Pulsed Neutron Logging Tool Integrated with Wash Pipe

Solution Overview

Problem

Conventional pulsed neutron logging methods for gravel pack completions in subterranean wellbores are inefficient due to the need for separate deployment tools and slow logging speeds, which increase operational time and costs, and are unsuitable for use with larger tubulars due to battery life limitations.

Innovation Solution

Integration of a pulsed neutron logging tool directly with the wash pipe and advanced power management and data collection methods allow for simultaneous logging during gravel pack operations at faster speeds, enabling efficient quality assessment and monitoring of gravel packs without the need for separate tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional pulsed neutron logging methods are used with separate deployment tools, then logging can be performed in gravel pack completions, but operational time and costs increase due to slow logging speeds and separate deployment requirements

Engineering Contradiction:

Improvelogging speedVSAvoidoperational time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent combines the pulsed neutron logging tool with the wash pipe into a single integrated assembly. The logging tool is positioned within the wash pipe, allowing both the gravel packing operation and logging operation to occur simultaneously through the same tubular, eliminating the need for separate deployment and retrieval operations.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The wash pipe serves dual functions: it acts as both the conduit for delivering gravel during the gravel packing operation and as the deployment mechanism for the pulsed neutron logging tool. This multi-functionality allows the same equipment to perform both completion and logging tasks.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of operation

If conventional pulsed neutron logging methods are used with separate deployment tools, then logging can be performed, but device complexity increases due to the need for multiple separate tools

Engineering Contradiction:

Improveoperational simplicityVSAvoidnumber of deployment tools

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines the pulsed neutron logging tool with the wash pipe into a single integrated assembly. The logging tool is positioned within the wash pipe, allowing both the gravel packing operation and logging operation to occur simultaneously through the same tubular, eliminating the need for separate deployment and retrieval operations.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The wash pipe serves dual functions: it acts as both the conduit for delivering gravel during the gravel packing operation and as the deployment mechanism for the pulsed neutron logging tool. This multi-functionality allows the same equipment to perform both completion and logging tasks.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If pulsed neutron logging tool is integrated with wash pipe, then logging speed and efficiency improve, but battery life becomes limiting factor for larger tubulars

Engineering Contradiction:

Improvelogging speedVSAvoidbattery life

Core Design Contradiction:

ProductivityVSDuration of action of moving object

Solution Approach 1:

The pulsed neutron logging tool emits neutrons in periodic pulses rather than continuously. This pulsed operation mode reduces average power consumption and extends battery life, allowing the logging operation to complete before battery depletion occurs during high-speed wash pipe withdrawal.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The logging system is designed to operate dynamically during the wash pipe withdrawal process, adjusting the logging parameters and pulse frequency to match the changing conditions and available time window provided by the battery life constraint.

Inventive Principle:

Principle #15Dynamics

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 time and costs by enabling high-speed logging during wash pipe withdrawal, improving the economic viability of gravel pack completions and reservoir surveillance while maintaining data quality.

Implementation Method 1

A pulsed neutron logging tool integrated with the wash pipe is lowered into the wellbore to emit pulses of neutrons into the wellbore and surrounding formation

Methodology Applied

Scientific EffectNeutron interaction: Nuclear Fission

Implementation Method 2

detect the resulting gamma ray response to determine a presence or absence of voids within the gravel pack

Methodology Applied

Scientific EffectGamma ray emission: Radioactive Decay

Data Source

PatentUS11402537B2Systems and methods for pulsed neutron logging in a subterranean wellbore

Publication Date: 2022.08.02 BP CORP NORTH AMERICA INC

AI summary

Methods and associated systems are disclosed for performing a logging operation within a subterranean wellbore extending within a subterranean reservoir. In an embodiment, the method includes (a) emitting neutrons into the subterranean wellbore or the subterranean reservoir, and (b) detecting gamma rays emitted from atoms disposed within the subterranean wellbore or the subterranean reservoir. In addition, the method includes (c) determining a first gamma ray count within a first energy window of the gamma rays detected at (b), and (d) determining a second gamma ray count within a second energy window of the gamma rays detected at (b). The second energy window is different than the first energy window. Further, the method includes (e) calculating a ratio of the first gamma ray count to the second gamma ray count.