Pages: 43-53

Abstract

Today, directional drilling of oil wells serves to increase the exploitation of underground oil reserves. Moreover, acquiring the exact knowledge of the spatial position by measuring the inclination and azimuth and finding the three-dimensional well coordinates for controlling the drilling path is a necessity actualized using the measurement while-drilling (MWD) tools including accelerometers and magnetometers, which are manufactured by the microelectromechanical systems (MEMS) technology. The microelectromechanical systems technology is a combination of microelectronics (electronic integrated circuits), micro-machining and complex mechanical systems. These sensors reduce energy consumption, costs, volume, and weight and improve reliability and speed. However, their measurement is erroneous and lacks adequate accuracy. Hence, the calibration of these sensors in addition to the calibration by the manufacturer is necessary for reducing these errors and improving the measurement accuracy. In this paper, 2 methods of calibrating the microelectromechanical accelerometer sensors are proposed. To this end, a mathematical model is developed for the accelerometer and the model parameters (the scale factor, bias, and misalignment) are determined using the least squares error method and the particle swarm optimization algorithm. The compliance between the output components of the accelerometer sensor and the actual acceleration components is a criterion for assessing the model parameters. According to the results, these methods yield models with fewer errors and improve the performance of the acceleration sensors.