Induced Seismicity Monitoring at Geothermal Plant

Case studies

Geobit, May 2019

1. Introduction

GEObit supplied Pertamina Geothermal Energy Indonesia (PGE-Indonesia) [1] with six (6) C100/SRi320L [2] sensor/datalogger units, in order to be used for induced seismicity monitoring in their geothermal field in Indonesia. Our local distributor EXACT GLOBAL TEKNOLOGI [3] worked in the field for installation of the six seismographs.

2. Seismic Network

The six seismic stations were installed at the Geothermal field. They are monitoring induced seismicity by the geothermal operation of the power plant.

Picture 1

The GEObit SRi32L data-logger, the C100 sensor and the guiding wheels tool

Picture 2

The GEObit C100 sensor connected with the data-logger

Picture 3

The geothermal plant.

3. Installations

The C100 sensors were placed into 5m boreholes for providing good signal to noise ratio on the data. A small drilling machine was used for the borehole construction. Plastic pipes were used as borehole casing. The cementing (grouting) procedure [4] were followed with precision in order to achieve best sensor coupling.

Picture 4

The borehole construction

Picture 5 

The borehole construction

Picture 6

The borehole construction

After letting the cement to get hard, the sensor was installed into the casing, and the shelter has covered the borehole.

Picture 7

Sensor and shelter installation process

Picture 8 

Sensor and shelter installation process

Picture 9

Sensor and shelter installation completed

The last part of the work is the digitizer installation and testing. 

The seismic stations are getting power from a removable 12V battery. Overall power consumption is very low so the seismic station will be in operation for a very long time using only one 12V battery.

Picture 10, 11

Digitizer installation and testing

 4. References




[4]: Depth Borehole Installation.