Today Guralp Systems announced the delivery of a life of field seismic monitoring system to the Kashagan field. The Kashagan field is located in the Kazakhstan zone of the Caspian Sea and is one of the world’s largest discoveries in the last 30 years. Located in the northern extremities of the Caspian Sea, the water depth varies between 3m and 10m. The field is part of the North Caspian Sea Production Sharing Agreement (NCSPSA) operated by North Caspian Operating Company (NCOC) on behalf of a consortium consisting of KazMunayGas, ENI, Shell, ExxonMobil, Total, ConocoPhillips, and Inpex. A Shell / KMG joint venture, named NCPOC, has responsibility for NCSPSA production operations, of which the first phase will be from the Kashagan field. Guralp is to supply a life of field monitoring system to NCPOC, which comprises eleven CMG-3T borehole instruments. Each instrument houses a three component broadband seismometer capable of detecting low frequency seismic events down to 0.03Hz. Six instruments are located in boreholes close to the coast on the mainland of Kazakhstan, whilst the other five are located in boreholes drilled in the offshore artificial islands constructed specifically for producing the Kashagan field. All instruments are located approximately 100m below the surface. Mark Volanthen, Managing Director of Guralp’s Oil & Gas division stated, “I am delighted that NCPOC has selected Guralp equipment for Kashagan’s life of field monitoring system. Our broadband passive instrumentation delivers information that cannot be obtained using standard seismic equipment. Guralp’s oil & gas division continues to grow rapidly, fuelled by a demand for increased seismic monitoring for risk mitigation, production optimisation, exploration and legislative compliance.” The Guralp system operates continuously and detects passive seismic waveforms including both microseismic events generated in the field and more distant regional seismic events. Data from the instruments will be transmitted in real time to an operations centre. The Guralp system will be installed in the coming months. For more...
read moreMarch 13 Many customers have asked for it, and our firmware team has now implemented it: Uploaded with the latest firmware (starting with Platinum build 12457) our Enhanced Acquisition Module, the EAM, is now capable of automatically backing up and storing its configuration. Every hour, the system scans itself for configuration changes, and if any are found, a new backup is created. Up to 50 automatic backups are kept by the system. As a user, you can also manually create a backup of your current configuration settings. This creates a history of changes to the EAM settings, which can be queried at any time. The response to such a query also includes a listing of the differences in settings between the various configurations. This archive can be called up using the web interface (see screenshot). Why is this feature important? As you set-up your EAM, you may want to try out several different configurations before you decide which settings are best. Instead of manually reprogramming everything, you can now just call up the archive and click on the configuration you want. Another reason is that sometimes changes to the configuration settings happen by accident. Instead of going through your field notes and trying to reconstruct the correct settings, you can now query the history and simply upload the previous configuration. The configuration archive can also be downloaded for storage at a central location. This will save a lot of time when many EAMs need to be programmed using exactly the settings. Also, if you need to exchange an EAM, simply download the current configuration setting from your repository and transfer it to the replacement equipment. An easy to use web interface allows you to store and retrieve various EAM configurations. To access this feature from EAM’s main menu go to “Configuration” and “Save/Restore”. For details on how to upgrade the firmware for your EAM and how to use this new “Save/Restore” feature, see the release notes. For more information, contact us at...
read moreNew borehole installations in Taiwan and Korea January 21 With the recent installation of more than twenty borehole seismometers in Taiwan and Korea, Guralp Systems is continuing its role as the world leader in manufacturing and deploying seismic broadband instrumentation for both shallow and deep boreholes. In early December two installation teams from our headquarters in the UK spent almost two weeks in Taiwan to deploy a total of ten instruments in boreholes with depths ranging from 200 to 400 meters. These instruments consisted of six sensors each, a three component CMG-3TB broadband seismometer and a CMG-5TB tri-axial accelerometer. All six sensors were combined into one borehole package with typical diameter of 89 millimeters. The customer, Taiwan’s Central Weather Bureau (CWB), is using these borehole sensors to augment its extensive seismic monitoring network. The Korean Meteorological Administration (KMA) took a similar approach in ordering twelve CMG-3TB borehole seismometers for their existing network, which currently comprises more than 110 surface stations. The first of these sensors was recently installed on the premises of an elementary school in the town of Okcheon in the central part of Korea in a 95 meter deep borehole (station OKCB). These two projects are part of a growing trend among institutions monitoring seismic activity. More and more of them are starting to use borehole instruments in their respective networks. The main reason for going below ground is that unwanted seismic noise decreases with depth. Hence, adding borehole sensors to a network will usually increase its detection level. Such a gain can be especially pronounced in densely populated countries like Korea and Taiwan. Both recent installations would not have been possible without the close cooperation with GSL’s partners and distributors, San Lien in Taiwan and Heesong Geotek in Korea. Our partners not only negotiated the respective contracts with our customers, but they were also essential in organizing the drilling of the boreholes, building the necessary infrastructure and providing the all important logistical support during the installation procedure. Two very different installations Since its founding in 1985, Guralp Systems has been developing, building and deploying sensors and digitizers for installations in boreholes on land as well as on the seabed (Ocean Bottom Borehole Systems). Our product families range from pure analogue sensors to systems combined with down-hole digitizers. We also offer data transfer to the well head by optical fiber. All of our down-hole systems can be installed in dry or wet boreholes, be they shallow or over a thousand meters deep. In order to optimize the coupling between the sensor and the well casing, we recommend to always use our unique hole locks. They can be adapted to borehole diameters of almost any size and allow the retrieval of the sensor, even in those rare cases when the down-hole power to the instrument fails completely. For more information, email sales@ideaasgroup.com or call 905 882...
