Hydraulic Fracturing Breakdown Pressure Prediction Algorithm
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Solution Overview
Problem
Accurately determining formation breakdown pressure during hydraulic fracturing in oil and gas wells, particularly in tight sandstone formations, is challenging due to the reliance on incomplete physical parameters, leading to overestimation or underestimation, which can result in inappropriate well completion selection and operational failures.
Innovation Solution
An improved algorithm that uses a hybrid analytical and computational approach to predict formation breakdown pressure by incorporating in-situ stresses, formation strength, fluid properties, and rock permeability, including the computation of induced pore pressures and poroelastic stresses, is implemented. This algorithm utilizes the Stehfest method and modified Bessel functions to provide a more accurate breakdown pressure prediction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methodology is used to estimate breakdown pressure, then the estimation process is simple, but the accuracy of breakdown pressure prediction deteriorates leading to overestimation or underestimation
Solution Approach 1:
The patent incorporates additional physical parameters (fluid compressibility, viscosity, rock porosity, permeability) into the breakdown pressure prediction model beyond the conventional in-situ stresses and formation strength. This parameter expansion transforms the prediction accuracy while managing complexity through systematic integration of poroelasticity theory and numerical methods like Stehfest inversion and Composite Simpson's Rule
Solution Approach 2:
The patent introduces induced pore pressures and poroelastic stresses as intermediary physical quantities that mediate between the injection of fluids into the wellbore and the final breakdown pressure prediction. These intermediaries capture the complex fluid-rock interaction physics, allowing accurate prediction without requiring direct measurement of breakdown pressure
2Reliability
If breakdown pressure is overestimated, then operational safety is improved, but well completion selection becomes inappropriate and expenditure is lost
Solution Approach 1:
The patent validates the improved algorithm against measured breakdown pressure values from actual wells, creating a feedback mechanism that confirms prediction accuracy. This validated algorithm enables reliable breakdown pressure prediction that prevents both overestimation (avoiding expenditure loss) and underestimation (maintaining operational safety)
3Loss of energy
If breakdown pressure is underestimated, then expenditure is reduced, but operational failures occur
Solution Approach 1:
The patent performs preliminary computation of induced pore pressures and poroelastic stresses before determining breakdown pressure, incorporating all relevant physical parameters in advance. This preliminary action ensures that the breakdown pressure prediction accounts for fluid-rock interaction effects, preventing underestimation and subsequent operational failures while optimizing expenditure
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 algorithm effectively predicts breakdown pressure values that match measured values during hydraulic fracturing operations, reducing the risk of over- or under-estimation, thereby optimizing well completion selection and reducing operational failures and costs.
Implementation Method 1
The algorithm utilizes a hybrid analytical and computational approach to compute induced pore pressures during the injection of fluids into the wellbore together with the associated poroelastic stresses
Implementation Method 2
A poroelastic stress is determined for the wellbore using a poroelastic stress equation and based, at least in part, on the pore pressure determined for the wellbore, a Composite Simpson's Rule for numerical integration, an empirical parameter, a pore pressure, a Biot poroelastic parameter
Data Source
AI summary
Systems and methods include a method for determining a breakdown pressure for the wellbore. Input parameters are received for computing a breakdown pressure for a wellbore. A pore pressure is determined using a Stehfest method equation using a function of a time duration, a distance from the wellbore, an injection fluid compressibility, a Biot poroelastic parameter, and a modified Bessel function. A poroelastic stress is determined using a poroelastic stress equation based on the pore pressure determined for the wellbore, a Composite Simpson's Rule for numerical integration, an empirical parameter, a pore pressure, a Biot poroelastic parameter, tensile strength of rock, and a Poisson distribution. A breakdown pressure is determined using a tested time-based formula, poroelastic stress, a minimum and a maximum horizontal stress, using a formula tested against multiple wells and a distance from the wellbore in a radial direction.