A low-density reinforcing agent for oil well cement and its preparation method

Abstract

The invention discloses a low-density strengthening agent for oil well cement and a preparation method thereof. It is composed of a special early strength agent, microsilica fume and ultrafine slag powder, and the special early strength agent is composed of one or more of the following components: Various compositions: a mixture of sodium sulfate, aluminum ammonium sulfate, calcium chloride, polyaluminum chloride, nano-silicon dioxide, hydrotalcite, white carbon black and triisopropanolamine. The fluidity of the cement slurry prepared with low-density reinforcing agent for oil well cement is between 23 and 25cm, and the fluidity of the slurry is good; the density difference of the cement slurry under pressure is ≤0.02g / cm 3 , the stability of the cement slurry is good; zero free water can be realized; the strength of the cement stone develops rapidly, the compressive strength reaches above 7MPa in 24 hours, and the compressive strength reaches above 10MPa in 48MPa hours; , the comprehensive performance of cement slurry is good.

Description

technical field [0001] The invention relates to the technical field of petroleum exploration and development. Specifically, it relates to a low-density reinforcing agent for oil well cement and a preparation method thereof. Background technique [0002] With the process of oil exploration and development, more and more oil and gas wells encounter low-pressure formations, weak formations and other formations that are prone to leakage. The low-density cement slurry system is the main method to solve the problem of low-pressure and leakage-prone formations. [0003] Lightening materials for conventional low density grout systems are: [0004] (1) Fly ash low-density cement slurry system has disadvantages such as long thickening time and low cement stone strength; [0005] (2) Bentonite affects the thickening time and slurry fluidity, and at the same time, the strength of cement stone is low; [0006] (3) The pressure resistance of ordinary floating beads is poor. Although th...

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Problems solved by technology

[0004] (1) Fly ash low-density cement slurry system has disadvantages such as long thickening time and low cement stone strength;

[0005] (2) Bentonite affects the thickening time and slurry fluidity, and at the same time, the strength of cement stone is low;

[0006] (3) The pressure resistance of ordinary floating beads is poor. Although the pressure resistance of power plant floating beads and glass beads is improved, the cost is high and it cannot be widely used.

[0011] Therefore, the current low-density cement slurry systems often have problems such as poor pressure resistance, poor slurry stability, and low compressive strength. efficiency requirements

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