RST Snap Seal Casing that was previously damaged or cut can be repaired or extended using RST repair couplings. This process is typically done using an RST Coupling Tool. In the case where the user hopes to leave a ShapeArray within the borehole, and extend or repair the casing without the need to remove the SAAV, the SAAV Casing Alignment Tool has been developed.
Recommendations for using the casing alignment tool are outlined below:
Ensure that the top of the inclinometer casing is as square as possible and remove all burrs. This can be done using a hacksaw.
Insert the casing alignment tool into the RST repair coupling by the non-lip end. Ensure the grooves are aligned. Leave roughly one inch of space between the coupler and the lip end of the casing alignment tool.
Figure 1: SAAV Casing Alignment Tool
Figure 2: The SAAV Casing Alignment Tool, inserted into the RST repair coupling
Apply ABS 771 Cement to the inclinometer casing, following the dimensions shown in Figure 3. Extra caution is recommended to leave the top ¼” inch free from cement.
Figure 3: Casing Preperation, using ABS Cement
Slide the casing alignment tool (with the repair coupling attached) into the inclinometer casing, making sure that the communication cable is inserted and run through the casing alignment tool beforehand. The repair coupler will slide over top of the inclinometer casing, where the cement was applied. Ensure grooves are aligned.
NOTE: Do not install the tool all the way up to the 'lip' in the RST repair coupler, as the 'lip' will facilitate the easy removal of the tool after the ABS cement has 'set up' and the tool has to be removed.
Allow the cement to cure, as per the directions specific to the cement used.
Remove the casing alignment tool by pulling upwards and install the next section of Snap Seal casing as usual (directions provided by RST Instruments). Ensure that the keys and keyways are aligned.