Factorial Model Prediction for Performance of Ordinary Portland Cement Blended with Metakaolin and Sawdust Ash for Oil Well Cementing

Abstract

Factorial model exhibits good iteration and response
information for analysis and mathematical prediction model;
which may be manipulated using any design of experiment
(DOE) software such as Minitab for accurate and high
correlation analysis as well as correlated predictions. In this
study, the viability of using Sawdust Ash (SDA) and Metakaolin
(MK) as a blend to ordinary Portland cement (OPC) was carried
out using a mathematical arrangement of a factorial model
allowing combinations and percentages blend of the OPC with
Metakaolin for 10%,12.5% and, 15% whereas Sawdust Ash at
0%, 5% 10% which made up for 10 to 25% of both pozzolan
incombination to modify the properties of ordinary Portland
cement (class B), mitigate against the pollution challenges and
also provide an efficient, cheaper oil well-cementing material.
Materials for the study were characterized based on physical,
chemical, and pozzolanic test properties. Slurry property testing
was based on the mix formulation generated from Minitab
software for the Design of the Experiment (DOE) using two
domains three interactive factors (2x3) level factorial model.
The slurry was tested for thickening time, free fluid, fluid loss,
slurry density, and rheology parameters respectively at 45-65oC
conditioning temperature using a sensitometer following the
specifications of the America Institute of Petroleum (API) SPEC
10A and 10B). Metakaolin blend with OPC alone at 15% where
detrimental to rheology but the incorporation of Sawdust Ash up
to 10% with Metakaolin at both 10% and 15% improved the
slurry performance as shown by the various factorial outputs of
coefficients regarding free water (0.032-1.435%) which was far
below the 5.9% maximum and fluid loss decrement with API
RP-10B of 50 to 250ml for liner cementing, increment of
thickening time as well as modulating the rheology
characteristic to make the formulation pumpable. Results also
showed that a blend of oil well-cementing material for blend
samples (75%OPC, 10%MK, 10% SDA), (75%OPC, 15%MK,
10%SDA), and (90% OPC, 10%MK, 10%SDA) had an optimal
performance with respect to both slurry and mechanical
properties; giving an indication of the effectiveness of the
factorial model for studying the interaction of material when in
underuse and overuse.