Since their introduction in the mid-1970's, microprocessor-based data acquisition systems have been used to improve safety and reduce costs on drilling rigs. Recent advances in hardware and software technology now enable designers to develop data acquisition systems which are more powerful, accurate, and reliable than previously possible. previously possible. This paper describes the goals, design features, and implementation of an advanced, ruggedized data acquisition system for use by drilling contractors on both offshore and onshore drilling rigs.
The results will show that substantial technical improvements can be made in designing such a system. These improvements will allow the drilling contractor and operator to be better equipped for reducing drilling costs and providing a greater safety margin.
TOTCO, a subsidiary of Baker International, has been a developer and supplier of microprocessor-based instrumentation systems for drilling rigs since the mid-1970's. In fact, TOTCO produced the first unmanned commercial data acquisition system for produced the first unmanned commercial data acquisition system for drilling rigs, called the VISULOGGER which is still in wide use today. Various other instrumentation companies have also developed similar systems like the VISULOGGER, that provide contractors with a tool to drill the well more efficiently and consequently reduce drilling costs. These systems have also been useful in maintaining safety factors. Generally, the operation of these systems has been very similar.
Various sensors on the rig convert physical parameters into electrical signals. These signals are converted into digital information and compared against alarm limits which are manually set by the user. When a parameter exceeds an alarm limit, an audible and visual alarm is activated. The results of the information processing are typically displayed on a CRT monitor and logged on a printer. The user sets limits and other rig configuration through a ruggedized keyboard.
These systems allow the driller to operate the rig on a "management by exception" basis; specifically, the user defines the acceptable rig fluctuations for a given drilling operation, enters these as channel limits into the system, and makes corrections only when the drilling operation exceeds these predetermined limits.
Enhancements have been added to these systems over the last decade but the basic operation has not changed. Some of these enhancements include:
limited graphics on both the CRT and printer, and
limited storage and recall of selected rig data. printer, and
limited storage and recall of selected rig data.
As the usefulness of these systems has been proven over the last decade, the demands upon the systems have increased. Drilling operators have become aware of the benefits in using intelligent systems. They are ready for systems that not only monitor the drilling process, but aid in the real-time analysis of the drilling process. process.
This paper presents guidelines for developing a next generation data acquisition system that can be used as a host for real-time well display and analysis. The application of the information contained in this paper will be useful to both drilling contractors that are in-terested in reducing drilling costs and to instrumentation designer that are developing new products for the industry. The topics will include:
Operational limitations of previous systems.
Goals and technical specifications of a proposed system.
Design features (hardware and software).
Implementation and field application data.
The results reported here are from a three-year development project devoted to developing such a system. The project resulted project devoted to developing such a system. The project resulted in a more powerful, ruggedized, accurate, and flexible system for use by the driller than had previously been produced.