Downhole Generator With Detachable Flow Controller
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Solution Overview
Problem
Conventional downhole generators for oil and gas exploration are difficult to maintain and replace, as their designs make it challenging to interchange flowgear or adjust flow rates without removing the entire generator from the drill string, leading to costly delays and inadequate power output.
Innovation Solution
A fluid-flow-driven generator with an annular power generation assembly and a detachable flow controller allows for the removal of parts without taking the entire generator out of the drill string, enabling easier maintenance and adjustment of flow rates, and providing a more stable and higher power output by relocating the magnet and coil assemblies to the outer circumference of the drill pipe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If conventional flow-based generator systems use turbine blades with central shaft and on-axis electrical generator, then power generation function is achieved, but retrieval and replacement of flowgear becomes extremely difficult or impossible during downhole operations
Solution Approach 1:
The generator is divided into separable modules: the flowgear assembly (turbine blades and stator) can be detached from the drive shaft and electrical generator components. This segmentation allows the flowgear to be retrieved independently through the drill pipe without removing the entire generator assembly, enabling easy replacement and maintenance of worn components.
Solution Approach 2:
The flowgear assembly is designed to be extractable from the generator housing through a retrieval port in the drill pipe. The turbine blades and stator can be pulled out individually for replacement without tripping the drill string, allowing maintenance personnel to access and replace flowgear components while the generator remains in-place in the wellbore.
2Productivity
If conventional generators require removal from tool string to change flowgear, then component replacement is possible, but drilling delays occur and capital asset investment increases
Solution Approach 1:
The generator system includes a retrieval port and associated mechanisms that enable the flowgear to be serviced in-place without requiring removal of the generator or tripping the drill string. Worn turbine blades and stators can be replaced using simple retrieval tools passed through the drill pipe, allowing the generator to continue operating immediately after component replacement and eliminating costly drilling delays.
3Power
If conventional generators are implemented within drill collar insert, then downhole power generation is achieved, but adequate power output and stability are not provided
Solution Approach 1:
The stator blades are designed with adjustable pitch angles that can be modified to optimize performance under varying drilling conditions. The ability to adjust stator blade angles allows the generator to maintain stable and adequate power output across different flow rates and operational scenarios, improving reliability and adaptability compared to fixed-geometry conventional designs.
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 design facilitates the replacement of generator components at the drilling site, reduces downtime, and provides a more consistent and higher electrical power output, addressing the limitations of conventional generators by allowing for part retrieval and adjustment without removing the entire generator, thus minimizing capital asset investments and operational delays.
Implementation Method 1
a fluid-flow-driven impeller coupled to one of a magnet assembly or an electrical coil assembly
Implementation Method 2
the magnet assembly and the coil assembly being arranged for magnetic coupling between them and being arranged to enable relative movement between them, such that fluid flowing past the impeller causes relative rotation between the magnet assembly and the coil assembly for the generation of electrical power
Data Source
AI summary
Apparatus is provided for use in power generation, including a fluid-flow-driven power generator for use in a fluid-containing pipe such as a drill pipe as used in oil and gas exploration and extraction. Parts of the generator are removable from the pipe—for example while a drill pipe is downhole within a drilling well—to leave a clear through bore for survey and fishing operations and to enable replacement of the removed parts. The flow-driven generator comprises an impeller connected to a magnet assembly to rotate the magnet assembly when fluid flows past the impeller. This causes relative movement between the magnet assembly and an adjacent electrical coil assembly, the relative movement and magnetic coupling generating an electrical current in the coil assembly. This generated electrical current is used to power electrical devices within the pipe.