Recirculating Core Flooding Apparatus for Stable Backpressure Control
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Solution Overview
Problem
Existing methods for determining residual saturation and flow properties of core samples from hydrocarbon-bearing reservoirs face challenges in maintaining stable backpressure and equilibrium during fluid flooding, leading to inaccurate measurements of single and multiphase flow properties.
Innovation Solution
A recirculating, constant backpressure apparatus and method for flooding core samples with fluids, utilizing dual-cylinder injection pumps and a high-volume separator pressure regulator to maintain stable backpressure and equilibrium, allowing for full recirculation of fluids over a large range of flow rates and reducing uncertainties in residual saturation measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional flooding methods are used to determine flow properties of core samples, then fluid can be injected through the core, but stable backpressure and equilibrium cannot be maintained, leading to inaccurate measurements
Solution Approach 1:
The system employs a backpressure regulator that continuously monitors outlet pressure and adjusts the regulating valve position in real-time to maintain constant backpressure. This feedback control mechanism ensures stable equilibrium conditions throughout the flooding process, enabling accurate measurement of flow properties without pressure fluctuations.
Solution Approach 2:
The invention changes the pressure parameter control method by implementing a regulated backpressure system that actively maintains constant outlet pressure. This parameter control transformation from unregulated to regulated pressure conditions enables reliable and repeatable flow property measurements by eliminating pressure instability.
2Quantity of substance
If additional fluids are used to maintain flooding experiments, then fluid availability is improved, but system complexity and fluid management requirements increase
Solution Approach 1:
The system implements a recirculation configuration where effluent from the core outlet is returned to the inlet through a recirculation line. This allows the same fluid to be reused multiple times throughout the flooding experiment, eliminating the need for continuous addition of fresh fluids while simplifying fluid management and reducing system complexity.
3Adaptability or versatility
If pressure and temperature variations occur during flooding, then flow conditions change, but unintended saturation variations are generated, introducing uncertainties in residual saturation measurements
Solution Approach 1:
The backpressure regulator provides continuous feedback control of outlet pressure, automatically adjusting to maintain constant pressure conditions. This feedback mechanism prevents pressure variations that would otherwise cause unintended saturation changes and measurement uncertainties, ensuring accurate residual saturation measurements while maintaining adaptable flow conditions.
Solution Approach 2:
The system provides beforehand cushioning against pressure and temperature variations by implementing a regulated backpressure system and recirculation configuration before variations can affect the core. This preventive approach stabilizes flow conditions and prevents saturation variations before they occur, protecting measurement accuracy.
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
The apparatus provides stable and accurate measurements of single and multiphase flow properties, minimizing the need for additional fluids and reducing uncertainties introduced by pressure and temperature variations, resulting in more reliable fluid displacements and improved characterization of core samples.
Implementation Method 1
A recirculating, constant backpressure apparatus for flooding a core with at least one chosen fluid
Implementation Method 2
Fluid saturation may be measured using x-ray attenuation
Implementation Method 3
Core flooding measurements for determining material permeability to various fluids as a function of temperature and pressure have been performed using computed tomography (CT) technology
Implementation Method 4
creating a more stable equilibrium between the phases throughout the apparatus
Data Source
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AI summary
An apparatus and method for simulating production conditions in hydrocarbon-bearing reservoirs, as an example, by flooding of core samples from such reservoirs, are described. Full recirculation flow measurements permit several fluids (for example, crude oil, brine, and gas) to be simultaneously injected into core samples having varying dimensions. Accurate and stable back pressures are maintained at total flow rates of as high as 200cc/min., for a large range of fluid viscosities. Accurate and stable net overburden pressures relative to pore pressure are also maintained, thereby simulating the formations at depth. Core samples from formations may also be investigated using the apparatus and method hereof, for carbon dioxide sequestration potential, as another example.