LWD Data Synchronization Using In-Slips Correlation Shifts
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Solution Overview
Problem
Existing methods for synchronizing tool acceleration as a function of time with driller depth as a function of time in logging while drilling (LWD) are cumbersome, time-consuming, and expensive.
Innovation Solution
A method and system for synchronizing driller depth data as a function of time with downhole tool acceleration data as a function of time by retrieving and time-stamping data from a well string during and after drilling, using sensors and a common time grid to align data points, and determining a shift based on maximum correlation coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional time synchronization methods are used between surface clock and downhole clock, then data merging can be achieved, but the process becomes very cumbersome, time consuming, and expensive
Solution Approach 1:
The system performs preliminary time synchronization by establishing a time offset between surface and downhole clocks before actual drilling operations begin. This preliminary action allows subsequent data to be automatically time-stamped and synchronized without requiring cumbersome real-time adjustments during drilling, thereby reducing both time and cost while maintaining accuracy.
Solution Approach 2:
The invention introduces an intermediary time-stamping mechanism that automatically records precise timestamps for both surface and downhole events. This intermediary system acts as a mediator between the two clocks, enabling automatic data merging without requiring manual intervention or complex synchronization procedures, thus eliminating the cumbersome and expensive traditional methods.
2Measurement precision
If traditional time synchronization methods are used between surface clock and downhole clock, then data merging can be achieved, but the process becomes very cumbersome, time consuming, and expensive
Solution Approach 1:
The system implements self-service synchronization where the downhole tool automatically time-stamps its own measurements using the downhole clock, and the surface system independently time-stamps surface measurements. The automatic correlation algorithm then self-adjusts by calculating time offsets and shifting data points without human intervention, making the complex synchronization process autonomous and eliminating the need for cumbersome manual procedures.
Solution Approach 2:
The invention replaces the mechanical/manual synchronization process with an automated computational system. Instead of physically adjusting clocks or manually aligning data, the system uses computer algorithms to automatically calculate time offsets, shift data points, and merge datasets, thereby reducing device complexity and eliminating cumbersome manual operations while maintaining synchronization accuracy.
3Productivity
If automatic time synchronization is implemented using time offsets and correlation coefficients, then synchronization efficiency is improved, but data processing complexity increases
Solution Approach 1:
The system applies partial action by initially calculating time offsets only for significant events (such as weight on bit changes or stick-slip events) rather than continuously processing all data points. This selective approach achieves sufficient synchronization efficiency for most applications without requiring excessive computational resources, thereby improving productivity while keeping data processing complexity manageable.
Solution Approach 2:
The invention dynamically adjusts processing parameters such as the threshold for event detection, the sampling rate for correlation analysis, and the maximum time offset values based on drilling conditions. By changing these parameters adaptively, the system optimizes synchronization efficiency for different scenarios without requiring maximum computational complexity in all cases, thus balancing productivity and processing complexity.
Data Source
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AI summary
Processes and systems for synchronizing driller depth data as a function of time with downhole tool acceleration data as a function of time. In some embodiments, the process can include determining one or more in slips conditions for a drill pipe; determining one or more in slips conditions for a downhole tool; interpolating the in slips status indicators on to a common time grid; determining one or more shifts for which an allowed minimum overlapping time period between the acceleration data and the driller depth data is not less than an allowed minimum overlapping time period; determining a correlation coefficient between the interpolated in slips status indicators for each of the one or more shifts; determining a maximum correlation coefficient and a time shift associated with the maximum correlation; and synchronizing the acceleration data and the driller depth data.