Polymer-Based Latex Drilling Fluid for Shale Stabilization
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Solution Overview
Problem
Current drilling fluids face challenges such as differential sticking, fluid channeling, formation of micro-annuli, fluid invasion, and reduced recovery factors due to inadequate filtration and viscosity, particularly in drilling through low permeability formations like shale.
Innovation Solution
A polymer-based latex drilling fluid composition is developed, comprising a first polymer of polyvinyl alcohol and polyvinyl acetate, and a second polymer derived from styrene, butadiene, and carboxylic acid, with specific molar ratios and concentrations, which forms a stable colloidal dispersion to create a thin filter cake, reduce filtrate loss, and improve viscosity, thereby stabilizing shale formations and enhancing hydrocarbon recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional drilling fluids are used, then drilling operations can proceed, but differential sticking, fluid channeling, and formation invasion occur due to inadequate filtration and viscosity control
Solution Approach 1:
The patent modifies the chemical composition parameters of drilling fluid by incorporating specific polymers (polyvinyl alcohol, polyvinyl acetate, carboxymethyl cellulose) at controlled concentrations (0.1-10 vol%) to optimize filtration and viscosity properties, thereby preventing differential sticking and fluid channeling while maintaining reliable drilling operations
Solution Approach 2:
The patent creates a composite drilling fluid system by combining multiple polymer types (polyvinyl alcohol, polyvinyl acetate, carboxymethyl cellulose) with traditional drilling fluid components, forming a multi-component system that provides synergistic effects for improved filtration control and viscosity management to eliminate harmful effects
2Object-affected harmful factors
If filtration is increased to prevent fluid invasion, then formation protection improves, but drilling fluid viscosity and flow properties deteriorate
Solution Approach 1:
The patent adjusts filtration parameters by controlling polymer concentration (0.1-10 vol%) and molecular characteristics to form optimal filter cakes that reduce fluid invasion while preserving adequate viscosity and flow properties for efficient drilling fluid circulation
Solution Approach 2:
The patent applies different polymer components with specific local functions: polyvinyl alcohol and polyvinyl acetate for filtration control at the formation interface, and carboxymethyl cellulose for bulk viscosity management, allowing simultaneous reduction of fluid invasion and maintenance of circulation efficiency
3Loss of substance
If polymer concentration is increased to improve viscosity, then fluid loss control improves, but filter cake thickness and formation damage increase
Solution Approach 1:
The patent optimizes polymer concentration parameters within a specific range (0.1-10 vol%) to achieve adequate filtration loss control while preventing excessive filter cake formation, balancing fluid loss reduction with formation protection
Solution Approach 2:
The patent uses partial hydrolysis of polyvinyl acetate (80-99% hydrolysis) to create a blend of polyvinyl alcohol and polyvinyl acetate that provides effective filtration control at lower overall polymer concentrations, preventing both fluid loss and excessive filter cake thickness
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 polymer-based latex drilling fluid composition effectively reduces differential sticking, fluid channeling, and filtration losses, improves viscosity, and stabilizes shale formations, leading to increased hydrocarbon recovery and improved well performance by forming a thin filter cake and bridging low permeability formations.
Implementation Method 1
Forming the first polymer includes stirring the second mixture for a first specified time duration sufficient to hydrolyze at least a portion of the polyvinyl acetate into polyvinyl alcohol and form the first polymer
Implementation Method 2
Forming the second polymer includes stirring the fourth mixture for a second specified time duration sufficient for carboxylation of the styrene-butadiene to occur and form the second polymer
Implementation Method 3
A polymer-based latex drilling fluid composition is developed, comprising a first polymer of polyvinyl alcohol and polyvinyl acetate, and a second polymer derived from styrene, butadiene, and carboxylic acid, with specific molar ratios and concentrations, which forms a stable colloidal dispersion to create a thin filter cake
Data Source
AI summary
A drilling fluid composition includes a latex including a first polymer and a second polymer. The first polymer includes polyvinyl alcohol and polyvinyl acetate. A molar concentration of the polyvinyl alcohol in the first polymer is greater than 80% and less than 100%. The second polymer has a general structure in which x is an overall molar ratio of styrene in the second polymer, y is an overall molar ratio of butadiene in the second polymer, and z is an overall molar ratio of carboxylic acid in the second polymer. A sum of x, y, and z is represented as s. Styrene (x) is in a range of from about 20% to about 30% of s. Butadiene (y) is in a range of from about 70% to about 80% of s. Carboxylic acid (z) is in a range of from about 1% to about 5% of s.