Effects of Metakaolin and Nano clay on the Rheological and Flow Characteristics of Oil-Well Class G Cement Slurry
1Salawudeen, T. O. 2Arinkoola, A. O., 1Afolayan, A. S., 1Salam, K. K., 1Jimoh, M. O., 1Dada, E. O., 3Duru I. U., 4Aladeitan, Y. M., and 1Olufayo, O. A.
1Department of Chemical Engineering, Ladoke Akintola University of Technology, Ogbomoso, Nigeria
2Department of Petroleum Engineering, African University of Science and Technology (AUST), Abuja, Nigeria
3Department of Petroleum Engineering, Federal University of Technology (FUTO), Owerri, Nigeria
4Department of Chemical Engineering, University of Abuja, Nigeria
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The rheology of Oil-Well Cements (OWCs) [is generally more complicated than that of the conventional cement pastes. To contend with a wide range of pressure and temperature, several additives are used. The slurries, however, exhibit different rheological characteristics depending on the combination of admixture used. This research investigated the rheological properties of class G cement partially substituted with Metakaolin (MK) in the presence of Nano clay (NC) additives. The variables were randomized using 5 – 15% MK by weight of cement and 5 – 15% NC by weight of MK. The blends obtained were tested for rheology at the bottom hole circulating temperature (BHCT) of 70 oC. The result showed a high dependency of MK and NC admixture on the rheological properties of OWC slurries. The viscosity decreased significantly at high MK irrespective of the NC dosage. The MK in the range of 10 – 15% improved fluidity and required less energy to flow. On the contrary, the slurry with 100% Class G cement has higher values of yield stress and Gels at 10- seconds and 10-minutes, hence require more energy. The analysis showed the Herschel-Bulkley Model with Sum of Square Error (SSE) of 0.001329 and the coefficient of correlation (R2) of 0.9982 adequately fitted the rheological behavior. The partial substitution using the MK and NC improved the pumpability and other rheological properties of the Class G cement.
Keywords: Class G cement, Supplementary cementitious materials, Rheological models, Metakaolin and nanoclay.