How many do you have in total?
Processing into LNG for export? If you work on gas pipelines you could end up getting work in the US next. Everyone is hunting shale now. Barnett is all the buzz here.
When I was building credit my banker told me that having a minimum of 3 different credit accounts was important. It's also important to keep them all down, like you said, but having too much credit available can also be bad because they worry that you could easily get yourself in over your head if you decide to max them all.
Which makes little sense if you have had the cards over a long period of time without trouble.