Recyclable Lost Circulation Fluids for Drilling
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Solution Overview
Problem
Current lost circulation treatments in subterranean formations face challenges such as fluid loss due to quick-reacting materials that require binary delivery and are not readily recyclable, making it difficult to maintain effective wellbore circulation and secondary cement/sealant placement.
Innovation Solution
A recyclable lost circulation composition is developed, comprising a treatment fluid with a polyvalent cation reactive polymer, a delayed source of polyvalent cation, and an acid precursor, which sets under subterranean conditions and can be re-fluidized using a breaker, allowing for efficient plugging and recycling of the material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If quick-reacting lost circulation materials are used to plug loss zones, then fluid loss is prevented effectively, but the materials require binary delivery and cannot be readily recycled
Solution Approach 1:
The patent applies preliminary action by pre-mixing all lost circulation materials (polymer, crosslinker, and delayed acid source) at the surface before injection. The delayed acid source is encapsulated or coated to prevent premature reaction, allowing single-stream delivery while maintaining the reliability of quick setting when the acid is released downhole
Solution Approach 2:
The patent uses an intermediary delayed acid source (encapsulated acid or acid-generating compound) that mediates between the polymer and crosslinker. This intermediary prevents premature crosslinking during transport but enables rapid crosslinking when the acid is released downhole, resolving the contradiction between single-stream delivery and reliable setting
2Reliability
If settable lost circulation materials are used to prevent fluid loss, then circulation is maintained, but the materials are not readily recyclable
Solution Approach 1:
The patent applies discarding and recovering by designing a lost circulation material that can be discarded (set) to maintain circulation, then later recovered (re-fluidized) using a breaker fluid. The breaker fluid reverses the crosslinking reaction, converting the set material back to a pumpable state for removal and recycling, thus resolving the contradiction between reliable circulation maintenance and material recyclability
3Reliability
If binary delivery system is used for lost circulation materials, then reliable plugging is achieved, but operational complexity increases
Solution Approach 1:
The patent applies merging by combining all lost circulation materials (polymer, crosslinker, and delayed acid source) into a single mixable formulation that can be delivered through one stream. The delayed acid source remains inert during transport but activates downhole to trigger crosslinking, achieving reliable plugging with simplified single-stream operation
4Ease of operation
If delayed acid source is used to enable single-stream delivery, then operational simplicity improves, but material composition complexity increases
Solution Approach 1:
The patent applies parameter changes by using a delayed acid source that changes its state from inert (during transport) to active (downhole). The acid is encapsulated or coated with a temperature- or pressure-sensitive barrier that breaks down under downhole conditions, enabling single-stream delivery while controlling the timing of the crosslinking reaction through parameter changes
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 solution enables effective plugging of loss zones, prevents fluid loss, and allows for the recycling of the treatment fluid, improving drilling efficiency and reducing material waste, while being tunable for specific wellbore conditions.
Implementation Method 1
a polyvalent cation reactive polymer and a source of a polyvalent cation, wherein the treatment fluid is settable in the formation to form a solid plug including the polyvalent cation reactive polymer crosslinked with the polyvalent cation
Implementation Method 2
contacting the solid plug with a breaker so as to transform the solid plug into a reclaimed treatment fluid
Data Source
AI summary
A method of drilling may include mixing, at the surface, a base fluid, a polyvalent cation reactive polymer, and a delayed source of polyvalent cation so as to form a treatment fluid; placing the treatment fluid in a subterranean formation to form a solid plug including the polyvalent cation reactive polymer crosslinked with the polyvalent cation; contacting the solid plug with a breaker so as to transform the solid plug into a reclaimed treatment fluid; and removing the reclaimed treatment fluid. A system for drilling may include a treatment fluid, at the surface, including a polyvalent cation reactive polymer, and a delayed source of a polyvalent cation, where the treatment fluid is settable in the formation to form a solid plug including the polyvalent cation reactive polymer and the polyvalent cation; and a breaker, separate from the treatment fluid at the surface, capable of liquefying the solid plug.