Superabsorbent Polymer Casing Flush Fluid for Proppant Removal
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Solution Overview
Problem
Current methods for casing flush and well cleanout fluids are inefficient in removing residual proppant from horizontal wells, leading to premature plug setting, failure to isolate zones, and reduced well productivity due to overflushing, which increases pumping time and chemical costs.
Innovation Solution
The use of superabsorbent polymers in casing flush and cleanout fluids, which effectively suspend and transport proppant from the wellbore to the fracture, allowing for reduced fluid volumes and improved wellbore cleanliness, enabling efficient bridge plug setting and maintaining proppant in the near wellbore region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional fluid is pumped above that required to flush the casing volume, then proppant removal is improved, but pumping time and chemical costs increase
Solution Approach 1:
The patent changes the physical-chemical parameters of the flush fluid by incorporating polymers (such as hydroxyethyl cellulose, xanthan gum, or polyacrylamide) that increase fluid viscosity and improve suspension capabilities. This allows the fluid to effectively carry proppant with reduced volumes, eliminating the need for excessive pumping while maintaining or improving proppant removal effectiveness.
Solution Approach 2:
The invention uses composite fluid formulations combining base fluids with polymer additives and potentially other chemicals to create a multi-functional flush fluid. This composite approach enhances the fluid's ability to suspend and transport proppant efficiently, achieving effective cleaning with optimized fluid volumes and reduced pumping time.
2Reliability
If additional fluid is pumped above that required to flush the casing volume, then proppant removal is improved, but chemical costs increase
Solution Approach 1:
By modifying the chemical composition of the flush fluid through polymer additives, the patent enhances the fluid's proppant-carrying capacity per unit volume. This allows effective proppant removal with smaller fluid volumes, reducing the total chemical consumption and associated costs while maintaining removal effectiveness.
Solution Approach 2:
The patent references and builds upon existing polymer technologies used in drilling and completion fluids, adapting proven polymer formulations for casing flush applications. This leverages established chemical solutions rather than requiring entirely new chemical developments, optimizing cost-effectiveness.
3Reliability
If overflush of the wellbore is performed, then proppant is removed from the casing, but proppant is displaced further into the fracture
Solution Approach 1:
The patent modifies the fluid properties through polymer additives to optimize the balance between casing cleaning and proppant placement. The enhanced suspension and carrying capabilities allow proppant to be effectively removed from the casing while maintaining controlled delivery to the fracture, preventing excessive displacement into distant fracture regions and preserving proppant in the near wellbore area.
Solution Approach 2:
The invention creates localized optimization by tailoring the flush fluid properties to address specific zone requirements - effectively cleaning the casing in the immediate wellbore area while controlling proppant distribution patterns to maintain adequate proppant presence in the near wellbore fracture region.
4Quantity of substance
If conventional flush fluid is used, then fluid volume is reduced, but proppant suspension and transport capability is insufficient
Solution Approach 1:
The patent fundamentally changes the physical parameters of the flush fluid by incorporating polymer additives that increase viscosity and improve suspension characteristics. This allows the use of reduced fluid volumes while maintaining or enhancing proppant suspension and transport capabilities through the modified rheological properties of the polymer-enhanced fluid.
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
Superabsorbent polymers enhance the efficiency of proppant removal and transport, reducing the need for excessive fluid volumes, minimizing well productivity losses, and facilitating the proper setting of bridge plugs, while allowing for the recycling and reuse of the polymers.
Implementation Method 1
a superabsorbent polymer present in an amount effective to suspend and carry proppant from the wellbore
Implementation Method 2
superabsorbent polymer...suspend and carry proppant
Data Source
AI summary
A method of removing residual proppant from a bottom of a casing after a fracturing operation comprises: circulating a casing flush fluid comprising a carrier and a superabsorbent polymer in the casing; and transporting the residual proppant from the bottom of the casing to a fracture created by a hydraulic fracturing operation. A method for cleaning a wellbore comprises: introducing a cleanout fluid through a conduit inserted into the wellbore, the cleanout fluid comprising a carrier fluid and a superabsorbent polymer; and receiving a returning fluid comprising debris at the surface of the wellbore from an annular space between the conduit and a wall of the wellbore.