Performance Assessment and Economic Analysis of Blended Class G Cement With Local Cement for Oil Well Cementing Operations: A Case Study of Ghana

Abstract

Good cementing job practices are required for an efficient advancement in drilling and production operations. Most drilled oil and gas wells in Ghana employ the use of class G cement in its cementing operations. This class G cement is imported, scarcely available and relatively more expensive compared to other forms of cements. It also does not promote the local content and local participation policy of the country in the oil and gas sector. This has therefore necessitated the need to research into available local cements (easily available and relatively inexpensive) as an alternative to serve the same purpose as the imported class G cement. This research therefore assesses the performance of class G cement blended with local cement at different ratios in an attempt to reducing the overdependence of the class G cement while considering the technical requirements and economic implications. All the blended samples met the minimum API compressive strength requirement of 1500 psi when cured for 8 hours at 140 °F. Though, free fluid values increased with increasing amount of local cement ratio, all values recorded were below the maximum field requirement value of 5.9%. The blended samples exhibited the ability to be pumpable, recording plastic viscosity less than the maximum recommended value of 100 centipoise (cP). It was therefore established that the use of blended samples (local and Class G) for oil well cementing operations in Ghana would save the industry from 19.57% to 78.28% of money over the use of class G cement only. Considering the performance and economic benefits of the blended cement over the class G cement only at the test conditions, it is highly recommended that, the industry adopts the blending of class G cement with the local cement in their cementing operations to boost the local economy as well as to reducing their cementing operation cost.