ABSTRACT
The Devonian/Mississippian Age clastics continue to be a major source of natural gas production in the Appalachian Basin. However, the generally low productivity of these sands and shales calls for innovative development strategies, particularly during this period of low gas prices. This paper examines a series of such alternative development strategies, including drilling for deeper pay, using improved well logging to better identify productive net pay, and larger stimulation treatments.
The plateau region of Southwest Virginia was selected as a case study for three reasons. First, gas production in this area has increased four-fold over the past five years (4 Bcf in 1983 vs. 20 Bcf in 1987). Second, drilling activity was up 50% in 1986 counter to a sharp drop for the basin as a whole. Third, by multiply completing and properly stimulating wells in the full tight gas/Devonian shale sequence, this area offers the promise of attractive gas recoveries per well.
Average reservoir parameters were derived for the study area to enable simulations to be run. Past and current drilling, completion, and operating practices were then analyzed to determine average cumulative 20-year productions in the region. After representative reservoir properties and completion practices were established, the effects of larger stimulations and improved pay selection were simulated. The results indicate that current reserves per well can be almost doubled using improved pay selection, larger stimulations and multiple well completions.
