Cementing a well is a procedure to develop and pump cement into place in a wellbore. It is meant to prepare a well for further drilling, abandonment, or production. It protects and seals the wellbore. Often, cementing is used to permanently shut off water penetration into the well. Cementing is part of the completion process of a possible production well. Cementing can be used for sealing the annulus after running a casing string in a wellbore. Companies like Renegade Wireline Service Company offer completion services that include cementing.
Furthermore, cementing is used for sealing a lost circulation zone or a location where there is zero or reduced flow within the well. It is used for plugging an existing well in directional drilling to run a directional well from this point.
Preparing the Well for Cementing
When preparing a well for the cementing process, operators must establish the amount of cement required for the job. They will measure the borehole’s diameter with its depth. Multifinger caliper logs measure the well’s diameter at different locations to accommodate for irregularities in the wellbore diameter and identify the openhole’s volume.
Moreover, the cement’s required physical properties are necessary before starting the cementing operations. It is also important to determine the proper set cement including the material’s density and viscosity before pumping the cement into the hole.
Dry cement is combined with water using special mixers to create the wet cement called slurry. Also, operators can use additives such as accelerators to reduce the setting time required for the cement. Lightweight and heavyweight additives are added to increase or decrease the cement’s density.
How to Cement the Well
Once the well is cased, the operator will fix an L-shaped cementing head to the wellhead’s top to get the slurry from the pumps. The bottom plug is introduced into the well to prevent the drilling fluids from mixing with the slurry. Then, the slurry is pumped into the well behind the plug. After pumping the proper volume of cement into the well, a top plug is pumped into the casing to push the remaining slurry through the bottom plug. When the top plug reaches the bottom plug, the operator will turn the pumps off and let the cement set. When setting wells at deep depths, under high pressure or temperature, operators need to use special cement. Thickening time is the amount of time it takes the cement to harden.