Okla. Stat. tit. 46, § 16
A mortgage on real property may be released by written instrument, duly signed and acknowledged and recorded in the office of the county clerk as register of deeds.
R.L. 1910, § 4024; Amended by Laws 1953, SB 157, p. 178, § 1; Amended by Laws 1977, HB 1305, c. 156, § 3, eff. October 1, 1977; Amended by Laws 1978, HB 1517, c. 92, § 2, eff. October 1, 1978.