Near-bit tool attitude measurement while drilling apparatus and method

US10202841B2 · kind B2 · utility

Assignee

• Institute of Geology and Geophysics, Chinese Academy of Sciences · CN

Inventors

• Wenxiu Zhang · Beijing, CN
• Qingyun Di · Beijing, CN
• Wenxuan Chen · Beijing, CN
• Yongyou Yang · Beijing, CN
• Yuntao Sun · Beijing, CN
• Jian Zheng · Beijing, CN
• Jianguang Liu · Changde, CN

Key dates

• Filing date: Aug 29, 2017
• Grant date: Feb 12, 2019
• Expiry date: Sep 14, 2037

Classification

• Technology area (CPC E): Fixed Constructions
• CPC primary: E21B17/16
• WIPO field: Civil engineering
• WIPO sector: Other fields

Abstract

A near-bit tool attitude MWD apparatus includes measurement sensors and a measurement circuit. The measurement sensors transmit measured signals to the measurement circuit, and the measurement circuit processes and calculates the signals to obtain attitude data. The measurement sensors include a triaxial accelerometer, a triaxial gyroscope, a triaxial magnetic sensor and a temperature sensor, the measured data of the triaxial accelerometer, the triaxial gyroscope and the triaxial magnetic sensor are respectively corrected using the measured data of the temperature sensor, a first attitude angle is calculated using the corrected measured data of the triaxial accelerometer and the triaxial magnetic sensor. Quaternions are initialized using the first attitude angle, and the initialized quaternions are subjected to time updating according to the measured data of the triaxial gyroscope, and further an attitude angle is calculated utilizing the updated quaternions. The quaternions are periodically initialized to eliminate cumulative errors of the triaxial gyroscope, so as to improve the near-bit tool attitude MWD accuracy.