Maxim Protasov

Fracture detection by Gaussian beam imaging of seismic data and image spectrum analysis

Localization of fractured areas is of primary interest in the study of oil and gas geology in carbonate environments. Hydrocarbon reservoirs in these environments are embedded within an impenetrable rock matrix but possess a rich system of various microheterogeneities, i.e., cavities, cracks, and fractures. Cavities accumulate oil, but its flow is governed by a system of fractures. A distinctive feature of wave propagation in such media is the excitation of the scattered/diffracted waves by the microheterogeneities. This scattering could be a reliable attribute for characterization of the fine structure of reservoirs, but it has extremely low energy and any standard data processing renders them practically invisible in comparison with images produced by specular reflections. Therefore, any attempts to use these waves for image congestion of microheterogeneities should first have a preliminary separation of the scattering and specular reflections. In this paper, the approach to performing this separation is based on the asymmetric summation. It is implemented by double focusing of Gaussian beams. To do this, the special weights are computed by propagating Gaussian beams from the target area towards the acquisition system separately for sources and receivers. The different mutual positioning of beams in each pair introduces a variety of selective images that are destined to represent some selected singular primitives of the target objects such as fractures, cavities, and edges. In this way, one can construct various wave images of a target reservoir, particularly in scattered/diffracted waves. Additional removal of remnants of specular reflections is done by means of spectral analysis of the scattered/diffracted waves’ images to recognize and cancel extended lineaments. Numerical experiments with Sigsbee 2A synthetic seismic data and some typical structures of the Yurubcheno-Tokhomskoye oil field in East Siberia are presented and discussed.

Seismic imaging and statistical analysis of fault facies models

AbstractInterpretation of seismic responses from subsurface fault zones is hampered by the fact that the geologic structure and property distributions of fault zones can generally not be directly observed. This shortcoming curtails the use of seismic data for characterizing internal structure and properties of fault zones, and it has instead promoted the use of interpretation techniques that tend to simplify actual structural complexity by rendering faults as lines and planes rather than volumes of deformed rock. Facilitating the correlation of rock properties and seismic images of fault zones would enable active use of these images for interpreting fault zones, which in turn would improve our ability to assess the impact of fault zones on subsurface fluid flow. We use a combination of 3D fault zone models, based on empirical data and 2D forward seismic modeling to investigate the link between fault zone properties and seismic response. A comparison of spatial statistics from the geologic models and the s...

Imaging of fracture zones by weighted summation of multi-component data and image spectrum analysis

An approach to seismic imaging of fracturations area by multicomponent surface data is presented and discussed. It is based on a specific imaging procedure, which consists in a weighted summation of multicomponent multishot/multioffset data. Additionally spectral removal is applied for more essential suppression of regular reflections footprint. Numerical experiments with synthetic data set computed for the typical seismogeological model of Yurubcheno-Tаkhomskoye area are presented and discussed.

Quasi Inversion of Walk-Away VSP Data on the Base of Gaussian Beams Decomposition

H013 Quasi Inversion of Walk-Away VSP Data on the Base of Gaussian Beams Decomposition I. Borodin (Schlumberger K.K.) D. Pissarenko (Schlumberger Moscow Resaerch) M. Protasov (Trofimuk Inst. of Petr. Geol. and Geoph.) & Vladimir A. Tcheverda* (Trofimuk Inst. of Petroleum Geology and Geophysics) SUMMARY We present an approach of true amplitude seismic imaging by means of weighted summation of walkaway VSP data. In order to compute these weights we trace a couple of Gaussian beams (GB) from the current point within target area towards acquisition system. Each GB possesses the minimal width at this starting point. That means that the