The Application of Well Load Monitors to Beam Pumping
Authors: Stoltz J.R. 
Published: December 2007

This paper was prepared for the 48th Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Las Vegas, Nev., Sept. 30-Oct. 3, 1973. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgement 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.

Abstract
The well load monitor and related electronics are designed to monitor, analyze and control the operation of a beam pumping unit. The theory of operation, design and installation are presented. Computer-controlled and stand-alone local logic types are discussed.
Case histories of field operation and results of operating fluid level control are included. One of the most significant results is that the operating fluid level can be effectively controlled to within approximately 100 ft of the pump intake.
The potential of the well load monitor as a diagnostic tool for the detection of surface and subsurface operating problems is presented together with field-determined test results that demonstrate a more efficient and economical operation of beam-type pumping equipment.

Introduction
The well load monitor is the result of work undertaken in the Midland Div. of Mobil Oil Corp. on a system that would provide continuous information of the polish rod loading conditions for beam pumping units. The basic concept was that a continuous analog signal proportional to rod loading could be obtained. This load signal would then be examined and the conditions would be analyzed by a computer. The raw information obtained would be similar to that which is normally obtained from standard dynamometer cards. With the knowledge of the actual load conditions, the computer would take the required control action.
The first transducer for the well load monitor system was installed on a well that is producing from the San Andres zone in the producing from the San Andres zone in the Pegasus field in the Permian Basin in West Pegasus field in the Permian Basin in West Texas. This first test and several later tests were very successful. The tests established that an analog signal representative of rod loading could be easily and accurately obtained. The next step in the development of the system dealt with analyzing the output and taking action. It was determined that, in order to accomplish this step, a system would be installed on a 44-well lease in the Slaughter field. Thus, a full-scale computer-controlled installation utilizing the WLM concept was undertaken. The techniques in telecomunications and computer control gained from the other projects that had previously been installed were projects that had previously been installed were modified to incorporate the new concepts of the use of the well load monitor. This completely new endeavor brought with it some completely new problems.