Real-Time Cement Slurry Thickening Time Control
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Solution Overview
Problem
The existing methods for designing cement slurries in well cementing are inefficient and rely on trial and error, with thickening time being difficult to predict due to variations in temperature and composition, leading to excessive safety margins and operational challenges in achieving the desired thickening time.
Innovation Solution
A system and method that utilize a thickening time model to calculate the required concentration of retarders and accelerators in real-time based on downhole temperature, pressure, and slurry composition, allowing for precise control of thickening time during cementing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trial and error approach is used to design cement slurry, then satisfactory placement and mechanical properties can be achieved, but the process is time consuming and complex
Solution Approach 1:
The patent applies preliminary action by pre-establishing a thickening time model that incorporates the effects of temperature, pressure, and slurry composition on cement thickening behavior. This model allows engineers to predict thickening time and optimize slurry design before actual cementing operations, eliminating the need for time-consuming trial and error testing while ensuring reliable placement and mechanical properties.
2Reliability
If multiple cement slurries with varying additives are tested, then the correct slurry can be selected, but the process becomes complex and requires excessive safety margins
Solution Approach 1:
The patent applies parameter changes by using a thickening time model that quantifies the relationships between temperature, pressure, slurry composition, and thickening time. This allows engineers to predict the behavior of cement slurries under specific downhole conditions without requiring extensive testing of multiple formulations, thereby simplifying slurry selection while maintaining reliability through accurate parameter-based predictions.
3Productivity
If thickening time is extended to ensure adequate pumping time, then pumping can be completed, but non-productive wait time increases
Solution Approach 1:
The patent applies dynamics by implementing a real-time thickening time model that continuously monitors downhole temperature and pressure conditions and dynamically adjusts thickening time predictions. This allows for optimized slurry design that provides adequate pumping time under actual downhole conditions without excessive safety margins, thereby reducing non-productive wait time while ensuring complete pumping operation.
4Manufacturing precision
If regional variations in cement components are accounted for, then accurate slurry design can be achieved, but the selection process becomes more complicated
Solution Approach 1:
The patent applies parameter changes by incorporating regional variations in cement components as specific parameters within the thickening time model. The model accounts for differences in slurry composition from different regions by adjusting the relevant compositional parameters, allowing for accurate slurry design tailored to specific regional conditions without complicating the selection process through extensive testing or comparison of multiple formulations.
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 approach enables real-time optimization of cement slurry viscosity, reducing non-productive wait times and overall rig time, while minimizing the use of retarders and accounting for dynamic temperature profiles, thus improving the efficiency and accuracy of cement placement.
Implementation Method 1
a cement slurry may be pumped into an annulus between the walls of the well bore and the exterior surface of the pipe string disposed therein. The cement slurry may set in the annular space, thereby forming an annular sheath of hardened, substantially impermeable cement
Data Source
AI summary
A method of cementing may include: measuring a feeding rate of water and a feeding rate of cement blend into a cement blender; calculating a cement retarder feeding rate and/or an accelerator feeding rate using a thickening time model, wherein the thickening time model uses at least a thickening time requirement, the feeding rate of water, and the feeding rate of cement blend, to calculate the cement retarder feeding rate and/or the accelerator feeding rate; introducing a cement retarder at the cement retarder feeding rate and/or an accelerator at the accelerator feeding rate into the cement blender; mixing at least the water, cement blend, and at least one of the cement retarder and/or the accelerator in the cement blender to provide a cement slurry; and placing the cement slurry in a wellbore.