Extension and development direction of Mud Motor

1. Overview

Mud Motor is a positive displacement downhole dynamic drilling tool which is powered by drilling fluid and converts liquid pressure energy into mechanical energy. When the mud pumped by the mud pump flows through the bypass valve into the motor, a certain pressure difference is formed at the inlet and outlet of the motor, and the rotor is rotated around the axis of the stator, and the speed and torque are transmitted to the drill through the universal shaft and the drive shaft, so as to achieve drilling operations.

As the engine in oil drilling operation, Mud Motor play an extremely important role. Using Mud Motors can increase drilling speed, reduce the number of trips, accurately hit the target layer, reduce the adjustment control time. With the maturity and development of drilling technology, near-bit measurement system, real-time monitoring system of Mud Motor status, self-electric Mud Motor and twin-Mud Motor rotary steering system based on Mud Motor  have been gradually developed, so that the function of Mud Motor can be extended and developed on the basis of strong power.

2.Mud Motor type near bit measurement system

The near-bit measurement system measures inclination, temperature, gamma and rotational speed data at the position closest to the bit, and can be extended to increase bit weight, torque and other parameters. The traditional near-bit measurement is assembled between the bit and the Mud Motor, and the wireless short-pass technology is used to send the near-bit measurement data to the receiving nipple connected to the MWD at the upper end of the Mud Motor. Then the data is transmitted to the ground through MWD for detection.

The Mud Motor near bit measuring system has gamma and deviation measurement units built into the stator of the Mud Motor, and uses FSK single bus communication to connect the data with MWD, which greatly improves the reliability of communication. In addition, because there is no drill collar between the Mud Motor and the drill bit, the formation slope of the drill tool is not affected, and the risk of drill tool fracture is reduced, improving the safety of drilling. Mud Motor near bit measurement system, without changing the length of the original Mud Motor, integrates the dual functions of dynamic drilling and near bit measurement, so that the Mud Motor this heavy engine has a pair of “eyes”, providing power for the drilling project and indicating the direction.

3.self-electric Mud Motor technology

Self-electric Mud Motor, the use of Mud Motor rotor rotation, through the flexible shaft or fork structure to eliminate the rotor revolution and then connected to the generator to generate electricity, can provide power for MWD wireless drilling measurement system and Mud Motor near the bit measurement system, thus solving the waste and environmental pollution caused by the use of batteries.

4.Mud Motor status real-time monitoring system

Real-time monitoring system of Mud Motor status, install sensors in the parts where the Mud Motor is easy to fail, such as adding strain gauges at the thread of the upper end of the anti-drop assembly to detect whether the thread connection is loose. In addition, the timing measurement on the Mud Motor rotor can count the total time of the Mud Motor working in the underground, and it needs to be replaced in time when the use time of the Mud Motor is reached. At the same time, the speed measurement sensor is installed on the rotor of the Mud Motor, and the torque and pressure measurement sensor is installed on the transmission assembly to detect the working status of the Mud Motor in real time, so that the ground can understand the working status of the Mud Motor in the underground, which can provide data reference for the optimization design of the Mud Motor and the drilling process.