Point Pleasant Formation Produced Water Characterization and Estimation of Future Production
The Point Pleasant Formation is the primary producing rock unit of the Utica-Point Pleasant Shale Play of the Appalachian Basin. Exploration and production operations commenced in 2011 and by the end of 2018 approximately 2000 wells were in production. The volume of water produced along with natural gas, natural gas liquids and oil over this same time period stands at approximately 73.2 MMbbls (ODNRDOG, 2019). The handling, recycling and disposal of produced water is a significant operations expense. Therefore, an accurate means of predicting water production can be a useful tool for estimating and controlling production expense. The source of data used for this research is the quarterly production reports provided by the Ohio Department of Natural Resources Division of Oil and Gas. The research involved sixty representative producing wells from twelve counties in eastern Ohio. The wells were selected on the basis of: 1) a minimum of seven consecutive quarters of production, 2) production for at least 80 percent of the days within each quarter and 3) location within the play. Well selection was also limited to one well per drill pad. Stimulation reports provided by ODNRDOG were analyzed to determine the total perforation interval. The broad variation in perforation interval lengths of laterals mandates that production data be normalized. This was accomplished by dividing production by the length of the perforation interval expressed as barrels per thousand feet (bbls/Mft). These production data were used to create production decline curves for each of the sixty wells along with a spatial analysis of annual production and cumulative production using ArcGIS 10.5. The produced water spatial analysis results show distinct northern and southern production zones within the Point Pleasant Formation. The northern zone, with relatively lower production volumes, is distinguished from the southern zone with relatively greater production volumes. The east-west line of demarcation separating the northern and southern zones corresponds to the boundary of the over-pressured “Utica Seal” zone in the south from the “Utica Source” zone in the north as discussed by McClain (2013). Based on these findings, separate composite production decline curves were created for the northern zone and southern zone. The northern zone composite decline curve used twenty eight wells and the southern zone composite decline curve used thirty two wells. The composite northern region production decline when compared to the southern region production decline yields the following annual findings: year one northern region is 69 percent decline compared 63 percent in the southern region; year two is 83 percent compared to 81 percent; year three 88 percent compared to 91 percent. By year five both the northern zone and southern zone have comparable production declines of 95 percent. These findings can be used to estimate ultimate water production for future wells of the Point Pleasant Formation of Ohio.
AAPG Datapages/Search and Discovery Article #90373 © 2019 AAPG Eastern Section Meeting, Energy from the Heartland, Columbus, Ohio, October 12-16, 2019