P. N. Onwuachi-Iheagwara and K. I. Idigbe
This paper documents an analysis of the Ughelli and Benin sands. These sands are located in two adjacent states in the Niger delta of Nigeria; namely Delta and Edo states respectively. The mineralogical components of these two sands were examined. Slurries prepared from API grade G cements and stabilized with these sands were curried for 30 minutes at atmospheric conditions and the development of early compressive strength studied in an attempt to understand the use and effect of these sands in the prevention of cement retrogression in the Niger Delta. The investigation centred on the substitution of Silica flour; an additive in high temperature high pressure (HT HP) [1] cementation with indigenous sand. It was observed that Ughelli sands can be a substitute for the more expensive silica flour commonly used by the drilling companies in Nigeria to combat the effect of the cement retrogression in HT HP terrain in the country, especially in the Niger Delta Basin. Ughelli and Benin sands contain approximately 93 % and 90% silica respectively. At over 60 % substitution Ughelli sands can be used for HT HP operations in the Niger Delta. The compressive strengths analyses were conducted at 300 deg F in order to mimic the HT HP condition. These experiments showed that slurries prepared using Ughelli sands as additives had an acceptable compressive strength for HT HP usage.
