Crosslinked Polymeric Fluid Loss Agent for High-Temp Drilling
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Solution Overview
Problem
Existing wellbore drilling fluids face challenges in maintaining viscosity and fluid loss control under high temperature, high pressure, and low pH conditions, leading to formation damage and reduced hydrocarbon production due to the degradation of polymeric additives and filter cakes.
Innovation Solution
A wellbore fluid formulation incorporating a crosslinked and branched polymeric fluid loss control agent formed from acrylamide and sulfonated anionic monomers, which provides enhanced thermal stability and effective fluid loss control, allowing for the use of degradable additives that can be easily removed, thus minimizing formation damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polymeric additives are used in drilling fluids, then fluid loss control is achieved, but the additives degrade under high temperature, high pressure, and low pH conditions leading to formation damage
Solution Approach 1:
The patent modifies the chemical structure of polymeric additives by incorporating crosslinking agents and specific monomer combinations (acrylamide, sulfonated anionic monomers, and optionally carboxylic acid monomers) to change the polymer's stability parameters. This allows the additives to maintain their fluid loss control function while resisting degradation under extreme wellbore conditions of high temperature, high pressure, and low pH.
Solution Approach 2:
The patent creates composite polymeric additives by combining multiple monomers (acrylamide, sulfonated anionic monomers, and carboxylic acid monomers) with crosslinking agents. This composite approach results in a polymer structure that integrates the beneficial properties of each component: acrylamide provides viscosity control, sulfonated monomers provide stability, and crosslinking agents provide structural integrity under extreme conditions.
2Object-affected harmful factors
If degradable additives are used to minimize formation damage, then filter cake removal is improved, but fluid loss control under extreme conditions becomes insufficient
Solution Approach 1:
The patent adjusts the chemical composition parameters of the polymeric additives by selecting specific monomer ratios and crosslinking degrees. This allows the additives to maintain optimal fluid loss control properties while being designed to degrade completely after serving their purpose, minimizing formation damage during production.
Solution Approach 2:
The patent employs polymeric additives that are designed to be temporary and degradable. These additives perform their fluid loss control function during drilling and completion operations, then completely degrade and are removed from the formation, avoiding long-term harm. The crosslinked structure provides temporary stability during operation but allows complete degradation afterward.
3Stability of the object's composition
If crosslinked polymeric fluid loss control agents are used, then thermal stability and viscosity control are improved, but complete removal of filter cakes becomes more difficult
Solution Approach 1:
The patent carefully controls the crosslinking degree and selects specific monomer combinations to achieve the optimal balance. The crosslinking is sufficient to provide thermal stability and viscosity control during drilling, but not so extensive as to prevent complete degradation and removal during production. The carboxylic acid monomer component specifically aids in degradation.
Solution Approach 2:
The patent creates polymeric additives with non-uniform crosslinking density and varying monomer distributions throughout the polymer structure. This local variation allows different regions of the polymer to serve different functions: highly crosslinked regions provide thermal stability during drilling, while less crosslinked regions facilitate degradation and removal during production.
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 maintains stable viscosity and gel strength under extreme conditions, effectively prevents fluid loss, and facilitates complete removal of filter cakes, enhancing hydrocarbon production and reducing the risk of wellbore equipment strain.
Implementation Method 1
a crosslinked and branched polymeric fluid loss control agent formed from at least an acrylamide monomer and a sulfonated anionic monomer
Implementation Method 2
the fluid loss control agent has an extent of crosslinking that is selected so that the fluid loss control agent has a viscosity that is within a peak viscosity response of the viscosity response curve
Implementation Method 3
a crosslinked and branched polymeric fluid loss control agent formed from at least an acrylamide monomer and a sulfonated anionic monomer
Implementation Method 4
filter cake may build up on the walls of a wellbore in which varying sizes and types of particles accumulate
Data Source
AI summary
A wellbore fluid includes a base fluid; and a crosslinked and branched polymeric fluid loss control agent formed from at least an acrylamide monomer and a sulfonated anionic monomer; wherein the fluid loss control agent has an extent of crosslinking that is selected so that the fluid loss control agent has a viscosity that is within a peak viscosity response of the viscosity response curve.