Microseismic source positioning method based on first arrival time difference and waveform superposition

Abstract

The invention provides a microseismic source positioning method based on a first arrival time difference and waveform superposition. The method comprises the following steps: S1: inputting a velocitymodel; S2: picking up and inputting an actual first arrival time, and reading seismic data; S3: calculating a theoretical first arrival time table of all mesh points in a feasible solution area to each detector according to the velocity model in S1; S4: constructing a travel time residual function Tr; S5: constructing a waveform superposition function Ews; S6: inputting a weight coefficient beta,and constructing an improved objective function according to the travel time residual function Tr in S4 and the waveform superposition function Ews in S5; and S7: finding a minimum value of the improved objective function through a grid search method, and the corresponding optimal solution being the seismic source location. According to the microseismic source positioning method provided by the invention, in view of the problem that the positioning method based on the travel time objective function is sensitive to the first arrival error, the improved objective function is constructed in combination with the first arrival time difference and the waveform superposition information, so that the anti-noise ability of the positioning method can be enhanced, the convergence of the inversion method can be improved, and the microseismic source positioning accuracy can be improved as a result.

Description

technical field [0001] The invention belongs to the technical field of petroleum geophysical exploration and development, and in particular relates to a microseismic source positioning method based on first arrival time difference and waveform superposition. Background technique [0002] Hydraulic fracturing microseismic monitoring technology is a reservoir geophysical technology to monitor the stimulation and effect of unconventional reservoirs such as tight oil and gas and shale gas. Its application results can evaluate fracturing effects, adjust fracturing design and well pattern layout, and Provide effective guidance for the next step of development, so as to increase the productivity of unconventional oil and gas reservoirs. [0003] In the processing of hydraulic fracturing monitoring data, the core part is microseismic source location. Predecessors basically use a single traveltime information or waveform information to establish an objective function, which can be d...

AI Technical Summary

Problems solved by technology

However, in real-time hydraulic fracturing monitoring operations, the collected microseismic data may have characteristics such as low signal-to-noise ratio, weak energy, and large background noise, which greatly affects the accuracy of first-arrival picking.

The positioning method based on the travel time information objective function is more sensitive to the first arrival error, while the positioning method based on the waveform information objective function does not require accurate first arrival time, but its calculation is huge, resulting in low positioning efficiency

Images