Geophysical investigations in exploration
In the mining and natural resources sector the term "exploration" stands for all activities connected to the search for deposits and the investigation and evaluation thereof. Our exploration projects typically use ground and airborne geophysical techniques. Geophysics is used to delineate underground structures in 2D or 3D, to optimize and guide exploration programs, to build geological models and to save drilling costs.
Seismic techniques play a major role in geophysics due to their precise mapping of structures and depth. They are carried out on land (Onshore), as well as in shallow waters (Transition Zone; TZ) or the open sea (Offshore), but also from boreholes to surface, from borehole to borehole and from underground mines into the surrounding strata. Especially our equipment and experience in the field of 2D/3D non-destructive exploration seismics make us the perfect partner in the early assessment of reservoirs.
Sophisticated seismic studies require the comprehensive expertise of an interdisciplinary team consisting of geotechnical engineers, geologists and geophysicists. Our experts from these disciplines cooperate closely in the planning of surveys, acquisition of field data, data processing and subsequent geological interpretation. We perform 2D and 3D seismic measurements and apply both the explosion seismic and the vibroseismic method, using different types of vibrators or explosive charges as signalling devices in boreholes (depending on the depth of the exploration). For TZ measurements we deploy so-called "airguns" as a source for seismic waves and register the data via bay-cable systems. It goes without saying that we always take the highest QHSE standards into consideration. DMT is certified in accordance with ISO 9001 and SCCP, as well as meeting the requirements of OHSAS 18001 and IAGC directives.
In conjunction with "direct" information from drilling, geophysical borehole surveys and often also in combination with Vertical Seismic Profiling, we are able to determine the quality of a deposit. For more than 25 years, for example, the in-seam seismic method has proved successful in the exploration of underground hard coal deposits.
One significant part of seismic exploration is the "processing" of recorded data. This entails preparing the measurement data that was collected in a way that it can be interpreted geologically.
In this respect DMT's far-reaching experience is indispensable for drawing up individual solutions for the optimal visual realisation of each project. In cases where the geological conditions are more complex, in addition to the so-called standard 2D/ 3D-processing applications, such as "Comprehensive Statics Solutions" and "Post-Stack Time Migration", further data processing steps may be required. These include "Pre-Stack Time Migration (PSTM)", " Pre-Stack Depth Migration (PSDM)" and "Common Reflection Surface Stack (CRS)".
In the run-up to a measuring campaign it can be of some benefit to subject any so-called old data, which might still be stored on round tapes, to reprocessing. The new survey can then be carried out based on the results of the reprocessing, or the results of the two measurement campaigns can be combined.
DMT provides not only services for seismic exploration, but a comprehensive range of almost all underground, ground, airborne and spaceborne geophysical techniques. For example gravimetry techniques, magnetics, electromagnetics (EM), geoelectrics (ERT), seismic, radiometric or ground penetrating radar techniques. We often use a combination of several procedures and our extensive geological expertise to give our clients particularly detailed and reliable information. These methods can be applied in the exploration of all raw materials: Whether crude oil, oil sands, natural gas, shale gas, coal, ores, salt, stones and earth or even geothermal energy or the most important raw material of all, water.
Our comprehensive range of geophysical methods comprises:
- 2D and 3D reflection seismic
- Refraction seismic
- Surface wave analysis
- Seismic tomography
- VSP Vertical Seismic Profiling
- In-Seam seismic
- Seismoacoustic underground networks
- Seismic monitoring
- Seismic processing and modelling
Ground Penetrating Radar (GPR)
- High/low frequency
- Rough terrain antennas
- Interpretation and integration of GPR
- Frequency domain (FEM)
- Time domain sounding (TDEM)
- Buried metal detectors
- Electrical resistivity imaging
- Electrical resistivity tomography
- Complex resistivity
- Induced polarization
- Capacitive coupled resistivity
- Spontaneous (self) potential
- Geophysical borehole logging
- Borehole and cavern directional radar
- Borehole shuttles
- Airborne frequency domain electromagnetics
- Airborne time domain electromagnetics
- Gamma ray spectrometry
- Integrated geo-modelling
- Sidescan sonar
- Seismic reflection
- Marine EM