Unless the parties agree in writing to the contrary, if ownership of any land subject to an oil and gas lease is thereafter subdivided into separate interests, the land shall be developed and operated for oil and gas purposes as an entirety and the rentals and royalties shall be divided and paid to the separate owners in the proportion that the acreage or interest owned bears to the entire leased acreage. (Added 1981, No. 240 (Adj. Sess.), § 2, eff. April 28, 1982.)