Soluble Bridge Plug for Gas Well Pipe Lowering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for lowering an oil pipe in a gas well either result in high costs or damage to the reservoir due to the use of expensive materials and kill fluids, and existing soluble bridge plugs lack sufficient strength and controllability.
Innovation Solution
A method involving a soluble bridge plug made of an Mg—Al—Zn—Sn alloy, which is lowered to a predetermined location in the wellbore, followed by injection of a dissolving solution to dissolve the plug, allowing for the lowering of an oil pipe without well-killing, thereby reducing costs and protecting the reservoir.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional soluble metal materials containing expensive metals like indium are used, then the bridge plug can be dissolved, but the production cost becomes very high
Solution Approach 1:
The patent replaces expensive soluble metal materials (containing indium, gallium, etc.) with a cheap soluble alloy system based on zinc, aluminum, and magnesium. This disposable bridge plug is designed to be dissolved after serving its temporary purpose of blocking the wellbore, eliminating the need for expensive rare metals while maintaining the essential solubility function.
Solution Approach 2:
The patent changes the chemical composition parameters of the soluble material from conventional expensive metal systems to a zinc-aluminum-magnesium alloy system. By adjusting the elemental composition ratios (Zn: 60-80%, Al: 10-30%, Mg: 5-15%), the patent achieves both cost reduction and maintained solubility performance.
2Reliability
If conventional soluble metal materials are used, then the bridge plug can be dissolved, but the material strength index becomes low and cannot meet oil field development demands
Solution Approach 1:
The patent creates a composite alloy material combining zinc, aluminum, and magnesium in specific proportions. This composite material achieves both high strength (meeting oil field requirements) and high solubility (for temporary blocking function), resolving the contradiction between strength and solubility that plagues conventional soluble materials.
Solution Approach 2:
The patent optimizes the compositional parameters of the alloy, specifically controlling the content ranges of Zn (60-80%), Al (10-30%), and Mg (5-15%). This parameter optimization ensures the material achieves sufficient mechanical strength for bridge plug application while maintaining rapid solubility characteristics.
3Reliability
If well-killing with kill fluid is performed before lowering oil pipe, then the wellbore can be pressure-tested, but the reservoir is greatly damaged
Solution Approach 1:
The patent extracts and eliminates the harmful kill fluid step from the conventional wellbore pressure testing process. By using a soluble bridge plug that can be dissolved on demand, the patent enables pressure testing to be performed without introducing damaging chemicals into the reservoir, thus removing the harmful factor while preserving the testing function.
Solution Approach 2:
The patent converts the temporary blocking function (which would normally require harmful kill fluids for pressure testing) into a beneficial soluble plug system. The bridge plug provides necessary wellbore isolation for pressure testing, then dissolves harmlessly, converting what would be a harmful process into a beneficial one that protects the reservoir.
4Productivity
If a fracturing fluid is injected into the casing, then the wellbore can be treated, but the cost of directly lowering an oil pipe becomes very high
Solution Approach 1:
The patent introduces a soluble bridge plug as an intermediary tool that enables cost-effective oil pipe lowering after fracturing treatment. The bridge plug temporarily blocks the wellbore to create safe working conditions, then dissolves to allow oil pipe installation, serving as a mediator that reduces overall operation costs compared to conventional methods.
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 method effectively reduces costs by 25-50% and shortens the operation period by 33%, while minimizing reservoir damage, and provides a strong, easily manufacturable bridge plug with quick dissolution properties.
Implementation Method 1
a soluble bridge plug made of an Mg—Al—Zn—Sn alloy, which is lowered to a predetermined location in the wellbore, followed by injection of a dissolving solution to dissolve the plug
Data Source
AI summary
The present invention discloses a method for lowering an oil pipe in a gas well without well-killing, a soluble bridge plug and a material preparation method thereof, wherein, the method comprises the steps of: lowering a bridge plug in a wellbore such that the bridge plug blocks the wellbore at a predetermined location in the wellbore; injecting water in the wellbore after the pressure in the wellbore has been relieved so as to replace gases in the wellbore; and lowering an oil pipe in the wellbore to the location of the bridge plug. The method for lowering an oil pipe in a gas well without well-killing, the soluble bridge plug and the material preparation method thereof provided in the present invention successfully solve the problem of high cost for lowering an oil pipe under pressure after a fracturing fluid has been injected into the casing.