Wellbore Flow Model and Process Optimization for Gas-Lift Leakage Drilling for Shallow Shale Formations.

The shallow surface karst landform in the Nanchuan-China shale gas area, with developed caves and underground rivers, frequently lost circulation during the drilling operation. To solve the issue, first, according to the actual drilling engineering, this paper analyzes the geological factors and drilling and completion characteristics, optimizes the construction plan, and suggests a new technology for gas-lift leakage drilling based on double-wall drill pipes. Second, a distributed coupling improved Beggs-Brill gas-liquid-solid multiphase flow model is established.

pH Effect of Natural Gas Hydrate on X80 Steel Solid-Liquid Phase Scouring Corrosion.

In order to solve the problem of pipeline erosion-corrosion under acidic conditions with different CO contents of natural gas hydrate (NGH), the influence of different pH values on the erosion corrosion of X80 steel under dynamic conditions was studied. The erosion and corrosion behavior of X80 pipeline steel in multiphase flow (0.5% sand + 3% NaCl aqueous solution) at different pH was studied by rotating a cylindrical electrode apparatus combined with the electrochemical method in this paper.