Electricity + Control April 2015

FLOW MEASUREMENT

* NOTES A As of the writing of this article in March 2015, API MPMS Ch. 21.1 has been revised and reprinted. As is common in many hydrocarbon measurement standards, it is necessarily vague in some sections while over-cooked in others due to the viewpoints and biases of the many authors and contributors all of whom (like all of us) have limited knowledge and individual opinions. B The selection of tested and verified values depends on the specific meter type, meter design, and intended use. In the example given, orifice meters have been selected as the primary measurement device. C Latest and pending revisions to industry measurement standards are reviewed to help ensure that all applicable measurement calculations and parameters are checked. For example, API MPMS Ch.14.3 (orifice metering) has undergone revision with additional changes pending. D The ‘intermediate’ and ‘transitional’ values mentioned in this article include discharge coefficient, compressibility, expansion factor, water vapor correction factors, acceleration of gravity correction, calculated Btu, calculated MMBtu (Dth), and other flow-dependent variables that are selected depending on the particular meter type for which the flow computer is designed.

Stephen T. (Steve) Stark is an inde- pendent advisor, consultant, coach, and teacher with over 35 years’ experience in measuring natural gas, crude oil, and hydrocarbon liquids. Before forming Stark &

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Associates, Inc. in 1997, he was Manager of Meas- urement Technology with Williams Energy having previously managed the Measurement Department for Williams Natural Gas Co. In the 1980s, he worked for Phillips Petroleum Co in the Corporate Engineer- ing Fluid Measurement Group at their headquarters in Bartlesville, Oklahoma. Before that, Steve was a field measurement technician with Transok Pipeline Company and even earlier worked as a Rigger with Jetco, Inc., a perforating and logging company located in Oklahoma City. Steve has served on numerous oil and gas measurement standards-writing committees including those of the API (American Petroleum Insti- tute), the AGA (American Gas Association), and the GPA (Gas Processors Association). He has been directly involved in writing many of the measurement stand- ards in use today, now serving mainly on various API committees. He has chaired activities of the Southern Gas Association and Gas Research Institute and served on the Board of Trustees and General Committee of the International School of Hydrocarbon Measurement (ISHM) where he founded and was the first Chairman of the ISHM Scholarship Fund in 1997. He currently serves as an ISHM Principal Advisor and teaches most years during the ISHM annual conference. He received the American Gas Association (AGA) Award of Merit in October 2006; the Laurance Reid Award in 2011 for out- standing contributions to hydrocarbon measurement and control; and the American Petroleum Institute 30 year Service Award in 2011. Steve was appointed an Emeritus Member of the American Petroleum Institute Committee on PetroleumMeasurement in 2013. Steve holds several U.S. patents relating to flow measure- ment and works regularly on new ideas. Enquiries: Stephen Stark. Email starkassoc@cox.net Visit www.StarkAssoc.com

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