Wellbore Packer System for High-Pressure Formation Testing
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Solution Overview
Problem
Current methods for pressure testing geological formations face challenges in accurately measuring pressure buildup characteristics due to high hydrostatic pressures and mechanical instability of packer elements, leading to inaccurate data and potential deformation.
Innovation Solution
The use of multiple packers to form sealed intervals around a testing tool, with outer guard intervals to control hydraulic pressure and reduce differential pressures across inner packers, stabilizing the sampling interval and facilitating accurate pressure testing by distributing pressure differences across the packers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple packers are used to seal intervals and control hydraulic pressure, then measurement precision and reliability improve, but device complexity increases
Solution Approach 1:
The wellbore is divided into multiple sealed intervals using multiple packers (first packer, second packer, third packer). The inner interval containing the sampling interval is isolated from outer intervals, allowing independent pressure control in each zone. This segmentation enables precise measurement of pressure buildup characteristics by eliminating interference from adjacent zones while distributing the mechanical load across multiple packer elements.
Solution Approach 2:
A fluid communication system acts as an intermediary between the pump and the sealed intervals. The pump reduces pressure in outer intervals through fluid communication, which stabilizes the inner interval by controlling differential pressures across packer elements. This intermediary fluid system enables indirect pressure control and stabilization without direct mechanical intervention in the sampling interval.
2Reliability
If guard intervals are used to control hydraulic pressure, then reliability of pressure testing improves, but device complexity increases
Solution Approach 1:
The guard intervals formed by the first and second packers act as intermediary zones between the wellbore environment and the inner sampling interval. These guard intervals control hydraulic pressure by providing a buffer zone that isolates the sampling interval from pressure fluctuations in the outer wellbore. The third packer creates an additional outer guard interval that further stabilizes the system by distributing differential pressures across multiple sealing elements.
Solution Approach 2:
Different intervals are given different functional qualities: the inner interval is optimized for sampling and pressure measurement, while the outer intervals serve as guard zones for pressure stabilization. The packer elements are strategically positioned to create zones with specific pressure control characteristics, allowing the sampling interval to maintain stable conditions for accurate testing while outer zones handle pressure differential management.
3Stability of the object's composition
If differential pressure across inner packers is reduced, then mechanical stability improves, but pressure testing capability is limited
Solution Approach 1:
The pressure differential is segmented and distributed across multiple packer zones. The first and second packers forming the inner interval experience reduced differential pressure because the third packer creates an outer interval that acts as a pressure buffer. This segmentation allows the inner packers to maintain mechanical stability while the overall system can still handle high wellbore pressures through the outer guard interval.
Solution Approach 2:
The outer interval created by the third packer serves as an intermediary pressure zone that absorbs and distributes differential pressures. This intermediary zone protects the inner sampling interval and its packer elements from extreme pressure differentials, maintaining their mechanical stability. The pump system manipulates fluid pressure in this outer interval to stabilize the inner interval while preserving the ability to perform pressure testing across a wide range of conditions.
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 approach allows for more accurate measurement of pressure buildup characteristics, reduces mechanical instability, and enables pressure testing in wellbores with high hydrostatic pressures, improving the reliability and precision of data collected.
Implementation Method 1
sealing a sample interval around the testing tool, sealing a first guard interval around the testing tool and adjacent to the sample interval
Implementation Method 2
reducing a first pressure in the sample interval, reducing a second pressure in the first guard interval
Implementation Method 3
measuring a plurality of pressure data for a fluid captured in the first chamber during the time interval
Data Source
AI summary
Example methods and apparatus to perform pressure testing of geological formations are disclosed. A disclosed example method comprises positioning a testing tool in a wellbore formed in the geological formation, sealing a sample interval around the testing tool, sealing a first guard interval around the testing tool and adjacent to the sample interval, reducing a first pressure in the sample interval, reducing a second pressure in the first guard interval, maintaining a volume of a first chamber fluidly coupled to the sample interval during a time interval, and measuring a plurality of pressure data for a fluid captured in the first chamber during the time interval.