Borehole Transit Time Estimation via Drilling Parameter Correlation
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Solution Overview
Problem
Current methods for determining the transit time of drilling fluid in a borehole are inaccurate due to reliance on estimated borehole geometry and do not account for unexpected phenomena like cavings, which can alter the borehole size.
Innovation Solution
A method and system that measure and compute transit time by analyzing signals from drilling parameters at the borehole bottom and exit, characterizing correlations between these signals to determine a shift, allowing for real-time estimation of transit time without requiring human intervention or specific markers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If theoretical transit time is calculated based on estimated borehole geometry, then the calculation is simple, but the accuracy is low due to unexpected phenomena like cavings that alter borehole size
Solution Approach 1:
The patent applies feedback by continuously monitoring drilling parameters (standpipe pressure, flow rate, mud weight) and using this information to iteratively correct the theoretical transit time model. The system compares measured parameters with model predictions and adjusts the model to match actual borehole conditions, thereby improving accuracy while maintaining the simplicity of theoretical calculations.
Solution Approach 2:
The patent changes parameters by transitioning from static estimated borehole geometry to dynamic parameter monitoring. It measures multiple drilling parameters (pressure, flow rate, mud weight) that vary over time and uses these changing parameters to calculate transit time, allowing the system to adapt to borehole geometry changes caused by cavings or other phenomena.
2Measurement precision
If markers are injected in the drilling fluid to determine transit time, then the measurement is direct, but the device complexity increases
Solution Approach 1:
The patent applies self-service by using the drilling fluid and drilling operations themselves to provide the measurement function. Instead of injecting external markers, the system uses naturally occurring variations in drilling parameters (pressure, flow rate, mud weight) that occur during normal drilling operations to determine transit time. The drilling process itself generates the signals needed for measurement.
Solution Approach 2:
The patent uses drilling parameters (standpipe pressure, flow rate, mud weight) as intermediaries to measure transit time. These parameters serve as mediators that connect the drilling operations at the bottom of the borehole with measurements taken at the surface, allowing indirect measurement of transit time without requiring direct marker injection or complex tracking systems.
3Extent of automation
If automatic transit time estimation is implemented using drilling events, then human intervention is eliminated, but the algorithm complexity increases
Solution Approach 1:
The patent replaces mechanical/manual transit time determination with an automated computational system. Instead of manual calculations or physical marker tracking, it uses computer algorithms to process drilling parameter signals, automatically detect drilling events, calculate time shifts, and determine transit time. This substitutes mechanical operations with computational processes.
Solution Approach 2:
The patent applies preliminary action by pre-processing the drilling parameter signals to identify drilling events before calculating transit time. The system continuously monitors and stores drilling parameters, pre-identifies characteristic events (such as changes in pressure or flow rate patterns), and prepares the data structure needed for rapid transit time calculation when required.
Data Source
AI summary
The disclosure relates to a method for estimating a transit time of an element circulating in a borehole during the drilling of the borehole. The transit time is representative of a time period for the element to move from the bottom of the borehole to its exit at the surface. The method comprises measuring a plurality of drilling parameters, computing a first signal of a first indicator based on a first set of measured drilling parameters and a second signal of a second indicator based on a second set of measured drilling parameters versus time. The first indicator is representative of a first type of events happening at the bottom of the borehole and the second indicator is representative of a second type of events happening at the exit of the borehole linked to the first type of events. The method also comprises characterizing a correlation between the first and second signals and determining a shift between the first and second signals. An estimated transit time is then determined from the shift.