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Low Density Cementing Slurry Technology

Cementing operation is the most important part of the whole construction of a well, and no factor has greater impact on the productivity of oil (gas) reservoir than the cementing quality.

Particularity of cementing engineering:

(1) It is a one-time project. If the quality is poor, it is generally difficult to remedy;

(2) It is a hidden project. The main process is underground and cannot be directly observed during construction. Quality control is often determined by the accuracy of design and the quality of preparation, and is affected by a variety of factors;

(3) Affect the progress of subsequent works;

(4) It is an expensive project;

(5) The construction time is short, the process content is much, and the work volume is large, so it is a project with strong technology.

Difficulties in cementing engineering:

(1) Cementing quality requirements are high, especially for gas well cementing construction. Generally, cement is required to return to the ground.

(2) The one-time continuous sealing section is long and the construction pressure is high.

(3) The problem of cement slurry leakage and low return in low pressure leakage formation;

(4) The well diameter is irregular, and the displacement effect of cementing construction is poor.

Common low-density cement slurry system

Low density cement systems commonly used at home and abroad mainly include floating beads, bentonite, fly ash, diatomite and other low density cement systems.

The minimum density limit for low density of floating beads is 1.38g/cm³

The minimum density limit of bentonite system is 1.60g/cm³

The density limit of low density fly ash system is 1.55g/cm³

The density limit of diatomite low density system is 1.50g/cm³

Foam cement can make the density of cement slurry less than 1.0g/cm³

HGS glass microsphere cement slurry system is lower than 1.0g/cm³