VSO Petroleum Consultants is an industry leader in providing accurate and timely petroleum engineering services. The firm specializes in upstream projects including acquisition due diligence, economic evaluations, reserves reports, reservoir engineering studies, expert witness testimony, and fair market valuations for trusts. VSO, formerly known as Pressler Petroleum Consultants, has worked extensively for capital providers, operating companies, law firms, trust administrators, and those with interests in the oil and gas industry since 1992. VSO has substantial experience in every major producing basin throughout the continental United States, and has also evaluated numerous offshore and international projects.