Settable Spotting Fluid for Wellbore Displacement and Sealing
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Solution Overview
Problem
Drilling fluids in subterranean operations often develop gel strength over time, making it difficult to displace them from wellbores, leading to unwanted formation fluid entry during cementing processes, as they are not settable and do not form a rigid sealable mass.
Innovation Solution
A settable composition comprising water, pumice, hydrated lime, and a set retarder, which remains in a pumpable fluid state for extended periods and develops compressive strength when needed, preventing fluid migration and facilitating cementing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If drilling fluid is left static in the wellbore for an extended period, then gel strength increases making displacement difficult, but the drilling fluid does not set into a rigid sealable mass
Solution Approach 1:
The patent changes the fundamental parameter of the fluid from non-settable drilling fluid to settable composition. This transformation allows the material to develop both gel strength and ultimate compressive strength, converting a harmful property (gel strength causing displacement difficulty) into a beneficial sequence where initial gel strength aids displacement while final compressive strength provides sealing.
Solution Approach 2:
The settable composition undergoes a phase transition from fluid state to hardened mass. This phase change enables the material to first remain pumpable for displacement, then transform into a rigid sealable structure that prevents formation fluid entry, resolving the contradiction between displacement ease and sealing capability.
2Ease of operation
If settable spotting composition is used to displace drilling fluid, then displacement is improved, but the composition should not have undesirable increase in gel strength after being static
Solution Approach 1:
The settable composition is designed to perform preliminary displacement action while in fluid state, then subsequently set into a hardened mass. This preliminary action approach allows the composition to be pumped and displaced easily initially, then transform to prevent future gel strength problems and formation fluid entry.
Solution Approach 2:
The patent applies parameter changes by controlling the setting characteristics of the composition to maintain pumpability during displacement operations, then trigger setting after displacement is complete. This parameter control resolves the contradiction by separating the displacement phase (fluid state) from the sealing phase (hardened state).
3Strength
If drilling fluid remains static for long periods, then gel strength increases, but formation fluids can still enter and flow in the wellbore
Solution Approach 1:
The settable composition undergoes phase transition from fluid to hardened mass, providing both initial gel strength for handling and final compressive strength for reliable sealing. This phase transition resolves the contradiction by ensuring that as the material sets, it develops comprehensive strength properties that prevent formation fluid entry.
Solution Approach 2:
The settable composition is a composite material formulation that combines multiple components to achieve both gel strength development and compressive strength formation. This composite approach ensures that the material provides both temporary gel strength during operations and permanent compressive strength for reliable wellbore sealing.
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 settable composition effectively remains fluid for several days, allowing for displacement and subsequent setting to prevent fluid migration, enhancing the success of subterranean cementing operations by maintaining low gel strengths and developing compressive strength as required.
Implementation Method 1
A settable composition comprising water, pumice, hydrated lime, and a set retarder, which remains in a pumpable fluid state for extended periods
Implementation Method 2
develops compressive strength when needed, allowing for effective displacement and sealing in subterranean formations
Implementation Method 3
set into a hardened mass, thereby preventing or reducing the entry or flow of formation fluids in the annulus
Data Source
AI summary
Disclosed herein are settable compositions and methods of using settable compositions in a wellbore. In one embodiment a method of introducing a settable composition into a wellbore is described. The method comprises providing a settable composition comprising pumice, hydrated lime, a set retarder, and water. Introducing the settable composition into a wellbore. Allowing the settable composition to remain static in the wellbore, wherein the settable composition remains in a pumpable fluid state for a period of about 1 day or longer while static in the wellbore.