Abstract

A new fiber and gyro logging tool is designed to overcome magnetic field interference for open hole and cased wells in offshore oilfield applications. Fluxgate magnetometers are often used as a sensor in the conventional azimuth logging tool. However, magnetic field disturbance can cause inaccuracy. An inclinometer using fiber optic gyroscope is designed for well track measurement. Fiber optic gyroscope is used as azimuth sensor with data acquisition system based on DSP and FPAG in this inclinometer. Several tests are conducted and compared with the drill curve. Test results show that the tool is within the accuracy limit for engineering applications. The tool is unaffected by the magnetic field compared to traditional orientation logging and logging FOG orientation as the azimuth. The tool also can measure the attitude angle continuously so that it can guide the oil production operations by following continuous trajectory. The tool has potential to much broader application such as sonic flaw detector in combination, in the cement evaluation, well retest, cased damage detection and other engineering works. The tool also has to overcome operational limit when the wellbore temperature is above 75 C.

Keywords:
gyroscope, lefevre, attitude matrix, sensor, log analysis, imaging tool, orientation, application, upstream oil & gas, fgat
Subjects:
Formation Evaluation & Management, Information Management and Systems, Open hole/cased hole log analysis
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2014. International Society of Offshore and Polar Engineers
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