Packers are specialized devices used to insulate discrete intervals of an aquifer while testing its hydrogeological properties and are used to provide a higher level of definition and, consequently, accuracy of data, resulting in more reliable hydraulic and geotechnical estimates.
Packer tests are generally performed when a borehole is being drilled (during interruptions in drilling), with a packer used to isolate the tested interval from the overlying previously tested parts of the aquifer, ensuring the aquifer is studied in detail and providing significantly higher reliability of hydrogeological parameters. The packer is installed in the drill string in place of the core barrel after the rods are lifted from the face to the top of a tested section. A packer sleeve is then inflated providing insulation of the tested interval.
There are three main types of packers:
- hydraulic;
- gas;
- and mechanical.
Hydraulic packers are the most reliable and easy-to-use devices (IPI SWIPS); however, they are much more expensive than the alternatives.
Gas packers are relatively affordable but are quite demanding in terms of additional equipment. When compared to hydraulic packers, gas packers have considerable application constraints (Solid Drillings).
Mechanical packers have the simplest design and functionality, but they can only be used at very shallow depths. Consequently, they are only applied in the field to test horizontal wells (Geopro).
Some types of packers are designed to isolate the top and the bottom of an interval (straddle system) making it possible to complete interval testing of the aquifer or a fault after borehole drilling is completed. When using a double packer, the length of the tested interval is limited, but it can be located at significant depth.
SRK Russia has extensive experience of performing packer tests at various stages of a mining project. Since 2014, SRK completed over 500 packer tests at 16 projects located in Kazakhstan, Kyrgyzstan and Russia. SRK has a successful track record of undertaking hydrogeological investigations with packers at depths reaching 1200 m.
