Downhole Sampling Tool With Expandable Packer And Extendable Probe
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Solution Overview
Problem
Current formation sampling methods face challenges in efficiently isolating and sampling heavy oil from subterranean formations due to contamination with drilling fluids and water, which complicates the cleanup phase and reduces the accuracy of fluid properties measurement.
Innovation Solution
A downhole tool equipped with an expandable packer and an extendable probe is used, where the probe initially moves heavy oil towards the wellbore using higher drawdown pressure, and once the oil reaches the wellbore, the packer takes over to sample the virgin formation fluid, ensuring reduced contamination levels and accurate fluid property analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single sampling device is used to withdraw formation fluid, then the device structure is simple, but the sampling efficiency and cleanup speed are insufficient
Solution Approach 1:
The sampling system is segmented into two distinct functional components: an extendable probe for initial fluid withdrawal and an expandable packer for subsequent sampling. This segmentation allows each component to be optimized for its specific function, with the probe providing focused initial withdrawal and the packer providing broad-area sampling, thereby improving overall sampling efficiency without requiring a single overly complex device
Solution Approach 2:
The downhole tool is designed with multi-functionality by integrating both the extendable probe and expandable packer within a single tool assembly. This allows the tool to perform multiple functions (initial fluid withdrawal and subsequent sampling) in sequence, improving productivity while keeping the overall device structure manageable through modular design
2Stress or pressure
If the extendable probe is used for initial fluid withdrawal, then the drawdown pressure is high enough to move heavy oil, but the sampling surface area is limited
Solution Approach 1:
The extendable probe performs preliminary action by withdrawing formation fluid and moving heavy oil toward the wellbore before the expandable packer is deployed for sampling. This preliminary fluid movement creates the necessary conditions for subsequent effective sampling by the packer, ensuring that heavy oil is positioned appropriately for accurate sampling
Solution Approach 2:
The system transitions dynamically from the extendable probe configuration to the expandable packer configuration. The probe provides high drawdown pressure initially, then the packer expands to provide large sampling surface area. This dynamic transition allows the system to adapt its characteristics to match the different requirements of each sampling phase
3Area of stationary object
If the expandable packer is used for sampling, then the sampling surface area is large, but the device complexity increases
Solution Approach 1:
The expandable packer is designed with a nested structure that allows it to be compact during conveyance and then expand to provide large sampling surface area. The packing elements are stored in a compressed state within the tool body and only expand when needed at the sampling location, thereby providing large sampling area without permanently increasing device complexity
4Device complexity
If formation fluid is sampled without separating heavy oil movement and sampling phases, then the process is simple, but contamination levels are high
Solution Approach 1:
The sampling process is segmented into two distinct phases: heavy oil movement phase (using the extendable probe) and sampling phase (using the expandable packer). This segmentation allows each phase to be optimized independently, ensuring that heavy oil is properly moved to the wellbore first, then clean sampling is performed, thereby improving measurement precision without requiring overly complex integrated processes
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 accelerates the cleanup phase, reduces contamination, and enables more accurate sampling of heavy oil by employing the packer's larger sampling surface area once the oil is at the wellbore, improving the representativeness of the sampled fluid properties.
Implementation Method 1
pumping formation fluid into the downhole tool through the extendable probe to move heavy oil from within the subterranean formation towards the wellbore
Implementation Method 2
the expandable packer includes a drain for withdrawing a second portion of formation fluid into the downhole tool
Data Source
AI summary
A formation sampling method includes disposing a downhole tool that has an expandable packer and an extendable probe within a wellbore disposed in a subterranean formation, pumping formation fluid into the downhole tool through the extendable probe to move heavy oil from within the subterranean formation towards the wellbore, detecting arrival of the heavy oil at the wellbore, and performing formation sampling with the expandable packer in response to detecting the arrival of the heavy oil at the wellbore.