Salt Cavern Gas Storage Detection Using Test Gas and Packer Sealing
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Solution Overview
Problem
The existing methods for detecting the gas-storing performance of solution-mined salt caverns in high-insoluble salt mines face challenges due to high impurity content and poor gas-tightness, making it difficult to accurately evaluate the available gas storage space and meet the requirements for salt cavern gas storage, leading to increased construction costs and risks.
Innovation Solution
A method involving the detection of water-tightness and gas-tightness of caverns and wellbores, followed by the arrangement of gas sealing tubing and a packer, injection of test gas, and calculation of the brine volume discharged to determine the available gas storage space, allowing for accurate evaluation of gas-storing performance without the need for extensive reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If sonar survey technology is used to detect the salt cavern, then the detection process is simple, but the boundary of the salt cavern buried by sediment cannot be detected, making it impossible to evaluate the available gas storing space
Solution Approach 1:
The patent introduces an intermediary substance (gas or liquid) to fill the cavern and serve as a medium for accurate boundary detection. This intermediary allows the detection equipment to clearly identify the cavern boundary even when buried by sediment, solving the problem of insufficient detection precision while maintaining operational simplicity.
Solution Approach 2:
The patent changes the physical parameters within the cavern by injecting gas or liquid to create a detectable interface or pressure differential. This parameter change enables the detection system to distinguish the cavern boundary from surrounding sediment, thereby improving measurement precision without significantly increasing device complexity.
2Ease of manufacture
If the existing brine-extracted well is used for gas-tightness detection, then construction costs are reduced, but the well cannot meet gas-tightness requirements due to corrosion and poor initial gas-tightness
Solution Approach 1:
The patent applies preliminary repair actions to the existing wellbore, including cement retching and casing sealing, before conducting gas-tightness detection. These preliminary measures improve the gas-tightness of the corroded well while still utilizing the existing infrastructure, thereby maintaining cost-effectiveness while achieving the required reliability standard.
Solution Approach 2:
The patent converts the harmful effect of well corrosion into a detectable condition by using the corrosion-induced gaps as test subjects for gas-tightness evaluation. The existing deterioration becomes the focus of targeted repair and verification, transforming a liability into an opportunity for controlled assessment and improvement.
3Reliability
If extensive reconstruction of the wellbore is performed to meet gas-tightness requirements, then gas-tightness reliability is improved, but investment costs increase and cannot be recovered if the cavern fails detection
Solution Approach 1:
The patent applies partial repair actions only to the specific sections of the wellbore that exhibit gas-tightness deficiencies, rather than performing extensive reconstruction of the entire well. This targeted approach achieves the necessary reliability improvement while minimizing investment costs, allowing for cost recovery even if detection fails.
Solution Approach 2:
The patent implements a feedback mechanism where gas-tightness detection results guide subsequent repair decisions. The detection process provides information about specific deficiency locations, enabling targeted repairs that improve reliability efficiently. This feedback loop ensures investment is directed only where necessary, optimizing the balance between reliability improvement and cost control.
4Productivity
If the solution-mined salt cavern is rebuilt into gas storage without proper detection, then construction speed is accelerated, but technical and economic risks increase due to uncertain gas-storing performance
Solution Approach 1:
The patent performs preliminary detection of water-tightness and gas-tightness before finalizing the gas storage conversion. This preliminary action identifies potential issues early in the process, allowing for quick decision-making and minimal delays, thereby maintaining construction speed while ensuring reliability through adequate assessment.
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 method enables efficient and accurate detection of available gas storage space and gas-tightness, reducing engineering risks and costs by utilizing existing wells and overcoming obstacles posed by sediment and corrosion issues, providing reliable detection results.
Implementation Method 1
arranging a packer
Implementation Method 2
injecting test gas into the cavern through the gas sealing tubing at the gas-injection well, so that brine in the cavern is discharged through the gas sealing tubing at the debrining well
Implementation Method 3
detecting gas-tightness of the cavern
Data Source
AI summary
The present disclosure discloses a method for detecting gas-storing performance of solution-mined salt cavern in a high-insoluble salt mine, comprising: detecting water-tightness of the cavern and water-tightness of a wellbore; arranging a gas sealing tubing in a production casing for the wellbore, and arranging a packer; detecting gas-tightness of the wellbore; injecting test gas into the cavern through the gas sealing tubing at a gas-injection well; calculating a volume of a discharged brine; closing the debrining well, and injecting the test gas into the cavern through the gas sealing tubing at the gas-injection well; after a pressure value above a gas-liquid interface in the cavern reaches a set pressure value, closing the gas-injection well; and detecting gas-tightness of the cavern. The method can be used for effectively, accurately and economically detecting the available gas storing space volume and the gas-tightness of the solution-mined salt cavern in salt mine.