Foamed Acid System In-Situ Nitrogen Generation
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Solution Overview
Problem
Conventional methods for generating foamed acid systems in subterranean formations face challenges due to high energy consumption and limitations in pumping gas or viscous foam, often resulting in low foam quality, which hinders effective acid fracturing and stimulation treatments.
Innovation Solution
The method involves introducing a treatment fluid with an ammonium-containing compound and a nitrite-containing compound, along with a foaming agent, into the subterranean formation, where they react to generate nitrogen gas in-situ, forming a foamed acid system with an average foam quality greater than 52%, reducing the need for external gas injection and enhancing treatment efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas is injected into the acid system prior to injection into the subterranean formation, then a foamed acid system is achieved, but significant energy is consumed and pumping equipment limitations are exceeded
Solution Approach 1:
The foaming agent is pre-added to the acid system before injection, but the actual foam generation occurs in-situ after injection when the acid contacts the formation fluids. This preliminary preparation of the acid system with foaming agent, rather than pre-mixing with gas, reduces the energy required for gas pumping while ensuring foam formation occurs at the desired location and time.
Solution Approach 2:
The patent replaces the mechanical gas injection system with a chemical foam generation system. Instead of using mechanical pumps to inject gas into the acid system, the invention uses chemical reactions between the acid, formation fluids, and foaming agent to generate foam in-situ, eliminating the need for high-energy gas pumping equipment.
2Reliability
If conventional gas injection methods are used, then foam is generated, but the foam quality is insufficient (6.5%-10.3%) to achieve effective foamed acid system
Solution Approach 1:
The patent changes the key parameter of foam quality from low (6.5%-10.3%) to high (>52%) by modifying the foam generation mechanism. Instead of relying on mechanical gas injection that produces low-quality foam, the invention uses chemical reaction-based foam generation with optimized foaming agent concentrations and injection parameters to achieve high foam quality that ensures effective acid stimulation.
Solution Approach 2:
The foaming agent acts as an intermediary substance that facilitates the transformation from simple gas injection to high-quality foam generation. The foaming agent mediates between the acid system and the gas/formation fluids, creating stable foam structures with high foam quality that would not be achievable through direct gas injection alone.
3Productivity
If maximum achievable pressure is increased to improve injection rate, then the rate at which gas may be injected decreases dramatically
Solution Approach 1:
The patent inverts the conventional approach by not injecting gas at high pressure, but instead injecting the foaming agent with the acid and allowing foam generation to occur after injection. This inversion of the foam generation timing and location allows maintaining high injection rates without being constrained by the pressure limitations that would otherwise reduce gas injection effectiveness.
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 generates a high-quality foamed acid system within the formation, increasing permeability and hydrocarbon production by reducing acid reactivity and improving fluid transport capabilities, while minimizing energy consumption and equipment limitations.
Implementation Method 1
The solutions are mixed within the formation to generate a nitrogen gas
Implementation Method 2
allowing the compounds to generate the nitrogen gas in the presence of the foaming agent to form a foam
Implementation Method 3
The acid present in the foamed acid system reacts with soluble substances in the subterranean formation to increase permeability
Data Source
AI summary
A method for treating a subterranean formation with a foamed acid system is disclosed. The method includes introducing a treatment fluid into the formation. The treatment fluid includes a first solution and a second solution. The first solution includes an ammonium containing compound and an acid. The second solution includes a nitrite containing compound. One or both of the solutions further include a foaming agent. The solutions are mixed within the formation to generate a nitrogen gas. The method further includes, allowing the compounds to generate nitrogen in the presence of the foaming agent to form a foam and generate the foamed acid system within the formation. The acid present in the foamed acid system reacts with soluble substances in the subterranean formation to increase permeability of the subterranean formation and enable enhanced production of reservoir fluids.