Multiphase flow flowmeter in well and monitor method

The invention discloses a multiphase flow flowmeter in the well and a monitor method. The multiphase flow flowmeter in the well comprises an acquisition device in the well and a processing device on the ground. The acquisition device in the well comprises an optical fiber sound wave sensor, an optical fiber pressure sensor and an optical fiber temperature sensor. The optical fiber sound wave sensor, the optical fiber pressure sensor and the optical fiber temperature sensor are arranged on pipe wall at one side of a pipe in the well. A sound wave signal of the optical fiber sound wave sensor is transmitted to the processing device on the ground. A temperature signal of the optical fiber pressure sensor is transmitted to the processing device on the ground. A pressure signal of the optical fiber temperature sensor is transmitted to the processing device on the ground. The multiphase flow flowmeter in the well provided by the technical scheme of the invention is simple in structure design, convenient to operate, and suitable for on-site operation in an oil gas well. The multiphase flow flowmeter in the well can save work time, raise work efficiency, and and reduce the work time in the well, and manpower and material resources.