Controlled Wetting System for Shale Formation Friction Reduction
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Solution Overview
Problem
Conventional surfactants and friction reducing polymers used in subterranean treatments often precipitate due to incompatibility, leading to increased friction pressures, clogging, and reduced hydrocarbon recovery in low permeability shale formations.
Innovation Solution
A controlled wetting system comprising a water soluble polymer with a charge, a surfactant with an opposite charge, and a compatibilizer is introduced into the subterranean formation to create or enhance fractures, maintaining compatibility and reducing friction and capillary pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ionic surfactants and friction reducing polymers are used together in treatment fluids, then surface tension reduction and friction loss reduction are achieved, but the surfactant and polymer precipitate due to ionic interaction
Solution Approach 1:
A nonionic surfactant is introduced as an intermediary substance between the ionic surfactant and the friction reducing polymer. The nonionic surfactant acts as a compatibilizer that prevents direct ionic interaction between the cationic/anionic surfactant and the oppositely charged polymer, thereby preventing precipitate formation while allowing both components to function effectively in the treatment fluid.
2Productivity
If surfactants are used to lower surface tension and improve hydrocarbon flow, then capillary pressure decreases and cleanup is facilitated, but friction reducing polymer compatibility is compromised
Solution Approach 1:
The treatment fluid employs a composite surfactant system comprising both ionic surfactant (for surface tension reduction and wettability alteration) and nonionic surfactant (for compatibility with friction reducing polymer). This composite approach allows the fluid to simultaneously achieve improved hydrocarbon recovery through capillary pressure reduction and maintain composition stability by preventing polymer-surfactant precipitation.
3Loss of energy
If friction reducing polymers are added to reduce energy loss in turbulent flow, then horsepower requirements decrease, but the polymers interact with ionic surfactants to form precipitates
Solution Approach 1:
The nonionic surfactant serves as a protective intermediary that surrounds the friction reducing polymer chains, preventing direct electrostatic interaction with ionic surfactants. This allows the polymer to maintain its friction reduction functionality in turbulent flow while the nonionic surfactant barrier prevents precipitate formation that would otherwise occur due to ionic-polymer incompatibility.
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 solution improves hydrocarbon production by reducing water and gas blocks, maintaining compatibility of ionic surfactants and polymers, and enhancing fracture conductivity, thereby increasing water-flow rates and reducing formation damage.
Implementation Method 1
Surfactants, which contain a hydrophilic and a hydrophobic group, are mixed with a treatment fluid, inter alia, to lower the surface tension of the fluid in order to facilitate the cleanup and mitigate formation damage caused by either water blocks or gas condensates
Implementation Method 2
In addition to lowering surface tension, surfactants also may change the formation wettability. This results from a decrease in the capillary pressure of the fluid in the flow channels in the subterranean formation
Implementation Method 3
water soluble polymers have been included in aqueous treatment fluids as friction reducing polymers... to reduce frictional losses due to friction between an aqueous fluid in turbulent flow and tubular goods (e.g. pipes, coiled tubing, etc.) and/or the formation
Data Source
AI summary
Improved treatment fluids and methods for use in subterranean operations including the treatment of low permeability shale formations. In one embodiment the methods comprise: providing a treatment fluid comprising an aqueous base fluid and a controlled wetting system that comprises: a water soluble polymer having a charge, a surfactant having an opposite charge, and a compatibilizer; and introducing the treatment fluid into a subterranean formation.