FIELD Seismic Researches OF MOGT 2D AND 3D

In the process of field work, the observation methodology and parameters of the excitation source are promptly adjusted based on the results of experimental work. This approach helps to increase the reliability and quality of the information received.

The process of recording and subsequent processing of seismic data is focused on obtaining records with the maximum resolution of the wave field.

A comprehensive interpretation of seismic materials and GIS data allows you to perform reliable deep-time transformations, carry out mapping of any complexity, and perform seismic and geological modeling.

Performance.

• The enterprise’s resources - human, technical, hardware, software - provide obtaining, operational processing and interpretation of up to 7500 linear km of MOGT profile observations - 2D and up to 1600 square km of 3D data per year.
• The monthly productivity during two-shift work reaches 600 linear kilometers. MOGT profiles - 2D and up to 280 sq. km of 3D shooting.
• Field work is carried out by three seismic surveys equipped with modern recording systems and equipment that allows MOGT - 2D and 3D seismic surveys to be performed all year round, 30 days a month and depending on production needs up to 24 hours a day.
• Seismic exploration batches work in a mobile mode, creating field bases at the place of deployment, equipped with mobile comfortable residential and specially equipped wagon-houses for domestic use: showers, canteens, office, warehouse and others, in the amount necessary to ensure work. Fueling stations are organized.
  Each vibration unit is equipped with a mobile repair shop (PARM).

Field recording systems.Technical equipment and work support.

• PJSC VNG has 3 sets of telemetry recording systems (Sersel, France):

  • 408 UL station, 4,000 channel license.

  The number of groups of geophones - 3750.

  • Station 428 XL, license for 8000 channels.
  • Station 428 XL, license for 10,000 channels.

  The total number of licensed channels is 22,000 channels.

• Vibrational excitation sources.

  • The main source of excitation of seismic vibrations during seismic surveys of MOGT 2D and 3D are vibrators. Sercel’s state-of-the-art vibration systems, the Nomad-65, are used with the highest weight / base plate ratios (2.62) with a peak force of 62,000 pounds. The operating frequency range of the excited oscillations is from 7 to 250 Hz, which makes it possible to implement, under certain conditions, the technology of high-resolution seismic exploration (ARS).
  • At present, PJSC VNG is armed with 19 Nomad-65 vibrators.
  • There is work experience both in the plain and in desert regions and in mountainous terrain.

• Work using an explosive source.

  • The company has the ability to perform work also using an explosive source of excitation of seismic vibrations. For this, there is all the permits, storage facilities and modern technical means for its implementation in various modifications: surface screw and borehole (minimized) groups of charges or explosions in single wells under ZMS;
  • In recent years, an explosive source of seismic vibrations has been used by us mainly in the performance of VSP-NVP and in the execution of individual projects using high-resolution seismic surveying techniques;
  • PJSC “VNG” has 6 drilling rigs in service.

• Topographic and geodetic support for field work.

  Surveying is carried out with high accuracy using the Trimble 5700 (L1, L2), R7, R8, R8-4 GPS systems and Trimble 3605DR, M3DR and Nikon DPL-352 total stations.

• Examination of the upper section.

  • Attaching great importance to obtaining information on the structure of the upper part of the section (VChR), which significantly affects the quality and reliability of seismic structures, in each seismic batch we contain a special microseismic logging unit (MSK) equipped with a drilling rig, tanker, and an explosive excitation source - Yenisei KEM-2, and mini-recorders - Progress-L, VSP, AMC;
  • If it is impossible to carry out MSC works at a specific site or at the request of the customer, the study of the parameters of the upper part of the section is carried out by the MPV method with the same detachment with the addition of special equipment (seismic streamer, geophones);
  • Data processing of MSC and MPV is carried out at the field computer center.

Field Computer Center.

• For operational analysis of the quality of field materials, obtaining preliminary geological and seismic ideas about the object of study, planning 3-D seismic observations and geodetic calculations, field computing centers using geophysical processing systems, Geocluster (CGGVeritas, France) and topographic and geodetic software packages have been created in each seismic batch. TGO, Autodesk Map, Land Desktop, Credo Dat;
• In areal 3-D studies, the observation system is calculated and adjusted on the ground using the MESA Professional software, manufactured by ION's GMG Software. In addition to the selected parameters of the monitoring system, the result of planning work for 3D seismic surveys is a shooting scenario (script file) that allows input / output (exchange) of information from the design systems to the seismic station and vice versa.