Method for analogue measuring cementing strength and anti-fluid channeling capacity of oil well cement

Abstract

The invention discloses a method for analogue measuring cementing strength and anti-fluid channeling capacity of oil well cement. The method comprises the steps of fabricating a core meeting test specification; installing a cement mortar mold; pouring cement slurry to space between the cement mortar mold and core; putting into a curing kettle for curing, wherein the pressure at the core part is equal to the inner pressure of the curing kettle; lowering the inner pressure of the curing kettle gradually so as to form differential pressure between the inner part of the curing kettle and the core part; increasing the inner pressure of the curing kettle gradually when the fluid in the core occurs fluid channeling, wherein the pressure at core part is equal to the inner pressure of the curing kettle again when the fluid is completely channeled; and drawing a pressure-time curve by a computer. A difference value between a final pressure in the curing kettle and the pressure at an inflection point corresponding to the inner pressure of the curing kettle changing from reduction to increase is the cementing strength between the cement ring and the core interface. In the method, the cementing strength of the oil well cement is simulation measured analogously and the interface anti-fluid channeling capacity is evaluated, by using a differential pressure method. The method is intuitive, clear and convenient, and can be learnt easily.

Description

technical field [0001] The invention relates to a method for simulating and measuring the bonding strength and anti-channeling ability of an oil well cement sheath in the field of petroleum engineering. Background technique [0002] At present, in oil drilling projects at home and abroad, after the completion of cementing and cement injection, the bonding quality of the interface between the cement sheath and the formation or casing is a key factor affecting the life of the oil and gas well. Poor cementation quality at the cementing interface makes the sealing system of the interface ineffective, which will lead to the problem of annular channeling after cementing. [0003] The harm of annular channeling is huge, which is mainly reflected in the following aspects: 1. Channeling causes oil and gas to flow from the wellhead, causing a large amount of oil and gas to be lost and reducing oil and gas production; 2. Different pressure systems in the well are channeling between lay...

AI Technical Summary

Problems solved by technology

However, it is worth pointing out that most methods focus on the study of the shear bond strength of the interface, while ignoring the study of the hydraulic bond strength of the interface.

Secondly, in these methods, the curing pressure in the process of curing the cement slurry is constant, and the effect of weight loss on the cement slurry during the entire solidification process is not considered.

In addition, some methods indirectly reflect the characteristics of cement strength through compressive strength, with obvious semi-quantitative color, and the evaluation error is large

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