Cemented Wellbore Pressure Gauge With Temperature Compensation

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Solution Overview

Problem

Existing wellbore pressure measurement technologies face challenges such as sensor vulnerability to damage, clogging of buffer tubes, and sediment deposition in bellows, which affect accuracy and responsiveness, especially when cement hardens around the pressure gauge, isolating it from formation pressure changes.

Innovation Solution

A pressure gauge system with a housing permanently installed in cement outside the wellbore casing, equipped with temperature sensors to calculate temperature-compensated pressure signals, and a wetted filter port to prevent cement intrusion, ensuring dynamic bellows functionality and hydraulic conductivity, enhancing measurement accuracy and responsiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pressure gauge is permanently cemented in place outside the wellbore conduit, then the measurement location is stable and protected, but the cement hardening isolates the pressure gauge from formation pressure changes

Engineering Contradiction:

Improvemeasurement continuityVSAvoidpressure detection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The cement sheath is designed with porous properties that allow pressure transmission while maintaining structural integrity. The porous structure enables formation pressure to be transmitted through the cement to the pressure gauge, preventing isolation while maintaining the protective and stable positioning benefits of permanent cementing.

Inventive Principle:

Principle #31Porous materials

2Reliability

If a diaphragm is used to isolate the sensor, then the sensor is protected from fluids, but the diaphragm is vulnerable to damage and overexposure of its dynamic range

Engineering Contradiction:

Improvesensor protectionVSAvoiddiaphragm durability

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The bellows structure serves as a flexible protective shell that isolates the pressure sensor from direct fluid contact while maintaining pressure transmission capability. This flexible membrane approach provides robust protection against fluid damage and extends the dynamic range compared to rigid diaphragms.

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If buffer tubes are used to isolate shock or vibration, then the sensor is protected from mechanical damage, but the buffer tubes may clog up with time

Engineering Contradiction:

Improvesensor protectionVSAvoidoperational lifespan

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The invention extracts and eliminates the buffer tube component entirely, replacing it with a bellows structure that provides mechanical isolation without the clogging problem. The bellows maintains vibration and shock isolation functionality while removing the vulnerable buffer tube element that would clog over time.

Inventive Principle:

Principle #2Taking out (Extraction)

4Ease of operation

If the pressure port is open to the environment, then the bellows can function, but sediments deposit in the chamber housing the bellows

Engineering Contradiction:

Improvebellows functionalityVSAvoidsediment deposition

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The bellows acts as an intermediary element that allows pressure transmission while preventing direct contact between formation fluids and the internal chamber. This mediator structure enables the bellows to function while blocking sediment deposition pathways, as the sealed bellows interior remains isolated from environmental contaminants.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The system provides real-time, accurate formation pressure measurements by compensating for thermal effects and maintaining sensor integrity, reducing phase lag and offsets, and preventing cement-induced isolation of the pressure gauge.

Implementation Method 1

a pressure sensor with an output pressure signal

Methodology Applied

Scientific EffectPressure sensing:

Implementation Method 2

a first temperature sensor with a first temperature signal arranged to measure a first temperature outside the wellbore casing

Methodology Applied

Scientific EffectTemperature sensing:

Implementation Method 3

The isolation system may typically be established by a bellows or using a diaphragm

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 4

a wetted filter port to prevent cement intrusion

Methodology Applied

Scientific EffectFiltering: Filter (physical)

Data Source

PatentUS9677396B2Method and apparatus for permanent measurement of wellbore formation pressure from an in-situ cemented location

Publication Date: 2017.06.13 HALLIBURTON AS

AI summary

A pressure gauge system and a method for in-situ determination of a wellbore formation pressure through a layer of cement, where the pressure gauge system comprises: a housing arranged to be permanently installed in the cement on the outside of a wellbore casing, wherein said housing comprises a pressure sensor with an output pressure signal, wherein: the pressure gauge system further comprises: a first temperature sensor with a first temperature signal, a second temperature sensor with a second temperature signal; and a computer implemented compensation means arranged to receive the pressure signal, the first and second temperature signals, and calculate a temperature compensated output pressure signal.