As a contract landman, performing work related to oil and gas issues, is the company I contract out to responsible for paying me time and a half for hours over 40 hours per week?

If you are an independent contractor, your clients pay you what you and they agree to. That may include you charging them for overtime.

If you are a non-exempt employee, then your employer must pay you overtime when you work it.

And assuming, if a nonexempt employee, you are working in the U.S. or federal waters, not overseas.