Downhole Probe Dual Inlet Cleanup Confirmation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current downhole formation evaluation methods face challenges in ensuring that fluid samples are sufficiently clean, as contamination from mudcakes and invaded zones can contaminate the sampling process, leading to inaccurate data and sample quality issues.

Innovation Solution

A downhole tool with a probe having both a sampling inlet and a contamination inlet is used, where fluid is pumped through both inlets at varying flow rates, and optical density measurements are taken to determine the cleanliness of the fluid, allowing for adjustment of flow rates to achieve cleanup and ensure only clean fluid is sampled.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fluid is pumped through a single sampling inlet from the formation, then the sampling process is simple, but the fluid sample may be contaminated by mudcake and invaded zone fluids

Engineering Contradiction:

Improvesample qualityVSAvoidprobe structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The probe is segmented into multiple functional inlets: a sampling inlet for obtaining formation fluid samples and a contamination inlet for obtaining contaminated fluid samples. This segmentation allows separate measurement of clean and contaminated fluid properties, enabling accurate determination of formation fluid characteristics by compensating for contamination effects.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The contamination inlet acts as an intermediary that measures the properties of contaminated fluid (mixture of formation fluid and mudcake/invaded zone fluid). By measuring both clean (sampling inlet) and contaminated (contamination inlet) fluid properties, the system can calculate and compensate for contamination effects to determine accurate formation fluid characteristics.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If flow rate is increased to improve sampling speed, then productivity increases, but contamination effects are enhanced

Engineering Contradiction:

Improvesampling rateVSAvoidcontamination

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system uses feedback by continuously measuring fluid properties at both the sampling inlet and contamination inlet. By comparing measurements from both inlets at various flow rates, the system can determine the relationship between flow rate and contamination effects, then compensate for contamination to accurately determine formation fluid properties even at higher productivity rates.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system varies the flow rate parameter through the sampling and contamination inlets to establish a relationship between flow rate and contamination effects. By measuring at multiple flow rates and analyzing how contamination varies with flow rate, the system can compensate for contamination effects and determine accurate formation fluid properties while maintaining high productivity.

Inventive Principle:

Principle #35Parameter changes

3Measurement precision

If multiple flow rates are used to determine cleanup completion, then accurate cleanup confirmation is achieved, but the evaluation time increases

Engineering Contradiction:

Improvecleanup detection accuracyVSAvoidevaluation time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

Instead of requiring complete cleanup of all contaminated fluid, the system uses partial action by measuring at multiple flow rates to detect cleanup completion criteria. By establishing that contamination effects have been reduced to acceptable levels through flow rate variation analysis, the system can determine formation fluid properties without requiring exhaustive cleanup, thus reducing evaluation time while maintaining measurement precision.

Inventive Principle:

Principle #16Partial or excessive 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 effectively confirms the cleanliness of the fluid entering the sampling inlet, ensuring accurate formation evaluation by distinguishing between clean and contaminated fluid, thereby improving the quality of downhole fluid samples and reducing contamination-related errors.

Implementation Method 1

measuring parameters of the fluid passing through the sampling inlet and the contamination inlet (the fluid parameters comprising optical density)

Methodology Applied

Scientific EffectOptical density measurement: Absorption Spectroscopy

Data Source

PatentUS9752432B2Method of formation evaluation with cleanup confirmation

Publication Date: 2017.09.05 SCHLUMBERGER TECH CORP

AI summary

Methods of evaluating a downhole fluid with a downhole tool. The downhole tool is positionable in a wellbore penetrating a subterranean formation, and has a probe positionable adjacent a wall of the wellbore and pumps, the probe having a sampling inlet and a contamination inlet to draw fluid from the formation into the downhole tool with the pumps. The methods involve pumping fluid into the downhole tool through the sampling inlet and the contamination inlet, varying the pumping of the fluid through the sampling inlet and the contamination inlet at a plurality of flow rates, measuring parameters of the fluid passing through the sampling inlet and the contamination inlet (the fluid parameters comprising optical density), and determining cleanup of contamination during sampling by examining changes in optical density of the fluid entering the sampling inlet at the flow rates.