Create an excel list which order numbers are in which PDF invoices

I have a large number of PDF invoices which either just contain one order number or sometimes contain large blocks of order numbers. I need an excel list that lists the invoice file name and all of the order numbers in the invoice for future searches. I will provide about 1000 PDF files to be processed and I expect a clearly understandable Excel file as result. In some cases only the customer name is in the invoice without the order number. For these cases I will provide access to a list of names and order numbrs to cross-check.