Selective Electrode Assembly for Directional Pulse Power Drilling
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Solution Overview
Problem
Pulse power drilling faces challenges in supplying sufficient power downhole to create high internal pressure for rock fracturing, with inefficient electrical transmission from the surface and high energy requirements for plasma creation in the formation.
Innovation Solution
A drill string configuration that converts hydraulic energy from drilling fluid flow into mechanical energy, which is then converted into electrical power using a downhole motor and generator, and conditioned for storage in capacitors before being discharged as high-voltage pulses to fracture rock, incorporating adjustable electrode assemblies for directional drilling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If electrical power is transmitted from the surface to downhole electrodes, then power can be supplied for rock fracturing, but transmission losses increase and electrical efficiency decreases
Solution Approach 1:
Instead of transmitting electrical power from the surface to downhole electrodes (conventional approach), the invention inverts the approach by generating electrical power at the downhole location using hydraulic energy from drilling fluid flow through a downhole motor and generator. This eliminates long-distance electrical transmission and associated losses, directly addressing the technical contradiction by improving energy efficiency while reducing transmission losses.
2Reliability
If high voltage pulses are applied to fracture rock, then rock fracturing effectiveness improves, but energy requirements increase
Solution Approach 1:
The system uses the drilling fluid flow itself (which is already present in the drilling operation) to drive the downhole motor and generate electrical power. This self-service approach means the system powers itself using the existing hydraulic energy, reducing additional energy requirements while maintaining effective rock fracturing through high-voltage pulse generation.
Solution Approach 2:
The invention changes the physical state and parameters of energy by converting hydraulic energy (fluid flow) into mechanical energy (motor rotation), then into electrical energy (generator output), and finally into high-voltage pulses for rock fracturing. This multi-stage parameter transformation allows efficient energy utilization while achieving the required fracturing effectiveness.
3Manufacturing precision
If directional drilling control is implemented through adjustable electrode assemblies, then borehole orientation precision improves, but device complexity increases
Solution Approach 1:
The electrode assembly is divided into multiple independently controllable electrode segments or groups. By selectively activating specific segments, the system can direct the electrical discharge and resulting rock fracturing to specific方位, enabling precise borehole orientation control without requiring complex mechanical steering mechanisms.
Solution Approach 2:
The invention introduces a control system that acts as an intermediary between the power generation system and the electrode discharge mechanism. This controller selectively directs electrical power to specific electrode groups, providing directional control for borehole orientation while keeping the physical electrode structure relatively simple and manageable.
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 approach reduces transmission losses, improves electrical efficiency, and enables effective rock fracturing with directional control, enhancing the drilling process by ensuring sufficient power is delivered to break rock from the inside and allowing for precise borehole orientation.
Implementation Method 1
converts hydraulic energy from drilling fluid flow into mechanical energy
Implementation Method 2
converted into electrical power using a downhole motor and generator
Implementation Method 3
conditioned for storage in capacitors before being discharged as high-voltage pulses
Implementation Method 4
repeatedly applies a high electric potential across the electrodes of an electrocrushing drill bit, which ultimately causes the surrounding rock to fracture
Implementation Method 5
discharged as high-voltage pulses to fracture rock
Data Source
AI summary
An apparatus comprises an electrode assembly positioned at a bottom end of a pulse power drill string to be positioned in a borehole formed in a subsurface formation. The electrode assembly comprises multiple electrodes, wherein at least a subset of the multiple electrodes is to periodically emit a pulse of an electrical discharge into the subsurface formation to drill the borehole. The electrode assembly comprises a controller configured to alter a direction of drilling of the borehole based on selection of the subset from the multiple electrodes, wherein an effective attribute of at least one electrode of the multiple electrodes is different than the effective attribute of other electrodes of the multiple electrodes, wherein the effective attribute comprises at least one of a shape and a size.