Speed Control Sub for Jet Drilling Hose Feed
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Solution Overview
Problem
Current methods for drilling lateral boreholes using high pressure jetting hoses face challenges with depth, inclination angles, and control due to the use of small diameter coiled tubing, which limits sensitivity and control over the feed-in rate, especially when transitioning to standard size coiled tubing reduces sensitivity further.
Innovation Solution
A speed control sub is introduced between the tubing and the jetting hose, which maintains and adjusts the pressure of the jetting fluid based on the force applied, providing a noticeable pressure change to the operator when the tubing feed-in rate exceeds the thrust-determined jetting rate, allowing for improved control over the tubing feed-in rate relative to the jetting nozzle penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard size coiled tubing is used to advance the jetting hose, then depth, strength, angle, and feed unit problems are reduced or eliminated, but sensitivity and control over the jetting hose feed-in rate are greatly reduced
Solution Approach 1:
A speed control sub is introduced as an intermediary device between the standard coiled tubing and the jetting hose. This sub includes a movable piston that responds to force changes from the hose, converting them into noticeable pressure changes in the jetting fluid that can be detected at the surface. The piston acts as a mechanical amplifier, translating small force variations from the flexible hose into large pressure signals detectable through the standard tubing, thus restoring measurement sensitivity despite using standard-sized tubing.
2Manufacturing precision
If the tubing feed rate is too fast, then the jetting nozzle path becomes erratic and the borehole is not straight, but if the tubing feed rate is too slow, then the jetting nozzle creates a cavity behind itself resulting in loss of forward thrust and a shorter borehole
Solution Approach 1:
The speed control sub provides real-time feedback to the operator about the relative speeds of tubing feed-in and jetting hose penetration. The movable piston automatically responds to force changes caused by speed mismatches, generating pressure signals that indicate whether the tubing is being fed too fast or too slow. This closed-loop feedback system enables the operator to maintain optimal feed rates for both borehole straightness and penetration efficiency.
3Measurement precision
If small diameter coiled tubing is used, then sensitivity and flexibility for controlling the feed-in rate are maintained, but depth limitations and requirement for additional tube-feeding units occur
Solution Approach 1:
The speed control sub serves as a mechanical intermediary that bridges the gap between standard coiled tubing and jetting hose dynamics. It allows the benefits of standard tubing (depth capability, strength) to be combined with the sensitivity characteristics previously only achievable with small diameter tubing, by converting hose movement into detectable pressure signals.
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
The speed control sub enhances the operator's ability to accurately gauge and control the tubing feed-in rate, ensuring the jetting hose penetrates the formation at a rate equal to its advancement, maintaining borehole straightness and increasing the effectiveness of lateral borehole formation.
Implementation Method 1
The speed control sub is configured to maintain the pressure of the jetting fluid flowing to the speed control sub at a predetermined level when a force between the speed control sub and the jetting hose is at a first predetermined level and to change the pressure of the jetting fluid flowing to the speed control sub from the predetermined level when the force between the speed control sub and the jetting hose increases from the first predetermined level
Implementation Method 2
The configuration of the nozzle is such that it contains more opening area in the rearward facing direction than the forward direction, resulting in a forward thrust on the nozzle that pulls the hose behind it as the lateral borehole is created
Data Source
AI summary
A jetting hose is conveyed downhole retracted on the end of a tubing string (coiled tubing) for jetting lateral boreholes from a main wellbore. The apparatus allows the operator to sense the speed at which the jetting hose and nozzle are penetrating the formation and adjust the coiled tubing feed-in rate accordingly, optimizing both the direction and length of the lateral borehole relative to the main wellbore.