| In petroleum exploration and development process, ensure borehole stability is a prerequisite for successful completion of drilling operations. Drilling fluid is one of the key factors influencing the wellbore stability, therefore, development better anti-collapse of drilling fluid system to maintain wellbore stability, improved drilling and reservoir protection is of great significance.Through the borehole instability mechanism and control method to prevent borehole collapse analysis, analysis of mechanical, physical and chemical factors and factors on the effect of borehole collapse of drilling engineering, drilling fluids, measures needed to prevent borehole collapse. Describes the common types of polymer anti-sloughing drilling fluids and anti-collapse inhibitor, anti-collapse mechanism and influencing factors, propose technical measures to optimize polymer anti-sloughing drilling fluid properties.This paper optimizing rheological properties and anti-collapse properties of anti-sloughing inhibitors, according to the use of polymer mud experience, choose an original recipe. Based on this formula, adjusted and optimized suppression of anti-sloughing agent types and increase the volume of drilling fluid rheological, filtration, collapse of best fit. Through a series of laboratory selection experiments, finalization of low solids polymer anti-caving drilling fluid formula is: 4% bentonite slurry(soil)+3% soda +0.1% PHPA +0.1%K-HPAM +0.5%K-HPAN+0.5%CMC. Finally, Zhuang 3 evaluation of the drilling fluid system, comprehensive evaluation showed that:The drilling fluid system, resistance to clay, salt, calcium pollution ability, can effectively suppress drilling dust dispersion, achieving low solids drilling fluids, sloughing and well compatibility with the formation. Other polymers are commonly used in the formulation of additives, simple preparation process, adaptable, easy to maintain, compared to ordinary polymer anti-caving drilling fluid has been greatly improved. |
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