Super-cooled CO2 Fracturing Fluid for Tight Formations
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Solution Overview
Problem
Hydraulic fracturing in tight, hard rock formations often requires high breakdown pressures that exceed the limits of tubulars and pumping systems, making it difficult to fracture and produce hydrocarbons effectively.
Innovation Solution
The method involves super-cooling liquid carbon dioxide using liquid nitrogen to create a thermal shock in the hydrocarbon formation, reducing the breakdown pressure by injecting the cooled fluid into the formation, which is then followed by pumping fracturing fluid containing proppants to maintain fractures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If high hydraulic pressure is used to fracture tight, hard rock formations, then the breakdown pressure is sufficient to create fractures, but the pressure exceeds the pressure rating of the tubulars and pumping systems
Solution Approach 1:
The invention changes the temperature parameter of the fracturing fluid by super-cooling it to below its freezing point using liquid nitrogen. This temperature parameter change induces thermal shock in the formation, which reduces the breakdown pressure required for fracturing, thereby resolving the contradiction between achieving sufficient breakdown pressure and staying within tubular pressure ratings.
Solution Approach 2:
The invention applies preliminary thermal shock to the formation by injecting super-cooled fluid before the main fracturing operation. This preliminary action reduces the in-situ stress and breakdown pressure of the formation, making subsequent fracturing possible within equipment pressure limits.
2Productivity
If conventional hydraulic fracturing is applied to tight, hard rock formations, then fractures can be created, but the process becomes impossible when breakdown pressure exceeds equipment limits
Solution Approach 1:
The invention changes the physical state and temperature of the fracturing fluid by super-cooling it, which fundamentally alters the pressure requirements for fracturing. This parameter change enables effective fracturing of tight formations without requiring pressures that exceed equipment capabilities.
Solution Approach 2:
The invention replaces the purely mechanical approach of high-pressure fracturing with a thermal-mechanical approach. By using super-cooled fluid to induce thermal shock, the system substitutes thermal energy for mechanical pressure, reducing the mechanical pressure requirements while maintaining fracturing effectiveness.
3Stress or pressure
If super-cooled liquid carbon dioxide is injected into the formation, then thermal shock is created and breakdown pressure is reduced, but additional cooling equipment and infrastructure are required
Solution Approach 1:
The invention utilizes phase transitions of carbon dioxide, cooling it to below its freezing point to create a super-cooled liquid state. This phase transition enables the thermal shock effect that reduces breakdown pressure. The system uses liquid nitrogen as a cooling medium to achieve this phase transition and super-cooling.
Solution Approach 2:
The invention uses liquid nitrogen as an intermediary cooling medium to super-cool the carbon dioxide fracturing fluid. The liquid nitrogen serves as a heat exchange medium that transfers thermal energy from the CO2, enabling the CO2 to reach super-cooled temperatures without requiring direct contact with liquid nitrogen injection into the formation.
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 reduces the required breakdown pressure, allowing effective fracturing of hard rock formations within the limitations of pumping and tubular pressure ratings, while being cost-effective and easy to install, and provides a super-cooled liquid to induce thermal shock and lower in-situ stress.
Implementation Method 1
super-cooling liquid carbon dioxide to a temperature between −60° F. to −70° F. using liquid nitrogen having a temperature in a range of −100° F. to −200° F., as a heat exchanging medium
Implementation Method 2
injecting a cold liquid into the hot, hydrocarbon formation to create a thermal shock in the reservoir which helps lessen the in-situ stress of the reservoir and decrease the breakdown pressure
Data Source
AI summary
A method of fracturing a subsurface formation includes super-cooling liquid carbon dioxide to a temperature between −60° F. to −70° F. using liquid nitrogen having a temperature in a range of −100° F. to −200° F., pumping the lipid carbon dioxide down a wellbore to create fractures in the subsurface formation, and pumping fracturing fluid containing a proppant down the wellbore after pumping the liquid carbon dioxide down the wellbore.