Friction Reducing Copolymer for Subterranean Fluids
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Solution Overview
Problem
Aqueous subterranean treatment fluids used in high-rate water fracturing often experience significant energy losses due to friction, and existing friction reducing polymers can interact with formation fines and salts, leading to floc formation that clogs equipment and reduces fluid conductivity.
Innovation Solution
The use of a friction reducing copolymer comprising acrylamide and 2-(2-ethoxyethoxy)-ethyl acrylate, which reduces friction between the treatment fluid and tubular goods and the formation while minimizing flocculation and salt intolerance, is introduced into the subterranean formation to enhance fracture creation and reduce energy losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If friction reducing polymers are added to aqueous treatment fluids, then energy losses due to friction are reduced, but the polymers interact with formation fines and salts to form flocs that clog equipment and reduce fluid conductivity
Solution Approach 1:
The patent changes the chemical parameters of the polymer by selecting specific monomer compositions (acrylamide and 2-(2-ethoxyethoxy) acrylate in specific ratios) and molecular weight ranges to achieve friction reduction without floc formation. This parameter optimization resolves the contradiction by finding the right balance between friction reduction capability and compatibility with formation salts.
Solution Approach 2:
The invention uses a composite copolymer structure combining two different monomers with complementary properties: acrylamide provides friction reduction while 2-(2-ethoxyethoxy) acrylate enhances salt tolerance and prevents floc formation. This composite approach allows the material to simultaneously achieve multiple desired properties without the harmful interactions seen with single polymers.
2Loss of energy
If conventional friction reducing polymers are used, then friction between treatment fluid and tubular goods is reduced, but fluid conductivity is reduced due to floc formation and adsorption onto fracture faces
Solution Approach 1:
The patent optimizes polymer parameters including molecular weight (1,000,000 to 20,000,000 Daltons) and monomer composition ratios to achieve maximum friction reduction while maintaining fluid conductivity. The specific parameter range selection ensures the polymer provides adequate friction reduction without forming flocs that would adsorb onto fracture faces and reduce conductivity.
Solution Approach 2:
The copolymer structure provides different functional segments: one portion interacts with the turbulent flow to reduce friction, while another portion maintains compatibility with formation salts and fracture surfaces to preserve conductivity. This local differentiation of polymer segments allows simultaneous achievement of friction reduction and conductivity maintenance.
3Power
If friction reducing polymers are added to reduce energy losses, then additional horsepower is reduced, but the treatment fluid becomes more sensitive to salts and formation conditions
Solution Approach 1:
The patent changes the chemical composition parameters of the polymer to include 2-(2-ethoxyethoxy) acrylate units that specifically improve salt tolerance. This compositional modification allows the polymer to function effectively in high-salt formation conditions without precipitating or forming flocs, thereby maintaining adaptability while still providing friction reduction benefits.
Solution Approach 2:
The invention converts the potential harm of salt sensitivity into a benefit by designing a polymer that thrives in high-salt environments. The specific copolymer structure is engineered to be compatible with polyvalent metal cations and formation salts, transforming what would normally be a problematic condition into a non-issue, allowing the polymer to provide friction reduction without the usual salt sensitivity problems.
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 copolymer effectively reduces energy losses during fluid introduction, minimizes floc formation, and maintains fluid conductivity, thereby improving the efficiency of subterranean treatments by reducing friction and sensitivity to salts.
Implementation Method 1
friction reducing copolymer that comprises acrylamide and 2-(2-ethoxyethoxy)-ethyl acrylate and introducing the aqueous treatment fluid into the portion of the subterranean formation
Implementation Method 2
The term 'floc' as used herein, refers to a coagulated mass of particles in a liquid. The resulting flocs may be undesirable because, among other things, the flocs may facilitate the formation of agglomerates that may clog pumps, filters, surface equipment and possibly plug fractures.
Data Source
AI summary
Methods of treating a portion of a subterranean formation comprising: providing an aqueous treatment fluid comprising an aqueous fluid and a friction reducing copolymer that comprises acrylamide and 2-(2-ethoxyethoxy)-ethyl acrylate and introducing the aqueous treatment fluid into the portion of the subterranean formation. Methods of fracturing a subterranean formation comprising: providing an aqueous treatment fluid comprising an aqueous fluid and a friction reducing copolymer that comprises acrylamide and 2-(2-ethoxyethoxy)-ethyl acrylate and introducing the aqueous treatment fluid into the subterranean formation at or above a pressure sufficient to create one or more fractures in the subterranean formation. Aqueous treatment fluids comprising: an aqueous fluid and a friction reducing copolymer that comprises acrylamide and an acrylic acid ester.