External Casing Packer
Based on Saltel Xpandable technology
Set at low pressures to achieve zonal isolation.
Long-term pressure management using Saltel Xpandable expandable steel technology
The packer is made up to a casing string that is run into the open or cased hole. Once in position, pressure is applied by pumping from surface to expand the packer. The lower end of the casing can be sealed with a plug and then the full string above is pressurized. Alternatively, the expansion port can be isolated using a cup tool or polished bore receptacle with an inner string.
The pressure is transmitted through the expansion port to the packer’s integral sleeve. The sleeve expands into the annulus between the casing and borehole or outer casing string, conforming to the shape of the wellbore or casing and isolating the annulus below the packer from the annulus above. Expansion of the sleeve also centralizes the casing string.
Different AZIP models are available to optimize performance for a range of applications.
The expansion port features a valve system that is integrated within the casing thickness and serves as a safety feature. If the packer is expanded in front of a severe washout, the valve closes, preventing fluid loss.
These packers feature an expansion and pressure compensation valve at the top (1-0) or bottom (0-1) end that permanently closes the expansion port and establishes casing integrity once the packer is set and a predetermined pressure is reached. This activation pressure can be modified by replacing an easily accessible shear pin. The valve also serves as a safety feature in the event of washouts.
Closing the expansion port immediately establishes fluid communication and pressure balance between the annulus at the valve end of the packer and the space inside the expanded steel sleeve. Balancing these pressures enables the packer to withstand higher annulus pressures at that end, providing high sealing capacity and excellent resistance to thermal cycling. The appropriate AZIP model depends on whether high pressure is expected above or below the packer.
The elastomer is used with expandable dynamic seals for temperatures above 250 degF [121 degC]. The 1-1 AZIP comes with a pressure compensation valve at each extremity of the packer to balance the packer’s internal pressure with the highest annular pressure.
The 1-1 AZIP maintains sealing performance in all well conditions during injection, production, and stimulation. The dual-pressure compensation valve manages annular pressure over the life of the well, regardless of whether the highest pressure is above or below the packer. The packer seals effectively in wells with oval (up to 10% ovalization), out-of-gauge, and irregular boreholes, and even through thermal cycling.
Available for 13 3/8-in casings, the AZIP CWD model is designed to resist aggressive conditions experienced during specialty drilling applications, such as with the Allegro casing- and liner-while-drilling services. Its annular sealing capacity for cement support and backup applications matches that of the other AZIP models while adding increased resistance to torque, shocks, and abrasion that occur during casing drilling. The packer’s steel sleeve is expanded between the casing and the borehole by applying pressure in the casing until it conforms to the wellbore shape. Sealing with an uneven borehole surface is achieved through a thin layer of bonded elastomer.