Micro Geopolymer Cement with Enhanced Physical Properties for Well Cementing

Ordinary Portland Cement (OPC) has been used widely in oil well industry. However,
OPC creates high permeability between cement particles when exposes to HPHT
environment inside the wellbore and also releases large amount of carbon dioxide
(CO2) during manufacturing process. Previous research has been conducted to
substitute OPC with geopolymer based cement such as fly ash. Geopolymer cement
successfully reduces emission of CO2 to five to ten times less than OPC but still
resulted in the same permeability trend as OPC. This project introduced micro silica
in geopolymer cement to study its effect on the permeability problem in OPC and
geopolymer cement. Four samples are developed with the percentage of micro silica
range from 0% to 60%. The performance of developed samples are compared with
Class G Cement (OPC) in term of permeability at HPHT (4000psi and 120 ℃ )
environment for three curing durations; 24 hours, 72 hours and 120 hours and fluid
loss at LPLT environment (500psi and 70 ℃). Rheology and density test are compared
at standard room conditions. The test results show the permeability of cement increase
when increase the percentage of micro silica and curing duration. For static fluid loss
test, increase in micro silica reduced the volume of filtrate. Two rheological model are
observed from the samples; Power Law and Bingham Plastic Model. At standard
room condition, the viscosity of cement slurry increased and density of samples
decreased when increase the micro silica. Overall, Sample A, B and C can replace OPC
up to 4000psi and 120℃ condition while all samples have better performance than
OPC in term of fluid loss up to 500psi and 70℃, rheology and density environment
and standard room condition.