Companies in this state:

Exxon Mobil  

Oil and Gas corporation
Headquarters: Irving, Texas 75039
Find Exxon Mobil jobs at http://www.exxonmobil.com/Corporate/careers.aspx  

ConocoPhillips  

Oil and Gas corporation
Headquarters: Houston, Texas 77079
Find ConocoPhillips jobs at http://www.conocophillips.com/careers/