Drill Bit Performance Assessment Normalizing Rock Characteristics
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Solution Overview
Problem
The oil well drilling industry faces challenges in accurately comparing and selecting drill bit configurations due to natural variations in geological properties within rock formations, making it difficult to determine the most effective drill bit configuration for specific drilling conditions.
Innovation Solution
A method that assesses drill bit performance by determining performance parameters and rock characteristics at multiple points along the wellbore, normalizing performances based on rock characteristics, and applying weighting factors to account for varying rock types and drillability, allowing for a meaningful comparison of different drill bit configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If drill bit performance is compared using simple side-by-side comparison of measured rate of penetration or actual time taken, then the comparison process is simple and quick, but the comparison accuracy is low due to natural variations in geological properties
Solution Approach 1:
The patent transforms the assessment from using raw drilling parameters (rate of penetration, time taken) to using normalized performance metrics that account for rock characteristics. By changing the parameters from absolute measurements to relative performance indicators adjusted for geological variations, the system achieves accurate comparisons without requiring complex geological modeling at each comparison point.
Solution Approach 2:
The patent introduces rock characteristics as an intermediary factor between the drill bit configuration and the performance measurement. By using rock characteristics as a mediating variable, the system can normalize performance data across different geological conditions, enabling accurate comparisons while maintaining a relatively simple assessment framework.
2Reliability
If drill bit configurations are selected based on actual drilling results from field operations, then the selection is based on real-world performance data, but the results may be misleading due to variations in rock constitution between different drilling intervals
Solution Approach 1:
The patent extracts and isolates the effect of rock characteristics from the overall drilling performance data. By separating the geological variation component from the drill bit performance component, the system can eliminate the misleading influence of geological variations while preserving the reliable information about actual drill bit performance in real field conditions.
Solution Approach 2:
The patent performs preliminary normalization of performance data by accounting for rock characteristics before making comparisons or selections. By pre-adjusting the performance metrics to remove the influence of geological variations, the system ensures that subsequent drill bit selections are based on reliable, comparable data that reflects actual configuration performance rather than geological luck or misfortune.
3Productivity
If multiple drill bit configurations are tested in parallel wellbores to compare performance, then direct comparison data is obtained, but the comparison remains difficult due to differences in rock type proportion and rock strength between intervals
Solution Approach 1:
The patent creates an equipotential comparison framework by normalizing performance data across different geological conditions. By adjusting all measurements to a common reference level that accounts for rock characteristics, the system enables fair comparison of drill bit configurations drilled in parallel wellbores, even when they encountered different proportions of rock types and varying rock strengths.
Data Source
AI summary
There is disclosed herein a method for assessing the drilling performance of a drill bit configuration used to drill at least a portion of a wellbore in a formation, comprising: determining a value of at least one drill bit performance parameter at points along the wellbore, at least including at multiple points along an interval constituting at least part of the portion drilled using the drill bit configuration; determining rock characteristics for the interval; determining the drilling performance for said drill bit configuration in the interval based on the values for the drill bit performance parameter; and assessing the effectiveness of the drill bit configuration for drilling the interval based on the determined drilling performance and the determined rock characteristics. Also disclosed are related methods for comparing the performance of at least two different drill bit configurations; of designing a drill bit configuration for drilling at least part of a wellbore; for selecting a drill bit design for drilling at least part of a wellbore; and of well planning for drilling wells in a well field.