Surface observation microseism speed model correcting method based on amplitude stack

Abstract

The invention relates to a surface observation microseism speed model correcting method based on amplitude stack.Starting from the principle of a reverse time migration amplitude stack method, a very fast simulated annealing method is combined, seismic phase first arrival information does not need to be picked up, and a speed model is corrected by monitoring the energy focusing condition on a perforation point; perforation point relocation accuracy is used for judging whether the speed model can be used for follow-up microseism location.The problem that the maximal value and the maximum value are not separated in an existing algorithm can be effectively solved, the maximum value E of energy focusing on the perforation point can be found accurately, the perforation position is located accurately, and the speed module is effectively corrected.Noise interference can be effectively inhibited by adopting the reverse time migration amplitude stack algorithm, and a good location effect can still be obtained with a low signal-to-noise ratio.The more the speed model is close to an actual model, the more accurate perforation location becomes.Whether the speed model can be used for follow-up microseism location or not is judged according to perforation point relocation accuracy.

Description

technical field [0001] The invention relates to a microseismic positioning for fracturing in an oil field. Specifically, velocity model correction is carried out through microseismic monitoring data, thereby improving the accuracy of subsequent microseismic positioning. technical background [0002] At present, the exploration and development of low-permeability oil and gas reservoirs has become a new hot spot in the oil and gas industry at home and abroad, and the development of low-permeability oil and gas reservoirs through hydraulic fracturing technology has become a common trend. In an article titled "Improved microseismic fracture mapping using perforation timing measurements for velocity calibration" published by Warpinski on the SPE Journal in 2005, he pointed out that during the implementation of this technology, the extension of cracks causes the surrounding rocks to rupture, thus triggering a series of microseismic events that can be observed and recorded. In 2010...

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Problems solved by technology

In 2010, Bardainne et al. published an article titled "Constrainedtomographyofrealisticvelocitymodelsinmicroseismicmonitoringusingcalibrationsshots" on Geophysical Prospecting, pointing out that the seismic tomography method in seismic exploration can be used as a microseismic positioning velocity model calibration algorithm, but the source information is less and the number of ground receivers is insufficient. In the case of small and small coverage areas, it is difficult to obtain a finer velocity model of the work area using seismic tomography

However, when looking for the maximum point of energy focus, it is often difficult to distinguish between the maximum value and the maximum value, which will directly affect the positioning accuracy of the perforation and lead to inaccurate correction of the velocity model

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