Water Hammer Analysis for ISIP Estimation
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Solution Overview
Problem
Current methods for estimating initial shut-in pressure (ISIP) and fracture geometry in hydraulic fracturing are often invasive, require additional hardware, and provide non-unique solutions due to ill-constrained optimization problems.
Innovation Solution
A pragmatic approach that analyzes water hammer oscillations to provide consistent and reliable insights into reservoir characteristics and treatment effectiveness, using commonly available data and a simulator based on fluid-mechanics concepts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional ISIP estimation methods are used, then fracture geometry can be characterized, but additional hardware and invasive procedures are required
Solution Approach 1:
The method uses existing pressure data from routine fracturing operations to estimate ISIP, allowing the system to serve itself without requiring additional measurement hardware or invasive procedures. The water hammer oscillation analysis leverages data already collected during normal operations.
Solution Approach 2:
The patent uses water hammer oscillation characteristics as an intermediary to indirectly estimate ISIP. Instead of directly measuring pressure at shut-in, the method analyzes the oscillatory behavior of the fluid column, which serves as a mediator that contains information about the initial shut-in pressure.
2Measurement precision
If optimization methods are used to estimate fracture dimensions, then fracture geometry can be determined, but non-unique solutions result due to ill-constrained problems
Solution Approach 1:
The method uses water hammer oscillation characteristics (frequency, decay rate, number of periods) as feedback parameters that are directly related to fracture geometry. These oscillation parameters provide additional constraints that help resolve the non-uniqueness issue in traditional optimization approaches.
Solution Approach 2:
The patent transforms the estimation problem by changing from directly optimizing fracture geometry parameters to first determining water hammer oscillation characteristics, which then serve as intermediate parameters for estimating fracture dimensions. This two-step parameter transformation improves solution reliability.
3Measurement precision
If water hammer analysis is performed, then ISIP and fracture dimensions can be estimated, but analysis complexity increases
Solution Approach 1:
The method extracts specific features (water hammer oscillations) from the overall pressure data and analyzes them separately. By isolating and focusing on the oscillatory component, the analysis becomes more manageable and less complex than attempting to analyze the complete pressure signal.
Solution Approach 2:
The patent segments the pressure data analysis into distinct phases: identifying water hammer oscillations, extracting oscillation parameters (frequency, decay rate, periods), and then using these parameters for ISIP estimation. This segmentation of the analysis process reduces overall complexity.
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 efficient estimation of ISIP, fracture dimensions, and well productivity by analyzing pressure behavior at the end of treatments, reducing the need for additional hardware and improving the accuracy of fracture geometry predictions.
Implementation Method 1
The use of water hammer signatures as a cost-effective, scalable diagnostic solution to characterize aspects of hydraulically induced fractures has been of great interest to the industry and academic communities.
Data Source
AI summary
Water hammer is oscillatory pressure behavior in a wellbore resulting from the inertial effect of flowing fluid being subjected to an abrupt change in velocity. It is commonly observed at the end of large-scale hydraulic fracturing treatments after fluid injection is rapidly terminated. Factors affecting treatment-related water hammer behavior are disclosed and field studies are introduced correlating water hammer characteristics to fracture intensity and well productivity.