Foamed cement is a coarse dispersion of a base cement slurry, a gas (usually nitrogen), a foaming surfactant, and other materials to provide foam stability. Foamed cement is generally less expensive than systems containing glass microspheres or cenospheres (Edmondson and Benge, 1983); however, special equipment is required at the well site to inject nitrogen or …
Cementing plugs are semirigid barriers that separate cement slurry from drilling fluids, wipe the casing, and indicate when cement placement is complete. Plugs were once made of gunnysacks, wood, and leather. Present designs include top and bottom wiper cementing plugs constructed of nitrile or polyurethane molded over PDC drillable high-density plastic cores (Fig. 1). The …
Inner string or stinger cementing is a technique typically used with large-diameter casings in which drill pipe is placed inside the casing as the conduit for pumping fluids from the surface to the casing annulus (Fig. 1). The inner strings can be run in one of three ways that will be discussed later in this …
Guide shoe and float shoe in drilling are tapered, a commonly bullet-nosed device that is installed at the bottom of any types of casing string. They guide the casing toward the center of the hole to minimize hitting rock ledges or washouts as the casing is run into the well. The outer portions of these …
The device that is run on the bottom of the casing for primary cementing is called a “shoe”. There are four basic types of shoes that run on the casing, a guide shoe, a float shoe, an automatic fill shoe, and a differential fill float shoe. In this article, we will handle both the float …
Cement Design & Programming for primary cementing operations of any type of casings / Casing liner requires the following input: Although there are several placement techniques that can be used in primary cementing (Cementing in drilling), they have a number of features in common. Therefore and for the sake of simplicity, we discuss the most …
Additives are chemical compounds added in small quantities to change the physical properties of cement slurry and/or the set cement. Most cementing chemical additives are available either in solid or liquid form. Most of the cement additives available at present have been developed by specialized cementing Companies, although increasingly, products from independent chemical manufacturers are …
When a cement slurry is placed across a permeable formation under pressure, a filtration process occurs. The aqueous phase of the slurry escapes into the formation, leaving the cement particles behind. Such a process is commonly known as fluid loss ( one of the oil well cement properties) and it is put under control in …
Well cement slurries are highly concentrated suspensions of solid particles in water. Their rheological Cement properties are related to those of the supporting liquid rheology, the solid volume fraction (volume of particles/volume of slurry), and interparticle interactions. The aqueous phase of a cement slurry contains ionic species and organic additives. Therefore, the rheological properties of …
Cement Weighting Agents are used in certain cases as High pore pressures, Borehole instability, and deformable or plastic formations that shall be controlled by high hydrostatic pressures. Under such conditions, mud densities in excess of 18.0 lbm/gal [2.16 g/cm 3 ] are common. To maintain control of such wells, cement slurries of equal or greater …