Hyper-Branched Filtrate Reducer for 240°C Saturated-Salinity Drilling Fluids
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Solution Overview
Problem
Existing water-based drilling fluids lack a filtrate reducer that can withstand ultra-high temperatures (≥240°C) and saturated salinity, leading to instability and potential accidents in ultra-deep well drilling.
Innovation Solution
A hyper-branched filtrate reducer composed of anionic hydration-enhancing, cationic adsorption, main chain, cyclic, and polyether monomers, with a three-dimensional broom-like structure, providing strong adsorption and stability under extreme conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a polymer filtrate reducer is designed to resist ultra-high temperature (240°C), then temperature resistance is improved, but salinity resistance deteriorates (only 4% NaCl resistance)
Solution Approach 1:
The patent applies composite material principle by creating a copolymer containing both zwitterionic monomers (for temperature resistance) and quaternary ammonium salt monomers (for salinity resistance). The synergistic combination of different functional monomers in specific ratios enables the filtrate reducer to simultaneously withstand ultra-high temperature and saturated salinity conditions, resolving the contradiction between temperature and salinity resistance.
Solution Approach 2:
The patent applies local quality principle by introducing specific functional groups at different positions of the polymer chain. The zwitterionic groups provide thermal stability while quaternary ammonium salt groups provide salinity resistance. This localized functional distribution within the polymer structure allows different regions to address different environmental challenges simultaneously.
2Adaptability or versatility
If a low-molecular-weight filtrate reducer is designed to resist saturated salinity, then salinity resistance is improved, but temperature resistance deteriorates (only 200°C resistance due to ester monomer degradation)
Solution Approach 1:
The patent applies parameter changes principle by modifying the chemical structure parameters of the polymer. Specifically, replacing ester monomers with amide-containing zwitterionic monomers raises the thermal degradation temperature from 200°C to above 240°C, while maintaining the salinity resistance provided by the quaternary ammonium salt groups. This structural parameter modification resolves the temperature resistance limitation.
3Temperature
If a zwitterionic copolymer filtrate reducer is designed to enhance adsorption capacity at high temperature, then temperature resistance is improved, but resistance to cations (K+, Ca2+) deteriorates (does not meet deep stratum requirements)
Solution Approach 1:
The patent applies merging principle by combining zwitterionic copolymer with quaternary ammonium salt-containing monomers in a copolymer structure. The zwitterionic component provides high-temperature adsorption capacity through its dipole structure, while the quaternary ammonium salt component provides resistance to cations like K+ and Ca2+ through electrostatic repulsion. The merged structure achieves both functions simultaneously, meeting deep stratum drilling requirements.
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 filtrate reducer maintains desirable rheology and long-term stability under 240°C and saturated salinity, effectively reducing filtration loss and supporting safe and efficient ultra-deep well drilling.
Implementation Method 1
a second structural unit provided by a cationic adsorption monomer
Implementation Method 2
a second structural unit provided by a cationic adsorption monomer
Implementation Method 3
a first structural unit provided by an anionic hydration-enhancing monomer
Implementation Method 4
anionic hydration-enhancing monomer
Data Source
AI summary
The present disclosure relates to the technical field of well drilling, and discloses a strongly adsorbed hyper-branched filtrate reducer for water-based drilling fluid with resistance to 240° C. and saturated salinity, a preparation method therefor and use thereof. The filtrate reducer includes a first structural unit provided by an anionic hydration-enhancing monomer, a second structural unit provided by a cationic adsorption monomer, a third structural unit provided by a main chain monomer, a fourth structural unit provided by a cyclic monomer, a fifth structural unit provided by a polyether monomer, and a sixth structural unit provided by a hyper-branched structural monomer. The filtrate reducer of the present disclosure is capable of maintaining desirable rheology and filtrate reduction performance of the drilling fluid, and the long-term stability under the conditions of 240° C. and saturated salinity.