Positive Displacement Motor Condition and Performance Prediction Using Surface and Downhole Sensor Data

Abstract

Positive displacement motors (PDM) are utilized to drill deviated and horizontal sections and are a key technology for deep oil/gas and geothermal wells. The energy transferred at the drill bit is delivered from the drillstring and bottom hole assembly (BHA) components. Energy loss due to friction, wellbore problems (tight spots, poor hole cleaning, etc.), and damage to the drillstring reduce the energy delivered to the drill bit. As a result, there is a reduction in drilling efficiency and an increase in nonproductive time. Mud motor fatigue due to cycling loading significantly influences wellbore quality and drilling performance. This chapter aims to develop a framework using surface and downhole data to predict the condition and performance of mud motors. A systematic and automated approach to access data quality and operations recognition is a fundamental element in the study. The borehole trajectory is reconstructed by implementing the survey data with the corresponding generated forces acting on the drillstring. Mud motor operating efficiency is monitored by continuously evaluating the produced differential pressure, power efficiency, and modeled incremental torque produced from each drillstring element. The theoretical and actual torque produced from the motor and the drillstring is compared to establish a correlation with the measured sensor data.