Co-Bond (Well) for oil well cementing
Co-Bond (Well) – our multi-purpose super-plasticizer and admixture enhances the properties of the cement for oil well cementing.
In oil wells drilling – oil well drills penetrate the soil to reach the source of geo-thermal energy, water-migration, evaporative and other foreign matters, it is a standard practice to use cement to hold the well casing in position and selectively block or plug a portion of the strata through which the well extends to prevent the escape of undesirable fluid into the well bore or the loss of drilling muds.
The cement supports the casing, seals off the annulus, isolates the porous zones from each other and protects the casing from corrosive fluids. Co-Bond (Well) enhances all these properties of the cement.
The cements utilized in drilling operation are formulated so as to be sufficiently resistant to high temperature and pressure encountered in the wells.
The American Petroleum Institute has promulgated the specification for testing cement to ensure that it meets certain minimum requirements with respect to strength, permeability, setting time etc. These cements are called Oil Well Cement.
To resist the temperature and pressure, normally encountered in the wells, the Oil Well Cements have been developed to provide maximum physical properties under maximum pressure conditions encountered in the relatively deep wells.
These cements are conventionally Portland cement to which one or various additives are mixed to improve the mechanical strength and the thermal and chemical resistance of the set and hardened cement.
Although satisfactory for conventional well operation, this cement has been proven deficient particularly in case of ultra deep and geo-thermal wells, where temperature is in excess of 200° C. At this temperature – conventional cements quickly increase porosity and loose compressive strength, which may lead to a blow-out.
Such blowouts are very undesirable and extremely dangerous. They can prove very costly to repair. Accordingly, Oil Well Cements, particularly those used in geo-thermal wells and ultra deep wells sunk to a depth of 25000 ft or more, must have the ability to effectively maintain an adequate compressive strength, density, and porosity even under high temperature and pressure and in the presence of steam and hot brine.
Since the useful life of a typical well is measured in terms of 10-30 years, a good Oil Well Cement must operate under the afore mentioned severe conditions for a substantial period of time, preferably for the well’s life time.
Co-Bond (Well) features:
- Improves the mixing character of the cement slurries
- Setting time
- Compressive strength
- Permeability
- Set retarder along with fluid controllability
- Friction reducing character
- Improves cementing against evaporates
- Provides sufficient tackiness
- Withstands high temperature
Co-Bond (Well) is non-hazardous, non-inflammable, non-combustible, with an excellent mixing character with cement slurries. Co-Bond (Well) improves the slurry’s flow without any friction during pumping. It gives an excellent compact bond to the casing.