I do not know what is typical in OK. In Texas, SWD wells often require payment at a price per barrel of water disposed which can run over $10,000 per month. You should consult an OK attorney experienced in SWD contracts to review the original agreement and determine what you can demand. There may be differences in your rights between on-lease and off-lease water. You want to be protected in the event that there is an environmental damage due to spills or related pollution.