Dissolvable Blocking Element for Casing Wiper Plug Integrity Testing

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Solution Overview

Problem

Current casing wiper plug systems for oilfield applications require additional equipment and pressure applications to access hydrocarbon formations, and lack a reliable method for testing the mechanical integrity of production casings after cementing.

Innovation Solution

A top wiper plug system with a dissolvable blocking element and rupture disks that allows for a mechanical integrity test by temporarily blocking the central bore, which is then dissolved to enable fluid flow, eliminating the need for tubing-conveyed perforation guns or toe sleeves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a closed top wiper plug system is used for cementing, then cementing operation is simplified, but access to hydrocarbon formation requires additional equipment (tubing conveyed perforation gun)

Engineering Contradiction:

Improvecementing operation simplicityVSAvoidequipment required for formation access

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The system is divided into functional segments: the wiper plug assembly for cementing, the dissolvable blocking element for temporary sealing, and the float shoe for formation access. This segmentation allows each component to perform its specific function independently, eliminating the need for additional tubing conveyed equipment.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The dissolvable blocking element acts as an intermediary that temporarily blocks the central bore during cementing operations, then dissolves to allow fluid communication. This intermediary component replaces the need for permanent mechanical barriers like perforation guns or toe sleeves.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If a toe sleeve or toe valve is installed to eliminate perforation guns, then formation access is improved, but system complexity and additional pressure applications are required

Engineering Contradiction:

Improveelimination of perforation gunVSAvoidpressure application requirements

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The dissolvable blocking element is designed as a temporary, disposable component that performs its sealing function during cementing then automatically dissolves. This eliminates the need for complex, reusable toe sleeves or valves that require multiple pressure applications for operation.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The mechanical system of toe sleeves and valves requiring pressure applications is replaced with a chemical dissolution mechanism. The blocking element dissolves through chemical interaction with formation fluids, eliminating the need for mechanical pressure cycling to open or close components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If a dissolvable blocking element is used to temporarily block the central bore, then mechanical integrity testing is enabled, but the blocking element must be sufficiently large to block but small enough to dissolve

Engineering Contradiction:

Improvemechanical integrity test capabilityVSAvoidblocking element dimension constraints

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The blocking element's physical parameters (size, dissolution rate) are optimized to meet dual requirements: large enough to effectively block the central bore for pressure testing, yet small and compositionally suited to dissolve at an appropriate rate. The diameter is specifically controlled to be larger than but no greater than 1.5 times the central bore diameter.

Inventive Principle:

Principle #35Parameter changes

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 enhances the reliability of cementing operations, improves flow efficiency, and allows for a direct mechanical integrity test without residual cement issues, ensuring reliable access to hydrocarbon formations post-cementing.

Implementation Method 1

a dissolvable blocking element configured to fit in the narrower end of the interior structure and seat to block the entry aperture of the central bore, where the blocking element is dissolvable by a solvent

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 2

a rupture disk for initially closing off the central bore, These disks are breakable by fluids or fluid pressure to open the respective bores of the plugs

Methodology Applied

Scientific EffectFracture: Fracture Mechanics

Data Source

PatentUS10260306B1Casing wiper plug system and method for operating the same

Publication Date: 2019.04.16 SUMMIT CASING SERVICES LLC

AI summary

The present casing wiper plug system and method includes a novel top wiper plug and a dissolvable blocking element. The top wiper plug includes a rupture disk and an open tail section configured and dimensioned to receive the dissolvable blocking element. The blocking element can be dissolved by a solvent and can dissolve quickly given the size or materials of the blocking element. When used in conjunction with a bottom wiper plug and a displacement fluid, the central bores of the top and bottom wiper plugs and shoe track provide an open passage to the formation allowing future injection or fracking fluid to access the formation. The blocking element is released into a seat of the open tail section to temporarily block the passage so a casing test can be performed on the casing. After the test is complete, the blocking element is dissolved to reopen the passage.