Downhole Tracer Testing for Directional Permeability and Mobility
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Solution Overview
Problem
Existing well testing methods face challenges in determining horizontal permeability in various geographic directions, require large fluid volumes for accurate testing, pose safety and environmental risks due to surface production, and lack precise measurement of permeability and mobility over time, especially during the exploration and appraisal phases.
Innovation Solution
A method and apparatus for drilling a main production wellbore with sidetracked injection wellbores, releasing chemical tracers, and performing downhole production tests using a well test system with sensors to detect tracer signatures, allowing for directional permeability and mobility measurements, and enabling 4D reservoir mapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional drill stem test method is used to produce large volumes of formation fluids to surface for extensive reservoir testing, then the production volumes are sufficient to identify reservoir boundaries and map the extent of the reservoir, but safety risks increase due to receiving produced fluids at high pressure on surface and environmental effects occur from pollution and CO2 emission when burning the produced hydrocarbons
Solution Approach 1:
The invention extracts the harmful flammable hydrocarbon component from the produced formation fluids and separates it from the aqueous phase. The hydrocarbon layer is diverted to a flare stack for controlled burning, while the aqueous phase is reinjected into the formation, thereby eliminating the need to handle large volumes of high-pressure fluids at the surface and avoiding the environmental problems associated with conventional flaring.
Solution Approach 2:
The invention introduces an intermediary separation and diversion system that acts as a mediator between the formation fluids and the surface environment. This system separates the produced fluids into hydrocarbon and aqueous phases, diverts the hydrocarbon phase to controlled flaring, and reinjects the aqueous phase, thereby mediating the harmful effects of direct surface reception and burning of large volumes of formation fluids.
2Object-affected harmful factors
If wireline formation tester or Logging While Drilling formation tester is used to test formation fluids downhole, then safety risks and environmental effects are reduced by avoiding surface production, but the testing volume is limited to small scale with only a few litres capacity
Solution Approach 1:
The invention employs dynamic flow control mechanisms including chokes and valves that can be adjusted during the testing process. The system dynamically balances the drawdown flow from the formation with the capacity of the sample chamber and the reinjection rate, allowing the testing volume to be significantly increased beyond static small-scale testers while maintaining safe downhole operation.
Solution Approach 2:
The invention nests multiple functional components within the wellbore system: the sample chamber is positioned within the wellbore, the diversion system is integrated into the flow path, and the reinjection system is nested within the same wellbore structure. This nested arrangement allows for large-volume testing capability while maintaining a compact downhole footprint and avoiding surface production infrastructure.
3Device complexity
If conventional well testing methods are used without directional measurement capability, then the testing process is simpler, but the ability to determine horizontal permeability in various geographic directions and variations in permeability and mobility depending on flow direction cannot be achieved
Solution Approach 1:
The invention adds the dimensional aspect of directional measurement by incorporating flow meters and sensors oriented in multiple directions (vertical, horizontal, and at various angles). This allows the system to measure fluid flow and tracer concentration not just in magnitude but also in directional components, enabling the calculation of directional permeability and mobility values that reveal anisotropic reservoir characteristics.
Solution Approach 2:
The invention replaces simple mechanical flow measurement with advanced sensing technology including electromagnetic or acoustic flow meters that can detect flow direction and velocity in multiple dimensions. Tracer detection uses sophisticated analytical instruments that can precisely measure tracer concentration and calculate directional transport parameters, substituting complex measurement systems for simple testing procedures to achieve enhanced 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 safe, high-volume downhole testing with precise measurement of directional permeability and mobility, reducing environmental impact and providing real-time reservoir data for optimal well placement and management strategies.
Implementation Method 1
a device for detecting the chemical signature of the tracers upon entry into the well testing system
Data Source
AI summary
A method and apparatus for characterizing reservoir properties when producing formation fluids from a subsurface formation by releasing material(s) with distinct signature(s) into the formation fluids, allowing said material to flow through the reservoir with the formation fluids, registering the receipt of said material in a downhole well testing system or on surface of a production well, and determining the time, distance and direction of travel for the said material and using these parameters to determine permeability and/or mobility in the relevant direction of flow in the reservoir. Upon completion of a well test, the formation fluids may be re-injected into the formation it was produced from. The well testing system further includes downhole sensors for measuring parameters characterizing the formation fluids and a two-way communication system for transmitting information to surface.