Gas Disposal Systems for Offshore Platforms

Abstract

Abstract The different methods used in handling gas effluent from offshore platforms are discussed in this article. The presentation is directed toward the type of system to select for gas disposal based on production, location, and safety factors for an offshore site. Some of the means of gas effluent disposal to be discussed are vents, flares, and mechanical devices. The selection of the particular method for use would be dictated by the type of equipment used, water depth, ambient conditions, and the type of crude produced. Alternate applications of the methods such as undersea venting, local venting, or remote venting are reviewed to determine the best application for a particular platform. Safety factors which affect gas effluent are examined. A few of these items are the amount and type of gas to be released, type of equipment, and location. Introduction Offshore production platforms are built to provide a working area to separate water, liquid hydrocarbon and gas. Separation is required offshore because of the extremely large pressure drops experienced due to two (2) phase flow of liquid hydrocarbon and gas being shipped together by pipeline. The dissolved gas would also require a large storage system for barge or tanker transportation of crude oil. Separation of crude oil and gas then is made offshore to allow single phase transmission of crude and gas through their separate transportation systems. Means of handling the gas offshore have developed slowly as producers have tried many ways to safely and economically process the crude. Some of the various ways that have been used in the past are presented in this article. Factors used in the selection of a particular means of gas disposal are presented to assist operators in offshore operations. Safety and economics are the two yardsticks used to evaluate gas disposal applications. These two yardsticks are presented briefly in the following discussion.. But to arrive at the optimum system for gas disposal, the complete platform should be developed and studied.