The wells were drilled to ensure a safe passage for the new platforms and the metro line. However, due to the complexity of the project and the need to avoid survey data errors, a highly accurate survey tool, unaffected by magnetic disturbance, which could accurately measure all of the 100 boreholes without any downtime was required.

As time was of the essence, the SPT GyroLogic, which is a highly accurate and extremely reliable directional survey tool, was deployed. In addition, SPT provided the services of a technical engineer to train the client's team to initiate the survey operation. SPT's technical expert arrived at the site to train the personnel on how to correctly assemble the tool for this particular operation and ensure they followed the correct steps and protocols for a fast and accurate survey, and lastly, how to effectively use the data obtained after the survey.

SPT's GyroLogic tool exports the data in multiple industry-standard formats, for example, PDF, Excel, CSV, LAS, DXF. In this particular operation, the team required the data in CSV format, ensuring a 3D model is obtained for each of the independent holes that were surveyed.

Each of the 100 holes along the metro line platforms required independent surveys to ensure that each one along the 5km of the metro line were drilled accurately.

Using gyro survey tools in such civil engineering projects comes with a variety of complexities and challenges that are very different from the ones SPT usually faces in the mining or oil & gas sectors. Making sure that the tools are not affected by any sort of magnetic disturbances and able to export the data in the correct formats are critical factors for drilling holes in such close distance. Even one-degree of error can have a disastrous impact on the project.

Initially, 14 boreholes were surveyed, and the process of configuring the data obtained during the surveying was completed using the Gyrologic tool, into which SPT had programmed the starting coordinates of each borehole for use as a measurement reference.

Mirko Macari, surveyor in STR 92 -engineering company involved in the project, said: "Thanks to the support from SPT's technical engineer in the initial training, and the user-friendliness of the tool, we were able to efficiently complete the operation to the satisfaction of the client. After the first two days of training, our on-site engineers were able to independently perform the survey operations with ease, thanks to the remote technical support from SPT."

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