The data, analysis and simulation resulting from a three-well interference test performed in a tight, lenticular naturally fractured reservoir at the Department of Energy (DOE) Multiwell Experimental (MWX) site, near Rifle, Colorado,1 will be discussed. The test data, that includes bottomhole pressure measurements from a production well and two closely spaced observation wells, provides considerable evidence that reservoir gas production was dominated by flow through a layered, anisotropic naturally fractured system. The interference testing consisted of almost two months of continuous data acquisition that included the introduction of several pressure pulses from the production well and the subsequent observation of those reservoir pressure transients at the remote well locations.
A series of novel completion schemes using high pressure nitrogen gas and explosive fracturing were employed in the completion process of all three wells. The primary intent was to eliminate foreign liquids from entering the reservoir fracture system following perforation in order to minimize external intervention in the natural production process.
When wellbore storage effects were considered to negatively impact the data set, bottomhole shut-in tools were employed and virtually eliminated storage volume. Both observation wells made use of these shut-in tools throughout the entire test yielding an unobstructed pressure interference data set.