Azimuth adjustment allows you to orient the axes of the data returned from your SAAScan. This is particularly helpful when multiple boreholes are being scanned so that their data can be oriented to the same known direction. There are three options for determining the azimuth of your SAAScan.



Option 1 - Automatic Azimuth Offset Determination


Azimuth offset can be determined automatically in the SAARecorder software if the SAAScan reel is properly aligned with the angle of the borehole or the desired direction of measurement.


Figure 1: The SAAScan reel aligned with the desired direction of measurement or the angle of the borehole.


Step 1 - Select a Horizontal Segment


Select a nearly horizontal segment coming off the reel and make note of its segment number. Segment number is determined by counting sensorized segments from the cable end of the SAAScan to the segment in question.



Step 2 - Connect to the ShapeArray with SAARecorder and Open Site Properties


Connect the ShapeArray to a computer and start SAARecorder. Open the Site Properties by selecting the SAA Setup | Site Properties menu option. 


Figure 2: Select SAA Setup | Site Properties to open the Site Properties dialog



Step 3 - Use Determine Azimuth to Automatically Configure the Azimuth Offset


In the Site Properties window, click on the Determine Azimuth button. In the SAA Azimuth Determination window, enter the segment identified for the nearly horizontal segment (from step 1 above) in the SAA segment to use for determining azimuth field. Ensure that the Enter ‘A’ angle of SAA going into hole field is set to zero degrees.


Figure 3: A portion of the Azimuth Determination window in SAARecorder


SAARecorder calculates an appropriate azimuth offset to use in the SAA Azimuth field. The positive X-axis in the data recorded will be aligned with the direction to which the reel is aligned. Click OK to continue and note that the calculated azimuth offset value is automatically entered into the Azimuth Angle field. Click OK again to save the site properties.



Option 2 - Measuring Alignment with the X-mark Protractor


When the SAAScan reel cannot be placed such that it is aligned with the desired direction of measurement or the angle of the borehole, then the X-mark protractor will need to be used to properly determine the azimuth offset. This method uses a nearly vertical segment at the top of the borehole as a reference segment and a nearly horizontal segment on the reel for determining the azimuth offset, as shown in the figure below.


Figure 4: The suggested configuration for determining initial azimuth – (left) side view, (right) top view



Step 1 - Align Protractor Arrows with Desired Reference Direction


With the ShapeArray secured to a stable base, place the square protractor around the nearly vertical segment located near the top of the borehole. Align the arrows on the square protractor with the desired reference direction. For example, a survey marker on site, magnetic north as measured by compass, or the angle of the borehole is often used as the reference direction.



Step 2 - Select a Horizontal Segment


Select a nearly horizontal segment coming off the reel and make note of its segment number. Segment number is determined by counting sensorized segments from the cable end of the SAAScan to the segment in question. 



Step 3 - Measure Azimuth Offset with Clear Plastic Disk


Place the clear plastic disk over the square protractor. Draw an imaginary line through the centre of the nearly horizontal segment (selected in step 2 above) down to the protractor. Rotate the clear plastic disk until the X-line is aligned with the centre line of the nearly horizontal segment. Record the azimuth offset value highlighted on the square protractor.



Step 4 - Connect to the ShapeArray with SAARecorder and Open Site Properties


Connect the ShapeArray to a computer and start SAARecorder. Open the Site Properties by selecting the SAA Setup | Site Properties menu option. (see Figure 2 above)



Step 5 - Use Determine Azimuth to Configure the Azimuth Offset


In the Site Properties window, click on the Determine Azimuth button. In the SAA Azimuth Determination window, enter the segment identified for the nearly horizontal segment (from step 2) in the SAA segment to use for determining azimuth field. In the Enter ‘A’ angle of SAA going into hole field, enter the previously determined azimuth value (from step 3). (see figure 3 above)


SAARecorder calculates an appropriate azimuth offset to use in the SAA Azimuth field. The positive X-axis in the data recorded will be aligned with the direction to which the reel is aligned. Click OK to continue and note that the calculated azimuth value is automatically entered into the Azimuth Angle field. Click OK again to save the site properties.



Option 3 - Measuring Azimuth using the X-Mark and the Protractor


Each segment of an SAAScan has an X-mark scored into its surface. Azimuth offset can always be measured directly using the X-mark protractor and this marking.


Figure 5: X-Marks are scored into the surface of each segment of the SAAScan


Step 1 - Align Protractor Arrows with Desired Reference Direction


Place the square protractor on a near vertical segment coming out of the borehole. Orient the arrows on the square protractor so that they point in the desired direction of measurement. 



Step 2 - Measure Azimuth Offset with Clear Plastic Disk


Place the clear plastic disk over the square protractor and align the X-Line with the scored X-mark in the near vertical segment. Record the highlighted azimuth offset value.



Step 3 - Connect to the ShapeArray with SAARecorder and Configure Site Properties


Connect the ShapeArray to a computer and start SAARecorder. Open the Site Properties by selecting the SAA Setup | Site Properties menu option. In the Site Properties window, enter the recorded azimuth offset value (from step 2) into the Azimuth Angle field and click OK.