Underground multi-node signal acquisition synchronous error correction device and method

Abstract

The invention relates to an underground multi-node signal acquisition synchronous error correction device. A delay measuring unit of the device simulates a PPS (pulse per second) and sends a PPS signal to pulse receiving and forwarding modules at acquisition nodes of a seismic signal acquisition system through a logging cable, a telemetering unit and an interstage cable, and measures time consumed by sending the PPS to the acquisition nodes and passing back to the ground; and a delay correction unit calculates a delay correction amount according to each pulse measuring time, and seismic signal data collected by each acquisition node are delayed for corresponding time according to each delay correction amount and are the repackaged into independent data. The underground multi-node signal acquisition synchronous error correction device provided by the invention can accurately measure and correct transmission delays of all nodes, breaks through the limitation to the number of nodes, solves the problem that cable delay reaches up to several hundred of microseconds, and can reduce a synchronous error of seismic signals collected by multiple nodes to a nanometer scale, thereby realizing high-precision synchronous acquisition of all nodes in a system.

Description

Technical field: [0001] The invention relates to a seismic data acquisition system in geophysical exploration, in particular to a synchronization error correction device and method for a high-temperature downhole multi-node seismic signal acquisition system. Background technique: [0002] In the field of geophysical exploration, U.S. Patent Publication No. US20100198561A1, published on August 5, 2010, the name of the invention is a data acquisition device and method. As stated in the patent, all acquisition nodes must be synchronized so that they have the same sampling moment. In a land seismic exploration system, hundreds or even thousands of seismic data acquisition nodes are usually deployed in the detection area. The common laying method is to interconnect many collection chains composed of collection nodes into a detection array for laying. The acquisition process of each acquisition node is to convert seismic signals into digital signals. In downhole seismic signal ...

AI Technical Summary

Problems solved by technology

This patent is used in the submarine streamer seismic exploration system, but a high-precision clock needs to be built in each node. In the high-temperature environment underground, the crystal oscillator is prone to cumulative errors, resulting in inaccurate clock timing.

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