Water-in-oil emulsion for OBM sludge removal
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Solution Overview
Problem
The oil and gas industry faces challenges with oil-based mud (OBM) sludge deposition in wellbores, which forms impermeable filter cakes that resist fracturing operations, particularly in hydraulic fracking, due to the low solubility of barite particles in water and acidic solutions, leading to compromised fracturing efficiency.
Innovation Solution
A water-in-oil emulsion composition is introduced as a single-stage treatment, containing an organic phase with an organic solvent, emulsifier, and wetting agent, and an aqueous phase with a chelating agent at high pH, which penetrates and dissolves OBM sludge or filter cake, enhancing fracturing fluid injectivity and facilitating fracture initiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If water or acidic solutions are used to remove barite particles, then the treatment is simple and inexpensive, but the solubility of barite particles is low and filter cake removal is ineffective
Solution Approach 1:
The patent uses a composite treatment composition containing both organic solvents (for organic matter dissolution) and chelating agents (for barite particle removal). This composite approach overcomes the limitation of using simple water or acidic solutions alone, achieving effective filter cake removal by combining multiple chemical mechanisms in one formulation.
Solution Approach 2:
The patent changes the chemical parameters of the treatment fluid by introducing specific organic solvents and chelating agents with proven effectiveness against barite particles. This parameter change transforms the treatment from ineffective (water/acid alone) to effective (specialized chemical composition), resolving the solubility issue without excessive complexity.
2Reliability
If multiple treatment stages are used to remove sludge and filter cake, then removal effectiveness is improved, but treatment time and operational complexity increase
Solution Approach 1:
The patent merges multiple treatment functions into a single composition that simultaneously addresses organic matter removal and barite particle dissolution. This single-stage treatment combines the capabilities of what would traditionally require multiple sequential treatments, reducing both time and operational complexity while maintaining high removal effectiveness.
Solution Approach 2:
The treatment composition is designed with multi-functionality, serving both to dissolve organic matter and to remove barite particles through its dual chemical system. This universal approach eliminates the need for separate treatment stages, directly addressing the time and complexity concerns while ensuring comprehensive sludge removal.
3Reliability
If chemical volumes are increased to improve filter cake dissolution, then removal effectiveness increases, but treatment costs and environmental impact increase
Solution Approach 1:
The patent optimizes the chemical composition parameters to achieve high dissolution effectiveness at reduced concentrations. By selecting chemicals with superior solubility properties and optimizing their ratios, the treatment achieves effective filter cake removal with minimized chemical volumes, reducing both cost and environmental impact.
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 composition effectively removes up to 90% of OBM sludge, ensuring successful fracturing operations by dissolving barite particles and organic matter, thereby improving hydraulic fracturing effectiveness and reducing chemical volumes and treatment costs.
Implementation Method 1
The aqueous phase may include water and a chelating agent
Implementation Method 2
The organic phase may include an organic solvent
Implementation Method 3
The organic phase may include an emulsifier
Implementation Method 4
The organic phase may include an emulsifier
Implementation Method 5
The organic phase may include a wetting agent
Data Source
AI summary
Provided is a method that may include introducing into a wellbore as a single stage treatment a composition that may include a fluid formulation that is a water-in-oil emulsion having an organic phase and an aqueous phase, the aqueous phase dispersed in the organic phase; maintaining the wellbore by shutting-in the well; and hydraulic fracturing the wellbore. The composition may contain a chelating agent and may interact with an oil-based sludge or filter cake, which may contain barite, at a target zone, allowing the composition to remove a portion of the oil-based mud sludge or filter cake.