Ideas anyone?

Have a rather large order of cakes/cupcakes. I have the bridal shower cupcakes, bachelorette party cupcakes, wedding cake and the grooms cake. Now the grooms cake is the one I'm stumped on. The request is to have a cake that is one of two ideas. The prefered - Oil field. The alternate - hunting elk. I'm trying to do the prefered. So what would any ideas for an oil field cake be? Google hasn't offered much.