A Method for Recognition of Dynamic Fluid Level in Oil Well

Abstract

The invention discloses a method for identifying the dynamic liquid level of an oil well, which comprises the following steps: 1. Obtaining an estimated value of the depth of the dynamic liquid level and collecting an echo signal; 2. Filtering the echo sampling signal; 3. Band-pass filtering the echo signal Frequency domain transformation; 4. Extracting the sound velocity of the echo signal; 5. Data zeroing processing of the echo sampling signal; 6. Filtering of the zeroing echo sampling signal; 7. Finding the sudden peak and the position of the dynamic liquid surface 8. Obtain the sampling time of the position of the fluid surface; 9. Identify the actual depth of the fluid surface. According to different oil well depths, the present invention determines the window length and step length of the band-pass filter echo signal, identifies the echo cycle signal based on the tubing coupling, extracts the sound velocity of the echo signal, calculates the sound velocity accurately, and searches for the position of the dynamic liquid surface The sampling time of the position of the dynamic liquid level can be obtained from the sampling point of the sudden peak of the dynamic liquid level and the sampling point of the dynamic liquid level, so as to solve the problem that the signal of the dynamic liquid level is submerged by noise and cannot be directly identified.

Description

technical field [0001] The invention belongs to the technical field of downhole dynamic fluid level identification, and in particular relates to an oil well dynamic fluid level identification method. Background technique [0002] In the production of oil wells in oil fields, the depth of dynamic fluid surface is an important parameter for monitoring the production status of oil reservoirs. The dynamic liquid level reflects the liquid supply capacity of the oil well. It is not only used to detect the oil production status, but also used to analyze the water injection effect. It can reflect the production status of the oil well such as sand plugging and wax formation. There are two types of dynamic liquid surface identification methods, time domain method and frequency domain method, wherein, time domain method has manual identification, amplitude-zero-crossing rate function method to identify dynamic liquid surface and fuzzy clustering method, etc.; frequency domain method ha...

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Problems solved by technology

[0003] The technical problem to be solved by the present invention is to provide a method for identifying the dynamic liquid level of oil wells in view of the deficiencies in the above-mentioned prior art. The sound velocity of the echo signal is extracted based on the echo period signal of the tubing coupling, and the sound velocity is calculated accurately, and the sudden peak value of the dynamic liquid level position and the sampling point of the dynamic liquid level position are searched to obtain the sampling time of the dynamic liquid level position to solve the dynamic liquid level signal. Submerged by noise, it is impossible to directly identify the problem, which is convenient for promotion and use

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