Solid-free anti-salt cleaning type well cementation spacer fluid and preparation method thereof

Abstract

The invention discloses a solid-free anti-salt cleaning type well cementation spacer fluid and a preparation method thereof. The spacer is prepared from the following components in parts by weight: 100 parts of water, 20-350 parts of soluble weighting agent, 0.1-1.0 part of additive, 0.2-0.5 part of thickening agent, 0.5-3.0 parts of fluid loss agent, 5-10 parts of non-ionic surfactant, 1.5-2.5 parts of anionic surfactant, 0.1-0.3 part of pH adjusting agent and 0.1-0.5 part of defoaming agent, wherein the additive is sodium tripolyphosphate, ethylenediamine tetraacetic acid disodium or ethylenediamine tetraacetic acid sodium. The solid-free anti-salt cleaning type well cementation spacer fluid is free of solid phase, so that virtual thick sludge cake cannot be formed on a well wall, the function of effectively spacing a drilling liquid from cement slurry is achieved, and meanwhile the well cementation is improved. In the preparation process, the substances are added to reaction in different batches, so that the operation method is simple.

Description

technical field [0001] The invention relates to the field of petroleum drilling, in particular to a solid-phase-free and salt-resistant cleaning type cementing spacer fluid and a preparation method thereof. Background technique [0002] In the cementing operation, it is necessary to replace the drilling fluid with cement slurry to form a cement sheath between the well wall and the casing, so as to support the casing and seal the formation. Excellent cementing operation not only requires the smooth progress of the construction process, but also effective sealing and cementation between the cement sheath and the formation and casing to prevent different oil layers, gas layers, and water layers from communicating with each other. Extend the production life of oil and gas wells. [0003] However, in the process of cement slurry replacing drilling fluid, there are often some complicated situations that affect the smooth progress of construction, and even affect later mining oper...

AI Technical Summary

Problems solved by technology

[0004] 1) The cement slurry system has poor compatibility with most drilling fluid systems. After the cement slurry is mixed with the drilling fluid during the displacement process, the frictional resistance of the fluid in the mixing section increases, which leads to an increase in pump pressure and the risk of leakage in weak formations

Some chemical components in the drilling fluid may also shorten the thickening time of the cement slurry, resulting in unsmooth construction operations

[0005] 2) During the mud circulation process, the drilling fluid is easy to adhere to the well wall to form a virtual mud cake, which is not conducive to the cementation between the cement and the well wall and affects the cementing quality

During the cementing operation, the cementing spacer fluid that uses weighting materials such as barite as the weighting agent contains a certain solid phase, which is bound to affect the downhole open hole section, especially the main oil layer section such as sandstone with high permeability. Cause pollution and form thick mud cake, which also has adverse effects on cementing quality

In addition, the traditional spacer fluid has poor settlement stability and often needs to be mixed and used at the cementing site

This requires investment in instruments and equipment, which is not conducive to saving costs

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