Drillable Window Assembly for Multilateral Wellbore Geometry Control

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Solution Overview

Problem

Traditional multilateral wellbore construction methods are costly and inefficient, particularly in the unconventional frac market, as they require numerous operations and additional workover rig days, making them economically unviable compared to single wells.

Innovation Solution

A drillable window assembly with radially offset slots and a sidewall opening, combined with an exit assembly featuring radially offset keys, allows for simplified selective access to form lateral wellbores without the need for whipstocks or angled deflection devices, reducing the number of construction operations and costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional whipstock assembly and window milling methods are used to form multilateral wellbores, then wellbore geometry can be controlled, but construction cost and operational complexity increase significantly

Engineering Contradiction:

Improvewellbore geometry controlVSAvoidconstruction operations

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The casing is pre-cut with slots and openings at the desired window locations and orientations before the wellbore is completed. This preliminary preparation eliminates the need for complex whipstock assembly and window milling operations later, as the exit paths are already geometrically defined in the casing structure itself

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent extracts and removes the complex whipstock assembly and window milling equipment from the construction process. Instead, a simplified drillable assembly is used that can be easily inserted through the pre-formed openings in the casing, eliminating the need for these complex intermediate tools

Inventive Principle:

Principle #2Taking out (Extraction)

2Adaptability or versatility

If traditional multilateral wellbore construction methods are used, then lateral wellbores can be formed, but the number of construction operations and workover rig days increase

Engineering Contradiction:

Improvelateral wellbore formationVSAvoidconstruction operations

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The pre-cut casing structure serves multiple functions simultaneously: it defines the geometry of the window, provides structural support, and creates the exit path for lateral wellbores. The drillable assembly also serves multiple purposes by being inserted through the opening to both establish the lateral path and potentially provide completion functions

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

All preparatory work for creating lateral wellbore paths is performed in advance during casing installation. The slots and openings are cut at the exact locations and angles needed, eliminating the need for subsequent complex operations to create these pathways

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If whipstock assemblies and milling assemblies are used in multilateral junction construction, then window exits can be formed, but construction cost increases

Engineering Contradiction:

Improvewindow exit formationVSAvoidconstruction materials and equipment

Core Design Contradiction:

Ease of manufactureVSQuantity of substance

Solution Approach 1:

The patent replaces expensive, complex whipstock and milling assemblies with a simpler, disposable drillable assembly. The pre-cut casing eliminates the need for costly milling operations, and the drillable assembly can be easily inserted and discarded after serving its purpose of establishing the lateral wellbore path

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentUS11448041B2Drillable window assembly for controlling the geometry of a multilateral wellbore junction

Publication Date: 2022.09.20 HALLIBURTON ENERGY SERVICES INC

AI summary

Provided, in one aspect, is a drillable window assembly. The drillable window assembly, in this aspect, includes a first precut casing joint, the first precut casing joint including a first casing tubular having two or more radially offset slots along an interior surface thereof, and a second precut casing joint coupled to the first precut casing joint, the second precut casing joint including a second casing tubular having a sidewall opening formed therein. The drillable window assembly, as contained within this aspect, further includes an outer sleeve surrounding the sidewall opening in the second casing tubular.