Bridget, you need a copy of the lease to see if it contained an extension option. There may not have been an extension option or the operator may have mailed the extension payment on the last day of the lease to the last known address.
Operators were stretched thin in 2011 and frequently commenced "operations" in the last month of a lease, operations leading up to a producing well would extend the primary term of the lease. 60, 90, 180, days, even for 1 year are common grace periods, 180 days being the most common in my opinion, grace period means that if the operator commenced "operations", built a road, dug a pit, drilled a water well, anything that cost substantial money/investment, as long as the operator did not cease trying to obtain production for longer than the time allowed in the grace period, the lease would be extended indefinitely, possibly years.
At this distance I can not tell if you had a valid lease or not at time operations commenced. If there was not a valid lease at the time operations commenced, the operator would still need/want to lease you. I would say no thank you and that the operator could send me an AFE to participate but they would probably end up force pooling me. When I am force pooled, I receive 16% royalty from the very first barrel, the operator takes the other 84% to pay for the well cost and a risk penalty/operating expenses until the operator recovers 150% of the well cost at which point I would become a working interest and receive 100% less taxes and cost of production. If the well never pays out or recovers the risk penalty, I owe nothing out of pocket. NDCC 38-08-08 is interesting reading.
I suspect that the operator did commence operations on your lease or they would have contacted you by now in an attempt to get you to sign a lease. The bonus and any upward royalty adjustments would be paltry compared to the loss of profit from the acres. In most cases the bonus is less than 1% of what the operator hopes to make from 80+% of your oil. The operator would be worried that someone else might lease you and participate [the operator would make nothing off your oil] or that you would be non-consent and that they would have to force pool you and the operator would make very little money off your oil. The operator expects to make multiple times the well cost from your oil, they do not go around drilling wells to recover a 50% of actual cost of drilling and completing risk penalty, 300% or more is more like it. A friend contacted me about the operator taking out a loan for $140,000,000 on 2,560 acres. I told them that is just a development loan, that the oil is worth more than that, obviously or a bank would not have loaned them money against the as yet non-producing [her spacing at least are not producing yet] acres as collateral. More than $54,000 per acre.
I think it likely that your operator commenced drilling in time, that does not mean I would not check to make sure.