Hydrostatic Sliding Sleeve Actuation via Ball Seat Piston

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Solution Overview

Problem

Existing sliding sleeve systems for subterranean fracturing face variability in rupture disc burst pressures, leading to unintended sleeve shifting and inefficiencies in opening multiple sleeves in a predetermined order, especially when cement is present in the annulus.

Innovation Solution

A ball seat mechanism that shifts under differential pressure, integrating a piston with one side at tubing pressure and the other at atmospheric pressure, applies a net force to shift the sliding sleeve against a travel stop, ensuring sequential opening of ports for fracturing, even with cement in the annulus.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If rupture discs are used to control sleeve shifting pressure, then sleeves can be shifted at predetermined pressure values, but variability in burst pressure causes unintended sleeve shifting and reduces reliability

Engineering Contradiction:

Improvepredetermined pressure controlVSAvoidsleeve shifting accuracy

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

A ball seat mechanism acts as an intermediary between the ball and the sliding sleeve. The ball seat receives the ball, shifts under differential pressure, and then releases the ball to pass to the next sleeve. This intermediary mechanism provides controlled, sequential sleeve activation without relying on rupture disc burst pressure variability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system uses the incoming ball itself to trigger the pressure differential that shifts the ball seat. The ball blocks the flow path, building pressure behind it, which then shifts the ball seat to release the ball and open the port. Each component serves its own activation function without external intervention.

Inventive Principle:

Principle #25Self-service

2Device complexity

If a single ball is used to trigger multiple sleeves in sequence, then device complexity is reduced, but ensuring sequential opening in predetermined order becomes more difficult

Engineering Contradiction:

Improvenumber of activation mechanismsVSAvoidsequential sleeve opening control

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The activation mechanism is segmented into discrete stages: ball entry, ball seat shifting, ball release, and port opening. Each sleeve has its own ball seat positioned at different depths, creating natural segmentation that ensures sequential activation as the ball progresses downhole.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The ball seats are pre-positioned at specific depths along the tubing before the ball is dropped. This preliminary positioning ensures that as the ball falls, it encounters each ball seat in the predetermined sequence, automatically triggering sleeves in the correct order without requiring complex control systems.

Inventive Principle:

Principle #10Preliminary action

3Force

If atmospheric chambers are used on sliding sleeves, then pressure differential can shift the sleeve, but cement in the annulus prevents effective fracturing

Engineering Contradiction:

Improvepressure differential forceVSAvoidcement interference with fracturing

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The port is opened by shifting the sliding sleeve to expose a previously blocked fracturing port. This extracts the port opening function from the atmospheric chamber system and provides direct access to the formation, allowing fracturing fluid to bypass any cement in the annulus and enter the formation directly.

Inventive Principle:

Principle #2Taking out (Extraction)

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 enables reliable and controlled sequential shifting of multiple sliding sleeves, ensuring effective fracturing access regardless of cement presence, by leveraging pressure differentials to apply a consistent boost force for each sleeve, enhancing the precision and reliability of the fracturing process.

Implementation Method 1

one side of a piston formed onto the outside of the sliding sleeve there is still atmospheric pressure. Different sleeves have different rupture disc pressure ratings and in that manner the sleeves can be shifted in a hoped for predetermined order

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

tubing pressure to communicate to a formerly atmospheric chamber on one side of a piston integrated into the back side of the sliding sleeve

Methodology Applied

Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 3

providing a ball seat that shifts with applied differential pressure to release the ball to go further downhole to the next ball seat

Methodology Applied

Scientific EffectDifferential pressure: Pressure Gradient

Data Source

PatentUS8739879B2Hydrostatically powered fracturing sliding sleeve

Publication Date: 2014.06.03 BAKER HUGHES CO

AI summary

A series of sliding sleeves is actuated by a single ball that lands on a first ball seat and shifts the ball seat. The shifting of the ball seat also allows tubing pressure to communicate to a formerly atmospheric chamber on one side of a piston integrated into the back side of the sliding sleeve. The other side of the piston remains at atmospheric pressure so that the shifting of the ball seat not only releases the ball to go to the next ball seat but also puts a net force on the sliding sleeve to shift it against a travel stop to open a port to allow fracturing, even if there is cement in the annulus around the opened port.