all Shipments are stored in /SAPAPO/VS_LCMAP and the orders are in /SAPAPO/ORDKEY . Since the Orders are actually stored in LiveCache and not tables - you have to use FMs to retrieve them.
However that probably is not the best route to get the data you're actually looking for. My suggestion is to use a BAPI like BAPI_TPVSSRVAPS_GETORDERSETS. You can fine tune it to look for specific shipment statuses (Planned, released, transferred. etcc) and it already retrieves the orders attached.
One issue is that the guids returned are 32 char so you'll have to use a FM like /SAPAPO/CIF_GUID_CONVERT if you want to be able to use the guids returned from the BAPI in other selects that might augment the data.
Hope that helps
Charles Ramey