Hydraulic Pump Control for Bore Drilling Directional Accuracy
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Solution Overview
Problem
Current bore drilling systems face difficulties in directional control, particularly in extended reach drilling, due to torsional oscillatory motion known as 'stick-slip' which can cause excessive stress and mechanical failures, and require high operator expertise for course corrections.
Innovation Solution
A hydraulic pump system with a closed loop oil-filled system and an orifice control system, operated by a control processor, is used to vary fluid flow and control the position of a main valve, allowing for precise directional control of the drill bit torque and damping of stick-slip oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a hydraulic pump system with closed loop oil-filled system and orifice control system is used, then directional control precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces traditional mechanical directional control systems with a hydraulic pump system controlled by a control processor. The control processor varies the rate of fluid flow through the hydraulic pump to control the position of a main valve, thereby controlling drill bit torque direction. This substitution of mechanical control with hydraulic-electronic control achieves higher precision while managing system complexity through integrated control architecture.
Solution Approach 2:
The patent employs a closed loop oil-filled hydraulic system with a hydraulic pump to provide precise directional control. The hydraulic system includes a main valve positioned by a control arrangement that varies fluid flow rate, enabling smooth and precise control of the drill bit torque vector. This hydraulic mechanism provides superior control precision compared to mechanical alternatives.
2Reliability
If continuous rotation of drill pipe is used to reduce stick-slip oscillations, then mechanical stress is reduced, but directional control capability deteriorates
Solution Approach 1:
The patent enables dynamic control of drill pipe rotation through the hydraulic pump system. The control processor can vary the hydraulic pump output to allow the drill pipe to rotate continuously when needed to reduce stick-slip oscillations, while simultaneously maintaining the capability to hold the drill pipe stationary for precise directional control. This dynamic adaptability resolves the contradiction between reducing mechanical stress and maintaining directional control capability.
Solution Approach 2:
The patent changes the operational parameters of the drill pipe rotation system through hydraulic control. By varying the hydraulic pump fluid flow rate, the system can transition between different rotational states (continuous rotation for stress reduction, stationary for directional control), allowing optimal parameter selection based on real-time drilling conditions to balance mechanical stress reduction and directional control capability.
3Measurement precision
If operator expertise is increased to handle course corrections, then drilling accuracy is improved, but ease of operation deteriorates
Solution Approach 1:
The patent implements a control processor that receives input signals and automatically varies the hydraulic pump fluid flow rate to control the main valve position and drill bit torque direction. This automated feedback control system maintains high drilling accuracy for course corrections while eliminating the need for high operator expertise, thereby improving ease of operation without sacrificing precision.
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
This solution enables more efficient and precise directional control, reducing operator expertise requirements and minimizing mechanical stress, allowing for smoother transitions between straight-through and course correction drilling modes.
Implementation Method 1
a hydraulic pump having an input shaft for receiving an input torque from a drill pipe and being connected in use to a drilling head; and a control arrangement for varying the rate of fluid flow through the pump
Implementation Method 2
an orifice control system operable to control the position of the main valve
Implementation Method 3
allowing for precise directional control of the drill bit torque and damping of stick-slip oscillations
Data Source
AI summary
Apparatuses are disclosed for providing directional control of bore drilling equipment. In an embodiment, the apparatus includes a hydraulic pump having an input shaft for receiving an input torque from a drill pipe and being connected in use to a drilling head. In addition, the apparatus includes control arrangement for varying the rate of fluid flow through the pump. The control arrangement includes a closed loop oil-filled system including the hydraulic pump and a main valve. Oil from the pump is routed through the main valve before returning to a pump input. In addition, the control arrangement includes an orifice control system which is operable to control the position of the main valve in response to an input signal from a control processor.