(plaintiff acquired sixteen oil and gas leases at sale by defendant which specified that rental payments for subsequent years were due before the beginning of the next lease year, and specified that leases would terminate unless there was a well currently being drilled, a producing well or a shut-in well; plaintiff failed to pay annual rents before beginning of next lease year and failed to have producing wells, wells that were being drilled or shut-in wells; provision providing for automatic termination of leases upheld).