Time-Dependent Wellbore Breakdown Pressure for Hydraulic Stimulation
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Solution Overview
Problem
In unconventional reservoirs with low permeability, determining the optimal breakdown pressure for hydraulic fracturing is challenging due to the time-dependent thermal and stress changes caused by drilling operations, which affect the required wellbore pressure for inducing fractures.
Innovation Solution
A method and system that utilize a reservoir simulator to determine wellbore breakdown pressure by analyzing thermal diffusivity, borehole stress, and geological data, adjusting the pressure based on elapsed time and thermal steady state conditions, and controlling hydraulic stimulation operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If drilling operations are performed before hydraulic stimulation, then wellbore creation is achieved, but thermal and stress changes complicate breakdown pressure determination
Solution Approach 1:
The system performs preliminary thermal and stress analysis during the drilling operation itself, calculating temperature fronts and stress changes before the hydraulic stimulation begins. This allows the breakdown pressure to be determined based on the actual thermal and stress state of the formation, rather than using static or assumed values.
Solution Approach 2:
The patent replaces traditional mechanical pressure testing methods with a computational approach that uses thermal diffusivity data and stress modeling to calculate breakdown pressure. Instead of relying solely on mechanical field tests, the system uses reservoir simulation and thermal analysis to predict the breakdown pressure more accurately.
2Measurement precision
If time-dependent thermal analysis is performed, then breakdown pressure accuracy is improved, but computational complexity increases
Solution Approach 1:
The reservoir simulation system performs the thermal and stress calculations autonomously using integrated models. The system automatically determines thermal diffusivity from formation data, calculates temperature fronts over time, and computes stress changes without requiring separate manual analyses or additional field measurements.
Solution Approach 2:
The simulation system is designed to handle multiple functions: it models thermal diffusion, calculates stress changes, determines breakdown pressure, and optimizes stimulation parameters all within a single integrated platform. This multi-functionality reduces the need for separate specialized tools and simplifies the overall workflow.
3Productivity
If thermal diffusivity and stress data are integrated, then fracture initiation effectiveness is enhanced, but data processing requirements increase
Solution Approach 1:
The system merges thermal diffusivity data, stress measurements, and formation properties into a unified breakdown pressure calculation. By integrating these data streams, the system produces a single comprehensive breakdown pressure value that accounts for both thermal and mechanical effects, rather than requiring separate analyses for each parameter.
Solution Approach 2:
The reservoir simulation model acts as an intermediary that processes and synthesizes multiple data sources. It takes raw thermal and stress data, applies appropriate physical models and transformations, and outputs the integrated breakdown pressure information needed for stimulation design, thereby managing data complexity internally.
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 determination of wellbore breakdown pressure, optimizing hydraulic fracturing by accounting for time-dependent thermal and stress changes, thereby enhancing the efficiency and effectiveness of fracture initiation.
Implementation Method 1
determining, by a computer processor, thermal diffusivity data regarding a temperature front in the geological region of interest based on the time elapse data, the reservoir data, and the geological data
Implementation Method 2
determining, by a computer processor, borehole stress data based on the wellbore, the reservoir data, and the geological data
Data Source
AI summary
A method may include performing, by a drilling system, a drilling operation to produce a wellbore in a geological region of interest. The method may further include determining time elapse data describing an amount of time between the drilling operation and a hydraulic stimulation operation. The method may further include determining borehole stress data based on the wellbore, reservoir data, and geological data. The method may further include determining thermal diffusivity data regarding a temperature front in the geological region of interest based on the time elapse data, the reservoir data, and the geological data. The method may further include determining a wellbore breakdown pressure of the geological region of interest based on the thermal diffusivity data, the geological data, the borehole stress data, and the reservoir data. The method may further include transmitting a command to a stimulation control system based on the wellbore breakdown pressure.