Channeling measuring method

Abstract

The invention relates to a channeling measuring method and device. Its main method: by using U-shaped grout cylinder and columnar grout cylinder to simulate the solidifying environment of the grout in the pit and by continuous determining and observing the changes of pressure difference between two ends of U-shaped grout cylinder and of pressure on the bottom end of columnar grout cylinder, achieve grout channeling pressure or stop measuring channeling in time when the grout does not channels, thus objectively evaluating the measured anti-channeling ability of grout. Its device includes: a U-shaped grout cylinder, one end connected to air pressure supply source and the other end to pressure measuring component; a columnar grout cylinder, the cylinder diameter equal to that of the U-shaped grout cylinder and the top end set with an isolating piston and connected to the air pressure supply source; a measuring component linked at the bottom end of columnar grout cylinder; a temperature control device to make temperature-ascending speed and constant temperature of the two grout cylinders consistent with those of the simulated stratum. It can qualitatively, quantitatively and objectively determine the anti-channeling ability of the grout.

Description

[0001] Field [0002] The invention relates to the field of petroleum cementing, in particular to a channeling measuring method for measuring the anti-channeling ability of cementing cement slurry. Background technique [0003] During cementing, annular channeling of cementing cement will cause oil and gas leakage at the wellhead, reduced production capacity, underground fluid pollution, and limited production stimulation measures. In order to avoid the above-mentioned hazards of cement annulus channeling, it is necessary to measure the anti-channeling ability of cement slurry before cementing, so as to adjust the formula of cement slurry properly, so as to prevent cement annulus channeling during cementing. [0004] According to the research results at home and abroad, there are three main ways for cement annulus channeling to occur: [0005] 1. Oil, gas and water channeling caused by cement slurry channeling and mud biscuit cracking. Due to the poor displacement efficiency...

AI Technical Summary

Problems solved by technology

Due to the poor displacement efficiency of cement slurry, the retained drilling fluid forms a weak link in channeling in the annular space; in addition, when the cement slurry solidifies, it may absorb the moisture of the retained mud cake, resulting in cracking of the mud cake, which may cause channeling of oil, gas and water. cement annulus channeling

[0006] 2. Oil, gas and water channeling caused by interface micro-gap

[0007] 3. Oil, gas and water channeling caused by weight loss of cement slurry

However, the gelling strength of cement slurry reflects the average shear stress of the cement slurry, and cannot reflect the stress at the weakest part of the cement bond, so the anti-channeling ability of the cement slurry cannot be scientifically evaluated.

Moreover, since the dehydration of the cement slurry reflects the ability of the cement slurry to retain the mixing water in the early stage of cement slurry hydration, while channeling mainly occurs in the middle and late stages of cement hydration, there is no necessary connection between the two, so it cannot be scientific reflect the anti-channeling ability of cement slurry

Images