Adaptive Stimulation System Resonance Control
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Solution Overview
Problem
Conventional high-pressure well-stimulation pumps experience high fluid-end failure rates due to destructive vibration resonances caused by mechanical shocks, leading to fatigue-related cracking and reduced reliability, while existing technologies struggle to efficiently fracture and characterize unconventional geologic formations for optimal well completion.
Innovation Solution
Adaptive stimulation systems combine impulse-generated swept-frequency vibration with cyclically-varying hydraulic pressure, using tunable down-hole stimulators to control vibration spectra and optimize geologic fracturing by shifting power spectral densities, thereby reducing resonance excitation and enhancing stimulation efficiency through closed-loop feedback control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional high-pressure pumps are used for well stimulation, then hydraulic pressure can be delivered to fracture geologic formations, but destructive vibration resonances from mechanical shocks cause high fluid-end failure rates and reduced reliability
Solution Approach 1:
The patent applies controlled mechanical vibration through impulse-generated swept-frequency vibration that cycles through a range of frequencies to deliberately excite resonant frequencies of geologic formations. This controlled vibration approach transforms the harmful mechanical shocks into beneficial stimulation that fractures formations while the closed-loop control prevents excitation of harmful resonances in pump components by dynamically adjusting vibration frequencies based on real-time feedback from accelerometers and backscatter analysis.
Solution Approach 2:
The system dynamically changes vibration frequency parameters in real-time using closed-loop control. The power spectral density of impulse-generated vibration is continuously adjusted by shifting frequencies based on feedback from backscatter vibration analysis and accelerometer data. This parameter adaptation allows the system to maintain stimulation effectiveness while avoiding resonant frequencies that would harm pump reliability.
2Productivity
If impulse-generated vibration is used to fracture geologic formations, then stimulation effectiveness is improved, but it is difficult to efficiently characterize formations and optimize well completion
Solution Approach 1:
The system implements closed-loop feedback control where accelerometers mounted on the stimulator and down-hole equipment continuously measure vibration responses. The control system processes this feedback data to analyze backscatter vibration characteristics, determine formation properties in real-time, and adjust stimulation parameters accordingly. This feedback mechanism transforms the difficulty of formation characterization into an efficient process by continuously adapting stimulation based on measured formation responses.
Solution Approach 2:
The patent uses swept-frequency vibration that systematically cycles through a spectrum of frequencies to probe formation properties. By analyzing how different frequency components interact with the formation and return as backscatter signals, the system efficiently characterizes formation mechanics, permeability, and fracture properties without requiring separate testing procedures.
3Productivity
If broad-spectrum impulse-generated vibration is applied to geologic formations, then fracturing effectiveness is enhanced, but it is difficult to localize and tailor stimulation to specific formation intervals
Solution Approach 1:
The system applies local quality by using multiple stimulators positioned at different locations along the wellbore, each capable of independent frequency control. The closed-loop system tailors the vibration frequency spectrum and power spectral density for each specific formation interval based on local formation characteristics detected by backscatter analysis. This allows localized optimization of stimulation parameters for each geological zone while maintaining overall system coordination through centralized control.
Solution Approach 2:
The system dynamically adapts stimulation parameters for each formation interval by continuously adjusting frequency spectra based on real-time feedback. The power spectral density is dynamically shifted to match the resonant characteristics of each specific formation zone, enabling the system to respond to changing formation properties as stimulation progresses through different intervals. This dynamic adaptation transforms the challenge of localized stimulation into an efficient process.
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
This approach significantly reduces fluid-end fatigue failures, improves frac pump reliability, and enhances well productivity by tailoring stimulation to the specific geologic formation, achieving more efficient and localized fracturing with real-time feedback and adjustment of vibration frequencies.
Implementation Method 1
a hammer element is longitudinally movable within the housing between the driver element and the fluid interface, the hammer element being responsive to the driver element for striking the fluid interface and rebounding therefrom during an adjustable rebound cycle time to generate impulse-generated vibration bursts
Implementation Method 2
each stimulator transmits (in response to a timed stimulator transmission signal) an impulse-generated vibration burst comprising a plurality of vibration frequencies
Implementation Method 3
a transverse coil is peripheral to and surrounds the fluid interface, the transverse coil for generating a step-wise adjustable steady-state longitudinal magnetic field intersecting the fluid interface, and the fluid interface being magnetostrictively responsive to the longitudinal magnetic field for altering its effective elastic modulus
Implementation Method 4
said fluid interface comprising at least one accelerometer for producing an accelerometer feedback signal representing vibration transmitted and received by said fluid interface
Implementation Method 5
The varying distances are functions of both the cyclically-varying down-hole hydraulic pressures and the inherent dynamic response of the stimulated geologic material
Data Source
AI summary
Adaptive stimulation systems combine impulse-generated swept-frequency stimulation vibration with cyclically-varying hydraulic pressure to provide adaptive down-hole stimulation. Swept-frequency stimulation vibration arises from cyclical shifts of the power spectral density (PSD) of each stimulator's fluid interface vibration (via closed-loop control of the rebound cycle time and/or the fluid interface's effective elastic modulus). PSD's are adjusted for resonance excitation and fracturing of geologic materials at varying distances from a wellbore, closed-loop control incorporating backscatter vibration from stimulated geologic material. One or more stimulators generate vibration in bursts comprising a plurality of vibration frequencies. Timed signals from a programmable controller affect directional propagation of combined vibration wave fronts from a stimulator array. As fracturing proceeds to smaller (e.g., proppant-sized) fragments having higher resonant frequencies, PSD's are up-shifted, increasing relative stimulation vibration power in higher frequencies. Progressive stimulation is thereby optimized, facilitating plain-water (or liquefied propane) fracs with self-generated proppant.