Coiled Tubing Bottom Hole Assembly for Zonal Testing
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Solution Overview
Problem
Current methods for performing Drillpipe Stem Tests (DSTs) are costly and time-consuming, limiting the ability to test multiple zones in an oil and gas well, and using coiled tubing to flow hydrocarbons to the surface poses safety risks due to the single barrier of the coiled tubing.
Innovation Solution
A coiled tubing system with a bottom hole assembly that includes means to isolate the formation, restrict fluid volume, and measure pressure and temperature, featuring a retrievable hydraulically set packer, perforating guns, and safety valves to prevent substantial fluid from reaching the surface, allowing for efficient testing of multiple zones in a single trip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If coiled tubing is used to flow hydrocarbons to the surface, then productivity increases by enabling formation testing, but reliability decreases due to safety risks from single barrier containment
Solution Approach 1:
The system divides the containment function into multiple independent barriers: the coiled tubing wall provides the first barrier, while downhole safety valves and formation isolation tools provide additional barriers. This segmentation ensures that if one barrier fails, others remain to prevent hydrocarbon release, resolving the safety concern while maintaining productivity.
Solution Approach 2:
The system implements preventive safety measures before formation testing begins. Downhole safety valves are pre-positioned and tested, and formation isolation tools are prepared in advance. These beforehand cushioning measures ensure that if unexpected conditions arise during testing, the safety barriers are already in place to prevent catastrophic failures.
2Measurement precision
If drillpipe stem testing is performed on multiple zones, then measurement precision improves by gathering comprehensive reservoir data, but loss of time increases due to requiring multiple trips in the hole
Solution Approach 1:
The coiled tubing system is designed with multi-functionality to perform formation testing on multiple zones during a single trip. The system includes adjustable formation isolation tools and multiple safety valves that can be positioned at different depths, enabling comprehensive reservoir characterization across multiple zones without requiring repeated trips, thus resolving both the measurement precision and time loss concerns.
Solution Approach 2:
The system enables continuous formation testing across multiple zones in a single continuous operation. Rather than interrupting the process for multiple trips, the coiled tubing with its multi-zone capability allows uninterrupted data collection from different formations, maintaining continuous useful action and eliminating time losses associated with repeated deployment and retrieval.
3Loss of time
If coiled tubing is used instead of drillpipe, then loss of time decreases by enabling single-trip multi-zone testing, but device complexity increases due to need for additional safety valves and isolation tools
Solution Approach 1:
The system merges multiple functions into integrated downhole tools. Formation isolation tools and safety valves are combined into unified assemblies that can be deployed together on the coiled tubing. This merging reduces the overall complexity compared to having separate tools for each function, while still enabling single-trip multi-zone testing and reducing time loss.
4Measurement precision
If substantial quantities of formation fluid are drawn to the surface, then measurement precision improves by obtaining sufficient sample volume, but object-affected harmful factors increase due to environmental and safety risks
Solution Approach 1:
The system extracts only the minimum necessary amount of formation fluid required for accurate pressure measurements and analysis. By using sophisticated measurement tools that require small sample volumes, the system takes out only what is needed, avoiding the environmental and safety hazards associated with drawing substantial quantities of formation fluid to the surface while still achieving measurement precision.
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 efficient testing of multiple zones without the safety risks associated with flowing hydrocarbons to the surface, reducing costs and increasing knowledge of reservoir properties and reserve estimation accuracy.
Implementation Method 1
retrievable hydraulically set packer
Implementation Method 2
means to isolate the formation
Implementation Method 3
safety valves to prevent substantial fluid from reaching the surface
Implementation Method 4
restrict the volume of formation fluid drawn from the formation
Implementation Method 5
measuring the formation pressure and temperature
Implementation Method 6
measuring the formation pressure until a required stabilization rate is achieved
Implementation Method 7
measuring the formation pressure and temperature
Implementation Method 8
allowing formation fluid from the hydrocarbon formation to enter the coiled tubing
Data Source
AI summary
A method and apparatus for measuring formation properties comprising coiled tubing fitted with a bottom hole assembly, wherein said bottom hole assembly comprises means to measure formation fluid properties, means to transmit said formation fluid properties to a surface monitoring system, means to isolate a section of a wellbore, and means to control the flow of fluid entering said coiled tubing.