Difference in ownership interest listed on DO and Tax Roll

I received new division orders for two recently inherited producing well units that were previously in my Mother’s estate. The decimal ownership listed on the Howard County (Texas) Tax Office website for the first well unit is 0.0007100 for tax years 2018 and 2019. The decimal interest listed on the division order that I received is 0.00035487. The decimal ownership listed on the Tax Office site for the second well is 0.0008900, while the decimal interest listed on the division order is 0.0004489.

It is my understanding that the oil company reports the actual decimal ownership in the well unit to the County Tax Office, so I am concerned that the decimal interest listed on the division orders is incorrect. To the best of my knowledge there have been no changes in the well units or the leases since 2018.

Shouldn’t the decimal interest be the same on the County Tax Office records and the division orders?

In both sets of number the tax rolls are showing you own twice as much interest (subject to rounding difference). Were you the only heir to your mother’s full mineral interest or did someone else receive half of it, and was a new division order issued in your name showing that ownership decimal amount you are referring to?

If you feel the division order is correct I’d contact the tax office and ask that it be corrected.

You are correct, the tax rolls are showing twice as much interest as the division orders. I am the only heir to my mother’s full mineral interest, and new division orders were issued after I notified the oil company of the change in ownership.

My mineral interest is an undivided one-sixty fourth (1/64) interest in and to all of the royalty on oil, gas, and other minerals in an under the following described land: the North one-half (N.1/2) of Section 45, Block 32, Township 3-North, T & P Railway Company land in Howard County, Texas. The decimal for 1/64 is 0.015625.

My royalty share is 25% (0.25 decimal) under the lease.

The wells are declared as production sharing wells, where the N. 1/2 of Section 45 where my mineral rights reside is combined with different pooled units to form the respective well units. The production sharing clause in the lease stipulates that for royalty purposes the productive well bore yardstick applies for the allocation of production. I will use one of the well units as an example of my calculations: the productive drain hole length in my section is 1,855.74 / 10,209.67, the total productive horizontal drain hole length, = 0.181762975 x RI 0.25 x MI 0.015625 = 0.007100, the ownership interest shown on the tax record. The well unit sizes under the lease are described as NW/4 Section 45, Block 32 Township 3 North, Abstract 297 for one well, and the NE/4 for the other well.

Also, child wells were drilled for each well, and they are shut-in.

Please advise me if my calculations or assumptions are incorrect.