Well cementing squeeze

In addition to primary cementing of the casing and liner, there are other important well cementing operations. These are squeeze cementing and plug cementing Such operations are often called secondary or remedial cementing [161]. 

Thick slurries will not fill a narrow channel well. Therefore squeeze cement slurries should be rather thin. Dispersants should be added for this reason. High compressive strength is not necessary for these types of slurries. 

Finally, technologies for well construction (drilling procedures, completion best practices, CO2-resistant cement and metallurgy) and well remediation (squeeze, well plugging) will allow controlling the man-made features to maximize performance while mitigating risks. 

A similar technique may also be applied later in the wells life to seal off perforations through which communication with the formation has become undesirable, for instance if water breakthrough has occurred ( squeeze cementation ). 

Cement is then placed across the open perforations and partially squeezed Into the formation to seal off all production zones. Depending on the well configuration it is normal to set a series of cement and wireline plugs in both the liner and production casing (see Figure 16.2), to a depth level with the top of cement behind the production casing. 

Most squeeze cementing operations take place in cased sections of a well. However, open-hole packers can be used to carry out squeeze cement operations of thief zones during drilling operations. 

Two other types of operations involve cement slurries. They are used to plug back a well from a deeper to a shallower depth for a number of reasons abandonment, whip stocking, lost circulation, or shutting olf water. Squeeze cementing consists of forcing a column of cement slurry... 

Neither a model of creep, nor the mechanism of this process is known as well. Obviously, the creep relates to the properties of cement gel and the presence of adsorbed water. The creep growth with moisture content in a paste, while the dried samples do not show this effect [127]. However, this latter statement is not quite sure perhaps only a substantial reduction of creep occurs [128]. The hypotheses assume the squeezing of water from the paste under load. 

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