read moreSeptember 12 After each big earthquake, the Earth rings like a bell. The sudden, extremely rapid movement of large blocks of rock within the Earth’s crust during a quake hits the rest of our planet like a clapper striking the body of a bell. As a consequence, the whole structure begins to hum. Inside the Earth, these vibrations are called normal modes or free oscillations and the may shake the whole planet for hours if not days. Researchers have found two types of this kind of ringing: The spheroidal mode changes the actual shape of the Earth while the toroidal mode twists the body of the Earth back and forth (see figure 1). Unlike strong earthquake waves, such free oscillations cannot be felt by humans. The reason: The periods of these vibrations are very long. They reach from 100 seconds for the shortest period up to 54 minutes. Figure 1 – The Earth’s two normal modes Such periods are well below the pass-band of modern broad band seismometers. Nevertheless, if the installation is done well, say in a properly insulated seismic observatory built on an outcrop of hard rock, free oscillations have been recorded around the globe by many Guralp seismometers. However, these free oscillations have been rarely – if at all – registered by seismometers located on the ocean bottom (OBS). Usually, the strong noise generated by the ocean waves masks the weak amplitudes of the bell-like vibrations. A very unique recording of free oscillations has now been found in the data collected by a very broadband Guralp OBS (CMG-3T, 360 sec – 100 Hz) after the huge magnitude 8.6 earthquake off the coast of Sumatra on April 11th 2012. The OBS is located in 2500 meters water depth at the bottom of the Mediterranean off the coast of Toulon, France. The sensor was installed (see figure 2) in November 2010 and has been operating flawlessly ever since. Figure 2 – CMG-3T OBS instrument deployed in the Mediterranean Figure 3 (courtesy of Anne Dechamps from the Laboratoire Geoazur, Nice, France) shows the spectrum of the free oscillations captured by the OBS (blue line, labelled ASEAF) as compared to the seismic land-station SSB (red line). The nomenclature describes the various modes of free oscillations in the period band (bottom axis) between 500 and 2000 seconds (8 to 33 minutes). Figure 3 – Spectrum of free oscillations For more information, email sales@ideaasgroup.com or call 905 882...
read moreMay 12 Guralp’s new Seismic Array for Downhole Investigations, CMG-SADI, has passed its first deployment with flying colours. Ordered by a Turkish company to be used in the exploration for coal, the tool was recently installed at 825 m depth in a borehole in Western Turkey. GSL cooperated with our regional distributor, Sentez Earth and Structure Engineering Ltd., during the deployment and the intensive testing. The downhole tool, CMG-SADI, can be used for classic Vertical Seismic Profiling (VSP), but also in a continuous sampling mode for ambient noise studies. The tool is very versatile: It currently has 24 elements but it can easily be extended with up to 128 independent seismometers. Passive geophones can be used as well as our newly developed miniature broadband feedback sensors, which have a flat frequency response to acceleration between 10 sec and up to 300 Hz. Each element has its own downhole digitiser with sampling rates down to 0.25 msec. The synchronisation accuracy between the digitisers is better than 3 mircoseconds. With an outer diameter of only 50 mm, it fits into almost any borehole (see image). During the test phase, CMG-SADI was operated in VSP-Mode with seismic energy being generated either by Vibroseis sweeps (20-200 Hz, sine wave sweeps) or by shots. The picture below shows all traces recorded at the same geophone for all shots over the line. The data shown are completely unfiltered and no processing corrections have been applied. Click the image for a larger version. We also have developed a new data-gathering and quick-view software for CMG-SADI. The software, called “VSP Viewer”, is based on our successful SCREAM software for regular data acquisition. The image below shows a screen shot of VSP Viewer with highlights of some features of the software. Click the image for a larger version. For more information, email...
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