Electronic Computer Production Management - A New Era
Authors: Cox J.B. , Underfiner C.F. 
Published: December 2007

This computer control system in the Pegasus field southwest of Midland, Texas, delegates to a digital computer most of the operational functions normally performed by humans and allows local management to be in contact with the entire operation on a real-time basis. The system has functioned better than anticipated and has effected notable improvements in production operations.

Introduction
The Pegasus Computer Control System is a highly sophisticated "real-time on-line" electronic system to control producing operations in the Mobil Oil Corp. Pegasus complex. The system, functioning on a Pegasus complex. The system, functioning on a management-by-exception basis, controls wells, gathers all pertinent operating data, checks status, and takes appropriate control action automatically and unattended. It was designed, programed, and installed between Dec., 1965, and Sept., 1968. The Pegasus complex is a six-zone oil and gas field and integrated gasoline plant approximately 22 miles southwest of Midland, Tex. (Fig. 1). Mobil Oil Corp. is the unit operator of the Pegasus Ellenburger, Pegasus Pennsylvanian, Pegasus Spraberry and Pegasus Pegasus Pennsylvanian, Pegasus Spraberry and Pegasus Field Unit No. 3 units, and in addition operates nonunitized San Andres wells. The field encompasses 351 wells (including 40 injection wells) with daily average oil production of 15,500 bbl. The gasoline plant processes 70 MMcf of natural gas per day and produces processes 70 MMcf of natural gas per day and produces 8,000 bbl of NGL per day. Active fluid injection projects are in operation in the Pennsylvanian, projects are in operation in the Pennsylvanian, Ellenburger, and Spraberry reservoirs. Before computer control, the field operations required a force of 36 employees, including supervisory employees, and exclusive of plant personnel. These employees operated, controlled, maintained and reported on Mobil's operations in the Pegasus held. Most of the repetitive operational functions previously performed by humans are now under computer program control, and the field operating force has been reduced by 22 percent. The control system allows local management, using the general-purpose digital computer through the control system, to be in contact with the entire operation instantaneously and simultaneously on a preprogrammed management-by-exception basis. This is similar to talking to all field operators with all the operational answers on a conference telephone call, and being able to assimilate the information instantaneously and take appropriate action immediately. Exceptions are handled by manual entries. The control system has input and output capabilities for on-line direct communication with larger accounting and scientific computer systems. The expanded use of the Pegasus Computer Control System will produce many new intangible benefits that should eventually be greater than the direct operational benefits.

Description of the System
The Pegasus Computer Control and Data Acquisition System consists of several functional parts as shown in Fig. 2. The system encompasses approximately 1,400 status, 1,400 control, and 1,400 data acquisition points and was designed to allow all prime mover devices to remain as they are when power prime mover devices to remain as they are when power is interrupted.
JPT
P. 793