A New Approach For Chemical Treatment Of Gas Storage Facilities
Authors: Robertson A.R. , Hawsey J.D. 
Published: December 2007

A new method of treating gas storage systems for internal corrosion protection has been developed. Previous methods involved expensive individual Previous methods involved expensive individual well treatment by truck. Also, side effects such as foaming and emulsions sometimes caused problems. A continuous treatment method for gas-lift systems is briefly discussed.

A single point, centrally located system of injection for chemical treatment has been developed and field proven. The program included means of detecting corrosion initially and monitoring corrosion control as provided by a three phase corrosion inhibitor designed for gas storage systems.

Introduction

The gas industry has long known the value of its investment in gas storage reservoirs, compressor stations, pipelines and related equipment. However, only in the last few years has more detailed attention been given to internal corrosion protection for well tubing and casing and injection and withdrawal Pipelines. This increased focus on internal corrosion has been brought about by the increased need to maintain gas supplies during critical periods caused by recent gas shortages. Further inflation has drastically increased replacement costs of pipe and equipment not to mention labor costs. Therefore, there has become an increased need for an economical, efficient, dependable method of applying corrosion protection to the internal surfaces of gas storage facilities.

Early treatment of gas storage systems was by truck at each individual well. Wright and Kepley reported ten years ago on a method of using a corrosion inhibitor-biocide by truck. This method is much more expensive by modern day standards and foaming of the chemical mixture was at times a problem to the storage field operations although problem to the storage field operations although the method and treatment was effective.

In 1975, Mutti, Atwood, Lafayette, and Landrum reported on a method to treat a gas lift system from one or more points. This method was the use of a venturi to atomize and disperse a corrosion inhibitor into the gas lines going to the various individual wells to prevent corrosion in the tubing and wellhead equipment. It was found that this method did not disperse the chemical into the gas stream well enough to be distributed properly to each well. The method was modified properly to each well. The method was modified to use more injection points with divider valves. A further modification of this method was to use electronic timers to alternately allow inhibitor to be pumped to individual wells for a specific length of time. Although these methods proved effective in controlling downhole tubular corrosion, they are expensive to install and maintain. It was thought that an improvement could be made in both the method of application and the type of corrosion inhibitor to use.

A three phase corrosion inhibitor has been developed for gas storage systems and related gas handling facilities as reported by Stanford, Chappell, Robertson and Hawsey. This material was designed to carry with and film from gas, water, and hydrocarbons. It is a light weight effective material that will carry long distances with the gas steam. However, an economical, effective and defendable method was required in order to apply the material so that distribution to each individual well could be assured.

The system developed called a Retractable Atomizing Chemical Injector, is simple and effective. It consists of a packing gland that contains a one quarter inch pipe or "stinger" to which is attached an atomizing nozzle. The packing gland attached to a one inch nipple is packing gland attached to a one inch nipple is then installed on a full opening valve. The valve may be a one inch, but a larger valve bushed down to a one inch is preferred. After the packing gland is tight, the valve is opened and the packing gland is tight, the valve is opened and the atomizing nozzle is forced into the gas stream by adjusting two draw bars installed above and below the packing gland by two all thread rods. The nozzle is moved to just inside the pipe wall.