The only way you can find that out is a rather backdoor way (besides asking the operator). You can look up the Oklahoma Corporation docket cases that pertain to the well and go through the respondents lists. Some will be leased or unleased owners and others will be working interest owners-lots of contacting to do until you narrow down who is who. The Division Order title opinion lists all the working interest owners, but that is the property of the operator and not usually public.
Contact the Grady County Clerk and ask for a copy of the tract index for the section in which the well is located. They will probably want $x/page for the copies and may want you to send them a check before they’ll make copies. Once you have the index then you can work it backward to the assignments coming out of the original operator; then, forward to the present day to determine current ownership. Pay attention to assignments, deeds, probates, etc. (anything that can transfer title). Watch for a Division Order or Affidavit of Pooling that may have been filed of record by the original operator. You can obtain copies of these instruments through okcountyrecords.com (a commercial service). Good Luck.