Real-Time Sonic Log Prediction at the Drill Bit
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Solution Overview
Problem
Current real-time geomechanical analysis tools for wellbore stability prediction are not effective at the drill bit due to the lack of immediate acoustic logging data, leading to delayed and inaccurate predictions of drilling events, as LWD sensors are typically installed 100 ft behind the bit.
Innovation Solution
Establishing correlations between mechanical specific energy (MSE) and sonic log data to predict formation properties at the drill bit, using drilling parameters and pseudo-sonic data from offset wells, enabling real-time prediction even when LWD logs are not available.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LWD sensors are installed 100 ft behind the bit to measure acoustic data, then measurement reliability is improved, but real-time prediction capability at the bit deteriorates
Solution Approach 1:
The patent creates a virtual sonic log at the bit location by copying and processing LWD acoustic data from sensors positioned 100 ft behind the bit. Through correlation analysis with drilling parameters (WOB, RPM, ROP), the system reconstructs formation sonic properties at the bit location in real-time, enabling timely predictions without requiring physical sensors at the bit.
2Measurement precision
If LWD sonic logging data is used for real-time geomechanical analysis, then prediction accuracy is improved, but availability of data deteriorates
Solution Approach 1:
The patent introduces drilling parameters (weight on bit, rotary speed, rate of penetration) as intermediary variables to bridge the gap between unavailable LWD sonic data and geomechanical analysis requirements. These parameters serve as mediators that, when correlated with available LWD acoustic data, enable reconstruction of sonic log information at the bit location.
Solution Approach 2:
The patent replaces the physical LWD sonic logging system with a computational model that uses drilling mechanics parameters to predict sonic properties. Instead of relying on mechanical acoustic sensors that may not be available at the bit, the system uses mechanical drilling parameters combined with correlation algorithms to substitute and reconstruct sonic log data.
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 real-time prediction of sonic logs at the drill bit, improving the accuracy and timeliness of wellbore stability analysis by correlating MSE with compressional wave velocity, which is influenced by rock porosity and strength.
Implementation Method 1
a transmitter configured to transmit a sonic pulse into a borehole; and one or more receivers configured to detect reflected sonic pulses as measured sonic data
Implementation Method 2
predicting sonic data at a bit with at least the correlation and at the one or more drilling parameters... correlating MSE with compressional wave velocity, which is influenced by rock porosity and strength
Data Source
AI summary
A method and/or system comprising disposing a logging tool into a borehole, wherein the logging tool comprises: a transmitter configured to transmit a sonic pulse into a borehole; and one or more receivers configured to detect reflected sonic pulses as measured sonic data. Further, the method and/or system may be further comprise forming a correlation between the measured sonic data and one measurement from the sonic data and the one or more drilling parameters; and predicting sonic data at a bit with the correlation and one or more drilling parameters. In addition to acoustics the method and/or system maya downhole transmitter configured to transmit a particle and/or wave into the borehole and observe a response from the particle and/or wave, wherein the response is a reflection of or an effect of the particle and/or wave within the borehole or within a formation surrounding the borehole.