Abstract

SCADA systems have played an important role in monitoring and optimizing gas and oil well production by providing information and enabling a well operator to exercise a certain level of control. However, factors such as economics and remoteness of well locations have prevented many wells from being overseen by a conventional SCADA system, thus hindering provision of timely information about the well.

This paper addresses technical difficulties such as temperature compensation and reliable half permanent power sources in the development of a portable SCADA system and describes prospective technologies that could provide intermediate and eventual solutions. Current advanced technology enables effective miniaturization of components and systems which immediately translates to a significant reduction in cost and size making this system economical and portable (a single hand-carrying box).

As a result, this new breed of SCADA presents solutions to the economic constraints as well as the technological barriers that many producers first saw when they considered the installation of such systems in the past.

Introduction

Over the last two decades, expertise associated with SCADA (Supervisory Control And Data Acquisition) applications has become diverse and advanced within many niches, particularly in the oilfield. A SCADA system starts in the field where sensory information is collected by a terminal unit and then sent through a communications system to the central SCADA node. At the central node, the data is processed, displayed, and then stored in a large database. SCADA companies have strongly focused on the development of centralized databases, Man-Machine Interfaces (MMI) and control functions, while leaving the field hardware and communications systems open to many other vendors.

Communications hardware furnishes field equipment on site and computers in the customer's office. The communications industry is presently going through explosive technological growth which is profoundly affecting SCADA systems. Cellular, RF (radio frequency) and satellite systems provide varied and cost-effective communication solutions. As a result, many SCADA communication companies are often distributors of general communication products.

A key segment in the SCADA system's chain is remote site equipment. Such equipment performs data acquisition, provides control capability and is linked to the central SCADA node via the communications system. This market niche has been filled by traditional manufacturers of factory and industrial automation equipment. In application, this data acquisition instrument is best suited for a plant environment, which generally has stable ambient conditions. When instrumentation devices are placed outdoors in remote locations, often surrounding effects are coupled into the data, degrading its quality. For generic monitoring and control applications this is fine, but in light of the economics attached to production optimization, there is a need for creating higher quality data.

Another weak area of conventional SCADA systems is their lack of portability. Most types of remote site devices, especially SCADA related equipment, are not portable and must have a steady supply of electrical power to operate, thereby restricting their use in remote applications. In addition, when there is no power, the majority of communications systems do not work. Thus it is very challenging to supply a reliable communications link.

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