In 1958, I.V.Litvinenko laid the foundation for seismic studies of the consolidated earth crust on the Baltic Shield: for the first time, depth seismic soundings were performed in Karelia.
During drilling of the SG-3 Kola well, technological complications in a number of cases resulted in the necessity to sink bypass wellbores. Vertical seismic profiling (VSP) observations were carried out in the deepest of them, including in the depth interval common for different wellbores.
The nature of waves associated with seismic boundaries is investigated in both oil and ore seismic.
In the Pechenga ore field in order to clarify its structures in the near-well and inter-well space seismoacoustic studies are carried out, including vertical seismic profiling (VSP) and acoustic logging (AL).
Seismic exploration in areas of crystalline rock development has proven to be an effective method of studying ore-controlling structures ...
The most important iss. of seismic data interpretation is the determination of the type and kinematics of the recorded waves. The specificity of solving this problem for ore areas is that the wave fields are characterized by high complexity, determined by a large number of in-phase axes, crossing each other and characterized by a wide range of apparent velocity ...
The Pechenga ore field, within the limits of which known commercial deposits are concentrated, remains one of the main objects of copper-nickel sulfide ore prospecting ...
Specificity of seismogeological conditions of ore areas composed of crystalline rocks, complicates the use of traditional seismic exploration methods of building velocity models based on generalization of data on the determination of the effective velocity ...
For a number of years during seismic exploration by the reflected wave method (RWM) in the Pechenga region ground azimuthal units are used, and since 1976 - and borehole - during works by the method of vertical seismic profiling (VSP) ...
Since 1961, the reflected wave method (RWM) seismic survey has been successfully applied to study the Pechenga structure of the Baltic Shield. In the wave fields registered in this area by the systems of elongated hodographs, along with longitudinal P waves, intensive direct transverse S waves are established. This allows us to expect the registration of reflections of different types: longitudinal, transverse, and exchange. When interpreting the wave field in these conditions, much attention is paid to determining the type of recorded waves. ...
When studying seismic exploration of ore areas, the rate for the construction of reflecting boundaries can not always be selected by methods developed in oil seismic exploration for horizontal layered media. This is due to the complexity of crystalline rock structures, intensive tectonics and magmatism, which determine the regularities of elastic wave velocity distribution in sections of ore districts. The study of these regularities in connection with the geologic structure of the Pechenga region of the Baltic Shield allowed us to substantiate the method of rate determination for the construction of reflecting boundaries on seismic sections of the Pechenga structure. ...
To study the deep structure of the Pechenga ore district, the reflected wave seismic (RWS) method has been successfully applied in recent years. Consistent complication of the tasks solved in this case, causes the need to detail the ideas about the velocity section of the studied area, for which data from both borehole and ground seismic observations are used.
The solution of the important question about the accuracy of seismic boundaries construction not only in the Pechenga, but also in other ore areas is complicated by the complex character of the registered wave fields and the change of velocity sections over the area, which is explained by the strong dislocation of folded structures composed of different complexes of high-velocity crystalline and metamorphosed rocks.
Vertical seismic profiling (VSP) in wells of the Pechenga region is carried out in conditions of steep dip of geological boundaries, and the wells themselves are inclined (zenith angles of 5 - 20°).
