Downhole Depth Computation Using Inertial Navigation
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Solution Overview
Problem
Current methods for determining the depth of a wellbore in subterranean rock formations are inefficient, requiring time-consuming and resource-intensive surveys, often necessitating a trip into the wellbore prior to drilling and lacking accuracy in older wells due to outdated technologies or cost constraints.
Innovation Solution
A method and apparatus utilizing a wellbore tool equipped with an accelerometer and a processor that measures acceleration and accesses a database to determine depth, incorporating survey data from instruments like gyroscopes and magnetometers, allowing for continuous or discrete orientation measurements and eliminating the need for pre-drilling surveys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional wireline survey methods are used to determine wellbore depth, then survey data can be obtained, but the process requires time-consuming trips into the wellbore and extensive resource consumption
Solution Approach 1:
The patent replaces the mechanical wireline survey system with an inertial navigation system using accelerometers and gyroscopes. The mechanical wireline method requires physical trips into the wellbore, while the inertial system uses motion sensors to calculate position through integration of acceleration data, eliminating the need for mechanical survey trips and enabling continuous depth monitoring during drilling operations
Solution Approach 2:
The inertial navigation system is self-contained within the wellbore tool, with onboard processors continuously calculating depth and position from sensor data. The system serves itself by integrating acceleration measurements over time to determine velocity and position without requiring external survey equipment or personnel, enabling autonomous depth determination throughout the drilling process
2Measurement precision
If conventional wireline survey methods are used, then depth information can be obtained, but the process is resource-intensive and requires pre-drilling trips
Solution Approach 1:
The patent replaces the mechanical wireline survey system with an inertial navigation system using accelerometers and gyroscopes. The mechanical wireline method requires physical trips into the wellbore, while the inertial system uses motion sensors to calculate position through integration of acceleration data, eliminating the need for mechanical survey trips and enabling continuous depth monitoring during drilling operations
Solution Approach 2:
The inertial navigation system provides continuous depth and position measurements throughout the drilling process, rather than requiring intermittent survey trips. The accelerometers and gyroscopes continuously track tool motion and orientation, allowing depth determination to proceed without interruption and maintaining productive drilling operations throughout
3Measurement precision
If iterative computation at the surface is used to process survey data, then final survey logs can be produced, but the process requires data matching and complex surface processing
Solution Approach 1:
The inertial navigation system is self-contained within the wellbore tool, with onboard processors continuously calculating depth and position from sensor data. The system serves itself by integrating acceleration measurements over time to determine velocity and position without requiring external survey equipment or personnel, enabling autonomous depth determination throughout the drilling process
Solution Approach 2:
The patent extracts the computational processing function from the surface facility and places it directly in the wellbore tool. The inertial navigation system performs all necessary calculations locally using onboard processors, eliminating the need for complex surface-based iterative computation and data matching processes
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 accurate and efficient determination of wellbore depth, reducing resource consumption and improving survey accuracy by processing acceleration measurements and correlating them with pre-measured parameters, thus facilitating more precise wellbore operations and reworking of older wells.
Implementation Method 1
measuring acceleration of the wellbore tool
Implementation Method 2
determining the depth of the wellbore tool using the processor by processing the acceleration measurements
Implementation Method 3
a gyroscopic survey instrument
Implementation Method 4
magnetometers
Data Source
AI summary
A method for determining depth in a wellbore uses inertial navigation in conjunction with a database having one or more measured parameters correlated with depth. The measured parameter may be the lengths of stands forming a drill string, prior survey data relating to a naturally occurring feature such as formation lithology, or data relating to a human made feature such as collars in a casing string. The downhole processor may use accelerometer measurements to calculate a measured depth of a BHA and access the database to retrieve a predicted depth that corresponds with one or more sensor measurements (e.g., motion indicating the addition of a stand to a drill string). Thereafter, if the downhole processor determines that the predicted depth is in agreement with the calculated depth, the processor stores the predicted depth and/or associates the predicted depth with directional surveys taken along the wellbore.