Roller Cone Drill Bit Embedded Gamma Ray Detector
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Solution Overview
Problem
Existing downhole formation measurement technologies face challenges in accurately determining characteristics of subterranean formations ahead of the drilling system due to difficulties in locating sensors effectively, which affects operational decisions in hydrocarbon extraction.
Innovation Solution
Integration of a gamma ray detector within a roller cone drill bit, positioned in a journal to minimize shielding and maximize directional sensitivity, coupled with external electronics for data processing and transmission, enabling 'look ahead' measurements of the formation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are located further from the drill bit to make measurements, then the drilling system can obtain formation characteristics, but the measurement accuracy and range are reduced due to increased shielding and distance
Solution Approach 1:
The gamma ray detector is nested within the drill bit structure, specifically positioned in the journal where it is surrounded by the bit body. This nesting allows the detector to be located as close as possible to the formation ahead of the bit while being protected by the bit structure, maximizing measurement range and accuracy without requiring the detector to be mounted on separate equipment further up the drill string.
Solution Approach 2:
The detector is positioned in a different spatial dimension within the drill bit - specifically in the journal area rather than on the external surface or further up the drill string. This repositioning in three-dimensional space allows the detector to achieve optimal proximity to the formation while utilizing the internal geometry of the drill bit to its advantage.
2Loss of information
If a gamma ray detector is integrated into the drill bit, then look ahead measurements are improved, but the drill bit design becomes more complex
Solution Approach 1:
The drill bit is designed to serve multiple functions: it maintains its primary drilling function while simultaneously housing the gamma ray detector for formation evaluation. The journal structure, which is a necessary component for bearing support, is utilized as the housing for the detector, allowing one component to fulfill multiple roles and reducing overall system complexity.
Solution Approach 2:
The drill bit's own structure - specifically the journal - is used to house and protect the gamma ray detector. The bit body and journal provide mechanical support, positioning, and protection for the detector without requiring additional external housing or mounting structures, allowing the system to serve itself.
3Measurement precision
If the gamma ray detector is positioned in the journal, then directional sensitivity is maximized, but the detector is exposed to higher mechanical stresses and temperatures
Solution Approach 1:
The detector is positioned within the journal structure before encountering the harshest downhole conditions. The journal and bit body act as a protective buffer that shields the detector from direct exposure to extreme mechanical stresses and temperatures that would be present at the cutting elements or external surfaces, cushioning the detector against these adverse conditions in advance.
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
Enhances the accuracy and range of gamma ray measurements, improving the ability to determine formation characteristics and make informed drilling decisions, while reducing costs by reusing electronics with new drill bits.
Implementation Method 1
a gamma ray detector positioned in a journal of the roller cone drill bit
Data Source
AI summary
An example apparatus includes a drill bit body and a leg extending from the drill bit body. A journal may extend from the leg, with a gamma ray detector at least partially within the journal. In certain embodiments, the gamma ray detector may be confined within a pressure protective cavity at least partially within the arm of the journal. In certain embodiments, the gamma ray detector may be a scintillator aligned with at least one of a photomultiplier, photodiodes, or phototransistors.