Wellbore Filter Cake Removal With Delayed Oxidizer Activation
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Solution Overview
Problem
Existing methods for removing filter cakes from wellbores are inefficient, requiring mechanical isolation and taking too long, leading to increased drilling costs and complications due to the rapid breakdown of filter cakes, especially when polysaccharide polymers are present.
Innovation Solution
A method involving the use of an alkaline aqueous fluid with an oxidizing agent and an activating agent, such as aldehydes or polyoxymethylene, to control the breakdown of filter cakes over an extended period, allowing for additional lateral well sections to be drilled without mechanical isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If oxidative breakers are used to break down filter cakes, then the filter cake breakdown time is reduced to several hours, but this is insufficient for drilling multiple lateral well sections before the well goes on suction
Solution Approach 1:
The patent applies preliminary action by introducing the oxidizing agent and activating agent into the wellbore before drilling operations commence, allowing the filter cake breakdown process to begin in advance. The delayed-activation mechanism ensures the breakdown occurs at the optimal time to permit completion of multiple lateral sections before suction begins, effectively preparing the system beforehand without premature breakdown.
Solution Approach 2:
The patent implements periodic action through the delayed-activation mechanism where the oxidizing agent remains dormant initially and then activates at a controlled later time. This creates a periodic pattern of action (initial introduction, dormant period, activation, breakdown) that allows drilling operations to proceed through multiple lateral sections before the filter cake breakdown completes, optimizing the timing to avoid suction conditions.
2Reliability
If mechanical methods are used to isolate already drilled lateral well sections, then isolation is achieved, but this increases costs and time and brings complications
Solution Approach 1:
The patent directly replaces the mechanical isolation system with a chemical breakdown system. Instead of using mechanical devices to isolate and protect already-drilled lateral sections, the invention uses oxidizing agents with delayed activation to chemically break down the filter cake in situ. This substitution eliminates the need for complex mechanical isolation equipment, reducing both device complexity and associated costs while maintaining the functional goal of preventing suction complications.
Solution Approach 2:
The patent introduces an intermediary substance (the oxidizing agent with delayed activation) that mediates between the filter cake and the drilling operations. This intermediary chemical agent facilitates the breakdown process without requiring direct mechanical intervention or isolation devices, simplifying the overall system while achieving the desired isolation effect through controlled chemical action rather than mechanical means.
3Stability of the object's composition
If polysaccharide polymers are present in the filter cake, then the filter cake provides good wellbore stabilization, but the encapsulation of bridging agents within the filter cake substantially increases the time required to remove the filter cake
Solution Approach 1:
The patent applies the extraction principle by selectively targeting and removing the polysaccharide polymer component of the filter cake through oxidation. The oxidizing agent with delayed activation specifically breaks down the polymer structure, extracting and removing this stabilizing component while allowing controlled breakdown timing. This enables the filter cake to maintain its stabilizing function during drilling, then be efficiently removed afterward without the excessive time delays associated with traditional removal methods.
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 method extends the breakdown time of filter cakes to 4-5 days, enabling efficient drilling of multiple lateral well sections by controlling the filter cake integrity, reducing the need for mechanical isolation and associated costs.
Implementation Method 1
a first alkaline aqueous fluid comprising an oxidizing agent... activating the oxidizing agent with the activating agent... decomposing at least a portion of the filter cake by activating the oxidizing agent
Data Source
AI summary
The present disclosure relates to a method for removing a filter cake from a well in a subterranean formation without the need for mechanical isolation. The method comprises the steps of introducing a first alkaline aqueous fluid comprising an oxidizing agent into a borehole, introducing an activating agent selected from the group consisting of an aldehyde, a dialdehyde, a polyoxymethylene, and any suitable combination thereof into the borehole, the activating agent for activating the oxidizing agent, controlling a time frame during which the activating agent activates the oxidizing agent, activating the oxidizing agent with the activating agent, decomposing at least a portion of a filter cake by activating the oxidizing agent with the activating agent, and removing at least a portion of the filter cake from the borehole.