As you researched, petroleum engineering is in fact instable. My cousin and two of my friends are in the field. After going to school in PA, they had to move to Texas because that is where most of the oil and gas jobs are. Either that or Alaska or the Middle East or offshore oil rigs near California and Texas. Petroleum engineering is the highest paying engineering field for many reasons. The high risks of the job, the extremely high responsibilities, and the unstable job security + working hours. Petroleum engineers help locate oil/gas and determine if it is financially feasible to drill for that oil. Some oil sites do not yield enough oil for it to be worth it considering that creating an oil drilling site, along with the planning and engineering, costs billions of dollars. If you make a mistake with your calculations, you can cost the company billions, giving you a bad reputation in the field. Currently, the oil and gas market is down. The companies that make oil & gas related products for measurement, testing, safety, flow, and drilling are suffering and laying off employees. This includes Siemen’s, Conoco Phillips, ABB, ExxonMobil, and Honeywell. I know because I work in this industry, but as a different kind of engineer.
Environmental Engineering is much more stable with more options for jobs and locations. You can work anywhere. You can work for the EPA or your state’s DOT. You can work for any architectural or construction firm that has a LEED or green building division. You can work for any environmental services consulting company that specializes in ground water remediation, green design, spill cleanup, waste disposal and minimization, and more. You can be an EHS or HSE Manager in a manufacturing plan, improving the environmental footprint on the products and manufacturing operations. There are many opportunities in this growing field.