In an application of nitrogen unbalanced drilling technology and coiled tubing technology to one domestic oil field, integrated wellhead of drilling and well completion was adopted. Because of the large gas flow in the process of drilling and well completion, the high-speed flow carrying rock particles led to erosion of the wellhead and the decline of bearing capacity of wellhead, resulting in increasing risk of well control. This paper combines the erosion simulation and quantitative calculation to qualitatively and quantitatively investigate the gas flow characteristics of Y-type gas production wellhead and the relationship between the defect depth and time. Safety times in production for different Y-type gas wellheads are calculated to provide a theoretical basis for high pressure application of integrated wellhead. It is shown that under the same condition, erosion depth increases with gas production and decreases with the increasing wellhead pressure.

integrated wellhead of drilling and completion  /  gas-solid two-phase flow  /  Y-type gas integrated wellhead  /  erosion attack  /  quantitative calculation