Rotatable Centralizer Helical Drive Cement Placement

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Solution Overview

Problem

In horizontal wellbores, the force of gravity causes casing strings to rest on the wellbore bottom, creating insufficient annular space for optimal cement bonding, and existing centralizers cannot effectively direct cement slurry to these areas, leading to suboptimal bonding and compliance issues with environmental regulations.

Innovation Solution

A positive cement placement tool with a rotatable centralizer and helical drive mechanism is used along the casing string, allowing for reciprocal stroking to rotate the centralizer in both directions, mechanically forcing the cement slurry around and along the casing string, ensuring adequate cement placement and bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cement slurry is injected into the annular space relying solely on fluid dynamics, then the cement takes the path of least resistance and travels along the open top and sides of the casing string, but this results in insufficient bonding at the bottom of horizontal or lateral sections

Engineering Contradiction:

Improvecement bonding qualityVSAvoidcement placement control

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

A rotatable centralizer with engagement elements (fins, paddles, or helical surfaces) is introduced as an intermediary mechanical component between the cement slurry and the casing string. This intermediary actively directs and forces the cement slurry to the bottom of the wellbore, overcoming the fluid dynamics limitation where cement would naturally follow the path of least resistance along the top and sides.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The centralizer is designed to be rotatable rather than fixed, allowing it to dynamically adjust its orientation and engagement with the cement slurry. The rotation can be driven by the flow of cement itself or by external means, enabling the centralizer to continuously direct cement in all directions around the casing string, ensuring complete coverage including the bottom areas.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If existing centralizers are used in horizontal wellbores to space the casing from the bottom, then the casing is positioned away from the wellbore bottom, but the centralizers cannot mechanically provide additional impetus to move cement slurry under the casing string

Engineering Contradiction:

Improvecasing positioningVSAvoidcement bonding at bottom

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent combines two functions into a single device: the centralizer's spacing function and the cement directing function. The rotatable centralizer with its engagement elements simultaneously maintains proper casing positioning and actively directs cement slurry to the bottom areas, eliminating the need for separate positioning and cement directing mechanisms.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The enhanced centralizer is designed as a multi-functional component that performs both spacing (positioning the casing away from the wellbore bottom) and active cement direction (mechanically forcing cement under the casing string). This universal device addresses multiple problems with a single solution, improving both ease of operation and bonding reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If the casing string rests on the wellbore bottom due to gravity in horizontal wellbores, then the annular space is insufficient for optimal cement bonding, but adding centralizers increases device complexity

Engineering Contradiction:

Improvecement bondingVSAvoidcentralizer structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Rather than making the entire centralizer structure complex, the patent applies local quality enhancement by adding specific engagement elements (fins, paddles, or helical surfaces) only to the portions of the centralizer that contact or direct the cement slurry. The basic centralizer structure remains simple for spacing, while localized features provide the active cement directing function.

Inventive Principle:

Principle #3Local quality

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 tool effectively directs and distributes cement slurry to previously under-bonded areas, enhancing cement bonding between the casing and wellbore, meeting regulatory requirements and improving downhole operation efficiency.

Implementation Method 1

a helical drive arrangement acting between the mandrel and the centralizer sleeve for actuating the centralizer sleeve along a length of the mandrel while rotating the centralizer sleeve thereabout

Methodology Applied

Scientific EffectHelical motion conversion: Helix

Data Source

PatentUS11021929B2Positive cement placement tool

Publication Date: 2021.06.01 SLURRY SOLUTIONS

AI summary

Cement slurry injected or delivered into a wellbore during cementing operations can be positively placed with a positive placement tool. The tool can be located along to a casing string and have a mandrel with a tubular centralizer sleeve rotatably fit thereabout, the centralizer sleeve having one or more radial guides extending longitudinally thereon. Reciprocal stroking of the casing string causes a helical drive arrangement, acting between the mandrel and the centralizer sleeve, to drive the centralizer sleeve longitudinally along a length of the mandrel while concurrently rotating the centralizer sleeve thereabout. The rotational movement of the centralizer sleeve provides positive impetus to force the injected cement slurry fully about the casing string.