Deposits in reservoirs of fractured and porous-fissured types refer to hard developed types. This is due primarily to the high differentiation of the characteristics of the reservoir over the laterals.
In addition, deposits of Eastern Siberia are characterized by the presence of zones of anomalous lithostatic pressures, which are critical for wells.Ignoring these features leads to a sharp decline in efficiency of field development.These issues are especially topical for the fields in Eastern Siberianewly on production.The lack of effective methods to avoid the aforementioned risks leads to low debit and high accident rate of deep wells, including those with a weighted construction.
The methods of seismic exploration on scattered waves, in particular the CSPD method, are designed to solve the problems of identifying fractured zones and zones with anomalous formation pressure and, thereby, to improve the efficiency of prospecting and developing oil and gas fields.
The CSPD method, developed by the specialists of the Research Institute of Applied Informatics and Mathematical Geophysics of the Baltic Federal University named after I.I. Kant, the only domestic method to date, that allows to indicate and rank fractureson resistive and open (impermeable and permeable).Since numerous small hydrocarbon deposits should be tied to open discontinuous faults, it is recommended that a new method be applied to the processing and interpretation of seismic data from previous years to create a refined structured tectonic model of the field.
Many years of experience in the processing of CDPM seismic data usingCSPD method (since 2004 at 45 fields) has shown its high efficiency in Western Siberia, Eastern Siberia and a number of other regions in the identification of faults, zones of excessive fissuring of the reservoir, as well as zones with anomalous formation pressure see Fig.1-6).
Fig. 1. The cubes of CSPD reflectors and CSPD diffractors form the basis for the traditional seismic attribute analysis. The results of attributive processing of cubes are used to construct a geological model of deposits, geological modeling, reserves estimation and hydrodynamic modeling. Western Siberia
Fig. 2. Permeable and impenetrable fractures. Time section of reflected (left) and scattered waves (right). Sungliao Basin, China
Fig. 3. Maps of scattered waves in horizons T2 and T4. Permeable and impenetrable faults in scattered waves. Sungliao Basin, China
Fig. 4. Map of the distribution of the total amplitudes of the scattered waves in the interval of tracing the Bilchir horizon in the Reflecting horizon window H3(the top of the Bilchir horizon) –Reflecting horizon window H4 (the bottom of the Bilchir horizon) with isochrones along the Reflecting horizon H3. Eastern Siberia
Fig. 5. Distribution of the total amplitudes of the scattered waves in the interval of the Bilchir horizon (isochronous surface horizon window H3). Eastern Siberia
- fractured zones in the Bilchir horizon
- fractured zones in the Christophoric and Balkhtinsky horizons
- fractured zones in the Parfenov horizon
Fig. 6 Scheme of the location of zones of possible geological complications during drilling of the Cambrian interval of the geological section (overproductive sediments) and promising zones of fracturing in the productive horizon. Eastern Siberia
Fig. 7 Vertical section of a cube of reflected (left) and a cube of scattered waves. Green horizon (B) the top of the Bazhenov layer. Western Siberia