In some cases, it is not possible to use a Measurand supplied SAAF Install Kit. In these cases you should create your own Set Screw Install Kit prior to going to the field to install the SAAF.
Step 1 - Assemble the Materials
For each Custom SAAF Install Kit you will need the following materials:
- PVC Conduit - The PVC conduit should have approximately 27 mm I.D. with a wall thickness of approximately 3 mm.
- 1 PVC coupler - Additional couplers may be handy during the installation of the Custom SAAF Install Kit.
- 1 PVC End Cap for the bottom of the PVC conduit used to house the SAAF
- 2 set screws with O-rings
Figure 1: Materials required to create a custom SAAF Install Kit
You will also need to obtain a tapping tool in order to tap and thread holes for the set screws. Make sure the bit matches the screw threads you purchase.
Step 2 - Cut the PVC
Cut PVC conduit to an approximate length of 150 mm. Make sure the inside of the PVC conduit is free of any burrs which could snag the SAAF.
Glue a PVC coupler to one end of the PVC conduit.
Figure 2: PVC conduit cut to a length of 150 mm
Step 3 - Tap Holes for Set Screws
Using a tapping tool, tap two holes for set screws.
Figure 3: Tapping holes for set screws
Make sure these holes go through both the PVC coupler and PVC conduit. This ensures that there are sufficient threads to resist stripping when the set screws are fully engaged. The set screw holes should be located approximately 90 degrees apart, as measured around the circumference of the PVC coupler.
Figure 4: Holes for set screws should be 90 degrees apart and through both the coupler and the conduit
Step 4 - Use the Custom SAAF Install Kit
Glue the Custom SAAF Install Kit at the top of the PVC conduit using PVC primer and cement. If necessary, use a coupler to join the install kit to the PVC conduit. It is best to attach the Custom SAAF Install Kit after you have inserted the SAAF into the conduit, but it can be done prior to installing the SAAF.
Figure 5: Attach the custom install kit to the top of the PVC conduit
Step 5 - Compress the SAAF
Once the SAAF in inserted inside the PVC conduit and the custom SAAF Install Kit is installed on the PVC conduit, compress the SAAF using 20 kg force (approximately 50 lbs) and tighten the set screws onto the PEX tubing.
Note: If the ShapeArray is installed in an area with heavy vibration or blasting, it is possible that the set screws will loosen with time. You should take steps to ensure that the set screws remain tight.
Be careful. Over-tightening the set screws will strip the threads in the PVC.
Step 6 - Finish Off the Top
Measure and record azimuth offset using the steps shown in the SAA X-mark Protractor guide. Cut PEX down to approximately 50 mm to 75 mm length.
Make a loop of cable to create strain relief and run cable going from the borehole to the data acquisition system through electrical conduit for protection and easier removal.
Secure any cable unprotected by conduit so that it will not cause unwanted movement of the SAAF.