Oil-Immiscible Solvent Cement for Zonal Isolation
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Solution Overview
Problem
Current cementing processes in wellbore operations face challenges in controlling the flow of fluids and managing reservoirs, particularly in multilateral wells where pressure differences between zones can lead to water production from higher pressure zones, reducing overall production.
Innovation Solution
Development of cement compositions containing a cement component, an oil-immiscible solvent, surfactants, and hydration retarders such as polycarboxylate polymers and sulfonated tannins, which set on demand when exposed to water, allowing for better control during cementing operations and zonal isolation by forming a hardened barrier that prevents gas or liquid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cement composition is placed in wellbore for zonal isolation, then formation sealing is improved, but uncontrolled hydration causes premature setting and loss of placement control
Solution Approach 1:
The patent applies preliminary action by incorporating a latent curing agent into the cement composition before placement. This agent remains dormant during pumping and placement operations, allowing the cement to maintain fluidity and be precisely positioned. Upon placement in the wellbore, the latent curing agent activates and initiates hydration, ensuring the cement sets only after proper placement is achieved.
Solution Approach 2:
The patent utilizes parameter changes by employing a latent curing agent that undergoes a state transition from dormant to active. The curing agent is in a latent state during handling and placement, then transitions to an active state upon exposure to wellbore conditions (temperature, pressure, or contact with formation water), triggering controlled hydration. This parameter change enables precise timing control of the setting process.
2Productivity
If cement composition sets quickly upon water contact, then zonal isolation is achieved rapidly, but placement precision is reduced due to premature hardening
Solution Approach 1:
The latent curing agent is prepared and incorporated into the cement composition in advance, but remains inactive during the placement operation. This allows the cement to be pumped and positioned with full control. The preliminary preparation includes formulating the cement with the latent curing agent and any necessary carriers or release agents that keep it dormant until placement.
Solution Approach 2:
The patent employs an intermediary substance (carrier or release agent) that mediates between the latent curing agent and the wellbore environment. This intermediary keeps the curing agent dormant during handling and transport, then allows activation upon placement. The intermediary protects the latent curing agent from premature activation while enabling controlled release when needed.
3Adaptability or versatility
If drilling fluid is removed from wellbore for casing installation, then casing setting is enabled, but additional operational time and complexity are required
Solution Approach 1:
The patent applies universality by developing a cement composition that can serve multiple functions: it acts as both the placement medium and the setting mechanism. The composition maintains fluidity for easy placement into the wellbore around the casing, then self-sets through the latent curing agent activation, eliminating the need for separate drilling fluid removal and cementing operations.
Solution Approach 2:
The cement composition is self-sufficient by incorporating the latent curing agent within its own formulation. The composition places itself into the wellbore in a controlled fluid state, then autonomously activates the curing process through exposure to wellbore conditions. This self-service capability eliminates the need for additional operational steps such as drilling fluid removal or external curing agent injection.
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 cement compositions provide controlled set times and improved zonal isolation, enhancing well production by preventing water production from higher pressure zones and increasing overall hydrocarbon recovery.
Implementation Method 1
reacting the cement composition with the formation water to form a hardened cement
Implementation Method 2
releasing an aqueous fluid stored in the latent curing agent
Data Source
AI summary
Cement compositions may contain a cement component and an oil-immiscible solvent and used in a number of cementing applications. In another aspect, methods for sealing subterranean zones may include emplacing a cement composition into a wellbore containing a cement component and an oil-immiscible solvent, contacting the cement composition with a water source, and reacting the cement composition with the water source to form a hardened cement.