Oil reservoir gas injection development gas channeling judgment method and experimental device

The invention discloses a gas channeling judgment method for oil reservoir gas injection development and an experimental device. The judgment method comprises the following steps that well flow sampling is conducted on a production well on site; sampling well flow of the production well to carry out a long core displacement experiment; the method comprises the following steps: analyzing the gas injection pore volume multiple, pressure difference, flow velocity, yield and oil gas component composition of an injection end and an output end of long core displacement in a long core displacement experiment process, and marking that gas channeling occurs when the oil displacement efficiency is suddenly reduced and the gas-oil ratio is suddenly increased; and integrating an injection well monitoring result, a production well monitoring result and a long core displacement experiment result to form a chart for gas channeling judgment. The experimental device comprises a long core clamping main body, a high-pressure di