Low Viscosity Fracturing Fluid for Low Permeability Formations
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydraulic fracturing in low permeability formations faces challenges with fluid loss and proppant transport, as conventional proppants and fracturing fluids can damage the proppant pack and reduce fracture conductivity, and existing solutions are not effective in higher permeability reservoirs.
Innovation Solution
A low viscosity fluid system comprising an aqueous medium, a low molecular weight viscosifying agent, and ultra-lightweight proppants is used, which has a viscosity of less than 50 CP at 170 sec−1 and contains viscosifying agents like hydroxyethyl cellulose or surfactant gels to minimize filter cake formation and enhance proppant transport without damaging the formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional polymer-based fracturing fluids with bridging solids are used to increase viscosity and reduce fluid loss, then fluid loss is mitigated, but filter cake is formed that damages proppant pack conductivity
Solution Approach 1:
The patent changes the molecular weight parameter of the viscosifying agent from conventional high molecular weight polymers to low molecular weight polymers (less than 150,000, preferably less than 100,000). This parameter change allows the fluid to provide sufficient viscosity for proppant transport while having small enough molecules to penetrate the rock matrix without forming a filter cake, thus resolving the contradiction between fluid loss control and filter cake damage.
Solution Approach 2:
Instead of using large polymer molecules that are filtered at the rock face to control fluid loss, the patent inverts the approach by using small low molecular weight polymer molecules that can penetrate into the matrix. This inversion transforms the harmful filter cake formation into beneficial matrix penetration, achieving fluid loss control without conductivity damage.
2Productivity
If ultra-lightweight proppants are used to reduce fluid velocity and increase fracture area, then fracture conductivity is improved, but fluid efficiency is compromised in higher permeability reservoirs
Solution Approach 1:
The patent changes the viscosity parameter of the fracturing fluid by using low molecular weight polymers to achieve optimal viscosity for ULW proppant transport. This allows sufficient fluid efficiency in higher permeability reservoirs while maintaining the low fluid velocity needed to maximize fracture area propped open by ULW proppants.
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 effectively reduces fluid loss and maintains fracture conductivity by allowing the fluid to penetrate the rock matrix without forming a damaging filter cake, thus improving the efficiency of hydraulic fracturing in low permeability formations.
Implementation Method 1
The viscosity of the fracturing fluid filtrate leaked into the rock matrix affects the rate of fluid loss since increased viscosity of the fluid flowing within the matrix creates resistance
Implementation Method 2
allowing the fluid to penetrate the rock matrix without forming a damaging filter cake
Data Source
AI summary
A low viscosity fluid for reducing fluid loss in a relatively low permeability formation has a viscosity of less that 10 CP and contains a low molecular weight viscosifying agent The aqueous medium may be fresh water, salt water, brine or slickwater. The invention has particular applicability when an ultra lightweight (ULW) proppant or sand control particulate is employed. The fluid may be used in reservoirs having a relative permeability less than 10 mD.