Abstract
A three-dimensional (3-D) reservoir model, developed from stratigraphic and petrophysical data, was used to understand the past behavior of the Hillsboro Gas Storage Field and to investigate the field’s performance under various future development. Twenty-two years of the gas storage reservoir history, comprising the initial gas bubble development and seasonal gas injection and production cycles, were examined with a full-field, gas-water, reservoir simulation model. Key issues in storage developments examined after successful history matches of the past gas storage performance included (1) the maximum possible total gas-in-place volume without gas loss and (2) the optimum base load volume that permits the achievement of the peak-day rate requirements.
The results from various simulated development strategies suggest that the gas-water front is already in the vicinity of the west observation well and that increasing the field’s total gas-in-place volume would cause gas to migrate beyond the east, north and west observation wells. They also suggest that storage enlargement through gas injection into the lower layers may not prevent gas migration. Concerning gas deliverability, simulated results suggest that a peak day rate of about 150 Mmscf/D can be achieved with up to 80% of the working gas produced before the peak day and that the peak day rate would fall below 125 Mmscf/D when 85% or more of the working gas is produced before the peak day. Furthermore, the results suggest that. the addition of strategically-located new wells would boost the simulated gas deliverabilities.
