Early hydration characteristics of oil well cement pastes admixed with newly prepared organic admixture

Abstract

A number of chemical and mineral admixtures are usually used in the oil-well cement (OWC) pastes to modify and control their fluidity to resist the higher temperatures and pressures during the drilling process of the well. In this study a newly prepared aliphatic organic compound namely cyclohexanone glyoxylate condensate (CG) was synthesized. The prepared compound (CG) was characterized using Fourier Transition Infrared spectroscopy (FT-IR) and microanalysis of carbon, hydrogen, oxygen and sulfur elemental analysis techniques. The effect of additions of 0.25, 0.50, 0.75 and 1 (mass%) of this admixture on the mechanical and early hydration characteristics of OWC pastes was studied. The phase composition for some selected hardened specimens was investigated using X-ray diffraction (XRD) and thermogravemtic analysis (DTGA) techniques. The results indicated that, addition of cyclohexanone glyoxylate condensate (CG) admixture to OWC pastes causes a slight retardation for the early rate of hydration of OWC. Addition of 0.25% of CG to OWC causes a slight improvement in the compressive strength values during nearly all ages of hydrations. XRD and DTGA results for the neat and CG admixed OWC pastes, indicate that the main hydration products are nearly amorphous calcium silicate hydrates (mainly as CSH-I and CSH-II), calcium sulfoaluminate hydrates (ettringite and monosulfate hydrate) as well as portlandite (CH).