Well Pad (image) Purdue University Caption This shows a well pad in southwestern Pennsylvania. A Purdue and Cornell study found high levels of the greenhouse gas methane above shale gas wells during the drilling stage -- a production point not thought to be a significant emissions source. Credit (Photo courtesy of Dana Caulton) Usage Restrictions None Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.