Logging vsp composite data acquisition system and acquisition processing method based on optical fiber sensing

Abstract

The invention discloses a logging VSP composite data acquisition system and a collection and processing method based on optical fiber sensing. The distributed optical fiber sensing modulation and demodulation instrument in the logging vehicle and the distributed optical fiber sensing armored photoelectric composite cable are connected near the wellhead. The optical fibers in the head end are connected to each other. When the logging instrument connected to the tail end of the distributed optical fiber sensing armored photoelectric composite cable is lowered to the bottom of the well, the pre-prepared ground seismic sources at the wellhead and around the Sensitive armored photoelectric composite cable and ground modulation and demodulation instruments quickly and synchronously collect the vertical seismic profile (VSP) data, temperature data and pressure data of the whole well section. The logging instrument then began to slowly lift up to collect logging data, realizing the composite collection of high-density, high-efficiency, low-cost logging and VSP data in one downhole. The invention solves the problems in the prior art that logging data and VSP data are collected separately by separate equipment, the equipment investment is large, the well occupies a long time, and the collection cost is high.

Description

technical field [0001] The invention belongs to the fields of applied geophysics, geophysical exploration technology, geophysical well logging technology, seismic exploration and well logging, and in particular relates to a logging VSP composite data acquisition system and acquisition processing method based on optical fiber sensing. Background technique [0002] Seismic Wave is the vibration that propagates from the seismic source to all directions, and refers to the elastic wave that is generated from the seismic source and radiates to the surroundings. According to the propagation mode, it can be divided into three types: longitudinal wave (P wave), transverse wave (S wave) (both longitudinal wave and transverse wave belong to body wave) and surface wave (L wave). Seismic exploration refers to the geophysical exploration method in which the elastic waves caused by artificial excitation use the difference in the elasticity and density of the underground medium to infer the...

AI Technical Summary

Problems solved by technology

Due to the heavy weight and high cost of the existing moving-coil three-component geophones in the well, the logging cable can run up to 100 moving-coil three-component geophones in the well at one time to collect the seismic data of the whole well section thousands of meters deep It is necessary to move or lift the moving-coil three-component geophone array in the well several times, and every time the moving-coil three-component geophone array in the well is lifted, all artificial excitation sources on the ground (explosives or weights or electric sparks or air guns or piezoelectric crystals) or vibrator) points need to be re-excited once, which not only results in the extremely high cost of collecting the vertical seismic profile data of the entire well section, but also makes it difficult to ensure that the energy of each excitation is consistent for repeated excitation at each ground artificial source point. The spectrum is consistent, and every coupling between the ground artificial source and the ground is also completely consistent

Due to the above well-known reasons, it is difficult for the general-purpose moving coil three-component geophone array in the well to perform the operation of the vertical seismic profile data in the well to be widely popularized and applied.

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