Figure 1. Schematic compares Straddle and Single Packers in a borehole. The Straddle Packer uses two packers to isolate a test interval between them, and the packers can be moved and reset. A second interval can be tested as well from the bottom packer to total depth. The Straddle Packer is used for hydrological testing as well as pulse and constant rate injection tests. The Single Packer uses one packer and tests the entire borehole below the packer. A flowmeter is shown on the logging wireline in the Single Packer schematic.