It's important that students take practice exams to determine if they are ready for their Petroleum final. If you're having trouble with a particular topic, go over the related material again and try some practice problems. You should also make sure that you know how to use all of the formulas required for the exam. Finally, it's important to have a good understanding of the concepts involved in the course. If you can answer most of the practice questions correctly and feel confident about your ability to complete the exam, then you're probably ready. However, if there are still some areas that need more work, don't hesitate to ask your instructor for help.