Dr. Theses

Seismic survey efficiency enhancement technology designed for intricate hydrocarbon prospects in Azerbaijan

Ahmadov Tofig R.

Seismic survey carried out within intricate geologic settings in Azerbaijan suffers significant challenges. The main purpose of the given thesis is to tackle problems encountered while searching for and exploring anticline and stratigraphic hydrocarbon deposits buried within intricate geologic setting within sedimentary basins in Azerbaijan. Additionally, along with reflection seismology efficiency enhancement the author elucidates both seismic and gravimetry data integration while direct search for hydrocarbons.
The study deals with basic seismic and geologic attributes of faulting system (FS), systematizes already known and identifies new traveltime and amplitude attributes of the FS, as well as “false faulting system” attributes occurrence have been studied through math modeling. The impact of the FS upon seismic wave pattern and traveltime charcteristics of elastic waves within distortion zones has been highlighted in detail. FS detection principles and their tracing technoloy have been elaborated to use while acquired seismic data processing and interpretation stages. The author has unraveled the impact of curvilinear surfaces upon reflection wave traveltime characteristics and particularly on velocity analysis data. Innovative tool to identify efficient velocity has been offered to use jointly with both single and multiple profiling that to a certain extend eliminates curvilinear surfaces influence. It is suggested to use horizontal velosity gradient to locate hydrocarbon accumulations based on a great deal of efficient velocity data derived from inline and dip sections. The impact of curvilinear and intermediate interfaces on the wave pattern formation while long record time has been studied using simple deduced formulae for two-layered media. It has been proven that curvilinear refraction surface strongly deteriorates wave pettern both on migrated and non-migrated time sections, and only depth migrated sections might reflect an actuel geologic setting. It has been shown that spectral decomposition and carrelation analysis enables us to locete precisely pinching out seismic horizons. Seismic survey technology has been offered to use within geologic settings with steeply diping interfaces. Furthermore, it has been highlighted that suitable problem solution might be achieved by means of 3D seismic survey. In case with applied 2D seismic survey there is a need to choose reasonable profiling grid with applied a priori data. In areas with sparse seismic data avaiable gravimetry data can be used aas a priori ones. The author has proposed a method how to choose a reasonable grid for seismic profiling in conjuction with gravimetry data. Elaborated algorithm and software program for geologic/seismic modeling has been applied in Tarsdallar area within Kur and Gabirry Rivers interfluve. Both geologic/seismic modeling and acquired seismic data underwent V.M.Berezins fully normalized gradient procedure. COMPAR algorithm and software program has been slated for the purpose. It is concluded that ought to impact of low-velocity layer, as well asexcitation and acquisition conditions, a single geophysical tool actually faces tremendous obstracles to discover hydrocarbon deposits. Integrated seismic/gravimetry parameter setting technology has been upgrated. An integrated seismic/gravimetry parameter consists of seven seismic and two gravimetry parameters have been calculated with the aid of COMPAR software program. Designed technology applied within Tarsdallar and Agamammadly areas has proven to be of vital efficiency.

Moreover, multiple reflection derived from curvilinear interfaces and their impact upon wave pattern formation within some petroleum regions in Azerbaijan. It has also been shown how to use multiple wave amplitude parameters as a source of useful information while seismic lithology prediction.