Pulsed Neutron Logging for Fracturing Zone Identification
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Solution Overview
Problem
Determining the most suitable locations for hydraulic fracturing in earth formations to maximize hydrocarbon production is challenging due to varying lithological facies and the need for efficient resource allocation, as existing methods are inefficient and often require multiple logging passes or delay well completion.
Innovation Solution
A logging tool equipped with pulsed neutron logging capabilities that measures hydrocarbon saturation, elemental activation, and emulates open-hole log data in a single pass through a cased borehole, allowing for the identification of zones with high hydrocarbon saturation and silica content, which are more conducive to hydraulic fracturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple logging passes or delayed well completion are used to determine optimal fracturing locations, then measurement precision can be improved, but productivity and time efficiency deteriorate
Solution Approach 1:
The patent combines multiple logging measurements (hydrocarbon saturation, silica content, and other formation properties) into a single logging pass through the cased borehole. This merging of multiple measurement functions into one operation eliminates the need for multiple separate logging passes, thereby maintaining measurement precision while significantly improving productivity and well completion efficiency.
Solution Approach 2:
The logging tool is designed with multi-functional capabilities to simultaneously perform hydrocarbon saturation measurement, silica content measurement, and other formation evaluation functions through the casing. This universal tool replaces the need for multiple specialized logging operations, resolving the contradiction between comprehensive measurement accuracy and operational efficiency.
2Reliability
If comprehensive formation analysis is performed to identify optimal fracturing zones, then reliability of hydrocarbon production increases, but device complexity and operational complexity increase
Solution Approach 1:
The logging tool integrates multiple measurement functions (neutron activation for hydrocarbon saturation, gamma ray detection for silica content, and other formation properties) into a single multi-functional device. This universal tool achieves comprehensive formation analysis for reliable fracturing zone identification without requiring multiple separate complex devices.
Solution Approach 2:
The patent uses gamma ray detection as an intermediary method to indirectly measure silica content in the formation. This intermediary approach allows for comprehensive formation analysis without directly complex measurement techniques, simplifying the overall device complexity while maintaining reliability in identifying optimal fracturing locations.
3Measurement precision
If comprehensive formation analysis is performed, then measurement precision of hydrocarbon saturation and silica content improves, but loss of time increases
Solution Approach 1:
The patent merges hydrocarbon saturation measurement and silica content measurement into a single logging pass through the cased borehole. This combining of multiple measurement operations into one simultaneous operation achieves comprehensive measurement precision while eliminating the time loss that would result from performing separate logging passes.
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 enables efficient data gathering and resource allocation by identifying optimal fracturing locations with high hydrocarbon saturation and silica content, increasing the probability of successful hydrocarbon extraction in a single logging pass without delaying well completion.
Implementation Method 1
using a pulsed neutron logging instrument to acquire during the same logging pass saturation measurements of oil, water, and/or gas
Implementation Method 2
measurements of a selected element through neutron activation
Implementation Method 3
hydraulic pressure is exerted in an interval of a reservoir rock. When the hydraulic pressure meets or exceeds the formation fracture pressure, the rock will fracture
Data Source
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AI summary
A method for estimating a property of an earth formation, the method includes: conveying a carrier through a borehole penetrating the earth formation; irradiating the formation with neutrons from a neutron source disposed at the carrier; detecting a first signal from the formation due to the irradiating using a first radiation detector, the first signal being related to a saturation of a fluid in the formation; detecting a second signal from an element in the formation due to the irradiating using a second radiation detector, the second signal being related to an element emitting the second signal in the formation; and estimating the property from the first signal and the second signal.