Study on Nano Composite Cement Slurry System Suitable for Low Temperature Formation

Abstract

In order to solve the problems of borehole wall collapse and well leakage during drilling in low temperature formation, a new nano-composite cement-based grouting material system suitable for low-temperature formations has been developed. The effect of nano-Al2O3 on the performance and process of low-temperature silicate-thioaluminate composite cement slurry was studied by combining macroscopic test and microscopic analysis. Through the synergistic hydration effect induced by mixing ordinary Portland cement with sulphoaluminate cement, together with nano-Al2O3, antifreeze agent (EG), water reducing agent (JS-1), early strength agent (TEOA), a new composite cement slurry (NAC) was developed, an integrated analysis of scanning electron microscopy, X-ray diffraction and exotherm was used to observe and analyze the patterns of the low temperature process of NAC. The experiment concluded, at a low temperature of –9 ℃, the nano-composite cement cement (NAC) had good initial fluidity, with a pumpable period of 57 min, and 24 h compressive strength of 6.9 MPa. Research shows that NAC has the effect of 'right angle thickening' and the performance is superior at low temperature, which can meet the performance requirements of borehole wall protection and plugging in low temperature formation drilling.