Downhole Gamma Sensor Directional Detection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Traditional gamma radiation counters in downhole drilling lack directional information, making it difficult for drillers to accurately determine the proximity to formation boundaries, which are crucial for maintaining the drill bit within the productive 'pay area' of hydrocarbon zones.

Innovation Solution

A downhole probe assembly equipped with a gamma sensor module, a gyroscope, and a controller that allocates measured gamma radiation to conceptual bins based on the rotation of a shielded window, allowing for the calculation of average radiation per unit time and transmission of key parameters to the surface for geosteering the drill bit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional gamma radiation counters are used, then gamma radiation levels can be detected, but directional information is lost making it difficult to determine proximity to formation boundaries

Engineering Contradiction:

Improvedirectional gamma radiation measurement precisionVSAvoidloss of directional information

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The gamma radiation detection is segmented into multiple directional bins (e.g., 8 bins of 45 degrees each) around the drill bit. Each bin captures gamma radiation from a specific angular sector, allowing directional information to be preserved while maintaining comprehensive coverage of the surrounding formation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention adds an angular/directional dimension to the gamma radiation measurement. Instead of measuring only the total gamma radiation intensity (one-dimensional), the system measures gamma radiation intensity as a function of angle around the drill bit (two-dimensional: intensity vs. angle), providing directional information that helps determine proximity to formation boundaries

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Loss of information

If the downhole probe assembly is rotated to collect gamma radiation data from all directions, then complete directional information is obtained, but the complexity of tracking and allocating radiation data to correct angular bins increases

Engineering Contradiction:

Improvecompleteness of directional informationVSAvoiddata tracking and allocation complexity

Core Design Contradiction:

Loss of informationVSDevice complexity

Solution Approach 1:

The gyroscope provides continuous feedback on the rotation angle and speed of the downhole probe assembly. This feedback is used by the controller to dynamically track which angular bin corresponds to which physical direction at any given moment, enabling accurate allocation of gamma radiation measurements to the correct bins even as the tool rotates

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The invention replaces complex mechanical tracking mechanisms with an electronic/software-based solution. The controller uses gyroscope data to calculate and update the angular position of each bin in real-time, allocating gamma radiation counts to bins through computational logic rather than mechanical indexing, thereby reducing mechanical complexity while maintaining measurement accuracy

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method provides real-time directional gamma radiation data, enabling drillers to maintain the drill bit within the productive zone and avoid formation boundaries, enhancing the efficiency and accuracy of hydrocarbon extraction by monitoring and adjusting the drill bit's trajectory based on gamma radiation patterns.

Implementation Method 1

measuring gamma radiation passing through the window and hitting the gamma sensor therebelow

Methodology Applied

Scientific EffectGamma radiation detection: Absorption (EM radiation)

Implementation Method 2

sampling gyroscope output at predetermined time intervals and determining speed of rotation of the downhole probe assembly

Methodology Applied

Scientific EffectGyroscope effect: Gyroscope

Data Source

PatentUS9464519B2Method and apparatus for detecting gamma radiation downhole

Publication Date: 2016.10.11 EVOLUTION ENG

AI summary

The embodiments described herein generally relate to a method for detecting gamma radiation downhole using a downhole probe assembly. The method includes rotating the downhole probe assembly and measuring gamma radiation passing through a window of a gamma sensor module and hitting a gamma sensor therebelow. A gyroscope output is sampled at predetermined time intervals to indicate the speed of rotation of the downhole probe assembly. The angle of rotation of the window is calculated based on the speed of rotation of the downhole probe assembly. Each revolution of the downhole probe assembly is conceptually divided up into a plurality of bins. Measured gamma radiation is allocated to one of the plurality of bins based on the calculated angle of rotation of the window to provide a real time indication of the direction and strength of gamma radiation emitted by the formation surrounding the borehole. This information can be used for real time geosteering of the drill bit during downhole drilling.