Oil well cement

Lafarge API Class G (HSR) cements is used in the production and exploration of oil and gas onshore and in deep water offshore wells to depths of up to 10,000feets (3,048 meters).

A typical well can be thousands of meters deep, less than a meter wide, and is constructed by using a metal casing surrounded by a special cement slurry mix that fills the annulus between the outer face of the tubing and the wall formation of the hole.

Lafarge well cements provide a base ingredient in the slurry mix that is pumped into the interior metal section of the well and forced back toward the surface from the base of the borehole filling the annulus. Well cement slurries are designed for a multitude of purposes from the establishment of the well's safety and structural integrity during drilling to the isolation of the zone of interest and the production of oil and gas upon completion. Given the complexity of the application and its extreme conditions of temperature and pressure, oil well cement must be carefully designed to meet demanding requirements such as predictable thickening time (set time), high sulfate resistance, high durability, fluid loss control, consistency, lowviscosity, low free fluid, and strength. Unlike surface construction, oil well completion is much less tolerant to errors. For instance, premature thickeningcan have disastrous consequencesdue to loss of circulation inthewell,whereas toolongthickeningtimescan cause financial losses duetoexcessive Wait-On-Cement (WOC) between drilling periods.

The types of cement are categorized according to the American Petroleum Institute (API) Specification10A standards, which has identified 8 classes of cement according to the depth of the well, the temperature and pressure. Cement is also classified in grades: Ordinary (O), Moderate Sulfate Resistant (MSR), and High Sulfate Resistant (HSR). Sulfate resistance is based upon the C3A (Tricalcium Aluminate) content, which has a bearing on the durability of the cement under sulfateattacks. When oil well cement is produced, the clinker is analyzed microscopically to ensure that the crystals and clinker mineralogy have the required characteristics. Oil well cement must also be designed and tested to perform with specific admixtures that are added to the slurry mix in order to achieve the desired thickening timeand rheology. The four most commonly used well cement types are Class A,Class C, Class G, and Class H.

Class A cements are being used inmilder, less demanding well conditions, while Classes G and H are specified for deeper, hotter and higher pressure well conditions. (HSR) cement meeting and ex-ceeding API specifications, and leads the industry in quality, and consistentperformance.

We know the needs of our oil & gas customers, locally and globally: state-of-the-art quality and innovation, time gains, and best costs. And when it comes to oil & gas well cement, you would expect from a solution provider: consistency in well cement quality and supply, global supply chain execution, inovation products that matchthe rapidly evolving drilling conditions.

LafargeHolcim operates the largest network of API licensed plants, with 17 established in 14 countries. We can supply all your oil and gas well drilling and construction projects across the world. Most of our well cement solutions are certified by the American Petroleum Institute (API). They go through a rigorous process to ensure quality and consistency to offer you the right performance for your application: offshore, onshore, shale gas/oil applications, high sulfate resistance, adjustable density, mechanical resistance, predictable setting and pumping time, and water tightness.