Support Programs for a Large-Scale Computer Production Control Project
Authors: Michie T.W. , Kidd A.N. , Page W.A. 
Published: December 2007

Training for computer center operators, design engineers, and maintenance personnel; equipment testing to locate design deficiencies; acceptance personnel; equipment testing to locate design deficiencies; acceptance testing to insure equipment quality and to minimize installation time; and programmed preventive maintenance--these are programs that have been programmed preventive maintenance--these are programs that have been instituted by one major company to assure equipment reliability and data integrity in its computer production control system.

Introduction
In four of its five operating divisions, Exxon Company, U.S.A. (a Division of Exxon Corporation) has instituted a Computer Production Control (CPC) program, using identical computer centers and program, using identical computer centers and program systems to monitor and control oil and gas program systems to monitor and control oil and gas producing operations. The company presently uses producing operations. The company presently uses CPC to operate 26 fields with a total of 4,100 wells. The daily production of these fields is 315,000 bbl of oil and 1 Bcf of gas. CPC is being installed in eight additional fields, which will bring total CPC-operated production in 34 fields to about 375,000 B/D. production in 34 fields to about 375,000 B/D. The objectives of the CPC program are to increase the effectiveness of producing operations and to use manpower more efficiently. The system is designed to continuously monitor and feed back operating data to field personnel and to perform control functions, generate reports for regulatory purposes, and enter oil and gas volumes directly into the accounting system. The CPC system is a multicomponent operation, with equipment ranging in complexity from a two-position switch to a real-time process control computer. Maximum benefits can be derived from such a system only if (1) personnel responsible for the design, implementation, operation, and repair of the individual components are adequately trained; (2) measurement accuracy and reliability are verified before equipment is selected; (3) equipment is factory and field tested before it is accepted; and (4) programmed preventive maintenance is begun as soon programmed preventive maintenance is begun as soon as the system is implemented.

Basic CPC Features
In each division office there is a central process-control computer (Fig. 1), which is process-control computer (Fig. 1), which is programmed to monitor and direct field operations. programmed to monitor and direct field operations. The computer has a core memory of 48K and disc storage of more than 7,500K. The peripheral equipment in the computer center includes a high-speed line printer, two type-writers, and a card reader. A computer interface unit connects the computer with a communication network that links the computer with the CPC fields. Field equipment includes end devices located at the wells, metering sites, and central facilities (Fig. 2). These end devices generate volume information, measure tank levels, indicate alarms and status, and perform control functions. The field cabling connects perform control functions. The field cabling connects the end devices to the remote terminal unit, where volume information is accumulated, status/alarms are monitored, and analog (A/D) measurements are made. Upon request, this information is coded and transmitted from the remote terminal unit to the computer. The remote terminal unit also receives and decodes control and set-point (D/A) messages from the computer and transmits them to the appropriate end devices for execution. Phase shift modulation techniques are employed for transmission between the remote terminal unit and the computer interface unit. Data are transmitted at rates of 100 and 600 bits/sec. Communication between the computer center and field operating personnel is maintained through a man-machine input-output (I/O) system.
JPT
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