Abstract

Cement is used as the primary sealant in oil and gas wells throughout the world and is manufactured to meet specific chemical and physical standards set up by the American Petroleum Institute (API). As a result, oil companies purchase cement manufactured according to specification of API for its oil well cementing. These special classes of cements are called Oil Well Cements (OWCs). In oil well cementing, less error is tolerated in the performance of the cement used as compared to conventional cementing work. This has resulted in more attention being placed on the usage of high grade API special class of cements as against any ordinary type of cement. However, there are some cementing operations that Construction Grade Cements (CGCs) have been used without resulting in any cementing challenges. This paper presents the progressions in experimental investigations and field applications of CGCs in oil well cementing. The experimental investigations on the physical properties such as thickening time and rheological properties revealed that local cements in its natural state lack sufficient technical properties for oil well cementing. However, with the right addition of oil well additives, local cements have proven to have the required technical properties for oil well cementing. Countries like Vietnam and Thailand have demonstrated the field applications potentials of CGC. Comparing the cost of CGCs and OWCs (imported), it is realised that more savings are made when CGCs are used in cementing operations.

Keywords: Additives; Universal cement system (UCS); Gelation; Construction grade cement (CGC); Oil well cements (OWCs)