X-ray Fluid Density Measurement in Boreholes

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Solution Overview

Problem

Existing methods for determining fluid density in oilfield environments face challenges such as spatial constraints, high temperature, and noise, and rely on chemical radiation sources that are hazardous and inefficient, especially in deep boreholes where optical techniques are insufficient and gamma ray photon attenuation measurements are limited.

Innovation Solution

An x-ray generator with dual filters producing high and low energy radiation is used, along with radiation detectors to measure the attenuation of x-rays passing through a fluid sample, allowing for reliable density determination in spatially constrained and harsh environments, such as boreholes, by analyzing the electron density index and correcting for the Z-effect.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If gamma ray photon attenuation measurement is used to determine fluid density, then measurement reliability is improved, but device size becomes too large for deep boreholes with small diameter

Engineering Contradiction:

Improvefluid density measurement reliabilityVSAvoidapparatus volume

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent replaces the mechanical/physical gamma ray source system with an x-ray generation system that produces x-rays electrically. This substitution allows for a more compact apparatus design while maintaining the photon attenuation measurement capability needed for reliable fluid density determination in constrained borehole environments

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the radiation parameter from gamma rays to x-rays, which have different penetration characteristics and can be generated in a more compact form factor. This parameter change enables the measurement system to fit within the volume constraints of deep boreholes while still providing reliable density measurements

Inventive Principle:

Principle #35Parameter changes

2Reliability

If chemical radiation source is used for density measurement, then measurement capability is achieved, but safety hazards and operating requirements increase

Engineering Contradiction:

Improvedensity measurement capabilityVSAvoidsafety hazards

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the chemical radiation source with an x-ray generation system that uses electrical energy to produce x-rays. This eliminates the safety hazards associated with chemical radiation sources while maintaining the ability to perform density measurements through photon attenuation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The x-ray source can be turned on and off as needed, unlike chemical radiation sources that remain active until depleted or disposed of. This allows for controlled exposure and eliminates long-term safety concerns, effectively making the radiation source 'short-living' in terms of active emission

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Object-affected harmful factors

If low intensity radiation source is used to meet safety regulations, then safety is improved, but measurement time increases and flow line size must be larger

Engineering Contradiction:

Improvesafety complianceVSAvoidmeasurement time

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The x-ray generation system allows for dynamic control of radiation intensity - the source can be adjusted to provide high intensity when needed for rapid measurement, then reduced or turned off for safety. This dynamic capability resolves the contradiction between measurement speed and safety compliance

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system uses periodic activation of the x-ray source, providing high intensity radiation in brief pulses for rapid measurement, then remaining off or at low intensity for safety. This periodic action achieves both fast measurements and safety compliance

Inventive Principle:

Principle #19Periodic action

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 accurate and reliable fluid density measurements in extreme conditions, enabling effective characterization of downhole fluids and overcoming limitations of previous techniques by using x-ray technology that is robust and suitable for small spaces and high temperatures.

Implementation Method 1

measuring the attenuation of x-rays from an x-ray generator passing through a fluid sample in a flow line

Methodology Applied

Scientific EffectX-ray attenuation: Absorption (EM radiation)

Data Source

PatentUS7507952B2Apparatus and method for fluid density determination

Publication Date: 2009.03.24 SCHLUMBERGER TECH CORP

AI summary

A fluid density determination apparatus and method comprising an X-ray generator emitting a high energy radiation signal and a low energy radiation signal; a sample cell housing a sample of interest and at least one of the high energy and low energy radiation signals being directed through the sample cell; and a radiation detector measuring the output radiation from the sample cell. Data gathered at the radiation detector using the high and low energy signals are used to calculate the density of the fluid sample of interest.