Downhole Solvent Extraction Sampling Tool for Heavy Oil
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for sampling and analyzing heavy oil and bitumen from subsurface reservoirs face challenges such as contamination, high viscosity variations, and difficulty in obtaining accurate fluid property measurements, especially in deep, buried reservoirs where fluids do not flow naturally, leading to inefficient recovery and production strategies.
Innovation Solution
A system comprising a sampling device with a cylindrical member and a penetration device that cleans the borehole wall, injects a solvent to extract oil and water samples, and uses in situ analysis to determine fluid properties like viscosity, using sensors and solvents like dichloromethane and methanol to obtain accurate and clean samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sampling methods are used to obtain reservoir fluid samples, then sampling can be performed, but the samples become contaminated and degraded
Solution Approach 1:
The system performs preliminary cleaning of the borehole wall using a rotating cleaner with brushes or abrasive elements before sampling. This removes contaminated layers and mud cakes that would otherwise contaminate the fluid sample, ensuring sample accuracy is maintained from the outset
Solution Approach 2:
A solvent extraction system acts as an intermediary between the reservoir and sampling apparatus. The solvent (e.g., dichloromethane, methanol) extracts fluid components from the cleaned borehole wall, separating the target analytes from contaminants and preventing direct contact between the sample and contaminated sampling surfaces
2Measurement precision
If deep reservoirs are sampled using conventional methods, then subsurface resources can be accessed, but fluid property measurements become inaccurate due to high viscosity variations
Solution Approach 1:
The system replaces mechanical direct sampling with solvent extraction and spectroscopic analysis. Instead of physically retrieving and measuring fluids from great depths, the system uses optical sensors (FTIR, Raman, NMR) to detect fluid properties through spectroscopic signatures, eliminating mechanical transmission errors and viscosity-related measurement inaccuracies
Solution Approach 2:
The system changes the measurement parameter from direct physical measurement of viscous fluids to spectroscopic parameter detection. By measuring absorption, emission, or resonance characteristics of the fluid molecules, the system obtains accurate fluid property data (composition, viscosity, density) without being affected by the fluid's physical state or depth-related pressure/temperature variations
3Loss of time
If in situ analysis is implemented, then real-time fluid property data can be obtained, but device complexity increases
Solution Approach 1:
The system integrates multiple functions into a single downhole tool: the solvent injection system, the spectroscopic sensor package, the data processing unit, and the communication system all work together in one device. This multi-functionality enables real-time analysis without requiring separate sampling, transport, and analysis systems, making the increased capability practical for field deployment
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
Enables accurate, in situ determination of fluid properties and sampling of heavy oils and bitumens, reducing contamination and sample degradation, allowing for more effective well placement and production strategies by providing real-time viscosity data and overcoming the limitations of conventional sampling methods.
Implementation Method 1
a solvent injecting device configured to extend from the sampling tube and inject a spectroscopically distinct polar solvent into the reservoir, wherein the solvent extracts a fluid sample from the reservoir
Implementation Method 2
a pump configured to withdraw fluid from the reservoir into the solvent injecting device, the fluid including the solvent and the fluid sample
Data Source
AI summary
Techniques for sampling a subsurface reservoir include lowering a downhole logging tool comprising one or more samplers, a cleaner system, and a sample probe bit into a borehole until at least one sampler is positioned correctly in a subterranean reservoir; advancing the cleaner system into the reservoir cleaning mud filtrate and contaminated reservoir material away into a mud column; advancing the sample probe bit into the reservoir; and solvent is injected into the reservoir from the solvent reservoir.