| According to real situation of Du 84 - Guanping 57 horizontal well in Liaohe oil field, inhibition tests of the silicates with different modulus were carried out. The results show that the bigger the silicate modulus, the stronger the inbibiting property. Some KCl added into the silicate system could increase the performance of its inhibition. The results of the compatibility between usual chemicals and sodium silicate suggest that the addition sequence of ammonium salt and sodium silicate will largely influence the filtration, that ammonium salt added before sodium silicate could have good filtration performance, while added after sodium silicate could not reduce water loss and worse compatibility. Sodium silicate could reduce the viscosity and gel strength when added into polymer drilling fluids such as KPAM and CMC with low clay contents. The addition sequence of the filtration reducers could not influence the rheologies of the base muds. The inhibition mechanism of the silicate drilling fluids and the formula have been studied. first, filtration property well and dehydration small. But when injecting sodium silicate. Optimized silicate drilling fluid has the properties of very strong inhibility and anti-collapse. Rolling recovery rate might reach 100%, the value of core permeability recovery might be more than 90%, and the system anti-temperature could be up to 120℃. The results of application in Du 84 - Guanping 57 and other horizontal wells indicates that this drilling fluid system could increase drilling vilocity, protect the oil reservoir, has good rheology, very strong inhibition, and regular cuttings, that it could carry debris along very easy and keep the wellbore very clean well, and that that it is safe and not corrosive.
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