It does make sense to have a skill section under projects section as you may have more skills than you used in your projects. But again, its a personal preference.
You could list the technologies used underneath each project. You can also do the reverse: list the skills and next to that the projects that showcase them.
It makes it easier for an employer to look through find the information you provide (for example when he or she has selected a number of portfolio’s and wants to review them to do a further selection).