Oil-Soluble Drag Reducing Agents for Wellbore Acidizing
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Solution Overview
Problem
Conventional water-soluble polymers used in treatment fluids for wellbore operations are ineffective in reducing friction pressure in hydrocarbon-based emulsions, leading to limited flow rates and increased corrosion at high temperatures, especially in deeper wells.
Innovation Solution
A two-phase treatment fluid with a hydrophobic continuous phase and an at least partially dispersed water phase, containing oil-soluble drag reducing agents (DRAs) with a molecular weight greater than 200,000, is used to reduce friction pressure and control acid diffusion in wellbore operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water-soluble polymers are used in treatment fluids, then friction pressure is reduced in water-based fluids, but they are ineffective in hydrocarbon-based emulsions and cause increased corrosion at high temperatures
Solution Approach 1:
The patent changes the solubility parameter of the drag reducing agent from water-soluble to oil-soluble. The conventional water-soluble polymers are replaced with oil-soluble polymers having similar drag-reducing functionality but compatible with hydrocarbon-based continuous phases, thereby maintaining effectiveness in emulsion systems while avoiding corrosion issues
Solution Approach 2:
The patent uses composite material strategy by selecting polymers that combine drag-reducing functionality with oil solubility. The oil-soluble polymers act as composite additives that simultaneously provide friction reduction and compatibility with hydrocarbon-based emulsion systems, resolving the ineffectiveness of conventional water-soluble polymers
2Speed
If treatment fluid flow rate is increased to achieve deeper acid penetration, then turbulence increases and pressure difference increases, but there is an upper limit on pressure handling capacity
Solution Approach 1:
The patent changes the flow regime parameter by reducing turbulence through the addition of oil-soluble drag reducing agents. These polymers modify the fluid's flow characteristics to suppress turbulent fluctuations, allowing higher flow rates to be achieved with lower pressure differences, thereby extending the operational window below the upper pressure limit
3Object-affected harmful factors
If oil-soluble drag reducing agents with high molecular weight are used, then friction pressure is significantly reduced, but the complexity of fluid formulation increases
Solution Approach 1:
The patent optimizes the molecular weight parameter of the oil-soluble polymer within a specific range (100,000 to 10,000,000 g/mol) to achieve effective drag reduction. By specifying this parameter range, the patent balances the drag-reducing effectiveness with formulation simplicity, avoiding the need for complex polymer synthesis or blending while maintaining performance
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 treatment fluid significantly reduces friction pressure, allows deeper acid penetration, and decreases corrosion, resulting in faster and more effective wellbore treatments with reduced energy consumption and equipment corrosion.
Implementation Method 1
oil-soluble drag reducing agents (DRAs) having a weight average molecular weight (Mw) of greater than 200,000... significantly reduces friction pressure
Implementation Method 2
The turbulence is measured by Reynolds number (Re), and it is typically higher than 4,000. Higher turbulence consumes more energy... Water-soluble friction reducers are typically used to reduce the turbulence
Implementation Method 3
The reaction rate between acids and carbonate reservoir rock increases with the increase of reservoir temperature... The acid in the water phase has to diffuse through oil to reach the surface of the carbonate reservoir, which significantly reduces the reaction rate
Implementation Method 4
A two-phase treatment fluid with a hydrophobic continuous phase and an at least partially dispersed water phase... an acid emulsion (acid-in-oil emulsion) based acidizing fluid is used
Data Source
AI summary
A treatment fluid for oilfield applications, such as matrix acidizing and acid fracturing. The treatment fluid is a two-phase fluid with an hydrophobic continuous phase and an at least partially dispersed water phase. The hydrophobic continuous phase can contain 1 ppm to 10 wt %, based on the total weight of the treatment fluid, of one or more types of oil-soluble DRAs having a weight average molecular weight greater than 200,000. The at least partially dispersed water phase can contain water and one or more reactive acids having a pH of 4 or less than 4.