Inhibiting effect mechanism of biopolymer MEG drilling fluid

Biopolymer MEG has a hydroxy (-OH),which has a strong absorptive action on the shale,and MEG has a methyl (-CH3),which makes the MEG become semi-permeable diaphragm after absorbing.To have measured the MEG adsorptive power to bentonite,it is up to 120% at 30℃;After mixing MEG and inorganic salt,the MEG have a better absorptive power;MEG build-up a semi-permeable diaphragm by the good absorptive power;The montmorillonit layer interspacing is 1.92 nm,this value is 1.77 nm after handling montmorillonit using MEG,it demonstrate that littler water absorbed after handling using MEG.Film efficiency have been measured using shale film efficiency evaluator,the effect is improved after handling shale by MEG;MEG is key additive in the drilling fluid formula in Zheng-X 41 well and the result demonstrate that MEG have a good inhibitive effect.