Method for correcting micro-seismic velocity models on basis of relative first arrival matching errors

Abstract

The invention provides a method for correcting micro-seismic velocity models on the basis of relative first arrival matching errors. The method includes determining locations of detection points for perforation points and first arrival of perforation signals; building initial velocity models by the aid of prior information of work areas or acoustic well logging data of wells close to fracturing segments; establishing velocity model correction objective functions by the aid of relative magnitude of first arrival matching errors of locations of the perforation points and first arrival matching errors of locations of reference points around the perforation points; carrying out nonlinear inversion on the micro-seismic velocity models by the aid of genetic algorithms. The method has the advantages that the velocity models corrected by the aid of the method have the obvious relative merit that first arrival matching error sections computed by the aid of the velocity models are close to the perforation points, and accordingly the method is favorable for further positioning micro-seismic events; micro-seismic event locations which are subjected to inversion by the aid of the corrected velocity models are reliable, and the method is low in positioning error.

Description

technical field [0001] The invention relates to the technical field of hydraulic fracturing microseismic monitoring data processing, in particular to a correction method for a microseismic velocity model. Background technique [0002] Hydraulic fracturing technology is the main way to improve the recovery rate of unconventional oil and gas reservoirs such as shale oil and gas. Microseismic monitoring is to locate the fracture location by collecting the signal generated by hydraulic fracturing, so as to guide the fracturing operation and Evaluation of fracturing results. The quality of the velocity model is crucial to the positioning accuracy of microseismic event points. Velocity model correction in conventional microseismic event location usually uses the matching error between the first arrival picked up by perforation signals and the first arrival of perforation point forward modeling as the objective function, and the velocity model is continuously adjusted. When the ob...

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Problems solved by technology

In other words, the velocity model inverted by the conventional velocity correction method can ensure that the perforation point has the largest first-arrival matching error. error in positioning results

Further analysis, even if the minimum first-arrival matching error can be obtained near the perforation point, if the first-arrival matching error has no obvious advantage at the perforation point, the difference in inversion method will often cause a large error in the inversion positioning result

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