Thermally Stable Core-Shell Particles for Wellbore Fluid Loss Control
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Solution Overview
Problem
Existing drilling fluids face challenges in maintaining wellbore stability and fluid loss control, particularly in high-temperature environments, due to the instability of conventional core-shell particles and filter cakes, which can alter reservoir permeability and cause formation instability.
Innovation Solution
Development of thermally stable core-shell particles with a polymer shell formed using thermally stable monomers and crosslinkers, such as N-vinylpyrrolidone and divinyl ether, to enhance thermal stability and maintain wellbore integrity at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional core-shell particles are used in drilling fluids, then fluid loss control is provided, but thermal stability deteriorates at high temperatures
Solution Approach 1:
The patent changes the chemical composition parameters of the shell polymer by selecting monomers with high thermal stability (acrylamide, acrylic acid, their salts and derivatives) and using specific crosslinking agents. This parameter change enables the shell to maintain its structural integrity and functional properties at high temperatures up to 350°F, resolving the thermal stability deterioration problem while preserving fluid loss control capability
Solution Approach 2:
The patent creates a composite core-shell particle structure where the shell is formed from a composite of thermally stable polymer monomers and crosslinkers. This composite material approach combines the benefits of different components to achieve both fluid loss control and high thermal stability, with the shell acting as a protective barrier that maintains its filtering function at elevated temperatures
2Reliability
If filter cake is deposited on wellbore walls, then fluid loss into formation is prevented, but reservoir permeability is altered and production is impeded
Solution Approach 1:
The patent applies dynamic properties to the filter cake by incorporating degradable polymers and enzymes that allow the filter cake to change its permeability over time. The filter cake is designed to be dynamically adjustable: highly impermeable during drilling to prevent fluid loss, then degradable during production to restore permeability and eliminate production impairment
Solution Approach 2:
The patent implements a temporary filter cake that serves its purpose during drilling operations and then is deliberately degraded and discarded. The degradable polymer components and enzymatic treatments enable the filter cake to break down into harmless byproducts, restoring reservoir permeability and eliminating the impediment to production while having previously provided effective fluid loss control
3Reliability
If drilling fluid pressure is reduced to minimize formation damage, then fluid loss control improves, but wellbore stability deteriorates
Solution Approach 1:
The patent introduces a specialized filter cake as an intermediary layer between the drilling fluid and the formation. This filter cake acts as a mediator that allows the drilling fluid to maintain higher pressure for wellbore stability while the filter cake itself controls fluid loss into the formation. The filter cake absorbs the conflicting requirements by providing a selective barrier that enables pressure maintenance without proportional fluid loss
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 thermally stable core-shell particles provide improved fluid loss control and wellbore stabilization, allowing for drilling operations in wells with bottom hole circulating temperatures up to 350°F, thereby preserving reservoir permeability and formation integrity.
Implementation Method 1
the polymer of the shell provides resistance to hydrolysis. In some embodiments, the polymer of the shell provides resistance to hydrolysis at temperatures of at least about 350° F.
Implementation Method 2
Drilling and treatment fluids may deposit a layer of particles known as 'filter cake' on the walls of the wellbores within the producing formations. The filter cake may help prevent the drilling and servicing fluids from being lost into the formation
Implementation Method 3
providing a hydrostatic head to maintain the integrity of the wellbore walls and prevent well blowouts
Implementation Method 4
The various functions of a drilling fluid include removing drill cuttings from the wellbore
Data Source
AI summary
A method of servicing a wellbore penetrating a subterranean formation, the method comprising: preparing a wellbore servicing composition comprising: (a) core-shell particles comprising a core and a shell, wherein the shell wholly or partially surrounds the core, and wherein: (i) the core of each of the core-shell particles comprises a particle selected from an inorganic particle or an organic particle; and (ii) the shell comprises a polymer that is a polymerization product of one or more monomers and optionally one or more cross-linkers, wherein the one or more monomers include a thermally stable monomer, the one or more cross-linkers include a thermally stable cross-linker, or wherein the one or more monomers include the thermally stable monomer and the one or more cross-linkers include the thermally stable cross-linker; and (b) a carrier fluid; and placing the wellbore servicing composition into the wellbore, the subterranean formation or both.