Self-Resonating Nozzle Stimulation for Low-Pressure Fracture Initiation
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Solution Overview
Problem
Current fracture stimulation and matrix stimulation techniques face challenges such as poorly located fractures, stress shadow effects, and inefficiencies in creating weak points in subterranean formations, leading to reduced hydrocarbon production and wellbore clogging issues, especially in horizontal wells.
Innovation Solution
Deployment of self-resonating nozzles that produce high-frequency pressure pulses to create channels or notches in the formation, reducing fracture initiation pressure and enhancing fluid communication by forming weak points prior to stimulation, using either aqueous fluids or acid to create efficient and effective hydro demolition or acid jetting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional water jetting is used to create weak points, then high pressure differential and velocity are achieved at the nozzles, but cavitation of water jets is suppressed by downhole pressure which significantly reduces the eroding capability
Solution Approach 1:
The patent applies mechanical vibration by introducing a pulsating water jet system that generates high-frequency pressure fluctuations and cavitation bubbles. The pulsating jet creates alternating high and low pressure zones that enhance cavitation erosion capability despite high downhole pressure, thereby improving the eroding capability to create effective weak points in the formation.
Solution Approach 2:
The patent employs periodic action through the pulsating water jet mechanism that delivers cyclic pressure pulses to the formation. This periodic injection creates repeated cavitation cycles, allowing the water jet to progressively erode the formation rock and create weak points more effectively than continuous high-pressure injection under downhole conditions.
2Manufacturing precision
If abrasive jetting is used to create weak points, then perforation of tubulars and cement is achieved, but sand particles accumulate around the jet gun in horizontal wells leading to wellbore clogging and pipe stuck
Solution Approach 1:
The patent extracts the harmful abrasive solids from the jetting system, using only clean water or non-abrasive fluids. This eliminates the wellbore clogging and pipe stuck problems caused by sand particle accumulation while maintaining the ability to create weak points through pulsating jet-induced cavitation and erosion mechanisms.
Solution Approach 2:
The patent replaces the mechanical abrasive erosion system with a pulsating hydrodynamic system that uses pressure fluctuations and cavitation to erode the formation. This substitution eliminates the need for abrasive particles that cause clogging, while still achieving effective weak point creation through the pulsating jet's mechanical energy delivery.
3Length of moving object
If high velocity fluid stream is used in abrasive jetting, then deep penetration into formation is achieved, but sand particles accumulate around the jet gun leading to operational issues
Solution Approach 1:
The patent replaces the high-velocity abrasive jet system with a pulsating water jet system that achieves deep penetration through cyclic pressure loading and cavitation erosion. This substitution maintains penetration depth capability while eliminating operational reliability issues caused by sand particle accumulation and wellbore clogging.
Solution Approach 2:
The patent uses periodic action in the form of pulsating pressure cycles to achieve deep penetration into the formation. The repeated pressure pulses progressively erode the rock, enabling deep weak point creation without requiring continuous high-velocity abrasive flow that would cause particle accumulation and operational problems.
4Productivity
If acid stimulation by bullheading is used, then high production rate is achieved, but overstimulation of high permeable zones occurs leaving low permeable zones unstimulated
Solution Approach 1:
The patent applies preliminary action by first creating weak points in the formation using pulsating water jet technology before conducting acid stimulation. These pre-created weak points serve as controlled entry points and pathways that guide acid flow into low permeable zones, ensuring uniform stimulation across all zones and preventing overstimulation of high permeable areas while maintaining high production rates.
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 self-resonating nozzle technology allows for efficient and effective creation of weak points or wormholes, reducing fracture initiation pressure and improving hydrocarbon production by enhancing fluid communication between the wellbore and the subterranean formation, while minimizing operational costs and equipment requirements.
Implementation Method 1
The self-resonating nozzle includes a resonant cavity formed upstream of a nozzle orifice. The fluid under pressure is configured to flow into the resonant cavity of the self-resonating nozzle to produce high-frequency pressure pulses.
Implementation Method 2
fluid under pressure is supplied to the at least one self-resonating nozzle to create a channel in a surface of the subterranean formation
Data Source
AI summary
Methods and equipment are provided for stimulating recovery of hydrocarbons from a subterranean formation traversed by a wellbore, which employ at least one self-resonating nozzle. Fluid under pressure is supplied to the at least one self-resonating nozzle to create a channel in a surface of the subterranean formation facing the at least one self-resonating nozzle. In embodiments, the equipment can be a downhole tool or completion equipment (such as a liner) that is deployed in the wellbore.