Crude oil family vs by-products: Both asphalt (bitumen) and wax can be obtained in significant quantities from which base type of crude oil?

Introduction:
Crude oils are often classified by their predominant hydrocarbon families as paraffinic, naphthenic (asphaltic), or mixed. This classification affects residue composition and, consequently, which by-products are obtainable in meaningful yield: waxes from paraffinic content and asphalt (bitumen) from asphaltic/naphthenic content. The question probes which crude family provides both in notable amounts.

Given Data / Assumptions:

• Paraffinic crudes: wax-rich residues but less asphaltic content.
• Naphthenic/asphaltic crudes: higher asphaltenes/resins (bitumen) but lower wax.
• Mixed-base crudes: contain appreciable amounts of both families.

Concept / Approach:
A mixed-base crude contains substantial paraffinics and naphthenics, allowing the refinery to recover wax from more paraffinic distillate/residue fractions and asphalt/bitumen from the asphaltic residue. Purely paraffinic crudes yield excellent wax but limited asphalt; purely naphthenic crudes give strong asphalt yields but little wax. Hence, mixed-base crudes uniquely support recovery of both products in significant quantities.

Step-by-Step Solution:

Verification / Alternative check:
Assay experience shows mixed-base crudes provide residues with intermediate wax/asphaltene balances, enabling production of both wax (post-dewaxing) and paving-grade bitumen (post vacuum processing).

Why Other Options Are Wrong:

• Naphthenic only: Asphaltic-rich but wax-lean.
• Asphalt base only: Same limitation; wax poor.
• Paraffin base only: Wax rich, asphalt poor.
• Ultra-light condensate: Too light; minimal residue for either product.

Common Pitfalls:
Thinking the presence of any heavy residue automatically implies both asphalt and wax; the colloidal and compositional balance matters.

Final Answer:
Mixed base crude (paraffinic–naphthenic)