Fabric-Nested Casing Cementing
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Solution Overview
Problem
Conventional cementing methods in wellbore operations often fail due to loss-of-circulation zones, leading to un-isolated open-holes and cement slurry loss, which compromises well integrity and requires costly remedial measures.
Innovation Solution
A fabric sheet is used to form a fabric-nested casing string within the wellbore, with a pre-cut center hole attached to a modified float joint, allowing cement slurry to inflate the fabric sheet against the wellbore, thereby ensuring cement containment and minimizing loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cementing methods are used, then cement slurry is pumped into the annulus, but cement loss occurs in loss-of-circulation zones leading to un-isolated open-holes
Solution Approach 1:
A flexible fabric sheet is used to create a nested casing structure that can conform to the wellbore geometry and contain cement slurry. The fabric sheet acts as a flexible barrier that prevents cement loss into loss-of-circulation zones while allowing the structure to adapt to varying wellbore conditions.
Solution Approach 2:
The fabric sheet is nested within the casing string, creating a nested structure where the fabric-containing cement system is placed inside the existing casing. This nested configuration allows cement to be contained and directed properly without requiring complete removal or replacement of the casing string.
2Reliability
If multi-stage cementing tools are used to introduce cement directly into the annulus, then cement placement is improved, but device complexity increases and un-cemented areas remain under the packer
Solution Approach 1:
The complex multi-stage cementing tool is replaced by extracting the cement containment function into a simpler fabric sheet system. The fabric sheet performs the containment and direction of cement without requiring complex mechanical tools, packers, or multiple staging mechanisms.
Solution Approach 2:
The fabric sheet serves as a temporary, disposable containment structure that is used during the cementing operation and then abandoned. This eliminates the need for expensive, complex, reusable multi-stage cementing tools while achieving the same cement placement objectives.
3Object-affected harmful factors
If low-density cement is used to avoid fracturing the formation, then formation damage is reduced, but cement containment and effectiveness are compromised
Solution Approach 1:
The fabric sheet acts as an intermediary between the cement slurry and the formation. It contains the cement slurry and directs it properly into the annulus, allowing the use of lower-density cement that would otherwise be lost, while still achieving effective cement placement without fracturing the formation.
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 effectively prevents cement loss in fractures, improves cement slurry displacement and circulation, and reduces operational costs associated with follow-up cementing operations.
Implementation Method 1
allowing cement slurry to inflate the fabric sheet against the wellbore, thereby ensuring cement containment and minimizing loss
Data Source
AI summary
A rig site may include a rotary table within a rig floor above a wellbore. A fabric sheet rolled into two symmetrical rolls is disposed on the rig floor. A pre-cut center hole of the fabric sheet is coaxial with the rotary table. A casing string, to be lowered in the wellbore, includes a first casing joint at a bottom of the casing string is a modified float joint. The pre-cut center hole of the fabric sheet is attached to a sleeve of the modified float joint. Union units are provided above the rotary table. The union units close the fabric sheet around the casing string to form a fabric-nested casing string within the wellbore. A cement slurry is pumped down the casing string and into a space between the fabric sheet and the casing string to cement the fabric-nested casing string to the wellbore.