Deep geological models of the ultra-deep well area Saatly DW-1 based on complex geophysical data
Authors:   Oil Gas Scientific Research Project Institute, SOCAR, Baku, Azerbaija, Gadirov Vagif 
Published: July 2024

The purpose of the article is to study the reasons for the failure to achieve the scientific and geological goals set for the ultra-deep well DW-1, drilled in the Saatli region of Azerbaijan. The analysis will focus on the existing deep models built for this region, which are deemed insufficient in reflecting the truth. The paper highlights the importance of adopting a new approach to the recently created deep model and its potential benefits to the scientific community.Methodology. The technique includes a detailed comprehensive analysis of the gravitational and magnetic fields in this region, the use of local magnetic anomalies to build a model of the deep geological structure utilizing data from deep seismic sounding (DSS) and the correlation method of refracted waves (CMRW). Results. The spatial position of effusive formations in the geological section was determined using the local anomaly of the geomagnetic field in the Saatly region. At the same time, the geometric dimensions of the volcanic body were chosen in such a way that the magnetic field created by it corresponded to the observed local magnetic field. Thus, a model of the geological section up to a depth of 15 km was developed, with the display of the spatial position of the volcanic formation. In this model, unlike the previous one, the spatial position of the volcanic formation in the vertical geological section is completely different. In the newly constructed model, it turns out that there is a separate volcanic formation in the area of the Saatly DW-1. And in the previous models, it was shown that the magma came here from the Muradhanly zone, located at a distance of 25-30 km. The boundaries of the crystalline foundation and the basalt layer in the area of the DW-1 in the zone of the volcanic body are not traced. The root of the volcano narrows and goes deep into the earth. At a depth of about 15 km, the magma-producing channel has a width of 1 km. Based on the established model, it was determined that the ultra-deep well DW-1 is located on the magma-producing channel of the volcano that existed here. From the analysis of the obtained model data, it turns out that the extension of the Saatly DW-1 to depth will not allow opening the consolidated crust (crystalline foundation) and basalt layer. Because, although these layers are closer to the earth's surface in the area of the DW-1, the active volcano here has destroyed these boundaries. Orginality. Seismic survey materials were used to study the deep structures of the region, gravimagnetic data on profiles with an observation step of 250 m, and a technique was applied to construct the spatial positions of effusive formations in the geological section. Scientific novelty. It has been established that the geomagnetic field of this region is formed from three main effects - the effect of the sedimentary complex, the effect of the thickness between the basement and Curie surfaces, and the effect of local manifestations of magmatism. The sum of the first two effects quite accurately corresponds to the regional background of the observed geomagnetic field. Local positive anomalies isolated from the observed field are associated with local heterogeneities - in this region with volcanogenic formations in the sedimentary complex. Practical significance. A new geological-geophysical model was created by determining the spatial position of effusive formations in the geological section near the Saatly DW-1 well using the local anomaly of the geomagnetic field. This model has real possibilities in the direction of installation of ultra-deep wells for the study of deep layers of the earth's crust.