See which Texas energy companies dominate Pennsylvania drilling

A majority of the most active energy companies in Pennsylvania are actually based out of Texas.
The natural gas boom took off in Texas more than five years ago and has proven transformative for many Houston and Dallas-area companies.  One of the major ongoing unconventional oil and gas plays using hydraulic fracturing, or fracking, is the Marcellus shale, much of which is in Pennsylvania.
Twelve of the top 20 well producers in Pennsylvania, particularly the booming Marcellus shale, either call Texas home or have a major Houston presence, according to data compiled by the Pittsburgh Business Times.
Click through the slideshow to see the top Texas energy companies producing in the Pennsylvania shale plays.
The surge in domestic natural gas production is big in Texas with the active Eagle Ford Shale formation and the Permian Basin, but Texas energy companies are active in other states as well, such as Pennsylvania.
The Marcellus shale is named for the small village of Marcellus, New York. The marine sedimentary rock formation runs across southwestern New York and into northern and western Pennsylvania, eastern Ohio, through western Maryland and throughout most of West Virginia.
The Marcellus bedrock in eastern Pennsylvania extends across the Delaware River into the edge of New Jersey.