DC Bus Fluid Extraction System with Independent Motor Speed Control
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Solution Overview
Problem
Conventional fluid extraction systems using AC power for electric submersible pumps in oil and gas mining are costly due to the need for multiple VSDs and extensive cable infrastructure, and they lack the ability to operate multiple pumps at independent speeds, which hampers well productivity.
Innovation Solution
A fluid extraction system utilizing a DC bus to power multiple electric machines with independently controlled rotational speeds through a control sub-system that adjusts phase current supply to phase windings, allowing each machine to operate at different speeds without the need for multiple VSDs or extensive AC power cables.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple VSDs and separate power cables are used for each ESP to enable independent speed control, then each ESP can operate at its own speed to increase well productivity, but the system cost increases significantly due to extensive cable infrastructure and multiple VSDs
Solution Approach 1:
The patent combines multiple ESP drives into a single VSD unit that can control multiple motors simultaneously. The power cables are also merged into a single cable that carries power to all ESPs. This consolidation reduces the overall system cost by eliminating redundant VSDs and cable infrastructure while maintaining the capability to control each ESP's speed independently through the shared VSD.
Solution Approach 2:
The single VSD is designed to perform multiple functions by controlling multiple ESPs simultaneously. Each ESP can be operated at different speeds independently, allowing the system to optimize productivity for different well sections. The power cable also serves a universal function by delivering power to all ESPs through a single infrastructure.
2Device complexity
If a common VSD is used to control multiple ESPs, then the system cost is reduced by using fewer VSDs and cables, but all ESPs must operate at the same speed which fails to optimize well productivity
Solution Approach 1:
The single VSD is segmented into multiple independent control channels, each capable of controlling a specific ESP at a different speed. This segmentation allows the VSD to function as multiple independent drives would, enabling each ESP to operate at its optimal speed for maximum productivity while still using a single consolidated VSD unit and power cable infrastructure.
3Ease of operation
If AC power is used to supply multiple ESPs, then each ESP can be controlled independently, but the cable infrastructure becomes extensive and costly due to the need for multiple conductors for three-phase AC power
Solution Approach 1:
The patent extracts the VSD function from the power distribution system and consolidates it into a single unit. By converting to a single-phase or reduced-conductor configuration fed by one VSD, the cable infrastructure is simplified. The extraction of the multi-phase AC requirement and replacement with a simpler power delivery method reduces the number of conductors needed while maintaining independent control capability through the VSD's internal architecture.
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 reduces the overall cost of the extraction system by using fewer conductors and enables optimal well productivity by allowing each electric machine to operate at its optimal speed, independent of others, improving reliability and efficiency.
Implementation Method 1
an electric machine configured to aid in the extraction of a fluid from a well, where the electric machine includes at least a plurality of phase windings and a rotor
Data Source
AI summary
A fluid extraction system is presented. The fluid extraction system includes a direct current (DC) bus and a plurality of fluid extraction sub-systems configured to be electrically coupled to the DC-bus. At least one fluid extraction sub-system includes an electric machine configured to aid in the extraction of a fluid from a well. The electric machine includes a plurality of phase windings and a rotor. The at least one fluid extraction sub-system further includes a control sub-system to control a rotational speed of the rotor by selectively controlling a supply of a phase current to the plurality of phase windings such that the rotational speed of the rotor of the electric machine is different from rotational speed of a rotor of another electric machine in at least one of other fluid extraction sub-systems. Related method for controlling rotational speeds of electric machines is also presented.