Wellbore Pressure Pulse Generation Using Sequential Rate Drops
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Solution Overview
Problem
Existing hydraulic fracturing operations in oil and gas wells face challenges in generating accurate pressure signals for analyzing fracturing results due to interference from prior system actions and operational limitations, which affect the determination of metrics such as stage efficiency.
Innovation Solution
A method involving a sequence of rate drops in the well system to generate a target pressure signal, adjusting the amplitude and step size of these drops based on system instrument sensitivity, operational noise, and pressure limits, while removing signal imprints and using machine learning for precise metric determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hydraulic fracturing operations are performed at normal operational rates, then productivity and permeability improvement are achieved, but accurate pressure signal generation for analyzing fracturing results is compromised due to interference from prior system actions
Solution Approach 1:
The patent divides the pressure signal generation into discrete rate drop steps, where each step creates a separate pressure pulse. By segmenting the operational rate into multiple smaller drops rather than a single large change, the system achieves accurate pressure signaling while maintaining overall productivity. Each rate drop step generates a distinct pressure pulse that can be individually analyzed.
Solution Approach 2:
The patent implements periodic rate drops at specific intervals during the fracturing operation. By introducing periodic excursions from the normal operational rate, the system creates repeatable pressure signals that can be consistently measured and analyzed. The periodic nature allows for standardized measurement protocols and improves signal distinguishability from background noise.
2Measurement precision
If the operational rate is adjusted to generate pressure signals, then measurement precision improves, but the fracturing operation time increases
Solution Approach 1:
The patent applies partial rate drops rather than complete operational changes. By using smaller, controlled rate reductions (partial action) rather than shutting down completely or making large abrupt changes, the system generates sufficient pressure signals for accurate measurement while minimizing time loss. The partial drops are strategically sized to achieve the necessary pressure pulse amplitude without excessive operational disruption.
Solution Approach 2:
The rate drops are implemented during the ongoing fracturing operation rather than stopping the process entirely. The useful action of fracturing continues between and during the rate drops, maintaining productivity while interspersing measurement opportunities. This continuous approach ensures that the fracturing process is not halted but rather enhanced with measurement capabilities.
3Stability of the object's composition
If signal imprints from prior operations are present, then operational continuity is maintained, but measurement precision deteriorates due to interference
Solution Approach 1:
The patent introduces rate drops as preliminary actions before the main fracturing measurement phase. By performing controlled rate drops at predetermined times, the system creates clean pressure signals before analyzing the fracturing results. These preliminary excursions ensure that any signal imprints from prior operations are accounted for and differentiated from the current measurement signals.
Solution Approach 2:
The system uses the pressure signals generated by rate drops as feedback to characterize the wellbore and fracturing conditions. By measuring the pressure response to controlled rate drops, the system obtains feedback information that helps distinguish current signals from prior operation imprints. This feedback mechanism enables more accurate separation and analysis of pressure signals.
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 the generation of a target pressure signal with controlled amplitude, allowing for accurate measurement of fracturing operation metrics like stage efficiency, improving operational efficiency and adaptability during fracturing processes.
Implementation Method 1
A sequence of continuous excitations may be performed in a well system to generate a pressure pulse signal
Data Source
AI summary
Systems, methods, and apparatus, including computer programs encoded on computer-readable media, for generating pressure signals in a wellbore of a well system. A target amplitude may be determined for a target pressure signal to be generated in the wellbore of the well system. A rate drop step size may be determined for each rate drop of a plurality of rate drops. During fracturing operations in the well system, the plurality of rate drops may be performed in sequence for a system operational rate to generate the target pressure signal. Each rate drop of the plurality of rate drops may have the rate drop step size. One or more fracturing operation metrics may be determined for the well system from the target pressure signal.