Foam Stimulation Surfactant Package for Unconventional Reservoirs
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Solution Overview
Problem
Oil and gas wells often experience production decline due to mechanical failures and formation damage, such as fines migration, scaling, paraffins/asphaltenes, clay swelling, water or condensate blockage, and fracturing interactions, leading to reduced economic viability.
Innovation Solution
The method involves providing an existing wellbore in fluid communication with an unconventional subterranean formation, injecting a foamed composition comprising a surfactant package and expansion gas, allowing it to contact the rock matrix, and producing fluids, which includes using a surfactant package with primary and optional secondary surfactants, water, and optionally viscosity-modifying polymers or co-solvents to create a foamed composition with specific interfacial tension and apparent viscosity characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional stimulation methods are used, then production decline can be addressed, but the wellbore requires refracturing which increases complexity and cost
Solution Approach 1:
The patent introduces foam as an intermediary medium to deliver stimulation chemicals to the formation. The foam acts as a carrier that can penetrate formation damage zones and deliver surfactants and proppants without requiring refracturing operations, thus resolving the contradiction between improving productivity and avoiding wellbore complexity
Solution Approach 2:
The patent changes the physical state and delivery parameters of stimulation chemicals by formulating them in foam rather than conventional liquid or gas forms. This parameter change allows the chemicals to be delivered under existing wellbore pressure conditions without requiring refracturing, thereby maintaining simplicity while improving production
2Productivity
If foam is injected to improve permeability, then contact with rock matrix is enhanced, but foam stability must be controlled to prevent premature breakdown
Solution Approach 1:
The patent applies local quality by using different surfactant packages in different regions of the foam formulation. The surfactant package is specifically designed to provide stability in the wellbore environment while allowing controlled breakdown at the formation interface, thus achieving both foam stability during transport and effective contact with the rock matrix upon injection
Solution Approach 2:
The patent creates a composite foam system combining multiple components including surfactants, proppants, and formation damage reversal chemicals. This composite formulation allows the foam to maintain structural integrity during injection while delivering multiple functional components to the formation, resolving the contradiction between stability and effectiveness
3Productivity
If surfactant package is used to reduce interfacial tension, then contact between fluid and rock matrix is improved, but formulation complexity increases
Solution Approach 1:
The patent segments the surfactant system into a dedicated surfactant package component within the foam formulation. This segmentation allows the surfactants to be optimized specifically for reducing interfacial tension with hydrocarbons and improving wetting of the rock matrix, while the rest of the foam formulation maintains its structural integrity, thus resolving the contradiction between improved contact and formulation simplicity
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 enhances hydrocarbon recovery by improving the permeability and contact between the injected fluid and the rock matrix, thereby increasing production from declining wells without refracturing the wellbore.
Implementation Method 1
The foamed composition can comprise a surfactant package comprising a primary foaming surfactant and optionally one or more secondary surfactants
Implementation Method 2
The foam precursor composition can exhibit an interfacial tension (IFT) of less than 0.5 dynes/cm between the foam precursor composition and the hydrocarbons present in the unconventional subterranean formation
Implementation Method 3
The aqueous foam precursor compositions can be foamed with an expansion gas to form foamed compositions for use in the stimulation methods described herein
Implementation Method 4
This approach enhances hydrocarbon recovery by improving the permeability and contact between the injected fluid and the rock matrix
Data Source
AI summary
Disclosed are foam precursor compositions, foamed compositions, and methods of using these foamed compositions for the stimulation of unconventional reservoirs.