The "Holy Grail" of borehole surveying.

A borehole survey tool that can accurately report the position of the drill head during drilling in real time is somewhat of a "holy grail" in drilling. There are Measurement While Drilling (MWD) systems, mostly in the Petroleum industry, that use relatively slow and restricted methods of data transmission such as pulses of drilling mud. These have applications but do not meet the "ideal" requirement of fast, complete data giving an accurate location of the drillhead.

In 1994 there was a perceived need by Reflex for a real time surveying system based on the Maxibor for ONE particular client to allow control of boreholes to be drilled under canals in Holland. The boreholes needed to be steered under the canal (below the canal floor) from one side to the other and emerge within a given zone on the far side.

A "wired" system was developed by Chardec Consultants that operated using a surface communications box to convert the low power three wire RS232 signals from the computer into a more powerful signal that could be transmitted down a single cable to an adapted connector on the Maxibor. The wire would be fed through the centre of the drill rods - the drill rods themselves would serve as the "ground" line for the signal. This meant that the cable had to be cut and reconnected as each drill rod was attached.

The Surface Readout System (or SRS) was an extensive control software system developed by GeoMEM based on the original Maxibor software. This allowed real-time viewing of the borehole path compared with a planned path and allowed the driller to change drilling operation in response to the visual feedback. It produced full borehole paths identical to the standard Maxibor survey process for later processing and print-out or data export.

The SRS was eventually used only twice in actual projects: Once on the intended original project in Holland and the second time on a long hole under Gotheburg harbour (in 1997). It needed a well trained operator to get the best from it and was never produced in a commercial form.
The SRS was an application, perhaps ahead of its time, that worked well in theory but practical problems made it somewhat unwieldy and less than "user-friendly" in the field.