(CHK:NYSE), for example, is one of the purest North American natural gas plays. It is focused on land-based natural gas exploration, primarily in the mid-continent. Another would be EOG Resources (EOG:NYSE). While not as "gassy" as Chesapeake, EOG is largely focused on U.S. and Canada natural gas exploration. There are a number of other companies that explore for gas but also have oil components: Anadarko (APC:NYSE), Apache (APA:NYSE), Devon (DVN:NYSE) and EnCana (ECA:NYSE) come to mind. There are some smaller exploration companies that tend to focus on natural gas, names like Carrizo Oil & Gas (CRZO:Nasdaq), NGAS Resources (NGAS:Nasdaq) and Quicksilver (KWK:NYSE), including unconventional gas reserves like coal bed methane and "tight gas." Generally, energy service companies tend to be "equal opportunity" players, looking for both natural gas and crude oil. However, land drillers like Nabors (NBR:Amex) continue to benefit from increased natural gas drilling, as do other service companies like BJ Services (BJS:NYSE).