Study On Anti - Collapse Inhibitor Of Water - Based Drilling Fluid And Its Action Mechanism

The inhibitor of water-based drilling fluids is a critical additive when drilling water-sensitive shale formation, it always an important research in drilling fluids technology. The most two common used inhibitor of drilling fluids are organic and inorganic inhibitors. This paper study on a cationic polymer inhibitor, and use this inhibitor as a main inhibitor to form a kind of inhibitive drilling fluid with the other additives.This paper based on the mechanism of common water-based drilling fluids inhibitor, presented a study on the cationic polymer inhibitor. The library use DMDAAC and AM to Synthesis a low hydration inhibitor called DAP by using solution polymerization. The best reaction condition is:the mole ratio is3:2, monomer concentration is20%, BPO concentration is0.8%, and the reaction temperature is55℃. Compared DAP with the other inhibitors potassium chloride, Octadecylamine, Potassium silicate and small cationic polymer JYG-02to evaluate their inhibitive performance, and evaluate its anti-high temperature, anti-salt, fluid loss control ability, the result prove that DAP not only have a good inhibitive performance, but also have good temperature resistance, salt resistance and fluid loss reducing ability.Used particle size analysis, X-ray diffraction analysis, and the analysis of drilling fluid’s inhibition to in-depth analysis the inhibitive mechanism of DAP:the DAP can get into the crystal layer gap to inhibit the shale hydration through electrostatic attraction.Based on the new inhibitor as the new inhibitor, cooperate with fluid loss additive, coating agent, lubricant and adding agents to form an inhibitive drilling fluid. The rolling recovery experiment and liner expansion experiment were conducted to evaluate its performance, the result prove that this drilling fluid has an excellent inhibitive property, and the other comprehensive performance evaluations show that it also has a good fluid loss reducing ability, rheological property, temperature stability, lubricity ability, salt tolerance and anti-pollution ability.