Production and Water Use in Pennsylvania’s Organic Shales
Thousands of shale gas and oil wells have been drilled in Pennsylvania since 2004. In addition to the Marcellus Formation, other organic-rich shales are being targeted, including the Upper Devonian Geneseo and Burket shales and the Upper Ordovician Utica Shale. Water is used to frac these wells, with a portion of these frac waters flowing back after stimulation. Formation water is also generated after the well has been turned into production. Shale wells produce hydrocarbons in 35 of Pennsylvania’s 67 counties. Most of the production comes from the two ‘sweet spots’ in the Marcellus play in southwest and northeast Pennsylvania. This study looks at production and water use in shale wells from 2010 through 2018. Producing formation information is from the Pennsylvania Geological Survey’s Exploration and Development Well Information Network (EDWIN). Frac water volumes are as reported by operators on well completion reports. Production and wastewater data are from PA DEP’s database. Information from these sources was compiled for almost 6800 wells that reported production between 2010 and 2018. Different regions were compared to identify patterns of fresh and recycled water use. More than 75% of the state’s hydrocarbon production comes from the two ‘sweet spots’ of the Marcellus play: Greene and Washington counties in the southwest and Bradford, Lycoming, and Susquehanna counties in the northeast. More than half of the natural gas production comes from the northeastern ‘sweet spot’ where county-wide average daily gas production per well ranges from 1808 to 3243 MCF/day. County-wide average daily gas production per well in the southwestern ‘sweet spot’ ranges from 1571 to 2088 MCF/day. The two counties with the highest average daily production per well, Wyoming (4889 MCF/day) and Sullivan (3944 MCF/day), are adjacent to the northeast’s ‘sweet spot.’ Ninety percent of the liquids production (oil plus condensate) comes from Washington County. All the liquids production comes from the western part of the state, but not necessarily from the ‘sweet spot.’ Liquids production is also significant in Butler and Mercer counties. The most shale wells have been drilled in Washington County. This county has also used the most frac water and produced the most oil and condensate. Susquehanna County has used the second-largest amount of frac water and has the highest natural gas production. Most of the wastewater from these wells is recycled and reused in other wells (80 to 95%).
AAPG Datapages/Search and Discovery Article #90373 © 2019 AAPG Eastern Section Meeting, Energy from the Heartland, Columbus, Ohio, October 12-16, 2019