Silica Control Agents for Subterranean Formation Stability
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Solution Overview
Problem
Hydraulic fracturing operations face challenges such as formation degradation, sloughing, and reduced fracture porosity due to the reactivity of subterranean formations with aqueous fluids, leading to instability and damage to wellbores and production systems.
Innovation Solution
The use of silica control agents in fracturing fluids, which are present at or above 75% saturation levels, to stabilize the formation by forming thin silicate coatings that prevent dissolution of in-situ silica and diageneous minerals, thereby maintaining formation integrity and reducing particulate migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If brines with high ion concentration are used to reduce ion exchange and reactivity of strata, then formation stability is improved, but fracture porosity is reduced
Solution Approach 1:
The invention changes the chemical parameters of the treatment fluid by controlling silica concentration and saturation state rather than using high ion concentration brines. This allows achieving formation stabilization through silica coating without the harmful effect of reduced fracture porosity associated with high-salinity brines.
Solution Approach 2:
Silica acts as an intermediary substance that coats formation surfaces and particulates, reducing their reactivity and preventing degradation without requiring high ion concentration. The silica coating mediates between the treatment fluid and formation minerals, preventing direct harmful interactions.
2Productivity
If high rate water frac operations are used to increase productivity, then fluid flow rate is improved, but damage to tubular conduit surfaces increases
Solution Approach 1:
The invention converts the potentially harmful effect of high-velocity fluid flow into a beneficial coating mechanism. The silica control agent in the treatment fluid deposits silicate coatings on formation surfaces and particulates during high-rate injection, which actually protects the system while enabling high productivity operations.
3Stability of the object's composition
If silica control agents are used to stabilize formation and prevent degradation, then formation integrity is improved, but operational complexity increases
Solution Approach 1:
The silica control agent in the treatment fluid provides self-service stabilization by automatically coating formation surfaces and particulates during the fracturing operation itself. The silica precipitation and coating formation occur in-situ during normal fracturing operations, eliminating the need for separate stabilization steps or complex operational procedures.
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
This approach enhances the stability of shale strata, reduces formation degradation, and minimizes damage to wellbores and production systems, making marginal wells more economical and reducing operational costs while providing effective corrosion inhibition.
Implementation Method 1
The localized mineral solubility near that point under strain may increase, causing the minerals to dissolve. Minerals in solution may then diffuse through the water film outside of the region where the mineral surfaces are in contact, where they may precipitate out of solution.
Implementation Method 2
forming thin silicate coatings that prevent dissolution of in-situ silica and diageneous minerals
Implementation Method 3
Many formation strata, particularly sandstone, shale, and/or clay, are reactive with water, resulting in ion exchange and absorption of aqueous fluids.
Data Source
AI summary
Methods involving the use of subterranean treatment fluids comprising a silica control agent and an aqueous base fluid wherein the treatment fluid is placed into a portion of a subterranean formation and wherein the silica control agent is present in an amount of at least 75% of the saturation point in the treatment fluid. The methods include fracturing and gravel packing operations using a treatment fluid including a silica control agent present in an amount of at least 75% of the saturation point in the treatment fluid.