If Company B had purchased the leases held by Company A, then you would have been under lease for the wells. You can confirm this by looking for any assignments from A to B in the deed records. Maybe A took leases with the plan to flip them to either B or some other company which wanted to participate in the wells and could not find any buyers. Or A only had leasing funds and could not afford to participate. Or B refused to allow A to participate. Lots of reasons. If you post the company names and well information, then someone may know something. If you were under lease to A at the time the wells were permitted by B, then you were out of leasing market at that time. You are being treated as WI, paying your share of costs but getting 100% of related revenue. If your lease was at 25% royalty, then you would only get 25% of the revenue for your minerals and your lessee would get 75% of revenues and pay the costs.