Micro earthquake monitoring and positioning method based on highly-deviated well

Abstract

The invention discloses a micro earthquake monitoring and positioning method. The method comprises the steps as follows: seismogenic azimuth angles, where a micro earthquake happens, detected by all detectors are calculated; a first objective function is established according to the azimuth angles, where the micro earthquake happens, detected by all detectors; an initial position (X0, Y0 and Z0) of a micro earthquake incident is estimated on the basis of the inversion of the first objective function; a second objective function is established according to the range from a P wave first arrival and an S wave first arrival of the micro earthquake incident near the initial position (X0, Y0 and Z0); and nonlinear inversion is performed on the second objective function, so that accurate x, y and z coordinates of a focus of the micro earthquake incident are obtained. According to the micro earthquake monitoring and positioning method, the micro earthquake incident positioning problem of the detectors located at a highly-deviated well section can be effectively inversed, and the method has the advantages that the calculation speed is high, an inversion operator is stable, and the like.

Description

technical field [0001] The invention relates to geophysical prospecting microseismic monitoring technology, more specifically, relates to a microseismic monitoring and positioning method based on highly deviated wells. Background technique [0002] Microseismic monitoring technology is an important technology developed rapidly in recent years to solve the development of low permeability oil and gas reservoirs. Although microseismic fracturing was monitored in the 1970s, it was only experimental at that time. With the further emphasis on and demand for energy development, microseismic monitoring and research play a vital role in the development of unconventional oil and gas reservoirs such as tight sandstone and shale. At least tens of thousands of wells in China need microseismic fracturing every year. Microseismic technology is to describe the fractures in the fracturing process by analyzing the microseismic signals (currently mainly referring to the microseismic first ar...

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Problems solved by technology

[0004] However, the currently popular microseismic monitoring and positioning technologies are all based on the positioning method that the monitoring well is a vertical well. Greatly affect the microseismic monitoring fracture distribution law

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