Call Box Offers Low-cost Automation

Past automation for the Oil and Gas Industry was in general developed for larger oil fields where large amounts of data could be gathered to a local central point on a continuous basis. The primary purpose for data collection was to better evaluate equipment performance to maximize recovery from these large oil fields. Such fields could economically justify a sophisticated automation system and its associated installation costs and radio communication network. Smaller gas fields provided little revenue to a producer’s total income stream thus capital cost to install and maintain an automation project was prohibitive.

Today the emphasis for natural gas has changed the scope of production operations Smaller gas fields covering a much larger geographic area have replaced the more concentrated oil fields as the producer’s primary source of income. In addition more and more gas wells have an associated compressor responsible for generating a producer’s total revenue stream which poses a problem for the producer whose trend is to minimize overhead by downsizing field staffing. Compressor automation can provide field personnel the necessary information to maximize a producer’s revenue stream while minimizing field support. For such applications, automation needs to be portable, user friendly, inexpensive, and provide only the information critical to the operation.

The Problem.

As a result of downsizing field operations there are fewer man-hours spent at any one location. Operators, recognizing that most of their cash-flow is dependent on compressor runtime, want to take advantage of automation to monitor compressor operations.

However, the option that had been historically available was to install automation after the compressor was installed and a large sum of money purchasing sensors and wiring the sensors to monitoring equipment was spent. As a result, the amount of critical information the operator would like to monitor, e.g., why the compressor is down, is often restricted due to the cost. Additionally, if the operator could afford to monitor multiple compressor points, a monitoring system to handle that many individual inputs quite often requires sophisticated software for programming and maintenance, and will only communicate with a computer, leaving the field personnel completely out of the loop.

The Solution.

A simple, cost effective callout system developed by Sentry Technologies, Inc., and marketed by Frank W. Murphy Mfr., interfaces with Frank W. Murphy Mfr. digital annunciators. Small enough to mount in the compressor’s control panel, the "Call Box" monitors up to 40 digital inputs through Murphy’s Mark III annunciator or eight inputs for compressor panels with mechanical tattletales(trademark).

A single cable is all that is needed to give individual notification of up to 32 alarms, eliminating the need for expensive field installation; and a local keypad is used for programming the "Call Box" eliminating need for programming software and support. The "Call Box" can be powered with 110VAC or compressor-supplied DC voltage. Standard landline communication is provided with the "Call Box" and cellular or radio interfaces are supported as well. Field personnel, field offices, and answering services can communicate with the "Call Box" as all dialouts are made in voice-synthesized English, eliminating need for host communication software to monitor incoming alarm calls.

Case History.

A small operator acquired a gas lift field located along the Gulf Coast area of Texas. Two compressors located some distance apart were providing lift gas to eight wells whose total oil production had declined to 100 BOPD and water production had increased to 4000 BWPD, making the field uneconomic for the previous operator. The small operator recognized that the production could not economically support full-time supervision made arrangements for a contract gauger to look after the field. The gauger integrated the wells and compressors into his normal route, stopping by each location each day to perform his normal duties. For the remainder of the day when the compressor sites are unattended, the operator chose to supervise the gas lift compressors with "Call Boxes".

The "Call Boxes" are programmed to call the gauger’s beeper first, then the main office, if the gauger fails to acknowledge the alarm. The "Call Boxes"’ have produced many successful results, including the following benefits to three involved personnel: the gauger, the operator, and the mechanic.

Prior to using the "Call Box", if the compressor went down in the afternoon after the gauger had been by the field, he would not return until the next day, only to find all wells dead and the lift gas gone. The remainder of the his day was then spent getting the wells back on-line and leveled off. With the "Call Box" the gauger responds immediately to the compressor and can either restart the unit or shut-in lift gas until a compressor mechanic arrives. In the gauger’s words, "I would much rather take an extra hour to come back to restart the compressor than spend a half a day restarting the field".

From the operator’s viewpoint, the field’s run time is at 98.5% every month with minimal supervision. Since the "Call Box" can be interfaced with by field personnel, the operator does not have to maintain automation with office software and hardware.

And the mechanic knows that if either of the two compressor had a mechanical failure overnight he will be called first thing in the morning. Prior to installing the "Call Box", the mechanic may not have found out until mid-day, long after he had left in another direction, costing both him and the operator time and money.