Non-intrusive ultrasonic detection method of mud flow rate in deepwater drilling riser

Abstract

The invention relates to a non-intrusive ultrasonic detection method of mud flow rate in a deepwater drilling riser. The method comprises the steps that 1) an emission sensor is close to the wall of a riser, and a receiving sensor is arranged on an ultrasonic wave propagation path in the direction vertical to the wall of the riser; 2) the actual work signal frequency and the echo signal intermediate frequency shift information of the emission sensor are acquired; 3) difference frequency signals are acquired, and the difference frequency signal frequency is calculated; 4) the difference frequency signal of the theoretical difference frequency signal frequency maximum is rejected; 5) time frequency conversion is carried out on the difference frequency signals to acquire the frequency domain information of amplitude-frequency or power-frequency; 6) difference frequency signals with amplitude value less than 2% of the maximum amplitude value or with power value less than 2% of the maximum power value are removed, and weighted integral is carried out on remaining frequency to acquire a frequency difference result; 7) a curve of the relationship between the mud flow rate and the frequency difference result is acquired; and 8) according to ultrasonic, the mud flow rate is calculated through the frequency difference result of the riser. The non-intrusive ultrasonic detection method provided by the invention can be widely used for the detection of the mud flow rate in the deepwater drilling riser.

Description

technical field [0001] The invention relates to a mud flow velocity detection method, in particular to a non-intervention ultrasonic detection method of the mud flow velocity in a deep sea drilling riser. Background technique [0002] As an important means to prevent blowout accidents, early overflow monitoring plays an extremely important role in the process of oil drilling. The traditional early overflow detection methods mainly include mud pool incremental method, outlet flow meter method and acoustic wave method. Among them, the actual principles of the mud pool incremental method and the outlet flowmeter method are the same, and both are judged by the incremental change of the outlet mud. Due to the pressure imbalance between the formation fluid and the drilling fluid, the formation fluid containing a large amount of natural gas invades the drilling fluid, and rapidly expands and upwells to form an overflow phenomenon. If it cannot be controlled in time, it may cause w...

AI Technical Summary

Problems solved by technology

The advantage of the interventional method is that the measurement is more accurate, but the pipeline structure needs to be modified during installation, which may have a great impact on the pipeline structure and performance

However, the riser used in the drilling industry itself has strict technical requirements, so the intrusive flow detection method is not suitable for the situation below sea level

On the other hand, the ultrasonic flowmeter is the most widely used in the non-invasive method, but the conventional ultrasonic flowmeter method cannot be applied due to the large attenuation of the ultrasonic wave by the mud

Other non-invasive methods, such as pressure difference method, radiation method, etc., are aimed at the deep sea drilling environment, and they all have relatively difficult defects to overcome

For the pressure difference method, since there is still a drill pipe in the riser that is constantly rotating, it will affect the flow state of the mud and affect the pressure of the pipe wall. At the same time, the complex pressure environment on the seabed also reduces the measurement accuracy of this method.

However, the radiation method cannot be applied because of its large size and high cost, and it is dangerous to install on the seabed.

However, in current deep-sea drilling applications, the measurement of mud flow velocity can only be carried out at the mud outlet, and the response to changes in mud flow velocity is slow, leaving a relatively short time for gas invasion treatment.

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