Rotational Directional Survey Processing for Continuous Drilling
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Solution Overview
Problem
Conventional methods for processing directional sensor data during rotational drilling are inefficient, leading to increased drilling time and increased chances of stuck-pipe events due to the inability to effectively process 6-axis directional sensor data collected during rotating operations, which are modulated by tool rotation and cannot be filtered using conventional low-pass filtering techniques.
Innovation Solution
Employing rotationally-invariant directional parameters derived from 6-axis sensor readings, using a data selection process based on error models and minimum rotational speed thresholds, enabling downhole processing to filter and reject non-compliant data, thereby allowing continuous directional surveying during drilling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional low-pass filtering techniques are used to process 6-axis directional sensor data during rotational drilling, then the processing method is simple, but the data cannot be effectively filtered because the sensor readings are modulated by tool rotation
Solution Approach 1:
The patent transforms the sensor data from the rotating tool coordinate system to the inertial coordinate system by applying rotation matrices. This changes the parameter representation of the data, converting modulated readings into de-modulated components that can be effectively filtered using conventional low-pass filtering techniques. The parameter transformation resolves the contradiction by making the data suitable for standard processing while maintaining simplicity.
Solution Approach 2:
The patent introduces an intermediary transformation process involving rotation matrices and coordinate system conversions. This intermediary step acts as a bridge between the rotating sensor frame and the inertial frame, allowing conventional filtering techniques to be applied effectively. The intermediary transformation decouples the rotation modulation from the data, enabling effective filtering without complicating the overall processing method.
2Productivity
If directional sensor data is collected during rotational drilling operations, then continuous surveying is possible, but the data is modulated by tool rotation making it difficult to process
Solution Approach 1:
The patent performs preliminary action by transforming the sensor readings into the inertial coordinate system before filtering and processing. This preliminary transformation de-modulates the rotation-induced variations, preparing the data for subsequent processing steps. By doing this preparation in advance, the patent enables continuous surveying during rotation while reducing the difficulty of downstream processing.
Solution Approach 2:
The patent replaces the mechanical rotation modulation effect with a mathematical transformation using rotation matrices. Instead of physically stopping the tool to obtain stable readings, the system uses mathematical operations to remove the rotation effect from the data. This substitution allows continuous surveying to proceed without the mechanical disruption of stopping or complex mechanical filtering systems.
3Loss of time
If data filtering is performed downhole during rotational drilling, then drilling time is reduced, but the processing unit must handle modulated sensor data
Solution Approach 1:
The patent implements a universal data processing approach that handles both rotating and non-rotating data using the same transformation and filtering framework. The downhole processing unit applies the same rotation matrix transformations and low-pass filtering operations regardless of whether the tool is rotating, simplifying the processing logic. This multi-functionality allows efficient processing during rotation without requiring separate handling procedures, thus reducing drilling time without proportionally increasing complexity.
4Duration of action of stationary object
If 6-axis sensor data is processed during rotation, then directional surveying can continue uninterrupted, but conventional filtering cannot be applied directly
Solution Approach 1:
The patent applies dynamic coordinate transformation that adapts to the rotating tool's orientation. The rotation matrices dynamically adjust based on the tool's current attitude and rotation state, allowing the system to continuously process 6-axis sensor data during rotation. This dynamic approach maintains surveying continuity while making the processing mathematically tractable through proper coordinate system management.
Data Source
AI summary
Method for obtaining a directional survey in a rotating downhole component include acquiring and generating, while rotating, sets of raw data having 3-axis magnetic field data and 3-axis gravity field data. A set of rotationally-invariant data is obtained for each of the sets of raw data to generate a first number of sets of rotationally-invariant data. An earth property value is calculated from each of the sets. An accuracy indicator is estimated for each of the sets using a respective earth property value, an earth property reference value, and an error model, to generate a plurality of accuracy indicators. A set of mean values is determined using the plurality of sets of rotationally-invariant data using a second number of sets of rotationally-invariant data of the plurality of sets of rotationally-invariant data. The directional survey is estimated and used to control the downhole component.