Effect of natural pozzolan on the fresh and hardened cement slurry properties for cementing oil well

Wells’ cementing is an important and costly step in the engineering sector for oil and gas well. The purpose of this study was to investigate the use of Algerian natural pozzolan (NP) in order to evaluate the influence of partial substitution of class G cement on slurry properties.

NP was characterized by X-ray fluorescence (XRF), scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) and Fourier-transform infra-red spectrometry (FTIR). Their pozzolanic activity was evaluated by measuring the electrical conductivity in aqueous suspensions of pozzolan/calcium hydroxide. The replacement ration cement/NP was 10, 20 and 30 per cent, and the rheological behaviour, compressive strength properties at different ages, elastic properties, X-ray diffraction analysis, rapid chloride penetration, porosity and permeability of all slurries were investigated and compared with a standard sample.

The obtained results indicated that the replacement with 20 per cent by weight of cement at 21 and 28 days had a higher compressive strength (+30.62 per cent) and lower chloride penetration.

The results show the potential of the use of locally available NP in well cementing.