What are the objectives of cementing in the borehole?
The objectives of the primary cementing operation are to remove drilling fluid from the casing interior and borehole, place a cement slurry in the annulus and fill the casing interior with a displacement fluid such as drilling fluid, brine or water.
What is the main purpose for cementing the casing in a well?
Cementing is one of the most important operations performed on a well in order to ensure complete zonal isolation, aquifer protection, and the structural integrity of the wellbore. Without it, the well may never reach its full production potential, and liquids from one zone could interfere with, or be lost to, another.
What is primary cementing?
Primary cementing Cementing is the process of mixing a slurry of cement, cement additives and water and pumping it down through casing to critical points in the annulus around the casing or in the open hole below the casing string.
What equipments are used in cementing process?
Centralizers, Turbolizers and Scratchers. Devices fitted with hinged collars and bow springs help keep the casing or liner in the center of the wellbore to help ensure efficient placement of a cement sheath around the casing string.
What are the different types of cementing methods?
These techniques are:
- Cementing through pipe and casing (normal displacement technique)
- Stage cementing (for wells with critical fracture gradients)
- Inner-string cementing through tubing (for large-diameter pipe)
- Outside or annulus cementing through tubing (for surface pipe or large casing)
What is cement plug in well completion?
A rubber plug used to separate the cement slurry from other fluids, reducing contamination and maintaining predictable slurry performance. A diaphragm in the plug body ruptures to allow the cement slurry to pass through after the plug reaches the landing collar. …
What are the function of cementing?
The two principal functions of the cementing process are to restrict fluid movement between the formations and to bond and support the casing.
What does remedial cementing do to a well?
Remedial cementing is undertaken to correct issues with the primary cement job of a well.
How does cementing of an oil well work?
• Oil well cementing is a process of mixing a slurry of cement and water and pumping it through the casing pipe into the annulus between the casing pipe and the drilled hole. • Cement plugs are also set in the wellbore to isolate zones e.g. loss zones, water bearing zones 20
How is cement slurry used in remedial cementing?
A cement slurry is prepared and pumped down a wellbore to the problem area or squeeze target. The area is isolated, and pressure is applied from the surface to effectively force the slurry into all voids.
What are the reasons for stage cementation of a well?
Stage Cementation: Reasons a.Down hole formations unable to support hydrostatic pressure exerted by a long column of cement b.To cement wells having two or more zones of interest separated by long intervals c.Limitations of cementing equipments d.Cementing of high pressure gas zones & water producing horizons. 13. Stage Cementation 14.