关键词:
松辽盆地,
井中地震,
VSP逆时偏移,
岩丘理论模型,
VSP脉冲响应,
成像条件,
有限差分,
吸收边界条件
Abstract:
In order to improve the precision of VSP seismic imaging, a VSP reverse time migration (RTM) operator with 16-order finite difference accuracy was constructed, and then the algorithm accuracy of VSP key links and the interchangeability of shot and receiver points were analyzed by using impulse responses to verify the accuracy of the 3D VSP RTM operator. Based on the standard theoretical model of lava dome, the imaging effects of normalized VSP RTM and conventional cross-correlation RTM were compared. It is found that VSP RTM can describe the geological body boundary and formation interface more clearly and more accurately, and can eliminate the uneven influence of folds to make energy distribution more uniform, with no well trace. The high-precision 3D VSP RTM technology was applied to the walkaway VSP data of Well L in the Songliao basin, and accurate and fine imaging of near-wellbore formations and small faults was achieved, which further verified the accuracy of the technology. The proposed VSP RTM technology can help improve the imaging accuracy of complex reservoirs around the wellbore.
Key words:
Songliao basin,
borehole seismic,
VSP reverse time migration,
theoretical model of lava dome,
VSP impulse response,
imaging condition,
finite difference,
absorbing boundary condition