microfracture vector scanning method

Abstract

Provided is a micro-rupture vector scanning method. The micro-rupture vector scanning method comprises the following steps: (1) initialization data is obtained, and micro-rupture vector monitoring data is pretreated; (2) a monitored object area is subjected to a meshing process, and a seismic wave three-dimensional speed model is established, and a minimum arriving time and an incident direction from each mesh point to various stations are obtained by means of 3D ray tracking; (3) fixed frequency noise interferences are eliminated through utilizing pre-monitored data; (4) record vectors which point to a mesh point K in different stations in a same period are synchronized, rotated to the incident direction, and subjected to a polarity superposition process to obtain the rupture energy of the mesh point K; (5) steps are repeated aiming at various mesh points; (6) the step (4) and the step (5) are repeated aiming at different time period windows to obtain a four-dimensional scan distribution of the rupture energy of the monitored object area. Noise enhancing useful signals can be effectively damped, and underground rupture points can be effectively located by means of scanning rupture energy.

Description

technical field [0001] The invention relates to geophysical prospecting microseismic positioning technology, more specifically relates to a vector scanning method for monitoring micro-fractures induced by natural structural activities or production in industrial fields such as petroleum and mineral products. Background technique [0002] Oil and gas mineral reservoirs are generally located at a depth of several hundred to several thousand meters underground, so they have a certain formation pressure. For example, after oil and gas wells are opened, there is a pressure difference between the well head and the reservoir, and driven by this pressure difference, oil and gas will spurt out along the well. However, as the formation pressure near the well gradually releases, the oil and gas eruption gradually weakens until it stops. This is the usual natural kinetic energy release process in the early stage of development. After that, rock fracturing and artificial fractures must ...

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Problems solved by technology

[0004] Microseismic fracturing monitoring technology is an important new technology in the field of low permeability reservoir fracturing in recent years. At present, the most reliable microseismic fracturing detection method is the downhole proximity observation method, which has strict restrictions and needs to be located in the vicinity. There are or newly excavated wells of several hundred meters in the fracturing area, and geophones are placed in the wells for observation. This method is extremely costly and complicated to implement

[0005] However, in the traditional observation method of seismic network deployed on the surface, since the energy released by underground microfractures induced by natural tectonic activities or production is extremely weak, it is easily affected or obscured by the surrounding noise. The seismic response waveforms of a large number of micro-fractures in the fracturing, that is, it is impossible to extract the first arrivals of longitudinal and shear waves, and it is difficult to realize the traditional positioning of the hypocenter based on the first arrivals; at the same time, the noise interference cannot be effectively removed when superimposing the seismic network data

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