Abstract
Natural gas has to be produced, transported and stored until it is needed by the eventual consumer. The gas is most commonly held in inventory underground under pressure in three types of facilities: (1) depleted reservoirs in oil and/or gas fields near the regional end markets, (2) aquifers, and (3) salt cavern formations.
Each type of gas storage field has its own unique set of physical characteristics (porosity, permeability, retention capability) and economics. The most important characteristics being the formations ability to hold natural gas as needed (volume, integrity and injectivity) and the rate at which it can be withdrawn (deliverability).
Studies have shown that with time, the repeated high-pressure injection and withdrawal of gas progressively damages gas storage wells by filling the permeability with inorganic precipitates, hydrocarbons, organic residues, production chemicals, bacterial fouling, emulsions, water blockages and naturally-occurring particulates. Many of these types of damage do not respond to normal acid stimulation treatments which are still being done at a cost of over $100 million to the gas storage industry.
This paper will discuss the types of damage, methods of removal and will include a case history of a new type of treatment to remove the specific types of damage being experienced in one aquifer gas storage field and the economic benefit experienced in that field.
