Pilot Study of Gas Production Analysis Methods Applied to Cottageville Field

摘要

Gas production data from 63 wells in the Cottageville Gas Field, producing from Devonian shales, are studied in relationship to structure above and below producing horizons, isopach data and dip of producing shales, and basement structure trends. Gas production data are studied from several aspects including highest accumulated production, mean annual production, initial well pressure, and calculated loss ratio values for four different time periods. A trend correlation of these parameters is presented. The initial pressure trends correlate with all geological parameters, i.e., Devonian shale dip and strike, 40 to 50 exp 0 NE fracture facies trend, structure on the base of the Huron, structure on the top of the Onondaga, and the basement magnetic density data. Production data trends show greatest correlation with structure on the top of the Onondaga and with fracture facies trends from the Baler well. Production decline data in terms of loss ratio values show trends correlating with all geologic parameters except the Onondaga. Two loss ratio maps correlate with the structure on the bottom of the Huron. The strike of Onondaga structure correlates with the 40 to 50 exp 0 NE fracture facies trend. These parameters may be generally viewed as the production maps representing free gas pockets and migration-accumulation trends; the loss ratios as possible permeability and migration trend indictors; and the geologic parameters as possible constraints or causative agents. The lack of correlation of geologic parameters with production data trends a few degrees west of north may be suggestive of a fault or faults in that direction, providing the correlative causative agent. This is not an unreasonable possibility from the production data maps. It is concluded that this approach could be useful in gas exploration and development evaluation of Appalachian Devonian shale gas fields. Similar relationships will be examined in the Eastern Kentucky Gas Field(s) Study presently in progress. (ERA citation 03:052022)