GEOPHYSICAL RESEARCH OF WELLS
VP-DEZ (Dipole Electric Sounding)
Description:
A classic probing method. The feed dipole (AB) sets the current, and the receiver (MN) records the response. By varying the spacing, the deep structure is explored.
Advantages:
- High depth;
- Suitable for 2D/3D inversion;
- Accurate determination of vertical sections.
Results:
- Apparent resistivity and chargeability curves;
- inversions in the form of geoelectric sections.
VP-SG (Mean Gradient)
Description:
The supply electrodes A and B are installed permanently, measurements are performed using a portable receiving dipole in the middle zone of line AB.
Advantages:
- High acquisition speed;
- uniform area coverage;
- ideal for mapping and early exploration.
Results:
- Apparent resistivity and chargeability maps;
- quick identification of anomalous zones.
Vector IP (RIP, Vector IP)
Description:
The method records the secondary electric field vector (amplitude and direction), which allows for the localization of sources and refinement of the geometry of anomalies.
Advantages:
- Effective in complex 3D geology;
- Helps identify elongated and overlapping objects;
- Improves the accuracy of drilling point selection.
Results:
- VP vector amplitude and azimuth maps;
- comprehensive interpretation in conjunction with remote sensing and geostationary geodesy.
Audio-magnetotelluric sounding (AMTZ, Audio-MT)
Description:
The method is based on recording the Earth's natural electromagnetic field in the "audio" range (1–20,000 Hz). Electrodes and magnetic sensors record field variations, allowing for the study of the electrical conductivity of the upper crust.
Advantages:
- High speed and ease of field work;
- no need for an artificial source;
- optimal for exploring the upper kilometers of a section;
- effective for searching for ore bodies, flood zones, and salt diapirs.
Results:
- Apparent resistivity curves and phase characteristics;
- 1D/2D conductivity distribution sections;
- maps of local anomalies and tectonic faults.
Spectral audio magnetotelluric sounding (SAMT)
Description:
This method is a development of the AMTZ method. It utilizes spectral analysis of natural electromagnetic signals in the audio range, allowing for the identification of useful signals against industrial interference and significantly improving the accuracy of interpretation.
Advantages:
- Increased noise immunity and sensitivity;
- Ability to operate in areas with high levels of electromagnetic noise;
- Improved resolution when plotting cross-sections;
- Suitable for both areal and profile surveys.
Results:
- Spectral curves of apparent resistivity;
- highly detailed conductivity maps and sections;
- refined localization of fault zones and prospective targets.
Magnetotelluric sounding (MTS)
Description:
The method records the Earth's natural electromagnetic field in the range from fractions of a hertz to thousands of hertz. Long-term measurements of electrical and magnetic components make it possible to study the electrical conductivity of the Earth's crust and upper mantle to depths of hundreds of kilometers.
Advantages:
- High depth of exploration;
- Detailed study of regional faults and lithospheric blocks;
- Indispensable for regional geology and assessing the oil and gas potential of basins;
- Effectively combined with seismic and gravimetric measurements.
Results:
- Impedance and phase shift curves;
- 2D/3D deep geoelectric models;
- identification of fault zones, intrusive massifs, and deep anomalies;
- regional maps of lithospheric electrical conductivity distribution.
Description:
The method is based on recording the response of a geoelectric section to alternating current of varying frequencies generated by an artificial source. As the frequency changes, the penetration depth of the electromagnetic field changes, allowing for the study of rock structure at different levels.
Advantages:
- The use of a controlled source guarantees high signal quality;
- a wide range of survey depths—from tens of meters to a few kilometers;
- high sensitivity to changes in electrical conductivity;
- the ability to conduct work even in areas with strong industrial interference.
Results:
- Frequency-apparent resistivity curves;
- Vertical geoelectric sections;
- Refinement of the thickness and nature of conductive layers;
Description:
The method is based on recording the response of a geoelectric section to alternating current of varying frequencies generated by an artificial source. As the frequency changes, the penetration depth of the electromagnetic field changes, allowing for the study of rock structure at different levels.
Advantages:
- The use of a controlled source guarantees high signal quality;
- a wide range of survey depths—from tens of meters to a few kilometers;
- high sensitivity to changes in electrical conductivity;
- the ability to conduct work even in areas with strong industrial interference.
Results:
- Frequency-apparent resistivity curves;
- Vertical geoelectric sections;
- Refining the thickness and nature of conductive layers;
- Location of fault zones, aquifers, and potentially promising ore bodies.
