Abstract
Pressure transient well testing is an important tool for evaluating well performance and reservoir characteristics. However, conventional pressure transient test often becomes impractical to wells in shale gas reservoirs due to the nature of extremely tight shale formations.
This study presents a new method for estimating fracture properties for a horizontal well with multiple hydraulic fractures in shale gas reservoirs. The method analyzes commonly available production rate and pressure data to provide reliable estimates of both fracture half-length and formation permeability. The method first converts variable rate-pressure data into an equivalent constant-rate pressure drawdown test, and then pressure transient analysis techniques are applied for property estimates.
Our new approach is primarily based on analysis of linear flow dominated data for estimates of both matrix permeability and fracture half-length. It doesn’t require the existence of the elliptical flow or the appearance of the pseudo-radial flow for independent estimate of matrix permeability. This is very important because we can estimate the properties from early-time production data for horizontal shale gas wells. Synthetic cases are presented to validate the proposed method and demonstrate its applicability.
