Sidetrack Window Milling via Integrated Cement Retainer

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Solution Overview

Problem

Current sidetrack wellbore drilling methods require multiple trips downhole and utilize whipstocks with packers, which are costly and time-consuming.

Innovation Solution

A sidetracking assembly with a cement retainer and whipstock assembly, fluidically coupled to a drill string, allows for a single trip to plug and drill a sidetrack window by using pressure-activatable packers and anchors to set and anchor the cement retainer and whipstock, enabling the milling system to cut a window in the cased wellbore.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional whipstock with packer is used for sidetrack drilling, then the wellbore can be plugged and drilled, but multiple trips downhole are required which increases time and cost

Engineering Contradiction:

Improvedrilling efficiencyVSAvoidtrip time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The invention combines the cement retainer and whipstock assembly into a single integrated downhole tool that can be deployed in one trip. The cement retainer and whipstock are fluidically coupled and can be set sequentially using ball valves and fluid pressure, eliminating the need for separate trips to deploy each component independently.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The cement retainer is set first to plug the wellbore, creating a sealed environment. Then the whipstock assembly is anchored downstream of the cement plug before drilling begins. This preliminary sequencing of operations within a single trip eliminates the need for multiple trips to establish each component.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If traditional whipstock with packer is used, then the wellbore can be isolated, but the cost increases due to expensive packer components

Engineering Contradiction:

Improvewellbore isolationVSAvoidequipment cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention extracts the packer component from the traditional whipstock assembly and replaces it with a cement retainer that uses cement plugs and simple mechanical anchoring mechanisms. This eliminates the expensive elastomeric packer while maintaining wellbore isolation functionality through the cement plug created by the retainer.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The cement retainer uses a disposable cement plug instead of a reusable expensive packer. The cement plug serves its isolation function and then the whipstock can be anchored independently downstream, replacing the need for costly packer materials with simpler, cheaper cement and mechanical components.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Ease of operation

If multiple trips are made to deploy whipstock and packer separately, then each component can be installed, but operational complexity increases

Engineering Contradiction:

Improveinstallation simplicityVSAvoidoperational steps

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The cement retainer and whipstock assembly are merged into a single deployable unit with integrated fluid channels and ball valve mechanisms. This allows both components to be installed in one trip while maintaining the ability to set them sequentially using the same fluid pressure system, reducing operational steps despite the integrated design.

Inventive Principle:

Principle #5Merging (Combining)

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 method saves time and resources by allowing a single trip to plug and drill a sidetrack wellbore, reducing costs by eliminating the need for a whipstock packer and minimizing operational complexity.

Implementation Method 1

applying fluidic pressure at the cement retainer to expand the packer

Methodology Applied

Scientific EffectFluid pressure: Pressure Increase

Implementation Method 2

applying fluidic pressure at the whipstock assembly to expand the anchor

Methodology Applied

Scientific EffectFluid pressure: Pressure Increase

Data Source

PatentEP4018068B1Cutting a sidetrack window in a cased wellbore

Publication Date: 2023.03.29 SAUDI ARABIAN OIL CO

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AI summary

A sidetrack window (210) is cut in a cased wellbore (102) by disposing a sidetracking assembly (100) within the cased wellbore. A first ball (130) is deployed into a drill string (106) of the sidetracking assembly. The first ball leaves the drill string and lands on a ball seat (124) of a cement retainer (104) to block fluid outlet (125) of the cement retainer. Then, the cement retainer is set and a second fluid outlet (126) of the cement retainer is exposed. Cement is flowed through the drill string to the portion (150) of the cased wellbore downstream of the cement retainer to plug the portion of the wellbore. The whipstock assembly (102) is separated from the cement retainer. A second ball (131) is deployed inside the drill string to land on the seat (122) of the whipstock assembly to block a fluid outlet (113) of the whipstock assembly. The whipstock assembly is anchored in the cased wellbore and the milling system (108) is actuated to begin cutting the sidetrack window.