Downhole Motor Assembly for Lateral Drilling Direction Control
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Solution Overview
Problem
Current lateral hole drilling methods face challenges in accurately controlling the direction and radius of curved holes, especially in soft formations, and managing cuttings during the drilling process, leading to inefficiencies and potential overgauge drilling.
Innovation Solution
A system comprising a motor assembly with a rotating torque generator and axial thruster, connected to a drill string via a dual or rotary transmission configuration, allowing for precise control of drilling direction and radius through angled and straight modes, and an adaptive cuttings management system using a fluid communication channel and downhole filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a steerable motor with bent drill pipe is used to drill curved holes, then the drilling direction can be controlled, but the effective radius of the curved hole becomes larger than the command radius in soft formations
Solution Approach 1:
The system dynamically switches between angled mode (for direction control) and straight mode (for radius control). The steerable motor can operate in angled mode to establish the desired drilling direction, then switch to straight mode to maintain a precise command radius, thereby resolving the contradiction between direction control and radius precision in soft formations
Solution Approach 2:
The system changes operational parameters by switching between two distinct modes: angled mode where the drill pipe is held at an angle to control direction, and straight mode where the drill pipe is kept straight to control radius. This parameter switching allows the system to achieve both direction control and radius precision that cannot be achieved in a single mode
2Measurement precision
If the drill string is pulled out to change stabilizer position for direction control, then the drilling direction can be adjusted, but the drilling process is interrupted and time is lost
Solution Approach 1:
The stabilizer system is made dynamic and adjustable during drilling operations. Rather than requiring the drill string to be pulled out to reposition stabilizers, the system allows stabilizer positions to be changed in situ, enabling continuous drilling while adjusting direction control parameters
Solution Approach 2:
The drill string assembly is designed with multi-functional capabilities where stabilizers can serve both as positioning elements and as adjustable direction control mechanisms. The ability to reposition stabilizers without removing them from the hole allows the same component to perform multiple functions: maintaining hole stability and controlling drilling direction
3Device complexity
If a single connector transmits both axial force and rotating torque to the drill pipe, then the system is simpler, but the control over drilling mode (angled/straight) is less flexible
Solution Approach 1:
The transmission system is segmented into separate functional components: one connector for transmitting axial force and another for transmitting rotating torque. This segmentation allows independent control of axial and rotational parameters, enabling flexible switching between angled and straight drilling modes while maintaining manageable system complexity through modular design
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise control of drilling direction and radius, reducing overgauge issues and improving cuttings management, enhancing drilling efficiency and accuracy.
Implementation Method 1
a motor to generate a rotating torque
Implementation Method 2
an axial thruster to generate an axial force
Implementation Method 3
The connector provides a fluid communication channel between the motor assembly and an inside of the drill pipe
Data Source
AI summary
A system for drilling a lateral hole departing from a main well. The system comprises a motor assembly (415) including a motor (412) to generate a rotating torque, an axial thruster (411) to generate an axial force, a blocking system (410) to fix the motor and the axial thruster downhole. The motor assembly further includes a drive shaft (414) to transmit the rotating torque. The system further comprises a first and second connector (402, 404) for transmitting the rotating torque and the axial force from the motor assembly to a drill string assembly. The first connector is connectable to the drill string assembly so as to transmit the axial force only to the drill pipe (401), and to transmit the rotating torque to a further drive (405) shaft positioned within the drill pipe. The second connector (402) is connectable to the drill string assembly so as to transmit both the axial force and the rotating torque to the drill pipe (401).