Not sure what version you are on. I know in R12, the oe_order_lines_all table has an "invoice_interface_status_code" that will tell you whether the line expected to be sent to invoicing - NOT_ELIGIBLE indicating that it isn't. But disregarding whether it was supposed to be invoiced or if you have records sitting in the interface unprocessed, this should give a start - it includes all order lines, even internal orders that do not invoice.
select oeh.order_Number, oel.line_number, oel.shipment_number, oel.invoice_interface_status_code, oel.*
from oe_order_lines_all oel, ra_customer_trx_lines_all ractl, oe_order_headers_all oeh
where oel.header_id = oeh.header_id
and oel.LINE_ID = ractl.INTERFACE_LINE_ATTRIBUTE6
and oel.open_flag = 'N'
and oel.shipping_interfaced_flag = 'Y'
and oel.fulfilled_flag = 'Y'
and ractl.customer_trx_line_id IS NULL
and oel.flow_status_code <> 'CANCELLED'