Casing Polymer Patch for Loss Circulation Zone Isolation

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Solution Overview

Problem

In oil or gas well drilling, loss circulation zones lead to inadequate cementing, exposing the casing to formation fluids and risking corrosion, as drilling fluid and cement slurry leak into geological fractures, resulting in poor cementation and potential casing leaks.

Innovation Solution

A polymer patch system is integrated into the casing, featuring a polymer layer, elastomer seals, and an internal support to create an annulus, which is mechanically activated to displace the polymer against formation fractures, isolating the loss circulation zone and providing a flow path for cement slurry to ensure effective cementation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cement slurry is pumped through the annulus in the presence of a loss circulation zone, then cementing can be performed, but the cement does not adequately continue upward and the casing surface area receives inadequate or no cement

Engineering Contradiction:

Improvecementation qualityVSAvoidcement slurry loss

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The casing is divided into multiple sections with different properties: a first section with a first cement bond and a second section with a second cement bond. This segmentation allows each section to be cemented independently with appropriate cement slurry properties, ensuring adequate cementation in both sections while preventing cement slurry loss into the loss circulation zone.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A bridge plate or cement basket is deployed as an intermediary device in the loss circulation zone to block the fracture and redirect cement slurry flow. This intermediary structure prevents direct communication between the annulus and the formation fracture, allowing cement to be pumped effectively without loss into the formation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a top job or differential valve tool is used to cement through the loss circulation zone, then cement can be pumped to the zone, but the interval of exterior casing opposite the loss circulation zone receives inadequate or no cement

Engineering Contradiction:

Improvecasing protectionVSAvoidcement placement accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The cementing process is segmented into multiple stages with different objectives: first cementing the upper annulus to protect the casing, then addressing the loss circulation zone separately using a bridge plate or cement basket, and finally cementing the lower annulus. This segmentation ensures accurate cement placement in each zone without compromising overall casing protection.

Inventive Principle:

Principle #1Segmentation

3Productivity

If the casing is left uncemented in the loss circulation zone to allow cement flow, then cementing can proceed, but the casing is exposed to formation fluids and potential future corrosion risk

Engineering Contradiction:

Improvecementing efficiencyVSAvoidcorrosion risk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The loss circulation zone fracture, which initially causes cement slurry loss, is converted into a beneficial feature by using it as a pathway to deploy a bridge plate or cement basket. This deployment strategy transforms the harmful fracture into an opportunity to isolate the zone and ensure adequate cementation of the casing, ultimately eliminating corrosion risk while maintaining cementing efficiency.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 polymer patch system effectively isolates loss circulation zones, preventing cement from entering fractures and ensuring full or partial cement circulation to the surface, thereby reducing corrosion risks and extending casing life by maintaining a sealed annulus for cementation.

Implementation Method 1

A casing for a wellbore has a polymer patch disposed on an outer diameter (OD) of the casing and to be mechanically activated to radially displace polymer against a formation fracture

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

The polymer patch has the polymer to be radially displaced to isolate the formation fracture, elastomer seals to isolate the formation fracture

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 3

An internal support is disposed in the internal space to maintain the internal annulus between the polymer layer and the casing

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentUS10982499B2Casing patch for loss circulation zone

Publication Date: 2021.04.20 SAUDI ARABIAN OIL CO

AI summary

A polymer patch system and method associated with a casing to be installed in a wellbore. The polymer patch has a polymer layer and an internal space radially under the polymer layer to form an internal annulus between the polymer layer and an exterior surface of the casing. An internal support is disposed in the internal space to maintain the internal annulus between the polymer layer and the casing.