Downhole Scraper With Onboard Power And Counter-Rotating Blades
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Solution Overview
Problem
Current debris removal tools face challenges in low-pressure formations, including fluid loss, operational issues due to sand buildup, and limitations in small diameter wells, with existing systems either not suitable for continuous flow or proper positioning, especially in deviated wells where gravity is insufficient for advancing bottom hole assemblies.
Innovation Solution
A downhole tubular scraper run on slickline with an onboard power supply, featuring counter-rotating scrapers or an anchor with single rotating scrapers, utilizing a modular design for continuous fluid circulation and centrifugal separation, and a drive system for counter-rotating motion, along with a control system for efficient operation and debris capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pressurized fluid circulation is used to remove debris, then debris removal effectiveness is improved, but fluid loss into low pressure formation occurs due to hydrostatic pressure
Solution Approach 1:
The patent changes the physical parameter of the circulating medium from liquid to foam. Foam has significantly lower density than liquid, reducing the hydrostatic pressure exerted on the formation. This allows continuous circulation for effective debris removal without causing fluid loss into low-pressure formations, as the reduced hydrostatic head eliminates the driving force for formation influx.
2Loss of substance
If foam is used instead of liquid circulation, then fluid loss is reduced, but specialized equipment cost and logistics complexity increase
Solution Approach 1:
The system generates foam in-situ downhole using a foam generator that mixes gas and liquid phases locally. This eliminates the need for complex surface foam generation equipment and extensive logistics for transporting specialized foam systems to remote well sites. The foam is produced on-demand where needed, simplifying the overall system while maintaining the benefits of reduced fluid loss.
3Adaptability or versatility
If tools are made small for use in small diameter wells, then adaptability to small wells is improved, but debris capture effectiveness may be reduced
Solution Approach 1:
The debris removal tool is designed as a modular segmented system with multiple debris capture chambers arranged in series. This segmentation allows the tool to maintain a compact overall diameter suitable for small wells while providing multiple capture zones that collectively achieve effective debris removal. The segmented design optimizes the balance between tool size and debris capture capability.
4Reliability
If continuous fluid circulation is implemented, then sand entrainment is improved, but energy consumption increases
Solution Approach 1:
The system employs periodic reciprocating motion of the pump rather than continuous operation. During the upward stroke, fluid is pumped to entrain sand; during the downward stroke, the system allows passive flow or reduced pumping. This periodic action maintains adequate sand entrainment while significantly reducing overall energy consumption compared to continuous circulation, optimizing the balance between reliability and energy use.
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 effective sand capture and continuous debris removal in small diameter wells, reduces trips to the surface, and facilitates advancement through deviated wells by using onboard power and centrifugal force, improving operational efficiency and reducing the risk of tool sticking.
Implementation Method 1
Other features that maintain fluid velocity to keep the sand entrained and further employ centrifugal force in aid of separating the sand from the circulating fluid
Data Source
AI summary
A downhole tubular scraper is run in on slickline with an on board power supply. It features counter-rotating scrapers without an anchor in one embodiment or an anchor with single rotating scrapers. The scraper is selectively operated to conserve power in the power supply. A drive system uses a single driver to obtain counter-rotating motion in the scrapers.