Method and system for solving oil reservoir reconstruction microseism monitoring fracture seismic source mechanism

Abstract

The invention provides a method and system for solving an oil reservoir reconstruction microseism monitoring fracture seismic source mechanism. The method comprises the following steps: step 1, obtaining observation microseism waveform data of a time domain; step 2, establishing a three-dimensional speed model of an oil reservoir transformation area; step 3, acquiring an energy ratio of longitudinal waves to transverse waves of microseism signals; step 4, according to a Bayesian formula, calculating a probability density function between a longitudinal wave and transverse wave energy ratio anda point seismic source property through a training sample; and step 5, according to the calculated probability density function, judging the seismic source property of a microseism event by utilizingthe longitudinal wave and transverse wave energy ratio, and solving the seismic source mechanism of the microseism event. According to the method and the system for solving the oil reservoir reconstruction microseism monitoring fracture source mechanism, whether an artificial fracture is a tensile fracture or a shear fracture can be determined through the method for solving the oil reservoir reconstruction microseism monitoring fracture source mechanism, so that the accurate characteristics of the artificial fracture are effectively described.

Description

technical field [0001] The invention relates to the technical field of microseismic monitoring for petroleum and natural gas reservoir reformation, in particular to a method and system for solving focal mechanism of cracks in microseismic monitoring for reservoir reformation. Background technique [0002] Reservoir stimulation operations such as hydraulic fracturing, water injection, gas injection, and heavy oil thermal recovery will induce microseismic events, and these microseismic activities play an important role in the exploration and development of various unconventional oil and gas fields. Extraordinary oil and gas resources have made great progress. Reservoir stimulation technologies such as hydraulic fracturing are inseparable from the support of related supporting technologies. Microseismic monitoring is one of the most effective technologies for evaluating reservoir stimulation effects and optimizing stimulation processes. At present, the conventional focal mechan...

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Problems solved by technology

At present, the conventional focal mechanism analysis method is to use the initial motion information of the longitudinal wave (P wave) to estimate the focal mechanism solution. The quality requirements are relatively high, and there are enough geophones to record the microseismic waveform, and the first arrival fluctuation signal with a high signal-to-noise ratio is required

In addition, solving the source mechanism based on the P-wave initial motion information of the microseismic signal has the disadvantages of low computational efficiency and high requirements for the objective function, and it is difficult to play a role in practical application

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