Magnetotelluric profile (MTP)
Description:
The MTP (magnetotelluric profiling) method is based on recording variations in the Earth's natural electromagnetic field in a fixed frequency range. Field measurements are performed along the profile, providing information on lateral changes in rock electrical conductivity.
Advantages:
- High speed of fieldwork;
- effective for mapping fault zones and contacts;
- suitable for identifying tectonic and hydrogeological structures;
- convenient as a rapid method for regional studies.
Results:
- Apparent resistivity profiles;
- conductivity distribution maps in plan view;
- identification of linear anomalies and fault zones.
Magnetovariational Sounding (MVS)
Description:
The method is based on studying electromagnetic variations arising in the Earth's ionosphere and magnetosphere as a result of solar-geomagnetic activity (dead-end storms). These low-frequency fields penetrate to depths of tens and hundreds of kilometers, allowing for the study of mantle conductivity.
Advantages:
- Exceptionally deep (up to hundreds of kilometers);
- the only method for directly exploring the upper mantle;
- effective for studying the structure of the lithosphere and asthenosphere;
- indispensable for solving regional and fundamental geological problems.
Results:
- Magnetic field variation curves;
- deep models of electrical conductivity distribution (lithosphere – mantle);
- identification of lithospheric plate boundaries and deep fault zones;
- construction of regional geoelectric models.
| Метод | Диапазон | Глубина | Применение | Результаты |
|---|---|---|---|---|
| АМТЗ | 1–20 000 Гц | десятки м – первые км | руды, соляные купола, зоны обводнения | кривые КУС, фазовые характеристики, 1D/2D разрезы |
| САМТ | 1–20 000 Гц (спектр) | десятки м – первые км | районы с индустриальными помехами | спектральные кривые, детализированные карты и разрезы |
| МТЗ | 0.001–1000 Гц | десятки – сотни км | региональная геология, нефтегазовые впадины, литосфера | импедансные кривые, 2D/3D модели глубинных структур |
| ЧЗ | десятки Гц – кГц (искусственный источник) | десятки м – первые км | инженерная геология, гидрогеология, экология | кривые частотного КУС, вертикальные разрезы |
| МПП | фиксированные частоты | сотни м – км | выделение разломов и зон нарушений | профили КУС, карты электропроводности |
| ЗСБ | <0.001 Гц | до сотен км | литосфера, мантия, фундаментальные исследования | региональные геоэлектрические модели, границы плит |
- Gamma Logging Method;
- Electrical Logging Method (Resistivity Logging (RL); Spontaneous Potential Logging (SP));
- Induced Polarization Logging Method;
- Caliper Logging Method;
- Magnetic Susceptibility Logging Method;
- Inclinometry Method;
- Inclinometry Method Using a Gyroscopic Inclinometer;
- Acoustic Televiewer Logging Method;
- Optical Televiewer Logging Method.
- Determining the stratigraphy and lithology of exposed rocks.
- Identifying reservoir rocks (sandstones, carbonates, etc.).
- Distinguishing between productive and impermeable formations.
- Studying tectonics, fracturing, and fault zones.
- Determining porosity, permeability, and fracturing.
- Assessing reservoir saturation (oil, gas, water).
- Identifying fluid types (hydrocarbons, formation water, mineralization).
- Monitoring drilling quality and wellbore condition (diameter, cavities, and collapses).
- Identifying behind-the-casing flow zones and casing leaks.
- Cementing quality control.
- Localization of absorption and influx zones.
- Monitoring the performance of productive formations during production.
- Determining current formation saturation and water cut.
- Identifying drainage zones and remaining reserves.
- Monitoring reservoir parameter changes over time.
The obtained data formed the basis for constructing a refined structural model of the area. The results of this work helped the client optimize the geological exploration program and minimize risks during subsequent drilling.
Additionally, geological unconformities were identified, the orientation of tectonic elements was refined, and deformation zones were identified. The prepared reports included borehole logs with detailed measurement results. This data formed the basis for adjusting the geological model and planning further drilling operations.
This method allowed for recording data on the distribution of ore bodies at great depths and estimating their thickness. Particular attention was paid to the search for massive pyrite ores, which are promising for industrial development. The final report, interpreting the field survey results, provided the client with a rationale for further exploration and deep drilling planning.
The results revealed the complex tectonic structure of the area and the presence of additional promising zones for geological exploration. The resulting report allowed the client to adjust exploratory drilling plans and identify the most priority areas. Thus, the project provided a reliable basis for further exploration and appraisal work.
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