Shale reservoirs are most commonly developed by horizontal wells coupled with multistage hydraulic fracturing to create a stimulated volume around the well. The rate transient analysis (RTA) has been used to estimate of the gas in place based on the production and flowing pressure data. RTA is particularly useful for the shale reservoirs where shut-in pressure data are rarely available. The application RTA to the shale reservoirs is however challenging because of the presence of the adsorbed gas, due to high organ…