*The Geomagnetic Field Transformants and Their Complexing with Data of Gravitational… DOI: http://dx.doi.org/10.5772/intechopen.111560*



#### **Table 3.**

*Statistics on transform values for anomalous magnetic, gravity, thermal, and radiogeochemical field transforms by local structures over the study region.*

transformants of this field, such as analytical signal magnetic anisotropy, autotracing axes of magnetic field anomalies, increased values of negative anomaly ΔTa, and horizontal and vertical magnetic field gradients, as well as the minimum values of the TDR.

The results of an integrated analysis of the geomagnetic, gravitational, thermal, and radiochemical fields allowed the authors of this chapter to study the behavior and characteristics of tectonic faults, and to make some judgments about the depth of occurrence of gravity and magnetically disturbing masses, about the degree of geological heterogeneity of large geostructures, and to trace the nature of the manifestation of local structures in geophysical fields.

The Shakhpakhty step with a relatively increased thermal field in some local structures is quite clearly distinguished into the regional gravity, geomagnetic, and thermal fields, and has a continuation in the Uzbek part of this step.

### *The Geomagnetic Field Transformants and Their Complexing with Data of Gravitational… DOI: http://dx.doi.org/10.5772/intechopen.111560*

The Shakhpakhty step is bounded by deep faults, identified by the gradients of anomalies of the regional geophysical fields. Three major regional faults are traced in the northwestern direction. On the southeastern flank of these faults, the Shakhpakhty and Dzhel gas fields are explored within the Jurassic sediments. On the western flank, the local structures Otynshi, Kozhantai, Northern Kozhantai, Utezhan, and others close to them in geological structure are isolated.

These local structures can be considered as prospective in terms of the localization of HC accumulations, if there is a good seal of rocks in the upper part of the predicted reservoirs. All of the aforementioned criteria give reason to recommend local structures within the Shakhpakhty step for priority study.

Сentral Ustyurt system of dislocations is characterized by elevated deformation of sedimentary rock assemblage that does not contribute to the preservation of hydrocarbon accumulations.

The Assakeaudan depression is characterized by thick sedimentary rock assemblages, which generated mostly by the oil-source suites. Faults that disrupt the integrity of the geological formations of this depression are considered as conduits for migration of hydrocarbons, deep fluids, heat, and mass transfer.

This statement is confirmed by aero gamma spectrometry data, processed and interpreted by the method of thorium normalization. A total of 15 anomalous zones were identified in the study region, 9 of which are located in the Shakhpakhty step, 2 in the Central Ustyurt system of dislocations, and 4 in the Assakeaudan depression.

The selected anomalous zones have low values of isoconcentrations of radioactive potassium isotope and reduced uranium concentration in relation to the background values and are considered as indicative criteria for the possible presence of hydrocarbon accumulations.

Thus, our studies of the transformants of the magnetic, gravitational, and geothermal fields, airborne gamma spectrometry data (processed and interpreted using the thorium normalization method) unequivocally testify in favor of the prospects for the oil and gas potential of the local structures Utezhan, Kozhantai, Northern Kozhantai, Otynshy, taking into account favorable historical and geological, structural, and lithofacies factors.

The author's study on advanced (relatively cheap) geophysical methods will provide a dependable foundation for enhancing and specifying the geological and structural-tectonic models of South Ustyurt. This will involve using existing information on the spatial distribution of already known oil and gas fields as well as serving as a basis for designing geological exploration to prospect and explore new hydrocarbon accumulations, using expensive and "heavy" methods of seismic exploration CDP-3D and deep drilling.
