Wiper Plug CFD Simulation for Cement Placement Mixing Control
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Solution Overview
Problem
The challenge in cementing operations for oil and gas wells is the degradation of cement quality due to mixing with wellbore fluids, which requires a method to determine intermixing without a plug or with at least one plug, and the computational complexity of modeling a moving wiper plug in the casing complicates efficient simulation.
Innovation Solution
A cementing displacement simulator using a static mesh with expanding and shrinking cell portions to model the movement of wiper plugs, combined with computational fluid dynamics (CFD) to simulate fluid flow and mixing, allowing simulation on standard processing power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a moving mesh model is used to simulate wiper plug movement, then the simulation accuracy is improved, but the computational complexity and processing power requirements increase significantly
Solution Approach 1:
Instead of making the mesh move with the plug (moving mesh approach), the patent inverts the approach by keeping the mesh static and moving the plug through it. This allows standard computational grids to be used without the complexity of dynamic mesh regeneration, while still accurately tracking plug position and fluid displacement.
Solution Approach 2:
The patent uses a geometric representation (copy) of the wiper plug within the CFD model rather than simulating the actual physical plug. This simplified geometric model captures the essential displacement behavior without requiring complex physical modeling, reducing computational demands while maintaining simulation accuracy.
2Reliability
If plugs are used to separate cement and wellbore fluids, then cement quality is improved, but the complexity of determining intermixing and modeling plug behavior increases
Solution Approach 1:
The patent replaces complex mechanical plug models with a simplified geometric representation in the CFD simulation. This substitution captures the essential fluid displacement and separation behavior without requiring detailed mechanical properties of the plug, reducing modeling complexity while maintaining the ability to predict cement quality and intermixing.
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
Enables accurate simulation of cement placement and mixing on standard computing devices, reducing computational demands and improving the quality of cement bonds by minimizing fluid intermixing.
Implementation Method 1
A cementing displacement simulator using a static mesh with expanding and shrinking cell portions to model the movement of wiper plugs, combined with computational fluid dynamics (CFD) to simulate fluid flow and mixing
Data Source
AI summary
A wellbore servicing method comprising transporting a pump unit comprising a unit controller and pumping equipment to a wellsite. Executing a design process on the unit controller to determine a concentration of a wellbore treatment fluid at a wiper plug within an oilfield tubular. The design process utilizes a CFD model to generate a static mesh representative of the geometry of the oilfield tubular, locate the wiper plug within the static mesh, and determine a fluid velocity on each side of the wiper plug with flexible static mesh cells. The CFD model can generate a prediction of the concentration of the wellbore treatment fluids in response to the wiper plug reaching a target location within the oilfield tubular.