Part of what is said by taseenb is right but unfortunately much is wrong or misleading and simply reflects the official propaganda around the petro. Only a few examples:
Petro ($PTR) will be a sovereign crypto asset backed by oil assets and issued by the Venezuelan State.
El Petro will not be backed by oil assets as is made clear by the white paper. There is no mechanism at all by which a holder of petros will be able to successfully claim oil assets or their value from the Venezuelan state.
That phrase is copied from the White Paper. You are wrong, $PTR is backed by oil assets and will be exchanged by its value in Bolivares. The mechanism is not in place yet, simply because the Petro is not even active yet.