Downhole Wellbore Gravity Tracking Beyond Electromagnetic Depth Limits
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Solution Overview
Problem
Current methods for calculating wellbore trajectory and BHA location in subterranean formations suffer from inaccuracies due to assumptions about wellbore geometry and formation properties, and electromagnetic methods are limited to shallow depths, leading to uncertainty in direction and depth measurements.
Innovation Solution
The use of gravity sensors, such as quantum or fiberoptic sensors, to measure gravity anomalies caused by wellbores and their contents, combined with an inversion algorithm to model the subterranean formation, allowing for accurate determination of wellbore position and trajectory up to 10,000 feet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electromagnetic measurement techniques are used to track wellbore trajectories, then measurement capability is provided, but the method is limited to shallow depths (a few thousand feet TVD) because electromagnetic waves cannot penetrate deep into earthen formations
Solution Approach 1:
The patent replaces electromagnetic measurement techniques with a gravity-based measurement system. Instead of using electromagnetic waves that cannot penetrate deep formations, the system uses gravity sensors to detect gravitational field variations caused by the wellbore and BHA, enabling depth measurement beyond the limitations of electromagnetic methods.
Solution Approach 2:
The patent changes the physical parameter used for measurement from electromagnetic field properties to gravitational field properties. By measuring gravitational acceleration variations rather than electromagnetic wave propagation, the system overcomes the depth penetration limitation of electromagnetic waves in earthen formations.
2Loss of information
If accelerometer or pressure sensor measurements are used to calculate wellbore trajectory, then direction and depth information is provided, but the measurements are unreliable and have uncertainty in providing feedback for steerable drilling systems
Solution Approach 1:
The patent replaces accelerometer and pressure sensor-based trajectory calculation with a gravity sensor system. The gravity-based measurement provides more reliable direction and depth feedback by directly measuring gravitational field variations, eliminating the uncertainties and reliability issues associated with accelerometer and pressure sensor measurements.
3Measurement precision
If existing methods calculate BHA location and wellbore trajectory using assumptions about wellbore geometry and formation properties, then trajectory calculation is possible, but inaccuracies occur due to these assumptions
Solution Approach 1:
The patent replaces assumption-based trajectory calculation methods with direct gravity measurement. Instead of relying on mathematical models that assume specific wellbore geometries and formation properties, the system directly measures gravitational field variations caused by the actual wellbore and BHA configuration, providing accurate location and trajectory data without requiring simplifying assumptions.
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
This approach provides precise wellbore and content positioning, enhancing the accuracy of subterranean formation modeling by resolving uncertainties in depth and direction, and enabling reliable tracking of drill bits and other downhole devices.
Implementation Method 1
measure gravity anomalies caused by wellbores and their contents
Data Source
AI summary
The present disclosure relates to systems and methods of determining a wellbore position in a subterranean formation by using gravity sensors to detect a gravity anomaly related to a presence of the wellbore, contents within the wellbore, and or fluid flowing through an interface of the wellbore. A model of the subterranean formation predicts a gravity profile, including the gravity anomaly, and the model may be constrained with a depth of the gravity anomaly as calculated with at least one of a known dimension or a known gravitational field change related to the gravity anomaly. The wellbore position is determined within the model by changing model input data until the gravity profile converges with the gravity anomaly.