Oilfield Data from A/D Converter for Computer-Controlled Digital Telemetering System
Authors: Woodhall Robert J. 
Published: December 2007

This paper was prepared for the 41st Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to held in Dallas, Tex., Oct. 2–5, 1966. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

A 16,000-word real-time process computer has been installed with a telemetering and supervisory control system to control oil-producing operations in the Elk Basin field, [Park County, Wyo. and Carbon County, Mont.]. This system transmits at a relatively high speed of 600 bits per second via data set equipment. This high speed, plus installation of an analog-to-digital [A/D] converter at each satellite station, makes possible the collection of much of the data on the basis of analog quantities. As a result, the system uses turbine meter readings, per cent water readings, and pressure readings in analog form; digitizes the analog readings in the A/D converter; and converts to meaningful numbers in the computer. Several pieces of specially modified equipment were installed for use with the computer system. Some of the problems associated with the equipment and design are discussed.

Introduction

Although supervisory control and telemetering systems are in operation in several oil fields around the country, a review of the literature shows that few, if any, direct analog signals have been reported in digital systems. Where analog signals are used to some extent, these signals are normally transmitted to the central station in some form similar to a time-duration pulse. This paper will describe the approach taken by Pan American in the Elk Basin system to use an analog to-digital converter [A/D] as part of a digital-computer-controlled system which reads the analog devices by direct address. No storage of the information is furnished until stored in the computer memory.

Pan American is the operator of the Elk Basin Unit [located in Northwest Wyoming] for itself, Humble, Marathon, Phillips, Sinclair, Continental, Atlantic, and numerous minor interests. Interest in telemetering for the field began in the late 1950's when the field was converted to LACT transfer of oil. The supervisory control system was-installed in the last quarter of 1965 and the first quarter of 1966, to control four producing horizons, producing from some 140 wells into 13 tank batteries. The reader is referred to other papers and articles for information on the producing characteristics and geology of Elk Basin.