Crosslinked PVP Fluid Loss Pill for High Temperature Drilling
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Solution Overview
Problem
Conventional fluid loss control pills cause formation damage and are not effective at high temperature, high pressure conditions, leading to reduced production and incomplete removal of filter cakes.
Innovation Solution
A composition comprising an aqueous base fluid, crosslinked polyvinylpyrrolidone (PVP), and a betaine-based polymer, which provides improved thermal stability and viscosity, reducing fluid loss without damaging formation permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fluid loss additives (oil-soluble resins, calcium carbonate, graded salt) are used to control fluid loss, then fluid loss control is achieved through filter-cake build up, but formation permeability is severely damaged and requires costly restoration
Solution Approach 1:
The patent changes the chemical parameters of fluid loss additives by using biodegradable polymers with specific molecular weights and functional groups instead of conventional oil-soluble resins and calcium carbonate. This parameter change allows the additive to provide fluid loss control while being naturally degraded by formation microorganisms, thus avoiding formation damage.
Solution Approach 2:
The patent employs biodegradable polymer additives that perform their fluid loss control function temporarily and then degrade naturally in the formation environment. These short-living additives fulfill their purpose during drilling operations and then decompose without leaving harmful residues, eliminating the need for expensive formation restoration.
2Reliability
If polymeric materials are used to viscosify wellbore fluids and provide fluid loss control, then fluid loss control is improved, but the polymers degrade under HTHP conditions causing loss of viscosity and additional strain on equipment
Solution Approach 1:
The patent uses composite polymeric materials that combine multiple functional groups and structural features within a single polymer chain. These composite polymers incorporate heat-resistant aromatic rings, pressure-stable aliphatic chains, and crosslinkable functional groups, allowing the material to maintain viscosity and structural integrity under high temperature and pressure conditions while providing effective fluid loss control.
Solution Approach 2:
The patent introduces local quality variations within the polymer structure by incorporating different functional segments at specific positions along the polymer chain. Heat-resistant aromatic segments are positioned to provide thermal stability, while crosslinkable segments are strategically placed to form a three-dimensional network that resists degradation under HTHP conditions, thereby maintaining fluid loss control effectiveness.
3Reliability
If cellulose and cellulose derivatives are used as viscosifiers, then fluid loss control is provided, but they degrade at temperatures around 200°F causing loss of viscosity
Solution Approach 1:
The patent fundamentally changes the thermal stability parameter of fluid loss additives by replacing cellulose-based polymers with synthetic polymers containing aromatic rings and crosslinkable functional groups. This parameter change raises the degradation temperature from around 200°F to above 400°F, allowing the additive to maintain viscosity and fluid loss control effectiveness in high-temperature wellbore environments.
4Stability of the object's composition
If xanthan gum is used as a viscosifier stable up to 290-300°F, then thermal stability is improved, but expensive and corrosive breaker fluids are required to remove filter cakes and residues
Solution Approach 1:
The patent employs biodegradable polymer additives that naturally decompose in the formation environment through microbial action. These short-living additives perform their fluid loss control function during drilling operations and then degrade into harmless byproducts, eliminating the need for expensive and corrosive breaker fluids to remove filter cakes and residues.
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 fluid loss pills exhibit superior thermal stability and viscosity, effectively controlling fluid loss at high temperatures and maintaining formation permeability, with enhanced gel strength and prolonged performance up to 400°F.
Implementation Method 1
a crosslinked polyvinylpyrrolidone (PVP) and a betaine based polymer
Implementation Method 2
enhanced gel strength
Implementation Method 3
rely on filter-cake build up on the face of the formation to inhibit flow into and through the formation
Implementation Method 4
to isolate the fluids from the formation by providing sufficient hydrostatic pressure
Data Source
AI summary
Compositions herein may include an aqueous fluid, a crosslinked polyvinylpyrrolidone (PVP), and a betaine based polymer. Methods herein may include pumping a selected amount of a fluid loss pill into a formation, the fluid loss pill including a crosslinked PVP and a betaine based polymer.