Systems for generating geothermal power in an organic Rankine cycle operation during hydrocarbon production based on wellhead fluid temperature
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Solution Overview
Problem
There is a need for systems and methods to generate geothermal power during hydrocarbon production, as existing geothermal generators are not designed to operate effectively at wellheads where high-pressure wellhead fluids are present, and existing solutions do not utilize the geothermal energy available during hydrocarbon production.
Innovation Solution
The implementation of a high-pressure heat exchanger system that can withstand the high pressures and temperatures of wellhead fluids, diverting a portion of the wellhead fluid to transfer heat to an organic Rankine cycle (ORC) working fluid, causing it to change phases and generate electrical power, which can be used to supply in-field equipment, energy storage devices, or the grid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a traditional geothermal generator is used, then it can generate electrical power from geothermal heat, but it cannot withstand the high pressure of wellhead fluids during hydrocarbon production
Solution Approach 1:
The system divides the geothermal power generation function into separate components: a high-pressure heat exchanger that can withstand wellhead fluid pressure, and a separate ORC power generation unit. This segmentation allows each component to be optimized for its specific function - the heat exchanger for pressure resistance and the ORC unit for power generation efficiency.
Solution Approach 2:
The patent introduces an intermediary organic working fluid that transfers thermal energy from the high-pressure wellhead fluid (via the heat exchanger) to the ORC power generation system. This intermediary fluid acts as a buffer, allowing the high-pressure heat source to be decoupled from the power generation mechanism, thus resolving the contradiction between pressure resistance and power generation capability.
2Power
If wellhead fluid is diverted to the heat exchanger for heat transfer, then geothermal power can be generated, but the flow of wellhead fluid to other processing equipment is reduced
Solution Approach 1:
The system diverts only a portion of the wellhead fluid flow to the heat exchanger rather than all of it, allowing simultaneous power generation and maintenance of sufficient flow to other processing equipment. This partial action approach balances energy recovery with production requirements.
Solution Approach 2:
The system changes the flow parameters of wellhead fluid by diverting a controlled portion to the heat exchanger based on temperature and pressure conditions. This dynamic parameter adjustment allows optimization of power generation while maintaining adequate flow for hydrocarbon production processes.
3Adaptability or versatility
If heat exchangers are designed for high pressure to withstand wellhead fluids, then they can be used at the wellhead, but they become more complex and expensive
Solution Approach 1:
The system segments the high-pressure environment from the heat exchanger by placing the heat exchanger in a position where it receives high-pressure fluid through a dedicated connection, while the rest of the ORC system operates at lower pressures. This allows the heat exchanger to be designed specifically for high-pressure thermal exchange without requiring the entire system to be high-pressure rated.
Solution Approach 2:
The patent uses an intermediary arrangement where the high-pressure wellhead fluid transfers heat to an organic working fluid through the heat exchanger, rather than directly driving the ORC components. This intermediary heat transfer approach allows the heat exchanger to be the primary high-pressure component, simplifying the design of other system elements.
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 solution enables the efficient generation of geothermal power at wellheads during hydrocarbon production, utilizing otherwise wasted heat to produce electrical power for operational equipment and potential grid supply, thereby optimizing energy utilization and reducing waste.
Implementation Method 1
The heat exchanger may indirectly transfer heat from the flow of the wellhead fluid to the flow of a working fluid
Implementation Method 2
As heat is transferred from the flow of the wellhead fluid to the flow of a working fluid, such a heat transfer may cause the working fluid to change phases from a liquid to a vapor
Implementation Method 3
The vaporous working fluid may then flow through an ORC unit to cause a generator to generate electrical power via rotation of a gas expander of the ORC unit
Implementation Method 4
The condenser or heat sink may cool the working fluid, causing the working fluid to change phase from the vapor to the liquid
Implementation Method 5
causing the working fluid to change phase from the vapor to the liquid
Data Source
AI summary
Systems and methods for generating and a controller for controlling generation of geothermal power in an organic Rankine cycle (ORC) operation in the vicinity of a wellhead during hydrocarbon production to thereby supply electrical power to one or more of in-field operational equipment, a grid power structure, and an energy storage device. In an embodiment, during hydrocarbon production, a temperature of a flow of wellhead fluid from the wellhead or working fluid may be determined. If the temperature is above a vaporous phase change threshold of the working fluid, heat exchanger valves may be opened to divert flow of wellhead fluid to heat exchangers to facilitate heat transfer from the flow of wellhead fluid to working fluid through the heat exchangers, thereby to cause the working fluid to change from a liquid to vapor, the vapor to cause a generator to generate electrical power via rotation of an expander.