Wellbore Cementing System with Shearing Substructure
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Solution Overview
Problem
The prolonged 'waiting-on-cement' (WOC) time in wellbore cementing processes delays well completion and increases costs, as cement slurry takes approximately 33 hours to thicken to the required compressive strength.
Innovation Solution
Incorporating capsules with accelerators like calcium dichloride and anhydrous sodium metasilicate into the cement slurry, which are broken by a rotating shearing substructure or turbulent flow, reducing the thickening time by releasing the accelerator and enhancing cement slurry thickening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cement slurry is used to form an isolation barrier in the wellbore, then the wellbore is protected and isolated, but the waiting-on-cement time is prolonged to approximately 33 hours
Solution Approach 1:
Accelerator capsules are pre-incorporated into the cement slurry before pumping. These capsules contain accelerators that will be released at the downhole location to speed up the thickening process, allowing the cement to reach required strength faster while maintaining reliable isolation barrier formation.
Solution Approach 2:
The chemical composition of the cement slurry is modified by adding accelerator capsules containing substances like calcium chloride or sodium metasilicate. These additives change the chemical parameters of the slurry to reduce thickening time from 33 hours to a shorter duration, while still achieving the required compressive strength for isolation.
2Loss of time
If accelerator capsules are incorporated into the cement slurry, then the thickening time is reduced, but the cement slurry composition is altered
Solution Approach 1:
The accelerator is divided into separate capsules rather than being mixed uniformly into the cement slurry. This segmentation allows the accelerator to remain isolated within capsules during pumping and transport, maintaining the stability of the base cement slurry composition while enabling rapid thickening when capsules are broken at the downhole location.
Solution Approach 2:
The capsules act as an intermediary carrier for the accelerator substance. They protect the accelerator from premature reaction with the cement slurry during mixing and pumping, while allowing controlled release at the target location. This intermediary approach reduces thickening time without fundamentally altering the base cement slurry composition.
3Loss of time
If a shearing substructure is used to break the capsules, then the accelerator is released to reduce WOC time, but the device complexity increases
Solution Approach 1:
The shearing substructure utilizes the natural turbulent flow and vibrational movements of the cement slurry during pumping and placement. Rather than requiring an active mechanical breaking mechanism, the system leverages the inherent mechanical energy and turbulence of the slurry flow to break the capsules, reducing device complexity while still achieving accelerator release and WOC time reduction.
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 significantly reduces WOC time without altering the cement slurry composition, ensuring consistent and rapid cement hardening, thereby accelerating well completion and reducing operational costs.
Implementation Method 1
The capsules include an accelerator. The accelerator reacts with the cement slurry to affect a thickening time of the cement slurry.
Implementation Method 2
The substructure is configured rotate to break at least some of the capsules in the cement slurry.
Implementation Method 3
The substructure may be configured rotate within the cement slurry to produce a turbulent flow within the cement slurry. The turbulent flow may have sufficient force to break at least some of the capsules.
Implementation Method 4
The capsules melt, at least partly, at a temperature of a region between the casing and a bottom of the wellbore.
Data Source
AI summary
An example wellbore cementing system includes a casing to line at least part of a wellbore, and a pipe to introduce cement slurry containing capsules into the wellbore. The capsules include an accelerator. The accelerator reacts with the cement slurry to affect a thickening time of the cement slurry. The example system also includes a substructure having shearing pins. The substructure is arranged to receive the cement slurry from the pipe. The substructure is configured rotate to break at least some of the capsules in the cement slurry.