3D Finite Element Model for Deviated Well Breakdown Pressure
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hydraulic fracturing simulators fail to accurately predict breakdown pressure in subsurface formations due to model simplifications, leading to improper selection of casing, tubing, and pump schedules, which can result in ineffective fracturing operations.
Innovation Solution
A nonlinear three-dimensional finite element model is developed to simulate the breakdown pressure of a deviated, cased, and perforated wellbore, incorporating full 3D geometry, in-situ stresses, and concrete damage plasticity to accurately predict fracture initiation and breakdown pressure, allowing for proper sizing of hydraulic fracturing components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional hydraulic fracturing simulators use simplified models, then device complexity is reduced, but measurement precision of breakdown pressure prediction deteriorates
Solution Approach 1:
The patent transitions from conventional simplified 2D or axisymmetric models to a full three-dimensional finite element model. This dimensional enhancement allows the model to capture complex geometries including deviated wellbores, cased holes, and perforation clusters with accurate spatial representation, thereby improving breakdown pressure prediction accuracy without being constrained by simplifying assumptions.
Solution Approach 2:
The patent employs advanced constitutive models that account for material non-linearity, including elastoplastic behavior and damage mechanics. By changing the mathematical parameters and material models from linear elastic to non-linear elastoplastic with damage, the simulation accurately captures rock failure processes and breakdown pressure under complex stress states, resolving the contradiction between model simplicity and prediction accuracy.
2Measurement precision
If a full 3D finite element model with damage plasticity is used, then breakdown pressure prediction accuracy is improved, but device complexity increases
Solution Approach 1:
The patent segments the subsurface formation into discrete finite elements, allowing the complex 3D domain to be divided into manageable computational units. This segmentation enables the use of advanced damage plasticity models by applying them element-by-element, thereby handling material non-linearity and geometric complexity through systematic discretization that makes the complex model computationally tractable.
Solution Approach 2:
The finite element method serves as an intermediary computational framework that bridges the gap between complex physical phenomena (damage plasticity, 3D geometry, deviated wellbores) and practical engineering prediction. This intermediary approach allows the complex constitutive models and geometries to be integrated systematically through numerical integration and iteration, resolving the complexity-accuracy contradiction by providing a structured computational pathway.
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 model enhances the accuracy of breakdown pressure prediction, enabling precise selection of wellbore components and pump schedules, thereby improving the effectiveness of hydraulic fracturing operations by accounting for complex geometries and material non-linearity.
Implementation Method 1
Rock around the perforation tunnel is modeled using concrete damage plasticity with both compression and tensile damage such that rock damage progression as a function of wellbore pressure is simulated in the finite element model
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
Some methods of hydraulic fracturing of a subsurface formation include using a three-dimensional finite element model to simulate a deviated well with a wellbore casing, a cement adjacent to the wellbore casing, and a perforation cluster with at least two perforations. The FEM is applied (or solved) to determine a breakdown pressure of the deviated well based on an amount of tensile damage of the perforation cluster induced by an applied pressure representing injected hydraulic fluid. The FEM accounts for the 3D complex configuration of wellbore and perforation cluster. A deviated well is drilled and completed with a wellbore casing size, tubing size, wellhead, and hydraulic fracturing pump schedule selected at least in part based on the determined breakdown pressure before hydraulic fluid is injected into the deviated well at an injection pressure, which represents the required breakdown pressure to cause hydraulic fracturing of the rock of the subsurface formation.