Multi-Temperature Resistivity Measurement for Formation Salinity

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods for determining formation salinity and identifying oil and water bearing zones in freshwater or low salinity formations are prone to contamination and analytical errors, particularly when using oil-based muds, which can lead to inaccurate salinity estimation and negatively impact reservoir development decisions.

Innovation Solution

A process involving measuring the resistivity of a formation fluid sample at two different temperatures, calculating a resistivity factor value, and determining the salinity based on this value and the temperature difference, which allows for accurate identification of oil and water bearing zones.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If direct measurement on collected water sample is used, then salinity can be obtained, but contamination from oil-based mud can cause analytical error

Engineering Contradiction:

Improvesalinity measurement accuracyVSAvoidcontamination from oil-based mud

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by measuring resistivity at multiple temperatures before final salinity determination. This allows detection of contamination effects through temperature-dependent resistivity behavior, enabling correction or rejection of contaminated samples before final analysis.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses feedback by comparing measured resistivity values at different temperatures against expected behavior patterns. When contamination is detected through anomalous temperature-resistivity relationships, the system can flag or correct the measurement, improving overall measurement accuracy.

Inventive Principle:

Principle #23Feedback

2Ease of operation

If wireline electrical logs are used to estimate salinity, then non-intrusive measurement is achieved, but contamination and analytical error persist

Engineering Contradiction:

Improvenon-intrusive measurement capabilityVSAvoidsalinity estimation accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent changes the measurement parameter from single-temperature resistivity to multi-temperature resistivity measurements. This additional dimensional parameter (temperature) provides extra information to distinguish between formation water properties and contamination effects, improving estimation accuracy while maintaining non-intrusive logging capability.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If oil-based mud is used for drilling, then drilling efficiency is improved, but contamination of formation water sample increases

Engineering Contradiction:

Improvedrilling efficiencyVSAvoidformation water contamination

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of oil-based mud contamination into a beneficial diagnostic tool. By measuring how resistivity changes with temperature, the system can identify contamination signatures and either correct for them or use them to infer formation properties, thereby maintaining drilling efficiency while improving measurement reliability.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Device complexity

If single temperature resistivity measurement is used, then measurement process is simplified, but salinity determination accuracy decreases

Engineering Contradiction:

Improvemeasurement process complexityVSAvoidsalinity determination accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent adds another dimension (temperature) to the resistivity measurement. Instead of measuring resistivity at a single temperature point, the system measures across a temperature range, creating a temperature-resistivity profile that provides additional information for accurate salinity determination while systematically managing the increased measurement complexity.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 improved accuracy in determining formation salinity and identifying hydrocarbon-bearing zones, reducing the risk of contamination-related errors and enhancing the reliability of reservoir engineering decisions.

Implementation Method 1

measuring resistivity of a formation fluid sample at a first temperature (T1) and measuring resistivity of the formation fluid sample at a second temperature (T2)

Methodology Applied

Scientific EffectTemperature dependence of resistivity: Electrical Resistance

Data Source

PatentUS20250116624A1Processes for determining formation salinity and identifying oil bearing zones in freshwater pay zones

Publication Date: 2025.04.10 SAUDI ARABIAN OIL CO

AI summary

Processes for determining formation salinity and/or processes for identifying oil bearing and/or water bearing zones in freshwater or relatively low salinity formations. In some embodiments, the process for determining formation water salinity can include measuring resistivity of a formation fluid sample at a first temperature (T1) and at a second temperature (T2), where T1 and T2 can be separated by a temperature difference (ΔT). The process can also include calculating a resistivity factor value based on the resistivities measured at T1 and T2. The process can also include determining a salinity of the formation fluid sample based on the resistivity factor value and the ΔT. The process can also include initiating a downhole operation using the determined salinity of the formation fluid sample.