Inflatable Slurry Plug for Lost Circulation Zone Sealing

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Solution Overview

Problem

Lost circulation zones in wellbores, characterized by fractures that prevent the return of drilling fluid and interfere with cementing operations, pose challenges in maintaining hydrostatic pressure and solidifying cement slurry.

Innovation Solution

An inflatable device is positioned near the lost circulation zone, filled with slurry that expands into fractures, sets to form a solid, and is drilled through, leaving the solid to seal the fractures and restore circulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If drilling fluid is introduced into the wellbore to maintain hydrostatic pressure, then the lost circulation zone causes fluid escape into fractures, but this prevents return of drilling fluid to surface and interferes with cementing operations

Engineering Contradiction:

Improvecirculation reliabilityVSAvoidfluid loss into fractures

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the harmful effect by removing the connection between the wellbore and fractures through cement plugs and LCM pills. These materials are introduced to block the fracture pathways, effectively taking out the lost circulation zone from the active drilling system, allowing normal circulation to resume in the remaining wellbore sections.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses intermediary materials such as lost circulation material (LCM) pills and cement plugs that act as mediators between the drilling fluid and the fractures. These intermediaries block the fracture entrances, preventing direct fluid escape while allowing the drilling operation to continue. The cement slurry serves as an intermediary that hardens to create a permanent barrier.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If cement slurry is introduced to seal fractures, then cementing operations are attempted, but formation fluids mix with the slurry and prevent hardening

Engineering Contradiction:

Improvecement hardeningVSAvoidfluid mixing with cement slurry

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by introducing LCM pills and cement plugs before the main cementing operation. These preliminary materials block the fracture pathways and isolate the formation fluids, creating a barrier that prevents mixing with the subsequent cement slurry. This preliminary isolation allows the cement to harden properly without interference from formation fluids.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses cement plugs and LCM pills as intermediary barriers between the formation fluids and the cement slurry. These intermediaries are introduced first to seal off the fractures, preventing direct contact between formation fluids and the cement slurry, thereby allowing the cement to set and harden without interference.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If lost circulation material pills and cement plugs are injected to cure the zone, then attempts are made to block fractures, but the complexity of multiple injection attempts increases

Engineering Contradiction:

Improvelost circulation cureVSAvoidmultiple injection attempts

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into a single integrated system. The inflatable balloon is combined with slurry containment and expansion capabilities, allowing simultaneous fracture isolation, material delivery, and sealing in one operation. This consolidation reduces the need for multiple separate injection attempts and simplifies the overall curing process.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces dynamics by using an inflatable balloon that can be expanded and contracted as needed. The balloon is inflated to block the fracture, the slurry is injected, then the balloon is deflated and removed. This dynamic approach allows the system to adapt to different fracture conditions and enables a single operation to replace multiple static injection attempts.

Inventive Principle:

Principle #15Dynamics

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 method effectively isolates fractures, prevents fluid escape, and allows for continued drilling by sealing the lost circulation zone, ensuring the return of drilling fluids and supporting cement hardening.

Implementation Method 1

forcing slurry into the inflatable to cause at least part of the inflatable containing the slurry to expand into the fracture

Methodology Applied

Scientific EffectElastic expansion: Elasticity

Implementation Method 2

allowing the slurry to set for a period of time to produce a solid

Methodology Applied

Scientific EffectSetting reaction: Phase Change

Data Source

PatentUS11236581B2Curing a lost circulation zone in a wellbore

Publication Date: 2022.02.01 SAUDI ARABIAN OIL CO

AI summary

An example method of forming a well includes identifying a lost circulation zone in a wellbore, where the lost circulation zone includes a fracture in a formation adjacent to the wellbore; arranging an inflatable in a vicinity of the lost circulation zone; forcing slurry into the inflatable to cause at least part of the inflatable containing the slurry to expand into the fracture; allowing the slurry to set for a period of time to produce a solid; and drilling through the solid in the inflatable in the wellbore, leaving the solid in the fracture.