Proppant Transport Optimization in Hydraulic Fracturing

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Solution Overview

Problem

Hydraulic fracturing treatments face challenges in achieving optimal proppant placement and effective fracture area due to poor proppant transportability, especially with slickwater fracturing, leading to reduced well productivity and steeper production declines.

Innovation Solution

A method to determine the minimum horizontal velocity and Slurry Properties Index for proppant transport, allowing for the estimation of propped fracture length and optimization of fracturing parameters such as injection rate and fluid viscosity, applicable to both ultra-lightweight proppants and non-damaging fracturing fluids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If slickwater fracturing is used with low viscosity treating fluid, then fracture conductivity damage is reduced and well productivity is improved, but proppant transportability deteriorates and proppant settles rapidly below target zone

Engineering Contradiction:

Improvefracture conductivityVSAvoidproppant transportability

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent changes the physical parameters of the treating fluid by adding polymers to increase viscosity and density, which directly addresses the proppant settling issue while maintaining the non-damaging nature of the slickwater system

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite treating fluid system combining slickwater base fluid with polymers and proppants, where the polymer-modified fluid provides both low damage characteristics and enhanced proppant suspension capabilities

Inventive Principle:

Principle #40Composite materials

2Productivity

If increased fluid viscosity is used to improve proppant transportability, then proppant placement is improved, but fracture height containment deteriorates and conductivity damage increases

Engineering Contradiction:

Improveproppant transportabilityVSAvoidfracture height containment

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent optimizes viscosity parameters by using polymer additives that provide viscosity only when needed for proppant suspension, rather than using high viscosity fluids throughout, thus balancing transportability with containment

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The treating fluid system dynamically adjusts its properties through polymer degradation and proppant settling during the fracturing process, allowing different regions of the fracture to have different fluid characteristics optimized for their specific functions

Inventive Principle:

Principle #15Dynamics

3Productivity

If increased pumping rates are used to improve proppant transport, then proppant placement is improved, but fracture height containment deteriorates and conductivity damage increases

Engineering Contradiction:

Improveproppant transportVSAvoidfracture height containment

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent changes the fluid rheological parameters through polymer addition, which improves proppant suspension at lower pumping rates, thereby reducing the harmful effects of high-rate pumping on fracture containment and conductivity

Inventive Principle:

Principle #35Parameter changes

4Area of stationary object

If fracture height develops beyond productive zone boundaries, then fracture area increases, but proppant placement in productive area is reduced

Engineering Contradiction:

Improvefracture areaVSAvoidproppant placement efficiency

Core Design Contradiction:

Area of stationary objectVSProductivity

Solution Approach 1:

The patent creates local quality differences in the treating fluid through polymer distribution and proppant concentration gradients, allowing different zones of the fracture to have optimized conditions for either containment or proppant placement

Inventive Principle:

Principle #3Local quality

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

Enables accurate estimation and optimization of propped fracture length, improving proppant placement and fracture conductivity, thereby enhancing well productivity and fracture area effectiveness.

Implementation Method 1

At high velocities, proppant is carried by suspension within the transport fluid

Methodology Applied

Scientific EffectSuspension transport: Suspension

Implementation Method 2

wherein Vt is the terminal settling velocity for the transport slurry

Methodology Applied

Scientific EffectTerminal settling velocity: Terminal Velocity

Implementation Method 3

Once natural reservoir pressures are exceeded, the fluid induces fractures in the formation

Methodology Applied

Scientific EffectPressure-induced fracturing: Pressure Increase

Implementation Method 4

Highly conductive pathways, radiating laterally away from the wellbore, are thereby provided to increase the productivity of oil or gas well completion

Methodology Applied

Scientific EffectProppant pack conductivity: Conduction (electrical)

Data Source

PatentUS7669655B2Method of fracturing a subterranean formation at optimized and pre-determined conditions

Publication Date: 2010.03.02 BAKER HUGHES CO

AI summary

Prior to a hydraulic fracturing treatment, the estimated fracture length may be estimated with knowledge of certain physical properties of the proppant and transport fluid such as fluid viscosity, proppant size and specific gravity of the transport slurry as well as fracture geometry and the treatment injection rate. The estimated fracture length may be determined by a specific equation.