Carbonyl Diversion Agent for Selective Fracture Plugging
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Solution Overview
Problem
Conventional methods for increasing fracture surface area and controlling fluid flow in subterranean formations, such as geothermal reservoirs and oil/gas fields, result in non-uniform flow patterns and inefficient heat exchange due to the creation of high and low permeability fractures, leading to compromised productivity and costly remediation processes.
Innovation Solution
Injecting a diversion agent comprising a carbonyl compound and an alkaline-earth halide salt into the formation to form a carbonate precipitate, which selectively blocks high-flow fractures and allows for controlled stimulation and plugging of fractures, thereby improving flow distribution and reducing downtime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydraulic stimulation is used to increase fracture surface area, then permeability increases, but flow becomes non-uniform with reduced heat exchange capability
Solution Approach 1:
The patent applies local quality by making different fractures have different permeability characteristics. High-flow fractures are selectively plugged with precipitated material while low-flow fractures remain open, creating spatially varying flow properties that distribute fluid uniformly across multiple fracture pathways, thereby improving heat exchange efficiency
Solution Approach 2:
The patent changes the permeability parameter of specific fractures by injecting a diversion agent that precipitates solid material within high-flow fractures. This chemical parameter change (from high to low permeability) in selected zones redistributes fluid flow to enhance overall heat exchange capability
2Area of stationary object
If additional stimulation is applied to increase surface area, then fracture permeability increases, but high-flow fractures expand further reducing effect on low-flow fractures
Solution Approach 1:
The patent applies preliminary anti-action by first injecting a diversion agent that precipitates and plugs high-flow fractures before conducting additional stimulation. This pre-plugging prevents further expansion of dominant fractures during subsequent stimulation, ensuring that new stimulation energy creates additional fracture surface area rather than merely enlarging existing high-flow pathways
Solution Approach 2:
The patent performs preliminary plugging of high-flow fractures with precipitated material before conducting additional hydraulic stimulation. This preliminary action modifies the flow regime in advance, so that subsequent stimulation creates more uniform flow distribution across the fracture network rather than concentrating flow in already-dominant pathways
3Productivity
If cement is used to plug high-flow fractures, then flow control is achieved, but removal requires expensive drilling operations
Solution Approach 1:
The patent uses a soluble precipitated material (calcium carbonate or barium sulfate) formed from chemical reaction between injected reagents and formation water. This material provides temporary plugging that can be easily removed by injecting acid or other dissolving agents, eliminating the need for expensive drilling operations required to remove cement plugs
Solution Approach 2:
The patent employs a plugging material that can be discarded (precipitated to plug fractures) and then recovered (dissolved by acid injection) when needed. The precipitated calcium carbonate or barium sulfate serves as a temporary barrier that can be completely removed by chemical dissolution, allowing restoration of original flow patterns without mechanical removal operations
4Productivity
If packers are used for plugging, then flow control is achieved, but removal requires expensive fishing procedures
Solution Approach 1:
The patent replaces mechanical packers with a chemical precipitate that provides temporary plugging. The precipitated material can be easily dissolved and removed by injecting acid or other dissolving agents, eliminating the time-consuming and expensive fishing operations required to retrieve stuck packers
5Productivity
If sodium silicate precipitation is used for plugging, then high-flow fractures are blocked, but the precipitate cannot be subsequently removed
Solution Approach 1:
The patent employs precipitated materials (calcium carbonate or barium sulfate) that can be completely recovered by dissolving with acid or other appropriate agents. This reversibility allows the plugging to be temporary and adjustable, enabling operators to restore original flow patterns if needed, unlike insoluble sodium silicate precipitates
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 enables uniform fluid flow and increased heat exchange by selectively blocking high-flow fractures, allowing for immediate resumption of operations without extensive downtime or specialized equipment, and provides a reversible plugging solution that enhances well productivity.
Implementation Method 1
injecting a diversion agent into the formation to form an alkaline-earth carbonate precipitate from decomposition of a carbonyl compound
Data Source
AI summary
A method of selectively blocking fractures in a subterranean formation by injecting a diversion agent into the well is disclosed. According to one embodiment, the method comprises injecting a diversion agent into a subterranean formation to form an alkaline-earth carbonate precipitate from decomposition of a carbonyl compound, wherein the diversion agent includes the carbonyl compound and an alkaline-earth halide salt.