To be 'well-heeled' is to be wealthy. Usually it refers to someone who is well-off, but not filthy rich, although it can be used in either case.
There are two stories as to how this expression originated:
First, it may come from the fact that rich people can afford to replace or repair their footwear more often than a poor person, thus providing them with good heels for their shoes. (An extension of the 'you can tell a lot about a man from his shoes' theory).
Second, it may come from the metal spurs that were attached to the back of cocks' legs in cockfights, the better to gouge the opponent with. This theory of the phrases' origin is reinforced by the fact that when it first appeared in the late 1800s it referred to a person who was adequately armed. It might then have been transferred to the world of business, to refer to wealthy people who were well able to compete in the business place due to their wealth.