in suspense.
Whatever company(ies) you initially contact should be able to tell you whether your royalties were in suspense (non-payment mode) when they acquired the property(ies) and, possibly, from who or what company they acquired the property(ies). And, most importantly, whether if, when they acquired the property(ies) they received any of your royalties that had been held in suspense by the previous company.
If, like you say, there have been numerous Operators of the subject property(ies) since 1961, then you can research the records of the Oklahoma Corporation Commission and / or the County Clerk's Office for each of the Counties involved to determine who owned the property(ies) when. That's known as a Working Interest Chain of Title (History of the ownership of the Lease(s) or Leasehold).
Then ask all of the companies you contact going back if they currently hold any of your suspended royalties.
Unless they passed them forward to the next succeeding company or turned them over to the State (which is required after a certain number of years), they will still have your royalties.
As soon as possible, you should research the State's Unclaimed Properties website under all of the possible names any royalties might have been under to see if they are holding any royalties for you. But be forewarned that after holding them for a certain number of years, the money goes to the State. Not the ownership of your mineral or royalty interests, although in some states you can lose them for various reasons, but the unclaimed royalties (monies).
As to how much in royalties your family is due, you would have to determine how much oil and gas (and possibly other products such as condensate and sulphur) were produced (actually, what was sold) over the years and how much they got for the products. If you could determine all of that, then you could multiply that by your decimal interests from your Royalty Division Order(s) to arrive at your royalties due.
You should be able to research the records of the OCC to determine total production figures for the Well(s), but because Oklahoma does not, to my knowledge, tax production you more than likely would not be able to determine what amount of oil and gas, etc. was actually sold (which is what your royalties are based upon - not what was produced) or how much they got for the products over the past 55 years.
How much they got for each load of oil trucked off and for each contract for gas, etc. over the past 55 years would be almost impossible to verify independently.
You need to also be forewarned that some of the companies may simply not exist anymore. Others may simply ignore you, hoping that you just go away or insist that you communicate with them through your Attorney.
You need to note that the first royalty checks you receive from any company(ies) that are holding monies in suspense for you may be quite large. I hope they are. But your subsequent checks will not be for anything close to the same amount.
And that you will owe at least Federal Income Tax on the royalty income. Possibly Oklahoma State or your own States' Income tax as well. So don't go spending it all until you've had time to do some planning.
If you or you and your Attorney would like to discuss your circumstances and issues in greater detail, accept my invitation to become A Friend on The Forum, which I will send you in a moment, where we can exchange personal contact information.
Hope this helps -
Charles Emery Tooke III
Certified Professional Landman
Fort Worth, Texas
PS: Pretty photo.