Drilling Fluid Sealing Composition: Seal Weight for Spurt Loss Control
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Solution Overview
Problem
Existing methods for quantifying the sealing capacity of drilling fluid particulates to prevent fluid loss into hydraulic fractures are inefficient and require multiple tests at varying concentrations, lacking a standardized parameter for comparison and determining the minimum concentration needed for effective sealing.
Innovation Solution
The use of 'seal weight', defined as the total weight of particulates required to seal a unit length of a hydraulic fracture entrance, as a constant parameter for comparing different sealing compositions and determining the minimum concentration needed to control spurt loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a very high concentration of sealing particles is used to control spurt loss, then sealing effectiveness is improved, but cost and limitation of drilling fluid effectiveness increase
Solution Approach 1:
The patent changes the parameter of sealing particle concentration from a trial-and-error approach to a calculated optimal value based on fracture geometry and particle properties. By using equations that relate fracture width, particle size, and concentration, the system determines the minimum required concentration rather than using excessively high concentrations, thus reducing cost while maintaining sealing effectiveness.
2Measurement precision
If multiple tests at varying concentrations are conducted to quantify sealing capacity, then measurement accuracy is improved, but time consumption and complexity increase
Solution Approach 1:
The patent extracts the essential parameters needed for sealing capacity quantification (fracture width, particle size, concentration) and formulates them into direct calculation equations. This eliminates the need for multiple iterative tests at varying concentrations, as the sealing capacity can be directly calculated from these extracted parameters, significantly reducing testing time while maintaining accuracy.
Solution Approach 2:
The patent creates a theoretical model (equation-based system) that copies or replicates the complex multi-concentration testing process through mathematical relationships. Instead of physically conducting multiple tests, the model allows sealing capacity to be determined through calculation based on fundamental parameters, saving time while preserving measurement precision.
3Reliability
If sealing particles much larger than clay particles are used, then sealing capacity is improved, but fluid loss control becomes more difficult
Solution Approach 1:
The patent applies local quality by using different particle sizes for different functions: larger sealing particles are concentrated at the fracture entrance where they are most effective for plugging, while smaller clay particles remain in the bulk fluid for suspension and lubrication. This spatial differentiation of particle functions optimizes sealing capacity while maintaining manageable fluid formulation complexity.
Data Source
AI summary
Determining a seal weight of a sealing composition for sealing a selected seal width and using the seal weight to compare different sealing compositions for sealing efficiency. The seal weight is also to be used to directly determine the minimum concentration of a sealing composition in drilling fluid for a desired level of spurt loss control in order to prevent losing drilling fluid into a hydraulic fracture.