Downhole Core Orientation Using Periodic Data Sampling
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Solution Overview
Problem
Existing core orientation systems face issues with inaccurate data due to drilling vibrations and continuous data recording, leading to battery life reduction and increased equipment costs, as they often record unnecessary data and require frequent replacement.
Innovation Solution
A method and system for core orientation that uses a data gathering device with a timer to record orientation data only when drilling is ceased and before the core is separated, allowing for random or regular interval recording, and entering a standby mode during drilling to conserve battery life, with data retrieval based on elapsed time and vibration thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous data recording is performed during drilling, then complete orientation data is captured, but battery life is reduced and equipment costs increase
Solution Approach 1:
The system performs data recording periodically at predetermined time intervals rather than continuously. The downhole tool records orientation data at regular intervals, and the surface device selects the appropriate recorded value based on timing information, thereby reducing battery consumption while maintaining data reliability.
Solution Approach 2:
The system pre-records orientation data at multiple time points before the actual core separation event. By having multiple pre-recorded values available, the system can select the most appropriate data point after the fact, ensuring data completeness without requiring continuous recording throughout the drilling operation.
2Productivity
If data is recorded at regular predetermined time intervals, then data collection is systematic, but many measured values are unusable due to drilling vibrations
Solution Approach 1:
The system uses timing feedback to determine data usability. The surface device receives timing information from the downhole tool and uses this feedback to identify which recorded orientation values were captured during stable periods versus during drilling vibrations, allowing selection of usable data points.
Solution Approach 2:
The system changes the selection criterion from fixed time intervals to time-based filtering. Instead of using all regularly intervalled data points, the system filters recorded values based on timing information to identify those captured during stable conditions, thereby improving data usability while maintaining systematic collection.
3Measurement precision
If two timers are synchronised at a reference time, then time measurement is accurate, but timer synchronisation errors occur
Solution Approach 1:
The downhole tool continuously records orientation data at predetermined time intervals as a preliminary action, creating a buffer of recorded values with associated timing information. This eliminates the need for precise real-time synchronisation between surface and downhole timers, as the system can retrospectively identify the correct data point using the stored timing information.
Solution Approach 2:
The system creates a copy of the timing information along with each recorded orientation value. This copied timing data allows the surface device to independently determine which recorded value corresponds to the correct moment without requiring the timers to remain synchronised, thereby eliminating synchronisation errors.
4Productivity
If drilling vibrations are present, then core orientation data becomes inaccurate, but drilling must continue to progress
Solution Approach 1:
The system records orientation data periodically at multiple time points during the drilling operation. By capturing data at regular intervals, the system ensures that at least some recordings occur during stable periods when vibrations are minimal, maintaining measurement precision while allowing drilling to continue uninterrupted.
Solution Approach 2:
The system uses timing feedback to identify which recorded values were captured during stable conditions versus during vibrations. This allows post-processing selection of accurate data points while the drilling operation continues to progress without interruption.
Data Source
AI summary
System and method for core sample orientating uses an orientation data gathering device recording core sample orientation belowground at irregular time intervals, preferably while drilling is ceased and the irregular time intervals can be randomly generated by the orientation data gathering device. Target orientation data is closest to time Tx, Tx being greater than, less than or equal to T−t, where T is the time recorded by the data gathering device and t is the recorded elapsed time commenced by a communication device at the surface. The data gathering device is interrogated at the surface by the communication device. Timers in each are stopped or their individual times associated with each other (survey time T and elapsed time t). Target recorded orientation data Tx is identifiable as the largest Tx value<T−(t−W), where W is a delay period.