Need help determing ORRI in Lea County

Hi,

Over the past year, I have been working to understand and then either sell or hold various mineral interest in NM and Texas that I (and siblings) inherited from father, who died almost four decades ago. The interest I am trying to figure out now is an ORRI in Lea County on five leases in Lea County, all in S24 and 25 of T21S R34E and in S19 and S20 in T21S R35E.

What I am working with is a recorded document in which a person conveyed/assigned ORRI to my father, which reads as follows:

“…an overriding royalty interest equal to one-half (1/2) of the market value at the wells as produced of all (8/8) oil, gas and other hydrocarbons produced depths lying below a depth of 5,200 feet beneath the surface. . .there is excepted from this interest the 5/7773.44 of 8/8 interest.”

So my main question is: How do I convert that info into the actual ORRI percentage? I have the names of the five leases (for example one is Wilson Oil Company and NM: K-6027; 1966) and the legal descriptions of the locations. Do I need anything (say royalty amount?) from the lease to figure the ORRI. I only have lease names and numbers. I have tried to find them on-line but no luck.

The other, possibly odd thing is that we (my family) have only received royalty from well in the tracts mentioned. It is the Quail Hollow 20 State No 1 operated by Mewbourne. They contacted us in 2010 saying that they were holding funds in suspense, that our father’s ORRI was .00654133. We had no knowledge had interest in Lea County and how he came to own it was a mystery. But just recently I found the above quoted Assignment of ORRI. One of the tracts listed is the exact acreage where the Quail Hollow well is. So my sense is that we would have a similar ORRI in the four leases, which amounts to about 1100 acres.

Any help would be greatly appreciated.