Data from: Utilization of metakaolin based geopolymer as a mud-cake solidification agent to enhance the bonding strength of oil well cement-formation interface

This research work designed a novel mud-cake solidification method to
improve zonal isolation of oil and gas wells. The calculation methodology
of mud-cake compressive strength was proposed. The optimal formula of
activator and solid precursors, the proper activating time and the best
activator concentration were selected by compressive strength test. The
effects of solid precursors on the properties of drilling fluid were
evaluated. The performances of this novel method were measured. Test
results show that the respective percentage of bentonite, metakaolin, slag
and activator is 1:1:0.3:0.8, as well as the optimum ratio of Na2SiO3/NaOH
is 40:1. The optimum concentration of activator is 0.21 due to the limited
proportion of solid precursors in mud-cake, and the activating time should
not lower than 10 min. The solid precursors did not show bad influence on
the rheological property of drilling fluids in different conditions. Even
though the compressive strength decreased when the solid precursors blend
with barite or other drilling fluid additives, the strength values can
still achieve 8 MPa. The reaction of metakaolin and activator formed
crosslink structure in the mud-cake matrix, which enhanced the connection
of the loose bentonite particles, lead to the significant enhancement of
shear bonding strength and hydraulic bonding strength. This mud-cake
solidification method provides a new approach to improve the quality of
zonal isolation.