Wellsite Wet Gas Measurement System in Saudi Arabia

Abstract

Abstract This paper describes an automated and compact wet gasmetering system that was installed and tested successfully at Saudi Aramco. The paper also describes the technology for determining individual liquid rates in production streams using the tracer dilution technique and its application in Saudi Aramco. The system operates at a wellsite and provides continuous online measurements of liquid and gas rates for a gas well. The wet gas metering system provides reliable measurement of well producing rates and, in turn, better control of field operations and more accurate production allocation. As a part of the wet gas metering system; the tracer dilution technology is capable of determining the magnitude of individual liquid flow rates at the wellhead, without separating the produced fluid. For a wet gas producer, this technique combined with a venturi meter can provide a three-phase measuring system, a complete alternative to a conventional welltest separator facility. The wet gas metering system is based on the venturi principle to measure gas and condensate. The venturi principle is a proven technique which has been commercially used in oil and gas metering for years. Venturi meters have the advantages of high pressure and temperature ratings, low pressure loss, minimal wear and well established correction factors to account for entrained liquids. The rate of the entrained liquids will be measured by the tracer dilution technique. The tracer dilution technique involves the injection of fluorescent tracers, one for hydrocarbon liquid and one for water, into the flowline and the subsequent collection of a sample at a suitable distance downstream of the injection point. The fluorescent intensity ratio of injected tracer to collected sample is used to determine the oil/condensate and water flow rates. The tracer dilution technique is viewed as a feasible and economical option to measure liquid rates in wet gas flow streams. The tracer dilution equipment is self-contained, compact, and portable. Saudi Aramco has field-tested tracer technology in conjunction with wellsite venturi meters, as an alternative to centralized conventional test separators. Field application showed water and condensate measurement to be within +/- 10% and a gas rate measurement to be generally less than 5% of the conventional measurement technique. P. 481