Borehole Logging via Pressure Sensor Depth Detection
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Solution Overview
Problem
Current borehole logging methods, such as wire-line and LWD, are costly and require specialized personnel, limiting the efficiency and accessibility of geophysical data collection in subsurface formation exploration, especially in core sampling operations.
Innovation Solution
A method and apparatus that deploy a logging instrument with a pressure sensor and accelerometer coupled to a drill string, using pressure changes to determine the actual depth of the instrument and correlate with gamma radiation readings to create a log of the subsurface formation, allowing drill operators to collect geophysical data without additional specialist personnel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wire-line logging is used to acquire complete rock property information, then measurement precision is improved, but operational cost increases and requires specialized personnel
Solution Approach 1:
The logging system performs self-positioning by detecting pressure changes during drill string movement. The system automatically correlates pressure data with drill rod removal/insertion events to determine instrument depth, eliminating the need for specialized logging personnel to operate complex positioning equipment.
Solution Approach 2:
The patent replaces complex mechanical cable-based positioning systems with a pressure-sensitive detection system. Instead of using mechanical encoders or cable length measurements, the system uses pressure sensors to detect depth changes caused by drill string movement, simplifying the overall system complexity.
2Loss of information
If LWD technique with mud pulse technology is used for real-time data transmission, then information availability is improved, but data transfer rate decreases and technology complexity increases
Solution Approach 1:
The patent extracts the logging instrument from the drill string and deploys it independently into the borehole using a simple release mechanism. This separates the data collection function from the drilling operation, allowing high-rate data transmission without the constraints of mud pulse technology while maintaining real-time information availability.
Solution Approach 2:
The patent introduces a pressure sensor as an intermediary to detect depth changes. This pressure-mediated measurement system provides a simple, high-bandwidth communication channel for depth information that does not suffer from the data rate limitations of mud pulse technology.
3Measurement precision
If specialized technical team is deployed for open hole logging, then measurement quality is improved, but operational cost increases
Solution Approach 1:
The logging instrument automatically performs depth determination by detecting pressure changes during drill string operations. The system self-calibrates and self-positions without requiring specialized technicians, maintaining measurement quality while eliminating the need for expensive specialized operational teams.
Solution Approach 2:
The pressure sensor serves multiple functions: it detects instrument depth, monitors drill string movement, and provides positioning data for geophysical measurements. This multi-functionality allows a single simple sensor to replace complex specialized logging equipment and personnel.
4Productivity
If drill string is continuously in borehole for logging, then data collection efficiency is improved, but depth measurement accuracy decreases
Solution Approach 1:
The patent uses periodic removal and re-insertion of drill rods as a measurement mechanism. Each rod removal/insertion cycle creates a detectable pressure change that marks a known depth increment, allowing accurate depth measurement while the drill string remains mostly in place for continuous data collection.
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 reduces operational costs and eliminates the need for specialized technicians, enabling efficient and autonomous geophysical data collection during drilling operations, thereby improving the accessibility and efficiency of subsurface formation exploration.
Implementation Method 1
using a pressure sensor to detect a pressure value and subsequent pressure changes
Implementation Method 2
the instrument includes a pressure sensor and accelerometer
Data Source
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Figure 4~5
AI summary
A method utilised in borehole logging, such as in surveying or exploration relating to a subsurface formation. The method includes deploying a logging instrument that includes a pressure sensor into a borehole drilled into the formation. The method includes the steps of obtaining a first pressure value at a first depth in the borehole, obtaining at least one further pressure value subsequent to the first pressure value during withdrawing or advancing the logging instrument in the borehole, and determining one or more characteristics of the subsurface formation, utilising at least one of the further pressure values, or a change in pressure (Δρ) between the first pressure value and a said further pressure value or values, or a change in pressure (Δρ) between a said further pressure value and another said further pressure value, or a combination of two or more of such values.